AU2013203176A1 - Microorganisms for the production of 1,4-butanediol,4-hydroxybutanal, 4-hydroxy-butyryl-coa, putrescine and related compounds, and methods related thereto - Google Patents

Abstract

The invention provides non-naturally occurring microbial organisms comprising a 1,4- butanediol (BDO), 4-hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine pathway comprising at least one exogenous nucleic acid encoding a BDO, 4 hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine pathway enzyme expressed in a sufficient amount to produce BDO, A- hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine and further optimized for expression of BDO. The invention additionally provides methods of using such microbial organisms to produce BDO, 4 hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine. f i -4w Cc 4'O 0) 1.0

Description

1 MICROORGANISMS FOR THE PRODUCTION OF 1,4-BUTANEDIOL, 4 HYDROXYBUTANAL, 4-HYDROXYBUTYRYL-COA, PUTRESCINE AND RELATED COMPOUNDS, AND METHODS RELATED THERETO The entire disclosure in the complete specification of our Australian Patent Application 5 No. 2010306785 is by this cross-reference incorporated into the present specification. BACKGROUND OF THE INVENTION This invention relates generally to in silico design of organisms and engineering of organisms, more particularly to organisms having 1,4-butanediol, 4-hydroxybutyryl-CoA, 4-hydroxybutanal or putrescine biosynthesis capability. 10 The compound 4-hydroxybutanoic acid (4-hydroxybutanoate, 4-hydroxybutyrate, 4-HB) is a 4 carbon carboxylic acid that has industrial potential as a building block for various commodity and specialty chemicals. In particular, 4-HB has the potential to serve as a new entry point into the 1,4-butanediol family of chemicals, which includes solvents, resins, polymer precursors, and specialty chemicals. 1,4-Butanediol (BDO) is a polymer intermediate and industrial solvent 15 with a global market of about 3 billion lb/year. BDO is currently produced from petrochemical precursors, primarily acetylene, maleic anhydride, and propylene oxide. For example, acetylene is reacted with 2 molecules of formaldehyde in the Reppe synthesis reaction (Kroschwitz and Grant, Encyclopedia of Chem. Tech., John Wiley and Sons, Inc., New York (1999)), followed by catalytic hydrogenation to form 1,4-butanediol. It has been estimated 20 that 90% of the acetylene produced in the U.S. is consumed for butanediol production. Alternatively, it can be formed by esterification and catalytic hydrogenation of maleic anhydride, which is derived from butane. Downstream, butanediol can be further transformed; for example, by oxidation to y-butyrolactone, which can be further converted to pyrrolidone and N-methyl-pyrrolidone, or hydrogenolysis to tetrahydrofuran. These compounds have varied 25 uses as polymer intermediates, solvents, and additives, and have a combined market of nearly 2 billion lb/year. It is desirable to develop a method for production of these chemicals by alternative means that not only substitute renewable for petroleum-based feedstocks, and also use less energy- and capital-intensive processes. The Department of Energy has proposed 1,4-diacids, and 30 particularly succinic acid, as key biologically-produced intermediates for the manufacture of the 2 butanediol family of products (DOE Report, "Top Value-Added Chemicals from Biomass", 2004). However, succinic acid is costly to isolate and purify and requires high temperatures and pressures for catalytic reduction to butanediol. Thus, there exists a need for alternative means for effectively producing commercial quantities 5 of 1,4-butanediol and its chemical precursors. The present invention satisfies this need and provides related advantages as well. SUMMARY OF INVENTION The invention provides non-naturally occurring microbial organisms containing a 1,4-butanediol (BDO), 4-hydroxybutanal (4-HBal), 4-hydroxybutyryl-CoA (4-HBCoA) and/or putrescine 10 pathway comprising at least one exogenous nucleic acid encoding a BDO, 4-HBal and/or putrescine pathway enzyme expressed in a sufficient amount to produce BDO, 4-HBal, 4 HBCoA and/or putrescine. The microbial organisms can be further optimized for expression of BDO, 4-HBal, 4-HBCoA and/or putrescine. The invention additionally provides methods of using such microbial organisms to produce BDO, 4-HBal, 4-HBCoA and/or putrescine. 15 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram showing biochemical pathways to 4-hydroxybutyurate (4-HB) and to 1,4-butanediol production. The first 5 steps are endogenous to E. coli, while the remainder can be expressed heterologously. Enzymes catalyzing the biosynthetic reactions are: (1) succinyl-CoA synthetase; (2) CoA-independent succinic semialdehyde dehydrogenase; (3) a 20 ketoglutarate dehydrogenase; (4) glutamate:succinate semialdehyde transaminase; (5) glutamate decarboxylase; (6) CoA-dependent succinic semialdehyde dehydrogenase; (7) 4 hydroxybutanoate dehydrogenase; (8) a-ketoglutarate decarboxylase; (9) 4-hydroxybutyryl CoA:acetyl-CoA transferase; (10) butyrate kinase; (11) phosphotransbutyrylase; (12) aldehyde dehydrogenase; (13) alcohol dehydrogenase. 25 Figure 2 is a schematic diagram showing homoserine biosynthesis in E. coli. Figure 3 shows the production of 4-HB in glucose minimal medium using E. coli strains harboring plasmids expressing various combinations of 4-HB pathway genes. (a) 4-HB concentration in culture broth; (b) succinate concentration in culture broth; (c) culture OD, measured at 600 nm. Clusters of bars represent the 24 hour, 48 hour, and 72 hour (if measured) 30 timepoints. The codes along the x-axis indicate the strain/plasmid combination used. The first 3 index refers to the host strain: 1, MG1655 lacI; 2, MG1655 AgabD lacI; 3, MG1655 AgabD AaldA lacI. The second index refers to the plasmid combination used: 1, pZE13-0004-0035 and pZA33-0036; 2, pZE13-0004-0035 and pZA33-0010n; 3, pZE13-0004-0008 and pZA33-0036; 4, pZE13-0004-0008 and pZA33-0010n; 5, Control vectors pZE13 and pZA33. 5 Figure 4 shows the production of 4-HB from glucose in E. coli strains expressing a ketoglutarate decarboxylase from Mycobacterium tuberculosis. Strains 1-3 contain pZE13-0032 and pZA33-0036. Strain 4 expresses only the empty vectors pZE13 and pZA33. Host strains are as follows: 1 and 4, MG1655 lacIQ; 2, MG1655 AgabD lacIQ; 3, MG1655 AgabD AaldA lacIQ. The bars refer to concentration at 24 and 48 hours. 10 Figure 5 shows the production of BDO from 10 mM 4-HB in recombinant E. coli strains. Numbered positions correspond to experiments with MG1655 lacIQ containing pZA33-0024, expressing cat2 from P. gingivalis, and the following genes expressed on pZE13: 1, none (control); 2, 0002; 3, 0003; 4, 0003n; 5, 0011; 6, 0013; 7, 0023; 8, 0025; 9, 0008n; 10, 0035. Gene numbers are defined in Table 6. For each position, the bars refer to aerobic, microaerobic, 15 and anaerobic conditions, respectively. Microaerobic conditions were created by sealing the culture tubes but not evacuating them. Figure 6 shows the mass spectrum of 4-HB and BDO produced by MG1655 lacIQ pZE13-0004 0035-0002 pZA33-0034-0036 grown in M9 minimal medium supplemented with 4 g/L unlabeled glucose (a, c, e, and g) uniformly labeled 1 3 C-glucose (b, d, f, and h). (a) and (b), mass 20 116 characteristic fragment of derivatized BDO, containing 2 carbon atoms; (c) and (d), mass 177 characteristic fragment of derivatized BDO, containing 1 carbon atom; (e) and (f), mass 117 characteristic fragment of derivatized 4-HB, containing 2 carbon atoms; (g) and (h), mass 233 characteristic fragment of derivatized 4-HB, containing 4 carbon atoms. Figure 7 is a schematic process flow diagram of bioprocesses for the production of Y 25 butyrolactone. Panel (a) illustrates fed-batch fermentation with batch separation and panel (b) illustrates fed-batch fermentation with continuous separation. Figures 8A and 8B show exemplary 1,4-butanediol (BDO) pathways. Figure 8A shows BDO pathways from succinyl-CoA. Figure 8B shows BDO pathways from alpha-ketoglutarate. Figures 9A-9C show exemplary BDO pathways. Figure 9A and 9B show pathways from 4 30 aminobutyrate. Figure 9C shows a pathway from acetoactyl-CoA to 4-aminobutyrate.

4 Figure 10 shows exemplary BDO pathways from alpha-ketoglutarate. Figure 11 shows exemplary BDO pathways from glutamate. Figure 12 shows exemplary BDO pathways from acetoacetyl-CoA. Figure 13 shows exemplary BDO pathways from homoserine. 5 Figures 14 shows the nucleotide and amino acid sequences of E. coli succinyl-CoA synthetase. Figure 14A shows the nucleotide sequence (SEQ ID NO:) of the E. coli sucCD operon. Figures 14B (SEQ ID NO:) and 14C (SEQ ID NO:) show the amino acid sequences of the succinyl-CoA synthetase subunits encoded by the sucCD operon. Figure 15 shows the nucleotide and amino acid sequences of Mycobacterium bovis alpha 10 ketoglutarate decarboxylase. Figure 15A shows the nucleotide sequence (SEQ ID NO:) of Mycobacterium bovis sucA gene. Figure 15B shows the amino acid sequence (SEQ ID NO:) of M. bovis alpha-ketoglutarate decarboxylase. Figure 16 shows biosynthesis in E. coli of 4-hydroxybutyrate from glucose in minimal medium via alpha-ketoglutarate under anaerobic (microaerobic) conditions. The host strain is ECKh 15 401. The experiments are labeled based on the upstream pathway genes present on the plasmid pZA33 as follows: 1) 4hbd-sucA; 2) sucCD-sucD-4hbd; 3) sucCD-sucD-4hbd-sucA. Figure 17 shows biosynthesis in E. coli of 4-hydroxybutyrate from glucose in minimal medium via succinate and alpha-ketoglutarate. The host strain is wild-type MG1655. The experiments are labeled based on the genes present on the plasmids pZE13 and pZA33 as follows: 1) empty 20 control vectors 2) empty pZE13, pZA33-4hbd; 3) pZE13-sucA, pZA33-4hbd. Figure 18 A shows the nucleotide sequence (SEQ ID NO:) of CoA-dependent succinate semialdehyde dehydrogenase (sucD) from Porphyromonas gingivalis, and Figure 18B shows the encoded amino acid sequence (SEQ ID NO:). Figure 19A shows the nucleotide sequence (SEQ ID NO:) of 4-hydroxybutyrate dehydrogenase 25 (4hbd) from Porphymonas gingivalis, and Figure 19B shows the encoded amino acid seqence (SEQ ID NO:).

5 Figure 20A shows the nucleotide sequence (SEQ ID NO:) of 4-hydroxybutyrate CoA transferase (cat2) from Porphyromonas gingivalis, and Figure 20B shows the encoded amino acid sequence (SEQ ID NO:). Figure 21A shows the nucleotide sequence (SEQ ID NO:) of phosphotransbutyrylase (ptb) from 5 Clostridium acetobutylicum, and Figure 21B shows the encoded amino acid sequence (SEQ ID NO:). Figure 22A shows the nucleotide sequence (SEQ ID NO:) of butyrate kinase (buk1) from Clostridium acetobutylicum, and Figure 22B shows the encoded amino acid sequence (SEQ ID NO:). 10 Figure 23 shows alternative nucleotide sequences for C. acetobutylicum 020 (phosphtransbutyrylase) with altered codons for more prevalent E. coli codons relative to the C. acetobutylicum native sequence. Figures 23A-23D (020A-020D, SEQ ID NOS: , respectively) contain sequences with increasing numbers of rare E. coli codons replaced by more prevalent codons (A<B<C<D). 15 Figure 24 shows alternative nucleotide sequences for C. acetobuytlicum 021 (butyrate kinase) with altered codons for more prevalent E. coli codons relative to the C. acetobutylicum native sequence. Figures 24A-24D (021A-021B, SEQ ID NOS: , respectively) contain sequences with increasing numbers of rare E. coli codons replaced by more prevalent codons (A<B<C<D). Figure 25 shows improved expression of butyrate kinase (BK) and phosphotransbutyrylase 20 (PTB) with optimized codons for expression in E. coli. Figure 25A shows sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) stained for proteins with Coomassie blue; lane 1, control vector with no insert; lane 2, expression of C. acetobutylicum native sequences in E. co/i; lane 3, expression of 020B-021B codon optimized PTB-BK; lane 4, expression of 020C-021C codon optimized PTB-BK. The positions of BK and PTB are shown. 25 Figure 25B shows the BK and PTB activities of native C. acetobutylicum sequence (2021n) compared to codon optimized 020B-021B (2021B) and 020C-021C (2021C). Figure 26 shows production of BDO and gamma-butyrylactone (GBL) in various strains expressing BDO producing enzymes: Cat2 (034); 2021n; 2021B; 2021C. Figure 27A shows the nucleotide sequence (SEQ ID NO:) of the native Clostridium biejerinckii 30 ald gene (025n), and Figure 27B shows the encoded amino acid sequence (SEQ ID NO:).

6 Figures 28A-28D show alternative gene sequences for the Clostridium beijerinckii ald gene (025A-025D, SEQ ID NOS: , respectively), in which increasing numbers of rare codons are replaced by more prevalent codons (A<B<C<D). Figure 29 shows expression of native C. beijerinckii ald gene and codon optimized variants; no 5 ins (control with no insert), 025n, 025A, 025B, 025C, 025D. Figure 30 shows BDO or BDO and ethanol production in various strains. Figure 30 shows BDO production in strains containing the native C. beijerinckii ald gene (025n) or variants with optimized codons for expression in E. coli (025A-025D). Figure 30B shows production of ethanol and BDO in strains expressing the C. acetobutylicum AdhE2 enzyme (002C) compared 10 to the codon optimized variant 025B. The third set shows expression of P. gingivalis sucD (035). In all cases, P. gingivalis Cat2 (034) is also expressed. Figure 3 1A shows the nucleotide sequence (SEQ ID NO:) of the adh1 gene from Geobacillus thermoglucosidasius, and Figure 3 1B shows the encoded amino acid sequence (SEQ ID NO:). Figure 32A shows the expression of the Geobacillus thermoglucosidasius adh1 gene in E. coli. 15 Either whole cell lysates or supernatants were analyzed by SDS-PAGE and stained with Coomassie blue for plasmid with no insert, plasmid with 083 (Geotrichum capitatum N-benzyl 3-pyrrolidinol dehydrogenase) and plasmid with 084 (Geobacillus thermoglucosidasius adh1) inserts. Figure 32B shows the activity of 084 with butyraldehyde (diamonds) or 4 hydroxybutyraldehyde (squares) as substrates. 20 Figure 33 shows the production of BDO in various strains: plasmid with no insert; 025B, 025B 026n; 025B-026A; 025B-026B; 025B-026C; 025B-050; 025B-052; 025B-053; 025B-055; 025B 057; 025B-058; 025B-071; 025B-083; 025B-084; PTSlacO-025B; PTSlacO-025B-026n. Figure 34 shows a plasmid map for the vector pRE1 18-V2. Figure 35 shows the sequence of the ECKh-138 region encompassing the aceF and ipdA genes. 25 The K. pneumonia ipdA gene is underlined, and the codon changed in the Glu354Lys mutant shaded. Figure 36 shows the protein sequence comparison of the native E. coli ipdA and the mutant K. pneumonia ipdA.

7 Figure 37 shows 4-hydroxybutyrate (left bars) and BDO (right bars) production in the strains AB3, MG1655 AldhA and ECKh-138. All strains expressed E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd on the medium copy plasmid pZA33, and P. gingivalis Cat2, C. acetobutylicum AdhE2 on the high copy plasmid pZE13. 5 Figure 38 shows the nucleotide sequence of the 5' end of the aceE gene fused to the pflB-p6 promoter and ribosome binding site (RBS). The 5' italicized sequence shows the start of the aroP gene, which is transcribed in the opposite direction from the pdh operon. The 3' italicized sequence shows the start of the aceE gene. In upper case: pflB RBS. Underlined: FNR binding site. In bold: pflB-p6 promoter sequence. 10 Figure 39 shows the nucleotide sequence (SEQ ID NO:) in the aceF-lpdA region in the strain ECKh-456. Figure 40 shows the production of 4-hydroxybutyrate, BDO and pyruvate (left to right bars, respectively) for each of strains ECKh-439, ECKh-455 and ECKh-456. Figure 41A shows a schematic of the recombination sites for deletion of the mdh gene. Figure 15 41B shows the sequence of the PCR product of the amplification of chloramphenicol resistance gene (CAT) flanked by FRT sites and homology regions from the mdh gene from the plasmid pKD3. Figure 42 shows the sequence of the arcA deleted region in strain ECKh-401. Figure 43 shows the sequence of the region encompassing a mutated gitA gene of strain ECKh 20 422. Figure 44 shows the citrate synthase activity of wild type gitA gene product and the R163L mutant. The assay was performed in the absence (diamonds) or presence of 0.4 mM NADH (squares). Figure 45 shows the 4-hydroxybutyrate (left bars) and BDO (right bars) production in strains 25 ECKh-401 and ECKh-422, both expressing genes for the complete BDO pathway on plasmids. Figure 46 shows central metabolic fluxes and associated 95% confidence intervals from metabolic labeling experiments. Values are molar fluxes normalized to a glucose uptake rate of 1 mmol/hr. The result indicates that carbon flux is routed through citrate synthase in the 8 oxidative direction and that most of the carbon enters the BDO pathway rather than completing the TCA cycle. Figure 47 shows extracellular product formation for strains ECKh-138 and ECKh-422, both expressing the entire BDO pathway on plasmids. The products measured were acetate (Ace), 5 pyruvate (Pyr), 4-hydroxybutyrate (4HB), 1,4-butanediol (BDO), ethanol (EtOH), and other products, which include gamma-butyrolactone (GBL), succinate, and lactate. Figure 48 shows the sequence of the region following replacement of PEP carboxylase (ppc) by H. influenzae phosphoenolpyruvate carboxykinase (pepck). The pepck coding region is underlined. 10 Figure 49 shows growth of evolved pepCK strains grown in minimal medium containing 50 mM NaHCO 3 . Figure 50 shows product formation in strain ECKh-453 expressing P. gingivalis Cat2 and C. beijerinckii Ald on the plasmid pZS* 13. The products measured were 1,4-butanediol (BDO), pyruvate, 4-hydroxybutyrate (4HB), acetate, y-butyrolactone (GBL) and ethanol. 15 Figure 51 shows BDO production of two strains, ECKh-453 and ECKh-432. Both contain the plasmid pZS* 13 expressing P. gingivalis Cat2 and C. beijerinckii Ald. The cultures were grown under microaerobic conditions, with the vessels punctured with 27 or 18 gauge needles, as indicated. Figure 52 shows the nucleotide sequence of the genomic DNA of strain ECKh-426 in the region 20 of insertion of a polycistronic DNA fragment containing a promoter, sucCD gene, sucD gene, 4hbd gene and a terminator sequence. Figure 53 shows the nucleotide sequence of the chromosomal region of strain ECKh-432 in the region of insertion of a polycistronic sequence containing a promoter, sucA gene, C. kluyveri 4hbd gene and a terminator sequence. 25 Figure 54 shows BDO synthesis from glucose in minimal medium in the ECKh-432 strain having upstream BDO pathway encoding genes intregrated into the chromosome and containing a plasmid harboring downstream BDO pathway genes. Figure 55 shows a PCR product containing the non-phosphotransferase (non-PTS) sucrose utilization genes flanked by regions of homology to the rrnC region.

9 Figure 56 shows a schematic diagram of the integrations site in the rrnC operon. Figure 57 shows average product concentration, normalized to culture OD600, after 48 hours of growth of strain ECKh-432 grown on glucose and strain ECKh-463 grown on sucrose. Both contain the plasmid pZS*13 expressing P. gingivalis Cat2 and C. beijerinckii Ald. The data is 5 for 6 replicate cultures of each strain. The products measured were 1,4-butanediol (BDO), 4 hydroxybutyrate (4HB), y-butyrolactone (GBL), pyruvate (PYR) and acetate (ACE) (left to right bars, respectively). Figure 58 shows exemplary pathways to 1,4-butanediol from succcinyl-CoA and alpha ketoglutarate. Abbreviations: A) Succinyl-CoA reductase (aldehyde forming), B) Alpha 10 ketoglutarate decarboxylase, C) 4-Hydroxybutyrate dehydrogenase, D) 4-Hydroxybutyrate reductase, E) 1,4-Butanediol dehydrogenase. Figure 59A shows the nucleotide sequence (SEQ ID NO:) of carboxylic acid reductase from Nocardia iowensis (GNM_720), and Figure 59B shows the encoded amino acid sequence (SEQ ID NO:). 15 Figure 60A shows the nucleotide sequence (SEQ ID NO:) of phosphpantetheine transferase, which was codon optimized, and Figure 60B shows the encoded amino acid sequence. Figure 61 shows a plasmid map of plasmid pZS*-13S-720 72lopt. Figures 62A and 62B show pathways to 1,4-butanediol from succinate, succcinyl-CoA, and alpha-ketoglutarate. Abbreviations: A) Succinyl-CoA reductase (aldehyde forming), B) Alpha 20 ketoglutarate decarboxylase, C) 4-Hydroxybutyrate dehydrogenase, D) 4-Hydroxybutyrate reductase, E) 1,4-Butanediol dehydrogenase, F) Succinate reductase, G) Succinyl-CoA transferase, H) Succinyl-CoA hydrolase, I) Succinyl-CoA synthetase (or Succinyl-CoA ligase), J) Glutamate dehydrogenase, K) Glutamate transaminase, L) Glutamate decarboxylase, M) 4 aminobutyrate dehydrogenase, N) 4-aminobutyrate transaminase, 0) 4-Hydroxybutyrate kinase, 25 P) Phosphotrans-4-hydroxybutyrylase, Q) 4-Hydroxybutyryl-CoA reductase (aldehyde forming), R) 4-hydroxybutyryl-phosphate reductase, S) Succinyl-CoA reductase (alcohol forming), T) 4 Hydroxybutyryl-CoA transferase, U) 4-Hydroxybutyryl-CoA hydrolase, V) 4-Hydroxybutyryl CoA synthetase (or 4-Hydroxybutyryl-CoA ligase), W) 4-Hydroxybutyryl-CoA reductase (alcohol forming), X) Alpha-ketoglutarate reductase, Y) 5-Hydroxy-2-oxopentanoate 30 dehydrogenase, Z) 5-Hydroxy-2-oxopentanoate decarboxylase, AA) 5-hydroxy-2-oxopentanoate dehydrogenase (decarboxylation).

10 Figure 63 shows pathways to putrescine from succinate, succcinyl-CoA, and alpha ketoglutarate. Abbreviations: A) Succinyl-CoA reductase (aldehyde forming), B) Alpha ketoglutarate decarboxylase, C) 4-Aminobutyrate reductase, D) Putrescine dehydrogenase , E) Putrescine transaminase, F) Succinate reductase, G) Succinyl-CoA transferase, H) Succinyl 5 CoA hydrolase, I) Succinyl-CoA synthetase (or Succinyl-CoA ligase), J) Glutamate dehydrogenase, K) Glutamate transaminase, L) Glutamate decarboxylase, M) 4-Aminobutyrate dehydrogenase, N) 4-Aminobutyrate transaminase, 0) Alpha-ketoglutarate reductase, P) 5 Amino-2-oxopentanoate dehydrogenase, Q) 5-Amino-2-oxopentanoate transaminase, R) 5 Amino-2-oxopentanoate decarboxylase, S) Ornithine dehydrogenase, T) Ornithine transaminase, 10 U) Ornithine decarboxylase. Figure 64A shows the nucleotide sequence (SEQ ID NO:) of carboxylic acid reductase from Mycobacterium smegmatis mc(2)155 (designated 890), and Figure 64B shows the encoded amino acid sequence (SEQ ID NO:). Figure 65A shows the nucleotide sequence (SEQ ID NO:) of carboxylic acid reductase from 15 Mycobacterium avium subspecies paratuberculosis K-10 (designated 891), and Figure 65B shows the encoded amino acid sequence (SEQ ID NO:). Figure 66A shows the nucleotide sequence (SEQ ID NO:) of carboxylic acid reductase from Mycobacterium marinum M (designated 892), and Figure 66B shows the encoded amino acid sequence (SEQ ID NO:). 20 DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the design and production of cells and organisms having biosynthetic production capabilities for 4-hydroxybutanoic acid (4-HB), y-butyrolactone, 1,4 butanediol (BDO), 4-hydroxybutanal (4-HB al), 4-hydroxybutyryl-CoA (4-HBCoA) and/or putrescine. The invention, in particular, relates to the design of microbial organisms capable of 25 producing BDO, 4-HBal, 4-HBCoA and/or putrescine by introducing one or more nucleic acids encoding a BDO, 4-HBal, 4-HBCoA and/or putrescine pathway enzyme. In one embodiment, the invention utilizes in silico stoichiometric models of Escherichia coli metabolism that identify metabolic designs for biosynthetic production of 4-hydroxybutanoic acid (4-HB), 1,4-butanediol (BDO), 4-HBal, 4-HBCoA and/or putrescine. The results described 30 herein indicate that metabolic pathways can be designed and recombinantly engineered to achieve the biosynthesis of 4-HBal, 4-HBCoA or 4-HB and downstream products such as 1,4- 11 butanediol or putrescine in Escherichia coli and other cells or organisms. Biosynthetic production of 4-HB, 4-HBal, 4-HBCoA, BDO and/or putrescine, for example, for the in silico designs can be confirmed by construction of strains having the designed metabolic genotype. These metabolically engineered cells or organisms also can be subjected to adaptive evolution to 5 further augment 4-HB, 4-HBal, 4-HBCoA, BDO and/or putrescine biosynthesis, including under conditions approaching theoretical maximum growth. In certain embodiments, the 4-HB, 4-HBal, 4-HBCoA, BDO and/or putrescine biosynthesis characteristics of the designed strains make them genetically stable and particularly useful in continuous bioprocesses. Separate strain design strategies were identified with incorporation of 10 different non-native or heterologous reaction capabilities into E. coli or other host organisms leading to 4-HB and 1,4-butanediol producing metabolic pathways from either CoA-independent succinic semialdehyde dehydrogenase, succinyl-CoA synthetase and CoA-dependent succinic semialdehyde dehydrogenase, or glutamate:succinic semialdehyde transaminase. In silico metabolic designs were identified that resulted in the biosynthesis of 4-HB in both E.coli and 15 yeast species from each of these metabolic pathways. The 1,4-butanediol intermediate 7 butyrolactone can be generated in culture by spontaneous cyclization under conditions at pH<7.5, particularly under acidic conditions, such as below pH 5.5, for example, pH<7, pH<6.5, pH<6, and particularly at pH<5.5 or lower. Strains identified via the computational component of the platform can be put into actual 20 production by genetically engineering any of the predicted metabolic alterations which lead to the biosynthetic production of 4-HB, 1,4-butanediol or other intermediate and/or downstream products. In yet a further embodiment, strains exhibiting biosynthetic production of these compounds can be further subjected to adaptive evolution to further augment product biosynthesis. The levels of product biosynthesis yield following adaptive evolution also can be 25 predicted by the computational component of the system. In other specific embodiments, microbial organisms were constructed to express a 4-HB biosynthetic pathway encoding the enzymatic steps from succinate to 4-HB and to 4-HB-CoA. Co-expression of succinate coenzyme A transferase, CoA-dependent succinic semialdehyde dehydrogenase, NAD-dependent 4-hydroxybutyrate dehydrogenase and 4-hydroxybutyrate 30 coenzyme A transferase in a host microbial organism resulted in significant production of 4-HB compared to host microbial organisms lacking a 4-HB biosynthetic pathway. In a further specific embodiment, 4-HB-producing microbial organisms were generated that utilized a- 12 ketoglutarate as a substrate by introducing nucleic acids encoding a-ketoglutarate decarboxylase and NAD-dependent 4-hydroxybutyrate dehydrogenase. In another specific embodiment, microbial organisms containing a 1,4-butanediol (BDO) biosynthetic pathway were constructed that biosynthesized BDO when cultured in the presence 5 of 4-HB. The BDO biosynthetic pathway consisted of a nucleic acid encoding either a multifunctional aldehyde/alcohol dehydrogenase or nucleic acids encoding an aldehyde dehydrogenawse and an alcohol dehydrogenase. To support growth on 4-HB substrates, these BDO-producing microbial organisms also expressed 4-hydroxybutyrate CoA transferase or 4 butyrate kinase in conjunction with phosphotranshydroxybutyrlase. In yet a further specific 10 embodiment, microbial organisms were generated that synthesized BDO through exogenous expression of nucleic acids encoding a functional 4-HB biosynthetic pathway and a functional BDO biosynthetic pathway. The 4-HB biosynthetic pathway consisted of succinate coenzyme A transferase, CoA-dependent succinic semialdehyde dehydrogenase, NAD-dependent 4 hydroxybutyrate dehydrogenase and 4-hydroxybutyrate coenzyme A transferase. The BDO 15 pathway consisted of a multifunctional aldehyde/alcohol dehydrogenase. Further described herein are additional pathways for production of BDO (see Figures 8-13). In a further embodiment, described herein is the cloning and expression of a carboxylic acid reductase enzyme that functions in a 4-hydroxybutanal, 4-hydroxybutyryl-CoA or 1,4 butanediol metabolic pathway. Advantages of employing a carboxylic acid reductase as 20 opposed to an acyl-CoA reductase to form 4-hydroxybutyraldehyde (4-hydroxybutanal) include lower ethanol and GBL byproduct formation accompanying the production of BDO. Also disclosed herein is the application of carboxylic acid reductase as part of additional numerous pathways to produce 1,4-butanediol and putrescine from the tricarboxylic acid (TCA) cycle metabolites, for example, succinate, succinyl-CoA, and/or alpha-ketoglutarate. 25 As used herein, the term "non-naturally occurring" when used in reference to a microbial organism or microorganism of the invention is intended to mean that the microbial organism has at least one genetic alteration not normally found in a naturally occurring strain of the referenced species, including wild-type strains of the referenced species. Genetic alterations include, for example, modifications introducing expressible nucleic acids encoding metabolic polypeptides, 30 other nucleic acid additions, nucleic acid deletions and/or other functional disruption of the microbial organism's genetic material. Such modifications include, for example, coding regions and functional fragments thereof, for heterologous, homologous or both heterologous and 13 homologous polypeptides for the referenced species. Additional modifications include, for example, non-coding regulatory regions in which the modifications alter expression of a gene or operon. Exemplary metabolic polypeptides include enzymes or proteins within a biosynthetic pathway for a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine family of compounds. 5 A metabolic modification refers to a biochemical reaction that is altered from its naturally occurring state. Therefore, non-naturally occurring microorganisms can have genetic modifications to nucleic acids encoding metabolic polypeptides or, functional fragments thereof. Exemplary metabolic modifications are disclosed herein. As used herein, the term "isolated" when used in reference to a microbial organism is intended 10 to mean an organism that is substantially free of at least one component as the referenced microbial organism is found in nature. The term includes a microbial organism that is removed from some or all components as it is found in its natural environment. The term also includes a microbial organism that is removed from some or all components as the microbial organism is found in non-naturally occurring environments. Therefore, an isolated microbial organism is 15 partly or completely separated from other substances as it is found in nature or as it is grown, stored or subsisted in non-naturally occurring environments. Specific examples of isolated microbial organisms include partially pure microbes, substantially pure microbes and microbes cultured in a medium that is non-naturally occurring. As used herein, the terms "microbial," "microbial organism" or "microorganism" is intended to 20 mean any organism that exists as a microscopic cell that is included within the domains of archaea, bacteria or eukarya. Therefore, the term is intended to encompass prokaryotic or eukaryotic cells or organisms having a microscopic size and includes bacteria, archaea and eubacteria of all species as well as eukaryotic microorganisms such as yeast and fungi. The term also includes cell cultures of any species that can be cultured for the production of a 25 biochemical. As used herein, the term "4-hydroxybutanoic acid" is intended to mean a 4-hydroxy derivative of butyric acid having the chemical formula C 4

H

8 0 3 and a molecular mass of 104.11 g/mol (126.09 g/mol for its sodium salt). The chemical compound 4-hydroxybutanoic acid also is known in the art as 4-HB, 4-hydroxybutyrate, gamma-hydroxybutyric acid or GHB. The term as 30 it is used herein is intended to include any of the compound's various salt forms and include, for example, 4-hydroxybutanoate and 4-hydroxybutyrate. Specific examples of salt forms for 4-HB include sodium 4-HB and potassium 4-HB. Therefore, the terms 4-hydroxybutanoic acid, 4-HB, 14 4-hydroxybutyrate, 4-hydroxybutanoate, gamma-hydroxybutyric acid and GHB as well as other art recognized names are used synonymously herein. As used herein, the term "monomeric" when used in reference to 4-HB is intended to mean 4 HB in a non-polymeric or underivatized form. Specific examples of polymeric 4-HB include 5 poly-4-hydroxybutanoic acid and copolymers of, for example, 4-HB and 3-HB. A specific example of a derivatized form of 4-HB is 4-HB-CoA. Other polymeric 4-HB forms and other derivatized forms of 4-HB also are known in the art. As used herein, the term "y-butyrolactone" is intended to mean a lactone having the chemical formula C 4

H

6 0 2 and a molecular mass of 86.089 g/mol. The chemical compound y 10 butyrolactone also is know in the art as GBL, butyrolactone, 1,4-lactone, 4-butyrolactone, 4 hydroxybutyric acid lactone, and gamma-hydroxybutyric acid lactone. The term as it is used herein is intended to include any of the compound's various salt forms. As used herein, the term "1,4-butanediol" is intended to mean an alcohol derivative of the alkane butane, carrying two hydroxyl groups which has the chemical formula C 4

H

10 0 2 and a molecular 15 mass of 90.12 g/mol. The chemical compound 1,4-butanediol also is known in the art as BDO and is a chemical intermediate or precursor for a family of compounds referred to herein as BDO family of compounds. As used herein, the term "4-hydroxybutanal" is intended to mean an aledehyde having the chemical formula C 4

H

8 0 2 and a molecular mass of 88.10512 g/mol. The chemical compound 4 20 hydroxybutanal (4-HBal) is also known in the art as 4-hydroxybutyraldehyde. As used herein, the term "putrescine" is intended to mean a diamine having the chemical formula C 4

H

12

N

2 and a molecular mass of 88.15148 g/mol. The chemical compound putrescine is also known in the art as 1,4-butanediamine, 1,4-diaminobutane, butylenediamine, tetramethylenediamine, tetramethyldiamine, and 1,4-butylenediamine. 25 As used herein, the term "tetrahydrofuran" is intended to mean a heterocyclic organic compound corresponding to the fully hydrogenated analog of the aromatic compound furan which has the chemical formula C 4

H

8 0 and a molecular mass of 72.11 g/mol. The chemical compound tetrahydrofuran also is known in the art as THF, tetrahydrofuran, 1,4-epoxybutane, butylene oxide, cyclotetramethylene oxide, oxacyclopentane, diethylene oxide, oxolane, furanidine, 15 hydrofuran, tetra-methylene oxide. The term as it is used herein is intended to include any of the compound's various salt forms. As used herein, the term "CoA" or "coenzyme A" is intended to mean an organic cofactor or prosthetic group (nonprotein portion of an enzyme) whose presence is required for the activity of 5 many enzymes (the apoenzyme) to form an active enzyme system. Coenzyme A functions in certain condensing enzymes, acts in acetyl or other acyl group transfer and in fatty acid synthesis and oxidation, pyruvate oxidation and in other acetylation. As used herein, the term "substantially anaerobic" when used in reference to a culture or growth condition is intended to mean that the amount of oxygen is less than about 10% of saturation for 10 dissolved oxygen in liquid media. The term also is intended to include sealed chambers of liquid or solid medium maintained with an atmosphere of less than about 1% oxygen. The non-naturally occurring microbal organisms of the invention can contain stable genetic alterations, which refers to microorganisms that can be cultured for greater than five generations without loss of the alteration. Generally, stable genetic alterations include modifications that 15 persist greater than 10 generations, particularly stable modifications will persist more than about 25 generations, and more particularly, stable genetic modifications will be greater than 50 generations, including indefinitely. Those skilled in the art will understand that the genetic alterations, including metabolic modifications exemplified herein are described with reference to a suitable source or host 20 organism such as E coli, yeast, or other organisms disclosed herein and their corresponding metabolic reactions or a suitable source organism for desired genetic material such as genes encoding enzymes for their corresponding metabolic reactions for a desired metabolic pathway. However, given the complete genome sequencing of a wide variety of organisms and the high level of skill in the area of genomics, those skilled in the art will readily be able to apply the 25 teachings and guidance provided herein to essentially all other organisms. For example, the E coli metabolic alterations exemplified herein can readily be applied to other species by incorporating the same or analogous encoding nucleic acid from species other than the referenced species. Such genetic alterations include, for example, genetic alterations of species homologs, in general, and in particular, orthologs, paralogs or nonorthologous gene 30 displacements.

16 An ortholog is a gene or genes that are related by vertical descent and are responsible for substantially the same or identical functions in different organisms. For example, mouse epoxide hydrolase and human epoxide hydrolase can be considered orthologs for the biological function of hydrolysis of epoxides. Genes are related by vertical descent when, for example, 5 they share sequence similarity of sufficient amount to indicate they are homologous, or related by evolution from a common ancestor. Genes can also be considered orthologs if they share three-dimensional structure but not necessarily sequence similarity, of a sufficient amount to indicate that they have evolved from a common ancestor to the extent that the primary sequence similarity is not identifiable. Genes that are orthologous can encode proteins with sequence 10 similarity of about 25% to 100% amino acid sequence identity. Genes encoding proteins sharing an amino acid similarity less that 25% can also be considered to have arisen by vertical descent if their three-dimensional structure also shows similarities. Members of the serine protease family of enzymes, including tissue plasminogen activator and elastase, are considered to have arisen by vertical descent from a common ancestor. 15 Orthologs include genes or their encoded gene products that through, for example, evolution, have diverged in structure or overall activity. For example, where one species encodes a gene product exhibiting two functions and where such functions have been separated into distinct genes in a second species, the three genes and their corresponding products are considered to be orthologs. For the production, including growth-coupled production, of a biochemical product, 20 those skilled in the art will understand that the orthologous gene harboring the metabolic activity to be introduced or disrupted is to be chosen for construction of the non-naturally occurring microorganism. An example of orthologs exhibiting separable activities is where distinct activities have been separated into distinct gene products between two or more species or within a single species. A specific example is the separation of elastase proteolysis and plasminogen 25 proteolysis, two types of seine protease activity, into distinct molecules as plasminogen activator and elastase. A second example is the separation of mycoplasma 5'-3' exonuclease and Drosophila DNA polymerase III activity. The DNA polymerase from the first species can be considered an ortholog to either or both of the exonuclease or the polymerase from the second species and vice versa. 30 In contrast, paralogs are homologs related by, for example, duplication followed by evolutionary divergence and have similar or common, but not identical functions. Paralogs can originate or derive from, for example, the same species or from a different species. For example, microsomal epoxide hydrolase (epoxide hydrolase I) and soluble epoxide hydrolase (epoxide 17 hydrolase II) can be considered paralogs because they represent two distinct enzymes, co-evolved from a common ancestor, that catalyze distinct reactions and have distinct functions in the same species. Paralogs are proteins from the same species with significant sequence similarity to each other suggesting that they are homologous, or related through co-evolution 5 from a common ancestor. Groups of paralogous protein families include HipA homologs, luciferase genes, peptidases, and others. A nonorthologous gene displacement is a nonorthologous gene from one species that can substitute for a referenced gene function in a different species. Substitution includes, for example, being able to perform substantially the same or a similar function in the species of 10 origin compared to the referenced function in the different species. Although generally, a nonorthologous gene displacement will be identifiable as structurally related to a known gene encoding the referenced function, less structurally related but functionally similar genes and their corresponding gene products nevertheless will still fall within the meaning of the term as it is used herein. Functional similarity requires, for example, at least some structural similarity in 15 the active site or binding region of a nonorthologous gene product compared to a gene encoding the function sought to be substituted. Therefore, a nonorthologous gene includes, for example, a paralog or an unrelated gene. Therefore, in identifying and constructing the non-naturally occurring microbial organisms of the invention having 4-HB, GBL, 4-HBal, 4-HBCoA, BDO and/or putrescine biosynthetic 20 capability, those skilled in the art will understand with applying the teaching and guidance provided herein to a particular species that the identification of metabolic modifications can include identification and inclusion or inactivation of orthologs. To the extent that paralogs and/or nonorthologous gene displacements are present in the referenced microorganism that encode an enzyme catalyzing a similar or substantially similar metabolic reaction, those skilled 25 in the art also can utilize these evolutionally related genes. Orthologs, paralogs and nonorthologous gene displacements can be determined by methods well known to those skilled in the art. For example, inspection of nucleic acid or amino acid sequences for two polypeptides will reveal sequence identity and similarities between the compared sequences. Based on such similarities, one skilled in the art can determine if the 30 similarity is sufficiently high to indicate the proteins are related through evolution from a common ancestor. Algorithms well known to those skilled in the art, such as Align, BLAST, Clustal W and others compare and determine a raw sequence similarity or identity, and also 18 determine the presence or significance of gaps in the sequence which can be assigned a weight or score. Such algorithms also are known in the art and are similarly applicable for determining nucleotide sequence similarity or identity. Parameters for sufficient similarity to determine relatedness are computed based on well known methods for calculating statistical similarity, or 5 the chance of finding a similar match in a random polypeptide, and the significance of the match determined. A computer comparison of two or more sequences can, if desired, also be optimized visually by those skilled in the art. Related gene products or proteins can be expected to have a high similarity, for example, 25% to 100% sequence identity. Proteins that are unrelated can have an identity which is essentially the same as would be expected to occur by 10 chance, if a database of sufficient size is scanned (about 5%). Sequences between 5% and 24% may or may not represent sufficient homology to conclude that the compared sequences are related. Additional statistical analysis to determine the significance of such matches given the size of the data set can be carried out to determine the relevance of these sequences. Exemplary parameters for determining relatedness of two or more sequences using the BLAST 15 algorithm, for example, can be as set forth below. Briefly, amino acid sequence alignments can be performed using BLASTP version 2.0.8 (Jan-05-1999) and the following parameters: Matrix: 0 BLOSUM62; gap open: 11; gap extension: 1; x_dropoff: 50; expect: 10.0; wordsize: 3; filter: on. Nucleic acid sequence alignments can be performed using BLASTN version 2.0.6 (Sept-16-1998) and the following parameters: Match: 1; mismatch: -2; gap open: 5; gap 20 extension: 2; xdropoff: 50; expect: 10.0; wordsize: 11; filter: off. Those skilled in the art will know what modifications can be made to the above parameters to either increase or decrease the stringency of the comparison, for example, and determine the relatedness of two or more sequences. Disclosed herein are non-naturally occurring microbial biocatalyst or microbial organisms 25 including a microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway that includes at least one exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase, CoA-independent succinic semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA dependent succinic semialdehyde dehydrogenase, glutamate:succinic semialdehyde transaminase, alpha-ketoglutarate decarboxylase, or glutamate decarboxylase, wherein the 30 exogenous nucleic acid is expressed in sufficient amounts to produce monomeric 4 hydroxybutanoic acid (4-HB). 4-hydroxybutanoate dehydrogenase is also referred to as 4 hydroxybutyrate dehydrogenase or 4-HB dehydrogenase. Succinyl-CoA synthetase is also referred to as succinyl-CoA synthase or succinyl-CoA ligase.

19 Also disclosed herein is a non-naturally occurring microbial biocatalyst or microbial organism including a microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway having at least one exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, or a 5 ketoglutarate decarboxylase, wherein the exogenous nucleic acid is expressed in sufficient amounts to produce monomeric 4-hydroxybutanoic acid (4-HB). The non-naturally occurring microbial biocatalysts or microbial organisms can include microbial organisms that employ combinations of metabolic reactions for biosynthetically producing the compounds of the invention. The biosynthesized compounds can be produced intracellularly 10 and/or secreted into the culture medium. Exemplary compounds produced by the non-naturally occurring microorganisms include, for example, 4-hydroxybutanoic acid, 1,4-butanediol and y butyrolactone. In one embodiment, a non-naturally occurring microbial organism is engineered to produce 4 HB. This compound is one useful entry point into the 1,4-butanediol family of compounds. The 15 biochemical reactions for formation of 4-HB from succinate, from succinate through succinyl CoA or from a-ketoglutarate are shown in steps 1-8 of Figure 1. It is understood that any combination of appropriate enzymes of a BDO, 4-HBal, 4-HBCoA and/or putrescine pathway can be used so long as conversion from a starting component to the BDO, 4-HBal, 4-HBCoA and/or putrescine product is achieved. Thus, it is understood that any 20 of the metabolic pathways disclosed herein can be utilized and that it is well understood to those skilled in the art how to select appropriate enzymes to achieve a desired pathway, as disclosed herein. In another embodiment, disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a 1,4-butanediol (BDO) pathway comprising at least 25 one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising 4-aminobutyrate CoA transferase, 4 aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA oxidoreductase (deaminating), 4-aminobutyryl-CoA transaminase, or 4-hydroxybutyryl-CoA dehydrogenase (see Example VII Table 17). The BDO pathway further can comprise 4 30 hydroxybutyryl-CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA reductase, or 1,4 butanediol dehydrogenase.

20 It is understood by those skilled in the art that various combinations of the pathways can be utilized, as disclosed herein. For example, in a non-naturally occurring microbial organism, the nucleic acids can encode 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, or 4-aminobutyrate-CoA ligase; 4-aminobutyryl-CoA oxidoreductase (deaminating) or 4 5 aminobutyryl-CoA transaminase; and 4-hydroxybutyryl-CoA dehydrogenase. Other exemplary combinations are specifically describe below and further can be found in Figures 8-13. For example, the BDO pathway can further comprise 4-hydroxybutyryl-CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA reductase, or 1,4-butanediol dehydrogenase. Additionally disclosed herein is a non-naturally occurring microbial organism, comprising a 10 microbial organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, 4 aminobutyrate-CoA ligase, 4-aminobutyryl-CoA reductase (alcohol forming), 4-aminobutyryl CoA reductase, 4-aminobutan-1-ol dehydrogenase, 4-aminobutan-1-ol oxidoreductase 15 (deaminating) or 4-aminobutan-1-ol transaminase (see Example VII and Table 18), and can further comprise 1,4-butanediol dehydrogenase. For example, the exogenous nucleic acids can encode 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, or 4-aminobutyrate CoA ligase; 4-aminobutyryl-CoA reductase (alcohol forming); and 4-aminobutan-1-ol oxidoreductase (deaminating) or 4-aminobutan- 1-ol transaminase. In addition, the nucleic acids 20 can encode. 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, or 4 aminobutyrate-CoA ligase; 4-aminobutyryl-CoA reductase; 4-aminobutan-1-ol dehydrogenase; and 4-aminobutan- 1 -ol oxidoreductase (deaminating) or 4-aminobutan- 1 -ol transaminase. Also disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a 25 BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising 4-aminobutyrate kinase, 4-aminobutyraldehyde dehydrogenase (phosphorylating), 4 aminobutan-1-ol dehydrogenase, 4-aminobutan-1-ol oxidoreductase (deaminating), 4 aminobutan-1-ol transaminase, [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase (deaminating), [(4-aminobutanolyl)oxy]phosphonic acid transaminase, 4-hydroxybutyryl 30 phosphate dehydrogenase, or 4-hydroxybutyraldehyde dehydrogenase (phosphorylating) (see Example VII and Table 19). For example, the exogenous nucleic acids can encode 4 aminobutyrate kinase; 4-aminobutyraldehyde dehydrogenase (phosphorylating); 4-aminobutan 1-ol dehydrogenase; and 4-aminobutan-1-ol oxidoreductase (deaminating) or 4-aminobutan- 1-ol 21 transaminase. Alternatively, the exogenous nucleic acids can encode 4-aminobutyrate kinase; [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase (deaminating) or [(4 aminobutanolyl)oxy]phosphonic acid transaminase; 4-hydroxybutyryl-phosphate dehydrogenase; and 4-hydroxybutyraldehyde dehydrogenase (phosphorylating). 5 Additionally disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising alpha-ketoglutarate 5-kinase, 2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating), 2,5-dioxopentanoic acid reductase, alpha-ketoglutarate CoA 10 transferase, alpha-ketoglutaryl-CoA hydrolase, alpha-ketoglutaryl-CoA ligase, alpha ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase, alpha-ketoglutaryl CoA reductase (alcohol forming), 5-hydroxy-2-oxopentanoic acid decarboxylase, or 5-hydroxy 2-oxopentanoic acid dehydrogenase (decarboxylation) (see Example VIII and Table 20). The BDO pathway can further comprise 4-hydroxybutyryl-CoA reductase (alcohol forming), 4 15 hydroxybutyryl-CoA reductase, or 1,4-butanediol dehydrogenase. For example, the exogenous nucleic acids can encode alpha-ketoglutarate 5-kinase; 2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating); 2,5-dioxopentanoic acid reductase; and 5-hydroxy-2 oxopentanoic acid decarboxylase. Alternatively, the exogenous nucleic acids can encode alpha ketoglutarate 5-kinase; 2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating); 2,5 20 dioxopentanoic acid reductase; and 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). Alternatively, the exogenous nucleic acids can encode alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA hydrolase, or alpha-ketoglutaryl-CoA ligase; alpha ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase; and 5-hydroxy-2 oxopentanoic acid decarboxylase. In another embodiment, the exogenous nucleic acids can 25 encode alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA hydrolase, or alpha ketoglutaryl-CoA ligase; alpha-ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase, and 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). Alternatively, the exogenous nucleic acids can encode alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA hydrolase, or alpha-ketoglutaryl-CoA ligase; alpha-ketoglutaryl-CoA 30 reductase (alcohol forming); and 5-hydroxy-2-oxopentanoic acid decarboxylase. In yet another embodiment, the exogenous nucleic acids can encode alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA hydrolase, or alpha-ketoglutaryl-CoA ligase; alpha-ketoglutaryl-CoA reductase (alcohol forming); and 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation).

22 Further disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising glutamate CoA transferase, glutamyl-CoA hydrolase, glutamyl-CoA ligase, 5 glutamate 5-kinase, glutamate-5-semialdehyde dehydrogenase (phosphorylating), glutamyl-CoA reductase, glutamate-5-semialdehyde reductase, glutamyl-CoA reductase (alcohol forming), 2 amino-5-hydroxypentanoic acid oxidoreductase (deaminating), 2-amino-5-hydroxypentanoic acid transaminase, 5-hydroxy-2-oxopentanoic acid decarboxylase, 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation) (see Example IX and Table 21). For example, the 10 exogenous nucleic acids can encode glutamate CoA transferase, glutamyl-CoA hydrolase, or glutamyl-CoA ligase; glutamyl-CoA reductase; glutamate-5-semialdehyde reductase; 2-amino 5-hydroxypentanoic acid oxidoreductase (deaminating) or 2-amino-5-hydroxypentanoic acid transaminase; and 5-hydroxy-2-oxopentanoic acid decarboxylase or 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). Alternatively, the exogenous nucleic acids can encode 15 glutamate 5-kinase; glutamate-5-semialdehyde dehydrogenase (phosphorylating); glutamate-5 semialdehyde reductase; 2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating) or 2 amino-5-hydroxypentanoic acid transaminase; and 5-hydroxy-2-oxopentanoic acid decarboxylase or 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). In still another embodiment, the exogenous nucleic acids can encode glutamate CoA transferase, 20 glutamyl-CoA hydrolase, or glutamyl-CoA ligase; glutamyl-CoA reductase (alcohol forming); 2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating) or 2-amino-5 hydroxypentanoic acid transaminase; and 5-hydroxy-2-oxopentanoic acid decarboxylase or 5 hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). In yet another embodiment, the exogenous nucleic acids can encode glutamate 5-kinase; glutamate-5-semialdehyde 25 dehydrogenase (phosphorylating); 2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating) or 2-amino-5-hydroxypentanoic acid transaminase; and 5-hydroxy-2 oxopentanoic acid decarboxylase or 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation). Also disclosed herein is a non-naturally occurring microbial organism, comprising a microbial 30 organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising 3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxybutyryl-CoA dehydratase, vinylacetyl-CoA A-isomerase, or 4-hydroxybutyryl-CoA dehydratase (see Example X and Table 22). For example, the exogenous nucleic acids can encode 3-hydroxybutyryl-CoA 23 dehydrogenase; 3-hydroxybutyryl-CoA dehydratase; vinylacetyl-CoA A-isomerase; and 4 hydroxybutyryl-CoA dehydratase. Further disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a BDO pathway comprising at least one exogenous nucleic acid 5 encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO pathway comprising homoserine deaminase, homoserine CoA transferase, homoserine-CoA hydrolase, homoserine-CoA ligase, homoserine-CoA deaminase, 4-hydroxybut-2-enoyl-CoA transferase, 4-hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2-enoyl-CoA ligase, 4 hydroxybut-2-enoate reductase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyryl-CoA 10 hydrolase, 4-hydroxybutyryl-CoA ligase, or 4-hydroxybut-2-enoyl-CoA reductase (see Example XI and Table 23). For example, the exogenous nucleic acids can encode homoserine deaminase; 4-hydroxybut-2-enoyl-CoA transferase, 4-hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2 enoyl-CoA ligase; 4-hydroxybut-2-enoyl-CoA reductase. Alternatively, the exogenous nucleic acids can encode homoserine CoA transferase, homoserine-CoA hydrolase, or homoserine-CoA 15 ligase; homoserine-CoA deaminase; and 4-hydroxybut-2-enoyl-CoA reductase. In a further embodiment, the exogenous nucleic acids can encode homoserine deaminase; 4-hydroxybut-2 enoate reductase; and 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyryl-CoA hydrolase, or 4-hydroxybutyryl-CoA ligase. Alternatively, the exogenous nucleic acids can encode homoserine CoA transferase, homoserine-CoA hydrolase, or homoserine-CoA ligase; 20 homoserine-CoA deaminase; and 4-hydroxybut-2-enoyl-CoA reductase. Further disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BOD, the BDO pathway comprising succinyl-CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA 25 hydrolase, 4-hydroxybutyryl-CoA ligase, 4-hydroxybutanal dehydrogenase (phosphorylating) (see Table 15). Such a BDO pathway can further comprise succinyl-CoA reductase, 4 hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyrate kinase, phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase, 4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol dehydrogenase. 30 Additionally disclosed herein is a non-naturally occurring microbial organism, comprising a microbial organism having a BDO pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, the BDO 24 pathway comprising glutamate dehydrogenase, 4-aminobutyrate oxidoreductase (deaminating), 4-aminobutyrate transaminase, glutamate decarboxylase, 4-hydroxybutyryl-CoA hydrolase, 4 hydroxybutyryl-CoA ligase, 4-hydroxybutanal dehydrogenase (phosphorylating)(see Table 16). Such a BDO pathway can further comprise alpha-ketoglutarate decarboxylase, 4 5 hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyrate kinase, phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase, 4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol dehydrogenase. The pathways described above are merely exemplary. One skilled in the art can readily select appropriate pathways from those disclosed herein to obtain a suitable BDO pathway or other 10 metabolic pathway, as desired. The invention provides genetically modified organisms that allow improved production of a desired product such as BDO by increasing the product or decreasing undesirable byproducts. As disclosed herein, the invention provides a non-naturally occurring microbial organism, comprising a microbial organism having a 1,4-butanediol (BDO) pathway comprising at least 15 one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO. In one embodiment, the microbial organism is genetically modified to express exogenous succinyl-CoA synthetase (see Example XII). For example, the succinyl-CoA synthetase can be encoded by an Escherichia coli sucCD genes. In another embodiment, the microbial organism is genetically modified to express exogenous 20 alpha-ketoglutarate decarboxylase (see Example XIII). For example, the alpha-ketoglutarate decarboxylase can be encoded by the Mycobacterium bovis sucA gene. In still another embodiment, the microbial organism is genetically modified to express exogenous succinate semialdehyde dehydrogenase and 4-hydroxybutyrate dehydrogenase and optionally 4 hydroxybutyryl-CoA/acetyl-CoA transferase (see Example XIII). For example, the succinate 25 semialdehyde dehydrogenase (CoA-dependent), 4-hydroxybutyrate dehydrogenase and 4 hydroxybutyryl-CoA/acetyl-CoA transferase can be encoded by Porphyromonas gingivalis W83 genes. In an additional embodiment, the microbial organism is genetically modified to express exogenous butyrate kinase and phosphotransbutyrylase (see Example XIII). For example, the butyrate kinase and phosphotransbutyrylase can be encoded by Clostridium acetobutilicum buk1 30 and ptb genes. In yet another embodiment, the microbial organism is genetically modified to express exogenous 4-hydroxybutyryl-CoA reductase (see Example XIII). For example, the 4-hydroxybutyryl-CoA 25 reductase can be encoded by Clostridium beijerinckii ald gene. Additionally, in an embodiment of the invention, the microbial organism is genetically modified to express exogenous 4 hydroxybutanal reductase (see Example XIII). For example, the 4-hydroxybutanal reductase can be encoded by Geobacillus the rmoglucosidasius adhi gene. In another embodiment, the 5 microbial organism is genetically modified to express exogenous pyruvate dehydrogenase subunits (see Example XIV). For example, the exogenous pyruvate dehydrogenase can be NADH insensitive. The pyruvate dehydrogenase subunit can be encoded by the Klebsiella pneumonia lpdA gene. In a particular embodiment, the pyruvate dehydrogenase subunit genes of the microbial organism can be under the control of a pyruvate formate lyase promoter. 10 In still another embodiment, the microbial organism is genetically modified to disrupt a gene encoding an aerobic respiratory control regulatory system (see Example XV). For example, the disruption can be of the arcA gene. Such an organism can further comprise disruption of a gene encoding malate dehydrogenase. In a further embodiment, the microbial organism is genetically modified to express an exogenous NADH insensitive citrate synthase(see Example XV). For 15 example, the NADH insensitive citrate synthase can be encoded by gitA, such as an R163L mutant of gitA. In still another embodiment, the microbial organism is genetically modified to express exogenous phosphoenolpyruvate carboxykinase (see Example XVI). For example, the phosphoenolpyruvate carboxykinase can be encoded by an Haemophilus influenza phosphoenolpyruvate carboxykinase gene. 20 It is understood that any of a number of genetic modifications, as disclosed herein, can be used alone or in various combinations of one or more of the genetic modifications disclosed herein to increase the production of BDO in a BDO producing microbial organism. In a particular embodiment, the microbial organism can be genetically modified to incorporate any and up to all of the genetic modifications that lead to increased production of BDO. In a particular 25 embodiment, the microbial organism containing a BDO pathway can be genetically modified to express exogenous succinyl-CoA synthetase; to express exogenous alpha-ketoglutarate decarboxylase; to express exogenous succinate semialdehyde dehydrogenase and 4 hydroxybutyrate dehydrogenase and optionally 4-hydroxybutyryl-CoA/acetyl-CoA transferase; to express exogenous butyrate kinase and phosphotransbutyrylase; to express exogenous 4 30 hydroxybutyryl-CoA reductase; and to express exogenous 4-hydroxybutanal reductase; to express exogenous pyruvate dehydrogenase; to disrupt a gene encoding an aerobic respiratory control regulatory system; to express an exogenous NADH insensitive citrate synthase; and to express exogenous phosphoenolpyruvate carboxykinase. Such strains for improved production 26 are described in Examples XII-XIX. It is thus understood that, in addition to the modifications described above, such strains can additionally include other modifications disclosed herein. Such modifications include, but are not limited to, deletion of endogenous lactate dehydrogenase (ldhA), alcohol dehydrogenase (adhE), and/or pyruvate formate lyase (pflB)(see Examples XII 5 XIX and Table 28). Additionally provided is a microbial organism in which one or more genes encoding the exogenously expressed enzymes are integrated into the fimD locus of the host organism (see Example XVII). For example, one or more genes encoding a BDO pathway enzyme can be integrated into the fimD locus for increased production of BDO. Further provided is a microbial 10 organism expressing a non-phosphotransferase sucrose uptake system that increases production of BDO. Although the genetically modified microbial organisms disclosed herein are exemplified with microbial organisms containing particular BDO pathway enzymes, it is understood that such modifications can be incorporated into any microbial organism having a BDO, 4-HBal, 4 15 HBCoA and/or putrescine pathway suitable for enhanced production in the presence of the genetic modifications. The microbial organisms of the invention can thus have any of the BDO, 4-HBal, 4-HBCoA and/or putrescine pathways disclosed herein. For example, the BDO pathway can comprise 4-hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA dependent succinic semialdehyde dehydrogenase, 4-hydroxybutyrate:CoA transferase, 4 20 butyrate kinase, phosphotransbutyrylase, alpha-ketoglutarate decarboxylase, aldehyde dehydrogenase, alcohol dehydrogenase or an aldehyde/alcohol dehydrogenase (see Figure 1). Alternatively, the BDO pathway can comprise 4-aminobutyrate CoA transferase, 4 aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA oxidoreductase (deaminating), 4-aminobutyryl-CoA transaminase, or 4-hydroxybutyryl-CoA 25 dehydrogenase (see Table 17). Such a BDO pathway can further comprise 4-hydroxybutyryl CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA reductase, or 1,4-butanediol dehydrogenase Additionally, the BDO pathway can comprise 4-aminobutyrate CoA transferase, 4 aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA reductase 30 (alcohol forming), 4-aminobutyryl-CoA reductase, 4-aminobutan- 1 -ol dehydrogenase, 4 aminobutan-1-ol oxidoreductase (deaminating) or 4-aminobutan-1-ol transaminase (see Table 18). Also, the BDO pathway can comprise 4-aminobutyrate kinase, 4-aminobutyraldehyde 27 dehydrogenase (phosphorylating), 4-aminobutan-1-ol dehydrogenase, 4-aminobutan-1-ol oxidoreductase (deaminating), 4-aminobutan-1-ol transaminase, [(4 aminobutanolyl)oxy]phosphonic acid oxidoreductase (deaminating), [(4 aminobutanolyl)oxy]phosphonic acid transaminase, 4-hydroxybutyryl-phosphate 5 dehydrogenase, or 4-hydroxybutyraldehyde dehydrogenase (phosphorylating) (see Table 19). Such a pathway can further comprise 1,4-butanediol dehydrogenase. The BDO pathway can also comprise alpha-ketoglutarate 5-kinase, 2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating), 2,5-dioxopentanoic acid reductase, alpha ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA hydrolase, alpha-ketoglutaryl-CoA 10 ligase, alpha-ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase, alpha ketoglutaryl-CoA reductase (alcohol forming), 5-hydroxy-2-oxopentanoic acid decarboxylase, or 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation)(see Table 20). Such a BDO pathway can further comprise 4-hydroxybutyryl-CoA reductase (alcohol forming), 4 hydroxybutyryl-CoA reductase, or 1,4-butanediol dehydrogenase. Additionally, the BDO 15 pathway can comprise glutamate CoA transferase, glutamyl-CoA hydrolase, glutamyl-CoA ligase, glutamate 5-kinase, glutamate-5-semialdehyde dehydrogenase (phosphorylating), glutamyl-CoA reductase, glutamate-5-semialdehyde reductase, glutamyl-CoA reductase (alcohol forming), 2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating), 2-amino-5 hydroxypentanoic acid transaminase, 5-hydroxy-2-oxopentanoic acid decarboxylase, 5-hydroxy 20 2-oxopentanoic acid dehydrogenase (decarboxylation)(see Table 21). Such a BDO pathway can further comprise 4-hydroxybutyryl-CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA reductase, or 1,4-butanediol dehydrogenase. Additionally, the BDO pathway can comprise 3-hydroxybutyryl-CoA dehydrogenase, 3 hydroxybutyryl-CoA dehydratase, vinylacetyl-CoA A-isomerase, or 4-hydroxybutyryl-CoA 25 dehydratase (see Table 22). Also, the BDO pathway can comprise homoserine deaminase, homoserine CoA transferase, homoserine-CoA hydrolase, homoserine-CoA ligase, homoserine CoA deaminase, 4-hydroxybut-2-enoyl-CoA transferase, 4-hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2-enoyl-CoA ligase, 4-hydroxybut-2-enoate reductase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA ligase, or 4-hydroxybut-2 30 enoyl-CoA reductase (see Table 23). Such a BDO pathway can further comprise 4 hydroxybutyryl-CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA reductase, or 1,4 butanediol dehydrogenase.

28 The BDO pathway can additionally comprise succinyl-CoA reductase (alcohol forming), 4 hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA ligase, or 4-hydroxybutanal dehydrogenase (phosphorylating) (see Table 15). Such a pathway can further comprise succinyl-CoA reductase, 4-hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA transferase, 5 4-hydroxybutyrate kinase, phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase, 4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol dehydrogenase. Also, the BDO pathway can comprise glutamate dehydrogenase, 4-aminobutyrate oxidoreductase (deaminating), 4-aminobutyrate transaminase, glutamate decarboxylase, 4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA ligase, or 4-hydroxybutanal dehydrogenase 10 (phosphorylating)(see Table 16). Such a BDO pathway can further comprise alpha-ketoglutarate decarboxylase, 4-hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA transferase, 4 hydroxybutyrate kinase, phosphotrans-4-hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase, 4-hydroxybutyryl-CoA reductase (alcohol forming), or 1,4-butanediol dehydrogenase. The invention additionally provides a non-naturally occurring microbial organism, comprising a 15 4-hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising succinyl-CoA reductase (aldehyde forming); 4 hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase (see Figure 58, steps A-C-D). The invention also provides a non-naturally occurring microbial organism, comprising a 4 20 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising alpha-ketoglutarate decarboxylase; 4 hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase (Figure 58, steps B-C-D). The invention further provides a non-naturally occurring microbial organism, comprising a 4 25 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising succinate reductase; 4-hydroxybutyrate dehydrogenase, and 4-hydroxybutyrate reductase (see Figure 62, steps F-C-D). In yet another embodiment, the invention provides a non-naturally occurring microbial organism, comprising a 30 4-hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising alpha-ketoglutarate decarboxylase, or glutamate dehydrogenase or glutamate transaminase and glutamate decarboxylase and 4-aminobutyrate 29 dehydrogenase or 4-aminobutyrate transaminase; 4-hydroxybutyrate dehydrogenase; and 4 hydroxybutyrate reductase (see Figure 62, steps B or ((J or K)-L-(M or N))-C-D). The invention also provides a non-naturally occurring microbial organism, comprising a 4 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 5 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising alpha-ketoglutarate reductase; 5-hydroxy-2 oxopentanoate dehydrogenase; and 5-hydroxy-2-oxopentanoate decarboxylase (see Figure 62, steps X-Y-Z). In yet another embodiment, the invention provides a non-naturally occurring microbial organism, comprising a 4-hydroxybutyryl-CoA pathway comprising at least one 10 exogenous nucleic acid encoding a 4-hydroxybutyryl-CoA pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutyryl-CoA, the 4-hydroxybutyryl-CoA pathway comprising alpha-ketoglutarate reductase; 5-hydroxy-2-oxopentanoate dehydrogenase; and 5 hydroxy-2-oxopentanoate dehydrogenase (decarboxylation) (see Figure 62, steps X-Y-AA). The invention additionally provides a non-naturally occurring microbial organism, comprising a 15 putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising succinate reductase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase (see Figure 63, steps F-M/N-C-D/E). In still another embodiment, the invention 20 provides a non-naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine 25 transaminase (see Figure 63, steps B-M/N-C-D/E). The invention additionally provides a non naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising glutamate dehydrogenase or glutamate transaminase; glutamate decarboxylase; 4-aminobutyrate reductase; and putrescine 30 dehydrogenase or putrescine transaminase (see Figure 63, steps J/K-L-C-D/E). The invention provides in another embodiment a non-naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a 30 putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate transaminase; 5-amino-2-oxopentanoate decarboxylase; and putrescine dehydrogenase or putrescine transaminase (see Figure 63, steps 5 O-P/Q-R-D/E). Also provided is a non-naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate dehydrogenase or 5-amino 2-oxopentanoate transaminase; ornithine dehydrogenase or ornithine transaminase; and ornithine 10 decarboxylase (see Figure 63, steps O-P/Q-S/T-U). In an additional embodiment, the invention provides a non-naturally occurring microbial organism having a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway, wherein the non naturally occurring microbial organism comprises at least one exogenous nucleic acid encoding an enzyme or protein that converts a substrate of any of the pathways disclosed herein (see, for 15 example, the Examples and Figures 1, 8-13, 58, 62 and 63). In an exmemplary embodiment for producing BDO, the microbial organism can convert a substrate to a product selected from the group consisting of succinate to succinyl-CoA; succinyl-CoA to succinic semialdehyde; succinic semialdehyde to 4-hydroxybutrate; 4-hydroxybutyrate to 4-hydroxybutyryl-phosphate; 4 hydroxybutyryl-phosphate to 4-hydroxtbutyryl-CoA; 4-hydroxybutyryl-CoA to 4 20 hydroxybutanal; and 4-hydroxybutanal to 1,4-butanediol. In a pathway for producing 4-HBal, a microbial organism can convert, for example, succinate to succinic semialdehyde; succinic semialdehyde to 4-hydroxybutyrate; and 4-hydroxybutyrate to 4-hydroxybutanal. Such an organism can additionally include activity to convert 4-hydroxybutanal to 1,4-butanediol in order to produce BDO. Yet another pathway for producing 4-HBal can be, for example, alpha 25 ketoglutarate to succinic semialdehyde; succinic semialdehyde to 4-hydroxybutyrate; and 4 hydroxybutyrate to 4-hydroxybutanal. An alternative pathway for producing 4-HBal can be, for example, alpha-ketoglutarate to 2,5-dioxopentanoic acid; 2,5-dioxopentanoic acid to 5-hydroxy 2-oxopentanooic acid; and 5-hydroxy-2-oxopentanoic acid to 4-hydroxybutanal. An exemplary 4-hydroxybutyryl-CoA pathway can be, for example, alpha-ketoglutarate to 2,5-dioxopentanoic 30 acid; 2,5-dioxopentanoic acid to 5-hydroxy-2-oxopentanoic acid; and 5-hydroxy-2-oxopentanoic acid to 4-hydroxybutyryl-CoA. An exemplary putrescine pathway can be, for example, succinate to succinyl-CoA; succinyl-CoA to succinic semialdehyde; succinic semialdehyde to 4 aminobutyrate; 4-aminobutyrate to 4-aminobutanal; and 4-aminobutanal to putrescine. An alternative putrescine pathway can be, for example, succinate to succinic semialdehyde; succinic 31 semialdehyde to 4-aminobutyrate; 4-aminobutyrate to 4-aminobutanal; and 4-aminobutanal to putrescine. One skilled in the art will understand that these are merely exemplary and that any of the substrate-product pairs disclosed herein suitable to produce a desired product and for which an appropriate activity is available for the conversion can be readily determined by one 5 skilled in the art based on the teachings herein. Thus, the invention provides a non-naturally occurring microbial organism containing at least one exogenous nucleic acid encoding an enzyme or protein, where the enzyme or protein converts the substrates and products of a pathway (see Figures 1, 8-13, 58, 62 and 63). While generally described herein as a microbial organism that contains a 4-HB, 4-HBal, 4 10 HBCoA, BDO or putrescine pathway, it is understood that the invention additionally provides a non-naturally occurring microbial organism comprising at least one exogenous nucleic acid encoding a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway enzyme or protein expressed in a sufficient amount to produce an intermediate of a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway. For example, as disclosed herein, 4-HB, 4-HBal, 4-HBCoA, BDO and 15 putrescine pathways are exemplified in Figures 1, 8-13, 58, 62 and 63. Therefore, in addition to a microbial organism containing, for example, a BDO pathway that produces BDO, the invention additionally provides a non-naturally occurring microbial organism comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme, where the microbial organism produces a BDO pathway intermediate as a product rather than an intermediate of the pathway. 20 In one exemplary embodiment as shown in Figure 62, for example, the invention provides a microbial organism that produces succinyl-CoA, succinic semialdehyde, 4-hydroxybutyrate, 4 hydroxybutyryl-phosphate, 4-hydroxybutyryl-CoA, or 4-hydroxybutanal as a product rather than an intermediate. Another exemplary embodiment includes, for example, a microbial organism that produces alpha-ketoglutarate, 2,5-dioxopentanoic acid, 5-hydroxy-2-oxopentanoic acid, or 25 4-hydroxybutanal as a product rather than an intermediate. An exemplary embodiment in a putrescine pathway includes, for example, a microbial organism that produces glutamate, 4 aminobutyrate, or 4-aminobutanal as a product rather than an intermediate. An alternative embodiment in a putrescine pathway can be, for example, a microbial organism that produces 2,5-dioxopentanoate, 5-amino-2-oxopentanoate, or ornithine as a product rather than an 30 intermediate. It is understood that any of the pathways disclosed herein, as described in the Examples and exemplified in the Figures, including the pathways of Figures 1, 8-13, 58, 62 and 63, can be utilized to generate a non-naturally occurring microbial organism that produces any pathway 32 intermediate or product, as desired. As disclosed herein, such a microbial organism that produces an intermediate can be used in combination with another microbial organism expressing downstream pathway enzymes to produce a desired product. However, it is understood that a non-naturally occurring microbial organism that produces a 4-HB, 4-HBal, 4 5 HBCoA, BDO or putrescine pathway intermediate can be utilized to produce the intermediate as a desired product. The invention is described herein with general reference to the metabolic reaction, reactant or product thereof, or with specific reference to one or more nucleic acids or genes encoding an enzyme associated with or catalyzing the referenced metabolic reaction, reactant or product. 10 Unless otherwise expressly stated herein, those skilled in the art will understand that reference to a reaction also constitutes reference to the reactants and products of the reaction. Similarly, unless otherwise expressly stated herein, reference to a reactant or product also references the reaction and that reference to any of these metabolic constitutes also references the gene or genes encoding the enzymes that catalyze the referenced reaction, reactant or product. Likewise, 15 given the well known fields of metabolic biochemistry, enzymology and genomics, reference herein to a gene or encoding nucleic acid also constitutes a reference to the corresponding encoded enzyme and the reaction it catalyzes as well as the reactants and products of the reaction. The production of 4-HB via biosynthetic modes using the microbial organisms of the invention 20 is particularly useful because it can produce monomeric 4-HB. The non-naturally occurring microbial organisms of the invention and their biosynthesis of 4-HB and BDO family compounds also is particularly useful because the 4-HB product can be (1) secreted; (2) can be devoid of any derivatizations such as Coenzyme A; (3) avoids thermodynamic changes during biosynthesis; (4) allows direct biosynthesis of BDO, and (5) allows for the spontaneous 25 chemical conversion of 4-HB to y-butyrolactone (GBL) in acidic pH medium. This latter characteristic also is particularly useful for efficient chemical synthesis or biosynthesis of BDO family compounds such as 1,4-butanediol and/or tetrahydrofuran (THF), for example. Microbial organisms generally lack the capacity to synthesize 4-HB and therefore any of the compounds disclosed herein to be within the 1,4-butanediol family of compounds or known by 30 those in the art to be within the 1,4-butanediol family of compounds. Moreover, organisms having all of the requisite metabolic enzymatic capabilities are not known to produce 4-HB from the enzymes described and biochemical pathways exemplified herein. Rather, with the possible 33 exception of a few anaerobic microorganisms described further below, the microorganisms having the enzymatic capability to use 4-HB as a substrate to produce, for example, succinate. In contrast, the non-naturally occurring microbial organisms of the invention can generate 4-HB, 4-HBal, 4-HBCoA, BDO and/or putrescine as a product. As described above, the biosynthesis 5 of 4-HB in its monomeric form is not only particularly useful in chemical synthesis of BDO family of compounds, it also allows for the further biosynthesis of BDO family compounds and avoids altogether chemical synthesis procedures. The non-naturally occurring microbial organisms of the invention that can produce 4-HB, 4 HBal, 4-HBCoA, BDO and/or putrescine are produced by ensuring that a host microbial 10 organism includes functional capabilities for the complete biochemical synthesis of at least one 4-HB, 4-HBal, 4-HBCoA, BDO and/or putrscine biosynthetic pathway of the invention. Ensuring at least one requisite 4-HB, 4-HBal, 4-HBCoA or BDO biosynthetic pathway confers 4-HB biosynthesis capability onto the host microbial organism. Several 4-HB biosynthetic pathways are exemplified herein and shown for purposes of 15 illustration in Figure 1. Additional 4-HB and BDO pathways are described in Figures 8-13. One 4-HB biosynthetic pathway includes the biosynthesis of 4-HB from succinate (the succinate pathway). The enzymes participating in this 4-HB pathway include CoA-independent succinic semialdehyde dehydrogenase and 4-hydroxybutanoate dehydrogenase. In this pathway, CoA independent succinic semialdehyde dehydrogenase catalyzes the reverse reaction to the arrow 20 shown in Figure 1. Another 4-HB biosynthetic pathway includes the biosynthesis from succinate through succinyl-CoA (the succinyl-CoA pathway). The enzymes participating in this 4-HB pathway include succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase and 4-hydroxybutanoate dehydrogenase. Three other 4-HB biosynthetic pathways include the biosynthesis of 4-HB from a-ketoglutarate (the a-ketoglutarate pathways). 25 Hence, a third 4-HB biosynthetic pathway is the biosynthesis of succinic semialdehyde through glutamate:succinic semialdehyde transaminase, glutamate decarboxylase and 4 hydroxybutanoate dehydrogenase. A fourth 4-HB biosynthetic pathway also includes the biosynthesis of 4-HB from a-ketoglutarate, but utilizes a-ketoglutarate decarboxylase to catalyze succinic semialdehyde synthesis. 4-hydroxybutanoate dehydrogenase catalyzes the conversion 30 of succinic semialdehyde to 4-HB. A fifth 4-HB biosynthetic pathway includes the biosynthesis from a-ketoglutarate through succinyl-CoA and utilizes a-ketoglutarate dehydrogenase to produce succinyl-CoA, which funnels into the succinyl-CoA pathway described above. Each of these 4-HB biosynthetic pathways, their substrates, reactants and products are described further 34 below in the Examples. As described herein, 4-HB can further be biosynthetically converted to BDO by inclusion of appropriate enzymes to produce BDO (see Example). Thus, it is understood that a 4-HB pathway can be used with enzymes for converting 4-HB to BDO to generate a BDO pathway. 5 The non-naturally occurring microbial organisms of the invention can be produced by introducing expressible nucleic acids encoding one or more of the enzymes participating in one or more 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathways. Depending on the host microbial organism chosen for biosynthesis, nucleic acids for some or all of a particular 4 HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathway can be expressed. For 10 example, if a chosen host is deficient in one or more enzymes in a desired biosynthetic pathway, for example, the succinate to 4-HB pathway, then expressible nucleic acids for the deficient enzyme(s), for example, both CoA-independent succinic semialdehyde dehydrogenase and 4 hydroxybutanoate dehydrogenase in this example, are introduced into the host for subsequent exogenous expression. Alternatively, if the chosen host exhibits endogenous expression of some 15 pathway enzymes, but is deficient in others, then an encoding nucleic acid is needed for the deficient enzyme(s) to achieve 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthesis. For example, if the chosen host exhibites endogenous CoA-independent succinic semialdehyde dehydrogenase, but is deficient in 4-hydroxybutanoate dehydrogenase, then an encoding nucleic acid is needed for this enzyme to achieve 4-HB biosynthesis. Thus, a non-naturally occurring 20 microbial organism of the invention can be produced by introducing exogenous enzyme or protein activities to obtain a desired biosynthetic pathway or a desired biosynthetic pathway can be obtained by introducing one or more exogenous enzyme or protein activities that, together with one or more endogenous enzymes or proteins, produces a desired product such as 4-HB, 4 HBal, 4-HBCoA, BDO and/or putrescine. 25 In like fashion, where 4-HB biosynthesis is selected to occur through the succinate to succinyl CoA pathway (the succinyl-CoA pathway), encoding nucleic acids for host deficiencies in the enzymes succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase and/or 4-hydroxybutanoate dehydrogenase are to be exogenously expressed in the recipient host. Selection of 4-HB biosynthesis through the a-ketoglutarate to succinic semialdehyde pathway 30 (the a-ketoglutarate pathway) can utilize exogenous expression for host deficiencies in one or more of the enzymes for glutamate:succinic semialdehyde transaminase, glutamate decarboxylase and/or 4-hydroxybutanoate dehydrogenase, or a-ketoglutarate decarboxylase and 35 4-hydroxybutanoate dehydrogenase. One skilled in the art can readily determine pathway enzymes for production of 4-HB or BDO, as disclosed herein. Depending on the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathway constituents of a selected host microbial organism, the non-naturally occurring microbial 5 organisms of the invention will include at least one exogenously expressed 4-HB, 4-HB, 4 HBCoA, BDO or putrescine pathway-encoding nucleic acid and up to all encoding nucleic acids for one or more 4-HB or BDO biosynthetic pathways. For example, 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthesis can be established in a host deficient in a pathway enzyme or protein through exogenous expression of the corresponding encoding nucleic acid. In a host 10 deficient in all enzymes or proteins of a 4-HB, 4-HB, 4-HBCoA, BDO or putrescine pathway, exogenous expression of all enzyme or proteins in the pathway can be included, although it is understood that all enzymes or proteins of a pathway can be expressed even if the host contains at least one of the pathway enzymes or proteins. If desired, exogenous expression of all enzymes or proteins in a pathway for production of 4-HB, 4-HB, 4-HBCoA, BDO or putrescine 15 can be included. For example, 4-HB biosynthesis can be established from all five pathways in a host deficient in 4-hydroxybutanoate dehydrogenase through exogenous expression of a 4 hydroxybutanoate dehydrogenase encoding nucleic acid. In contrast, 4-HB biosynthesis can be established from all five pathways in a host deficient in all eight enzymes through exogenous expression of all eight of CoA-independent succinic semialdehyde dehydrogenase, succinyl 20 CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, glutamate:succinic semialdehyde transaminase, glutamate decarboxylase, a-ketoglutarate decarboxylase, a ketoglutarate dehydrogenase and 4-hydroxybutanoate dehydrogenase. Given the teachings and guidance provided herein, those skilled in the art will understand that the number of encoding nucleic acids to introduce in an expressible form will, at least, parallel 25 the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway deficiencies of the selected host microbial organism. Therefore, a non-naturally occurring microbial organism of the invention can have one, two, three, four, five, six, seven, eight or up to all nucleic acids encoding the enzymes disclosed herein constituting one or more 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathways. In some embodiments, the non-naturally occurring microbial 30 organisms also can include other genetic modifications that facilitate or optimize 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthesis or that confer other useful functions onto the host microbial organism. One such other functionality can include, for example, augmentation of the 36 synthesis of one or more of the 4-HB pathway precursors such as succinate, succinyl-CoA, a ketoglutarate, 4-aminobutyrate, glutamate, acetoacetyl-CoA, and/or homoserine. Generally, a host microbial organism is selected such that it produces the precursor of a 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway, either as a naturally produced molecule or as 5 an engineered product that either provides de novo production of a desired precursor or increased production of a precursor naturally produced by the host microbial organism. For example, succinyl-CoA, a-ketoglutarate, 4-aminobutyrate, glutamate, acetoacetyl-CoA, and homoserine are produced naturally in a host organism such as E. coli. A host organism can be engineered to increase production of a precursor, as disclosed herein. In addition, a microbial 10 organism that has been engineered to produce a desired precursor can be used as a host organism and further engineered to express enzymes or proteins of a 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway. In some embodiments, a non-naturally occurring microbial organism of the invention is generated from a host that contains the enzymatic capability to synthesize 4-HB, 4-HlBal, 4 15 HBCoA, BDO or putrescine. In this specific embodiment it can be useful to increase the synthesis or accumulation of a 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway product to, for example, drive 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway reactions toward 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine production. Increased synthesis or accumulation can be accomplished by, for example, overexpression of nucleic acids encoding one or more of 20 the 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway enzymes disclosed herein. Over expression of the 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway enzyme or enzymes can occur, for example, through exogenous expression of the endogenous gene or genes, or through exogenous expression of the heterologous gene or genes. Therefore, naturally occurring organisms can be readily generated to be non-naturally 4-HB, 4-HlBal, 4-HBCoA, BDO or 25 putrescine producing microbial organisms of the invention through overexpression of one, two, three, four, five, six and so forth up to all nucleic acids encoding 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine biosynthetic pathway enzymes. In addition, a non-naturally occurring organism can be generated by mutagenesis of an endogenous gene that results in an increase in activity of an enzyme in the 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine biosynthetic pathway. 30 In particularly useful embodiments, exogenous expression of the encoding nucleic acids is employed. Exogenous expression confers the ability to custom tailor the expression and/or regulatory elements to the host and application to achieve a desired expression level that is 37 controlled by the user. However, endogenous expression also can be utilized in other embodiments such as by removing a negative regulatory effector or induction of the gene's promoter when linked to an inducible promoter or other regulatory element. Thus, an endogenous gene having a naturally occurring inducible promoter can be up-regulated by 5 providing the appropriate inducing agent, or the regulatory region of an endogenous gene can be engineered to incorporate an inducible regulatory element, thereby allowing the regulation of increased expression of an endogenous gene at a desired time. Similarly, an inducible promoter can be included as a regulatory element for an exogenous gene introduced into a non-naturally occurring microbial organism (see Examples). 10 "Exogenous" as it is used herein is intended to mean that the referenced molecule or the referenced activity is introduced into the host microbial organism. The molecule can be introduced, for example, by introduction of an encoding nucleic acid into the host genetic material such as by integration into a host chromosome or as non-chromosomal genetic material such as a plasmid. Therefore, the term as it is used in reference to expression of an encoding 15 nucleic acid refers to introduction of the encoding nucleic acid in an expressible form into the microbial organism. When used in reference to a biosynthetic activity, the term refers to an activity that is introduced into the host reference organism. The source can be, for example, a homologous or heterologous encoding nucleic acid that expresses the referenced activity following introduction into the host microbial organism. Therefore, the term "endogenous" 20 refers to a referenced molecule or activity that is present in the host. Similarly, the term when used in reference to expression of an encoding nucleic acid refers to expression of an encoding nucleic acid contained within the microbial organism. The term "heterologous" refers to a molecule or activity derived from a source other than the referenced species whereas "homologous" refers to a molecule or activity derived from the host microbial organism. 25 Accordingly, exogenous expression of an encoding nucleic acid of the invention can utilize either or both a heterologous or homologous encoding nucleic acid. It is understood that when more than one exogenous nucleic acid is included in a microbial organism that the the more than one exogenous nucleic acids refers to the referenced encoding nucleic acid or biosynthetic activity, as discussed above. It is further understood, as disclosed 30 herein, that such more than one exogenous nucleic acids can be introduced into the host microbial organism on separate nucleic acid molecules, on polycistronic nucleic acid molecules, or a combination thereof, and still be considered as more than one exogenous nucleic acid. For example, as disclosed herein a microbial organism can be engineered to express two or more 38 exogenous nucleic acids encoding a desired pathway enzyme or protein. In the case where two exogenous nucleic acids encoding a desired activity are introduced into a host microbial organism, it is understood that the two exogenous nucleic acids can be introduced as a single nucleic acid, for example, on a single plasmid, on separate plasmids, can be integrated into the 5 host chromosome at a single site or multiple sites, and still be considered as two exogenous nucleic acids. Similarly, it is understood that more than two exogenous nucleic acids can be introduced into a host organism in any desired combination, for example, on a single plasmid, on separate plasmids, can be integrated into the host chromosome at a single site or multiple sites, and still be considered as two or more exogenous nucleic acids, for example three 10 exogenous nucleic acids. Thus, the number of referenced exogenous nucleic acids or biosynthetic activities refers to the number of encoding nucleic acids or the number of biosynthetic activities, not the number of separate nucleic acids introduced into the host organism. Sources of encoding nucleic acids for a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway 15 enzyme can include, for example, any species where the encoded gene product is capable of catalyzing the referenced reaction. Such species include both prokaryotic and eukaryotic organisms including, but not limited to, bacteria, including archaea and eubacteria, and eukaryotes, including yeast, plant, insect, animal, and mammal, including human. Exemplary species for such sources include, for example, Escherichia coli, Saccharomyces cerevisiae, 20 Saccharomyces kluyveri, Clostridium kluyveri, Clostridium acetobutylicum, Clostridium beijerinckii, Clostridium saccharoperbutylacetonicum, Clostridium perfringens, Clostridium difficile, Clostridium botulinum, Clostridium tyrobutyricum, Clostridium tetanomorphum, Clostridium tetani, Clostridium propionicum, Clostridium aminobutyricum, Clostridium subterminale, Clostridium sticklandii, Ralstonia eutropha, Mycobacterium bovis, 25 Mycobacterium tuberculosis, Porphyromonas gingivalis, Arabidopsis thaliana, Thermus thermophilus, Pseudomonas species, including Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas stutzeri, Pseudomonasfluorescens, Homo sapiens, Oryctolagus cuniculus, Rhodobacter spaeroides, Thermoanaerobacter brockii, Metallosphaera sedula, Leuconostoc mesenteroides, Chloroflexus aurantiacus, Roseiflexus castenholzii, Erythrobacter, Simmondsia 30 chinensis, Acinetobacter species, including Acinetobacter calcoaceticus and Acinetobacter baylyi, Porphyromonas gingivalis, Sulfolobus tokodaii, Sulfolobus solfataricus, Sulfolobus acidocaldarius, Bacillus subtilis, Bacillus cereus, Bacillus megaterium, Bacillus brevis, Bacillus pumilus, Rattus norvegicus, Klebsiella pneumonia, Klebsiella oxytoca, Euglena gracilis, Treponema denticola, Moorella thermoacetica, Thermotoga maritima, Halobacterium 39 salinarum, Geobacillus stearothermophilus, Aeropyrum pernix, Sus scrofa, Caenorhabditis elegans, Corynebacterium glutamicum, Acidaminococcusfermentans, Lactococcus lactis, Lactobacillus plantarum, Streptococcus thermophilus, Enterobacter aerogenes, Candida, Aspergillus terreus, Pedicoccus pentosaceus, Zymomonas mobilus, Ace tobacter pasteurians, 5 Kluyveromyces lactis, Eubacterium barkeri, Bacteroides capillosus, Anaerotruncus colihominis, Natranaerobius thermophilusm, Campylobacterjejuni, Haemophilus influenzae, Serratia marcescens, Citrobacter amalonaticus, Myxococcus xanthus, Fusobacterium nuleatum, Penicillium chrysogenum, marine gamma proteobacterium, butyrate-producing bacterium, Nocardia iowensis, Nocardia farcinica, Streptomyces griseus, Schizosaccharomyces pombe, 10 Geobacillus thermoglucosidasius, Salmonella typhimurium, Vibrio cholera, Heliobacterpylori, Nicotiana tabacum, Oryza sativa, Haloferax mediterranei, Agrobacterium tumefaciens, Achromobacter denitrificans, Fusobacterium nucleatum, Streptomyces clavuligenus, Acinetobacter baumanii, Mus musculus, Lachancea kluyveri, Trichomonas vaginalis, Trypanosoma brucei, Pseudomonas stutzeri, Bradyrhizobium japonicum, Mesorhizobium loti, 15 Bos taurus, Nicotiana glutinosa, Vibrio vulnificus, Selenomonas ruminantium, Vibrio parahaemolyticus, Archaeoglobusfulgidus, Haloarcula marismortui, Pyrobaculum aerophilum, Mycobacterium smegmatis MC2 155, Mycobacterium avium subsp. paratuberculosis K-10, Mycobacterium marinum M, Tsukamurella paurometabola DSM 20162, Cyanobium PCC7001, Dictyostelium discoideum AX4, and others disclosed herein (see Examples). For example, 20 microbial organisms having 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic production are exemplified herein with reference to E. coli and yeast hosts. However, with the complete genome sequence available for now more than 550 species (with more than half of these available on public databases such as the NCBI), including 395 microorganism genomes and a variety of yeast, fungi, plant, and mammalian genomes, the identification of genes 25 encoding the requisite 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic activity for one or more genes in related or distant species, including for example, homologues, orthologs, paralogs and nonorthologous gene displacements of known genes, and the interchange of genetic alterations between organisms is routine and well known in the art. Accordingly, the metabolic alterations allowing biosynthesis of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine and other 30 compounds of the invention described herein with reference to a particular organism such as E coli or yeast can be readily applied to other microorganisms, including prokaryotic and eukaryotic organisms alike. Given the teachings and guidance provided herein, those skilled in the art will know that a metabolic alteration exemplified in one organism can be applied equally to other organisms.

40 In some instances, such as when an alternative 4-HB, 4-HBal, BDO or putrescine biosynthetic pathway exists in an unrelated species, 4-HB, 4-HBal, BDO or putrescine biosynthesis can be conferred onto the host species by, for example, exogenous expression of a paralog or paralogs from the unrelated species that catalyzes a similar, yet non-identical metabolic reaction to 5 replace the referenced reaction. Because certain differences among metabolic networks exist between different organisms, those skilled in the art will understand that the actual gene usage between different organisms may differ. However, given the teachings and guidance provided herein, those skilled in the art also will understand that the teachings and methods of the invention can be applied to all microbial organisms using the cognate metabolic alterations to 10 those exemplified herein to construct a microbial organism in a species of interest that will synthesize 4-HB, such as monomeric 4-HB, 4-HBal, BDO or putrescine. Host microbial organisms can be selected from, and the non-naturally occurring microbial organisms generated in, for example, bacteria, yeast, fungus or any of a variety of other microorganisms applicable to fermentation processes. Exemplary bacteria include species 15 selected from Escherichia coli, Klebsiella oxytoca, Anaerobiospirillum succiniciproducens, Actinobacillus succinogenes, Mannheimia succiniciproducens, Rhizobium etli, Bacillus subtilis, Corynebacterium glutamicum, Gluconobacter oxydans, Zymomonas mobilis, Lactococcus lactis, Lactobacillus plantarum, Streptomyces coelicolor, Clostridium acetobutylicum, Pseudomonas fluorescens, and Pseudomonas putida. Exemplary yeasts or fungi include species selected from 20 Saccharomyces cerevisiae, Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces marxianus, Aspergillus terreus, Aspergillus niger, Pichia pastoris, Rhizopus arrhizus, Rhizobus oryzae, and the like. E. coli is a particularly useful host organisms since it is a well characterized microbial organism suitable for genetic engineering. Other particularly useful host organisms include yeast such as Saccharomyces cerevisiae. It is understood that any suitable 25 microbial host organism can be used to introduce metabolic and/or genetic modifications to produce a desired product. Methods for constructing and testing the expression levels of a non-naturally occurring 4-HB-, 4-HBal-, 4-HBCoA-, BDO-, or putrescine-producing host can be performed, for example, by recombinant and detection methods well known in the art. Such methods can be found 30 described in, for example, Sambrook et al., Molecular Cloning: A Laboratory Manual, Third Ed., Cold Spring Harbor Laboratory, New York (2001); Ausubel et al., Current Protocols in Molecular Biology, John Wiley and Sons, Baltimore, MD (1999). 4-HB and GBL can be separated by, for example, HPLC using a Spherisorb 5 ODS 1 column and a mobile phase of 41 70% 10 mM phosphate buffer (pH=7) and 30% methanol, and detected using a UV detector at 215 nm (Hennessy et al. 2004, J. Forensic Sci. 46(6):1-9). BDO is detected by gas chromatography or by HPLC and refractive index detector using an Aminex HPX-87H column and a mobile phase of 0.5 mM sulfuric acid (Gonzalez-Pajuelo et al., Met. Eng. 7:329-336 5 (2005)). Exogenous nucleic acid sequences involved in a pathway for production of 4-HB, 4-HBal, 4 HBCoA, BDO or putrescine can be introduced stably or transiently into a host cell using techniques well known in the art including, but not limited to, conjugation, electroporation, chemical transformation, transduction, transfection, and ultrasound transformation. For 10 exogenous expression in E. coli or other prokaryotic cells, some nucleic acid sequences in the genes or cDNAs of eukaryotic nucleic acids can encode targeting signals such as an N-terminal mitochondrial or other targeting signal, which can be removed before transformation into prokaryotic host cells, if desired. For example, removal of a mitochondrial leader sequence led to increased expression in E. coli (Hoffmeister et al., J. Biol. Chem. 280:4329-4338 (2005)). For 15 exogenous expression in yeast or other eukaryotic cells, genes can be expressed in the cytosol without the addition of leader sequence, or can be targeted to mitochondrion or other organelles, or targeted for secretion, by the addition of a suitable targeting sequence such as a mitochondrial targeting or secretion signal suitable for the host cells. Thus, it is understood that appropriate modifications to a nucleic acid sequence to remove or include a targeting sequence can be 20 incorporated into an exogenous nucleic acid sequence to impart desirable properties. Furthermore, genes can be subjected to codon optimization with techniques well known in the art to achieve optimized expression of the proteins. An expression vector or vectors can be constructed to harbor one or more 4-HB, 4-HBal, 4 HBCoA, BDO or putrescine biosynthetic pathway and/or one or more biosynthetic encoding 25 nucleic acids as exemplified herein operably linked to expression control sequences functional in the host organism. Expression vectors applicable for use in the microbial host organisms of the invention include, for example, plasmids, phage vectors, viral vectors, episomes and artificial chromosomes, including vectors and selection sequences or markers operable for stable integration into a host chromosome. Additionally, the expression vectors can include one or 30 more selectable marker genes and appropriate expression control sequences. Selectable marker genes also can be included that, for example, provide resistance to antibiotics or toxins, complement auxotrophic deficiencies, or supply critical nutrients not in the culture media. Expression control sequences can include constitutive and inducible promoters, transcription 42 enhancers, transcription terminators, and the like which are well known in the art. When two or more exogenous encoding nucleic acids are to be co-expressed, both nucleic acids can be inserted, for example, into a single expression vector or in separate expression vectors. For single vector expression, the encoding nucleic acids can be operationally linked to one common 5 expression control sequence or linked to different expression control sequences, such as one inducible promoter and one constitutive promoter. The transformation of exogenous nucleic acid sequences involved in a metabolic or synthetic pathway can be confirmed using methods well known in the art. Such methods include, for example, nucleic acid analysis such as Northern blots or polymerase chain reaction (PCR) amplification of mRNA, or immunoblotting 10 for expression of gene products, or other suitable analytical methods to test the expression of an introduced nucleic acid sequence or its corresponding gene product. It is understood by those skilled in the art that the exogenous nucleic acid is expressed in a sufficient amount to produce the desired product, and it is further understood that expression levels can be optimized to obtain sufficient expression using methods well known in the art and as disclosed herein. 15 The non-naturally occurring microbial organisms of the invention are constructed using methods well known in the art as exemplified herein to exogenously express at least one nucleic acid encoding a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway enzyme in sufficient amounts to produce 4-HB, such as monomeric 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine. It is understood that the microbial organisms of the invention are cultured under conditions sufficient 20 to produce 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine. Exemplary levels of expression for 4 HB, 4-HBal, 4-HBCoA, BDO or putrescine enzymes in each pathway are described further below in the Examples. Following the teachings and guidance provided herein, the non naturally occurring microbial organisms of the invention can achieve biosynthesis of 4-HB, such as monomeric 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine resulting in intracellular 25 concentrations between about 0.1-200 mM or more, for example, 0.1-25 mM or more. Generally, the intracellular concentration of 4-HB, such as monomeric 4-HB, 4-HBal, 4 HBCoA, BDO or putrescine is between about 3-150 mM or more, particularly about 5-125 mM or more, and more particularly between about 8-100 mM, for example, about 3-20mM, particularly between about 5-15 mM and more particularly between about 8-12 mM, including 30 about 10 mM, 20 mM, 50 mM, 80 mM or more. Intracellular concentrations between and above each of these exemplary ranges also can be achieved from the non-naturally occurring microbial organisms of the invention. In particular embodiments, the microbial organisms of the invention, particularly strains such as those disclosed herein (see Examples XII-XIX and Table 28), can provide improved production of a desired product such as 4-HB, 4-HBal, 4-HBCoA, 43 BDO or putrescine by increasing the production of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine and/or decreasing undesirable byproducts. Such production levels include, but are not limited to, those disclosed herein and including from about 1 gram to about 25 grams per liter, for example about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 5 24, or even higher amounts of product per liter. In addition to the culturing and fermentation conditions disclosed herein, growth condition for achieving biosynthesis of BDO, 4-HB, 4-HBCoA, 4-HBal and/or putrescine can include the addition of an osmoprotectant to the culturing conditions. In certain embodiments, the non naturally occurring microbial organisms of the invention can be sustained, cultured or fermented 10 as described herein in the presence of an osmoprotectant. Briefly, an osmoprotectant refers to a compound that acts as an osmolyte and helps a microbial organism as described herein survive osmotic stress. Osmoprotectants include, but are not limited to, betaines, amino acids, and the sugar trehalose. Non-limiting examples of such are glycine betaine, praline betaine, dimethylthetin, dimethylslfonioproprionate, 3-dimethylsulfonio-2-methylproprionate, pipecolic 15 acid, dimethylsulfonioacetate, choline, L-carnitine and ectoine. In one aspect, the osmoprotectant is glycine betaine. It is understood to one of ordinary skill in the art that the amount and type of osmoprotectant suitable for protecting a microbial organism described herein from osmotic stress will depend on the microbial organism used. The amount of osmoprotectant in the culturing conditions can be, for example, no more than about 0.1 mM, no 20 more than about 0.5 mM, no more than about 1.0 mM, no more than about 1.5 mM, no more than about 2.0 mM, no more than about 2.5 mM, no more than about 3.0 mM, no more than about 5.0 mM, no more than about 7.0 mM, no more than about 10mM, no more than about 50mM, no more than about 100mM or no more than about 500mM. In some embodiments, culture conditions include anaerobic or substantially anaerobic growth or 25 maintenance conditions. Exemplary anaerobic conditions have been described previously and are well known in the art. Exemplary anaerobic conditions for fermentation processes are described herein and are described, for example, in U.S. publication 2009/0047719, filed August 10, 2007. Any of these conditions can be employed with the non-naturally occurring microbial organisms as well as other anaerobic conditions well known in the art. Under such anaerobic 30 conditions or substantially anaerobic, the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producers can synthesize 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine at intracellular concentrations of 5-10 mM or more as well as all other concentrations exemplified herein. It is understood that, even though the above description refers to intracellular concentrations, 4-HB, 44 4-HBal, 4-HBCoA, BDO or putrescine producing microbial organisms can produce 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine intracellularly and/or secrete the product into the culture medium. The culture conditions can include, for example, liquid culture procedures as well as 5 fermentation and other large scale culture procedures. As described herein, particularly useful yields of the biosynthetic products of the invention can be obtained under anaerobic or substantially anaerobic culture conditions. As described herein, one exemplary growth condition for achieving biosynthesis of 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine includes anaerobic culture or fermentation conditions. In 10 certain embodiments, the non-naturally occurring microbial organisms of the invention can be sustained, cultured or fermented under anaerobic or substantially anaerobic conditions. Briefly, anaerobic conditions refers to an environment devoid of oxygen. Substantially anaerobic conditions include, for example, a culture, batch fermentation or continuous fermentation such that the dissolved oxygen concentration in the medium remains between 0 and 10% of 15 saturation. Substantially anaerobic conditions also includes growing or resting cells in liquid medium or on solid agar inside a sealed chamber maintained with an atmosphere of less than 1% oxygen. The percent of oxygen can be maintained by, for example, sparging the culture with an

N

2

/CO

2 mixture or other suitable non-oxygen gas or gases. The invention also provides a non-naturally occurring microbial biocatalyst including a 20 microbial organism having 4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO) biosynthetic pathways that include at least one exogenous nucleic acid encoding 4 hydroxybutanoate dehydrogenase, CoA-independent succinic semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, 4 hydroxybutyrate:CoA transferase, glutamate:succinic semialdehyde transaminase, glutamate 25 decarboxylase, CoA-independent aldehyde dehydrogenase, CoA-dependent aldehyde dehydrogenase or alcohol dehydrogenase, wherein the exogenous nucleic acid is expressed in sufficient amounts to produce 1,4-butanediol (BDO). 4-Hydroxybutyrate:CoA transferase also is known as 4-hydroxybutyryl CoA:acetyl-CoA transferase. Additional 4-HB or BDO pathway enzymes are also disclosed herein (see Examples and Figures 8-13). 30 The invention further provides non-naturally occurring microbial biocatalyst including a microbial organism having 4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO) biosynthetic pathways, the pathways include at least one exogenous nucleic acid encoding 4- 45 hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, 4-hydroxybutyrate:CoA transferase, 4-butyrate kinase, phosphotransbutyrylase, a.-ketoglutarate decarboxylase, aldehyde dehydrogenase, alcohol dehydrogenase or an aldehyde/alcohol dehydrogenase, wherein the exogenous nucleic acid is 5 expressed in sufficient amounts to produce 1,4-butanediol (BDO). Non-naturally occurring microbial organisms also can be generated which biosynthesize BDO. As with the 4-HB producing microbial organisms of the invention, the BDO producing microbial organisms also can produce intracellularly or secret the BDO into the culture medium. Following the teachings and guidance provided previously for the construction of microbial 10 organisms that synthesize 4-HB, additional BDO pathways can be incorporated into the 4-HB producing microbial organisms to generate organisms that also synthesize BDO and other BDO family compounds. The chemical synthesis of BDO and its downstream products are known. The non-naturally occurring microbial organisms of the invention capable of BDO biosynthesis circumvent these chemical synthesis using 4-HB as an entry point as illustrated in Figure 1. As 15 described further below, the 4-HB producers also can be used to chemically convert 4-HB to GBL and then to BDO or THF, for example. Alternatively, the 4-HB producers can be further modified to include biosynthetic capabilities for conversion of 4-HB and/or GBL to BDO. The additional BDO pathways to introduce into 4-HB producers include, for example, the exogenous expression in a host deficient background or the overexpression of one or more of the 20 enzymes exemplified in Figure 1 as steps 9-13. One such pathway includes, for example, the enzyme activies necessary to carryout the reactions shown as steps 9, 12 and 13 in Figure 1, where the aldehyde and alcohol dehydrogenases can be separate enzymes or a multifunctional enzyme having both aldehyde and alcohol dehydrogenase activity. Another such pathway includes, for example, the enzyme activities necessary to carry out the reactions shown as steps 25 10, 11, 12 and 13 in Figure 1, also where the aldehyde and alcohol dehydrogenases can be separate enzymes or a multifunctional enzyme having both aldehyde and alcohol dehydrogenase activity. Accordingly, the additional BDO pathways to introduce into 4-HB producers include, for example, the exogenous expression in a host deficient background or the overexpression of one or more of a 4-hydroxybutyrate:CoA transferase, butyrate kinase, phosphotransbutyrylase, 30 CoA-independent aldehyde dehydrogenase, CoA-dependent aldehyde dehydrogenase or an alcohol dehydrogenase. In the absence of endogenous acyl-CoA synthetase capable of modifying 4-HB, the non-naturally occurring BDO producing microbial organisms can further include an exogenous acyl-CoA synthetase selective for 4-HB, or the combination of multiple 46 enzymes that have as a net reaction conversion of 4-HB into 4-HB-CoA. As exemplified further below in the Examples, butyrate kinase and phosphotransbutyrylase exhibit BDO pathway activity and catalyze the conversions illustrated in Figure 1 with a 4-HB substrate. Therefore, these enzymes also can be referred to herein as 4-hydroxybutyrate kinase and 5 phosphotranshydroxybutyrylase respectively. Exemplary alcohol and aldehyde dehydrogenases that can be used for these in vivo conversions from 4-HB to BDO are listed below in Table 1.

47 Table 1. Alcohol and Aldehyde Dehydrogenases for Conversion of 4-HB to BDO. ALCOHOL DEHYDROGENASES ec: 1.1.1.81 hydroxypyruvate reductase 60 ec:1.1.1.82 malate dehydrogenase (NADP+) ec: 1. 1. 1.1 alcohol dehydrogenase ec:1.1.1.83 D-malate dehydrogenase ec: 1.1.1.2 alcohol dehydrogenase (NADP+) (decarboxylating) .c:1.1.4 (R,R)-butanediol dehydrogenase ec:1.1.1.84 dimethylmalate dehydrogenase ec:1.1.1.4 (,-tn dehydrogenase ec:1.1.1.85 3-isopropylmalate dehydrogenase ec: 1.1.1.5 acetoin dehydrogenase 65 ec:1.1.1.86 ketol-acid reductoisomerase ec:1.1.1.6 glycerol dehydrogenase ec:1.1.1.87 homoisocitrate dehydrogenase ec:1.1.1.7 propanediol-phosphate ec:1.1.1.88 hydroxymethylglutaryl-CoA dehydrogenase reductase 10 ec:1.1.1.8 glycerol-3-phosphate dehydrogenase ec:1.1.1.90 aryl-alcohol dehydrogenase (NAD+) 70 ec:1.1.1.91 aryl-alcohol dehydrogenase (NADP+) ec: 1.1.1.11 D-arabinitol 4-dehydrogenase ec:1.1.1.92 oxaloglycolate reductase ec:1.1.1.12 L-arabinitol 4-dehydrogenase (decarboxylating) 15 ec: 1.1.1.14 L-iditol 2-dehydrogenase ec: 1.1.1.94 glycerol-3-phosphate dehydrogenase 15ec: 1. 1.1.14 L-iditol 2-dehydrogenase [NAD(P)+] ec:1.1.1.15 D-iditol 2-dehydrogenase 75 ec:1.1.1.95 phosphoglycerate dehydrogenase ec: 1.1.1.16 galactitol 2-dehydrogenase ec:1.1.1.97 3-hydroxybenzyl-alcohol ec:1.1.1.17 mannitol-1-phosphate 5- dehydrogenase dehydrogenase ec:1.1.1.101 acylglycerone-phosphate reductase 20 ec:1.1.1.18 inositol 2-dehydrogenase ec:1.1.1.103 L-threonine 3-dehydrogenase ec:1.1.1.21 aldehyde reductase 80 ec: 1.1.1.104 4-oxoproline reductase ec:1.1.1.23 hsdoldedroase ec:1.1.1.105 retinol dehydrogenase ec:1.1.1.26 glyoxylate reductase ec: 1.1.1.110 indolelactate dehydrogenase ec:1.1.1.27 L-lactate dehydrogenase ec: 1.1.1.112 indanol dehydrogenase 25 ec:1.1.1.28 D-lactate dehydrogenase ec: 1.1.1.113 L-xylose 1-dehydrogenase ec:1.1.1.29 glycerate dehydrogenase 85 ec: 1.1.1.129 L-threonate 3-dehydrogenase ec:1.1.1.30 3-hydroxybutyrate dehydrogenase ec:1.1.1.137 ribitol-5-phosphate 2-dehydrogenase ec:1.1.1.31 3-hydroxyisobutyrate dehydrogenase ec:1.1.1.138 mannitol 2-dehydrogenase (NADP+) ec:1.1.1.35 3-hydroxyacyl-CoA dehydrogenase ec:1.1.1.140 sorbitol-6-phosphate 2-dehydrogenase 30 ec:1.1.1.36 acetoacetyl-CoA reductase ec: 1.1.1.142 D-pinitol dehydrogenase ec:1.1.1.37 malate dehydrogenase 90 ec:1.1.1.143 sequoyitol dehydrogenase ec:1.1.1.38 malate dehydrogenase (oxaloacetate- ec: 1.1.1.144 perillyl-alcohol dehydrogenase decarboxylating) ec:1.1.1.156 glycerol 2-dehydrogenase (NADP+) ec:1.1.1.39 malate dehydrogenase ec:1.1.1.157 3-hydroxybutyryl-CoA 35 (decarboxylating)deyrgns ec:1.1.1.40 malate dehydrogenase (oxaloacetate- dehydrogenase decarboxylating) (NADP+) 95 ec:1.1.1.163 cyclopentanol dehydrogenase ec: 1.1.1.41 isocitrate dehydrogenase (NAD+) ec: 1.1.1.164 hexadecanol dehydrogenase ec: 1.1.1.42 isocitrate dehydrogenase (NADP+) ec:1.1.1.165 2-alkyn-1-ol dehydrogenase 40 ec:1.1.1.54 allyl-alcohol dehydrogenase ec:1.1.1.166 hydroxycyclohexanecarboxylate ec:1.1.1.55 lactaldehyde reductase (NADPH) 100 ec:1.1.1.167 hydroxymalonate dehydrogenase ec:1.1.1.56 ribitol 2-dehydrogenase ec: 1.1.1.174 cyclohexane-1,2-diol dehydrogenase ec:1.1.1.59 3-hydroxypropionate dehydrogenase ec: 1.1.1.177 glycerol-3-phosphate 1 ec:1.1.1.60 2-hydroxy-3-oxopropionate reductase dehydrogenase (NADP+) 45 ec:1.1.1.61 4-hydroxybutyrate dehydrogenase ec:1.1.1.178 3-hydroxy-2-methylbutyryl-CoA ec:1.1.1.66 omega-hydroxydecanoate 105 dehydrogenase ec:1.1.1.67 mannitol 2-dehydrogenase ec:1.1.1.185 L-glycol dehydrogenase ec:1.1.1.7 annol -dehydrogenase ec: 1.1.1.190 indole-3-acetaldehyde reductase ec:1.1.1.71 alcohol dehydrogenase [NAD(P)+] (NADH) 50 ec:1.1.1.72 glycerol dehydrogenase (NADP+) 1.1.1.191 indole-3-acetaldehyde reductase ec:1.1.1.73 octanol dehydrogenase 110 (NADPH) ec:1.1.1.75 (R)-aminopropanol dehydrogenase ec: 1.1 1.192 long-chain-alcohol dehydrogenase ec:1.1.1.76 (S,S)-butanediol dehydrogenase ec: 1.1.1.194 coniferyl-alcohol dehydrogenase ec: 1.1.1.77 lactaldehyde reductase ec: 1.1.1.195 cinnamy1-alcohol dehydrogenase 55 ec:1.1.1.78 methylglyoxal reductase (NADH- ec: 1.1. 1.198 (+)-borneol dehydrogenase dependent) 115 ec:1.1.1.202 1,3-propanediol dehydrogenase ec:1.1.1.79 glyoxylate reductase (NADP+) ec:1.1.1.207 (-)-menthol dehydrogenase ec:1.1.1.80 isopropanol dehydrogenase (NADP+) 48 ec:1.1.1.208 (+)-neomenthol dehydrogenase ec: 1.2.1.20 glutarate-semialdehyde ec:1.1.1.216 farnesol dehydrogenase dehydrogenase ec:1.1.1.217 benzyl-2-methyl-hydroxybutyrate ec: 1.2.1.21 glycolaldehyde dehydrogenase dehydrogenase ec: 1.2.1.22 lactaldehyde dehydrogenase 5 ec:1.1.1.222 (R)-4-hydroxyphenyllactate 65 ec: 1.2.1.23 2-oxoaldehyde dehydrogenase dehydrogenase (NAD+) ec:1.1.1.223 isopiperitenol dehydrogenase ec: 1.2.1.24 succinate-semialdehyde ec:1.1.1.226 4-hydroxycyclohexanecarboxylate dehydrogenase dehydrogenase ec: 1.2.1.25 2-oxoisovalerate dehydrogenase 10 ec:1.1.1.229 diethyl 2-methyl-3-oxosuccinate 70 (acylating) reductase ec: 1.2.1.26 2,5-dioxovalerate dehydrogenase ec:1.1.1.237 hydroxyphenylpyruvate reductase ec: 1.2.1.27 methylmalonate-semialdehyde ec:1.1.1.244 methanol dehydrogenase dehydrogenase (acylating) ec:1.1.1.245 cyclohexanol dehydrogenase ec: 1.2.1.28 benzaldehyde dehydrogenase 15 ec:1.1.1.250 D-arabinitol 2-dehydrogenase 75 (NAD+) ec:1.1.1.251 galactitol 1-phosphate 5- ec: 1.2.1.29 aryl-aldehyde dehydrogenase dehydrogenase ec: 1.2.1.30 aryl-aldehyde dehydrogenase ec:1.1.1.255 mannitol dehydrogenase (NADP+) ec:1.1.1.256 fluoren-9-ol dehydrogenase ec: 1.2.1.31 L-aminoadipate-semialdehyde 20 ec:1.1.1.257 4-(hydroxymethyl)benzenesulfonate 80 dehydrogenase dehydrogenase ec: 1.2.1.32 aminomuconate-semialdehyde ec:1.1.1.258 6-hydroxyhexanoate dehydrogenase dehydrogenase ec:1.1.1.259 3-hydroxypimeloyl-CoA ec:1.2.1.36 retinal dehydrogenase dehydrogenase ec: 1.2.1.39 phenylacetaldehyde dehydrogenase 25 ec:1.1.1.261 glycerol-1-phosphate dehydrogenase85 ec: 1.2.1.41 glutamate-5-semialdehyde [NAD(P)+] dehydrogenase ec:1.1.1.265 3-methylbutanal reductase ec: 1.2.1.42 hexadecanal dehydrogenase ec:1.1.1.283 methylglyoxal reductase (NADPH- (acylating) dependent) ec: 1.2.1.43 formate dehydrogenase (NADP+) 30 ec:1.1.1.286 isocitrate-homoisocitrate 90 ec: 1.2.1.45 4-carboxy-2-hydroxymuconate-6 dehydrogenase semialdehyde dehydrogenase ec:1.1.1.287 D-arabinitol dehydrogenase (NADP+) ec: 1.2.1.46 formaldehyde dehydrogenase butanol dehydrogenase ec: 1.2.1.47 4-trimethylammoniobutyraldehyde dehydrogenase 35 ALDEHYDE DEHYDROGENASES 95 ec:1.2.1.48 long-chain-aldehyde dehydrogenase ec: 1.2.1.2 formate dehydrogenase ec: 1.2.1.49 2-oxoaldehyde dehydrogenase ec: 1.2.1.3 aldehyde dehydrogenase (NAD+) (NADP+) ec:1.2.1.4 aldehyde dehydrogenase (NADP+) ec:1.2.1.51 pyruvate dehydrogenase (NADP+) ec:1.2.1.5 aldehyde dehydrogenase [NAD(P)+] ec:1.2.1.52 oxoglutarate dehydrogenase 40 ec:1.2.1.7 benzaldehyde dehydrogenase 100 (NADP+) (NADP+) ec:1.2.1.53 4-hydroxyphenylacetaldehyde ec: 1.2.1.8 betaine-aldehyde dehydrogenase dehydrogenase ec: 1.2.1.9 glyceraldehyde-3-phosphate ec: 1.2.1.57 butanal dehydrogenase dehydrogenase (NADP+) ec:1.2.1.58 phenylglyoxylate dehydrogenase 45 ec:1.2.1.10 acetaldehyde dehydrogenase 105 (acylating) (acetylating) ec: 1.2.1.59 glyceraldehyde-3-phosphate ec:1.2.1.11 aspartate-semialdehyde dehydrogenase (NAD(P)+) (phosphorylating) dehydrogenase ec: 1.2.1.62 4-formylbenzenesulfonate ec: 1.2.1.12 glyceraldehyde-3-phosphate dehydrogenase 50 dehydrogenase (phosphorylating) 110 ec:1.2.1.63 6-oxohexanoate dehydrogenase ec: 1.2.1.13 glyceraldehyde-3-phosphate ec: 1.2.1.64 4-hydroxybenzaldehyde dehydrogenase (NADP+) (phosphorylating) dehydrogenase ec: 1.2.1.15 malonate-semialdehyde ec: 1.2.1.65 salicylaldehyde dehydrogenase dehydrogenase ec: 1.2.1.66 mycothiol-dependent formaldehyde 55 ec:1.2.1.16 succinate-semialdehyde 115 dehydrogenase dehydrogenase [NAD(P)+] ec: 1.2.1.67 vanillin dehydrogenase ec: 1.2.1.17 glyoxylate dehydrogenase (acylating) ec: 1.2.1.68 coniferyl-aldehyde dehydrogenase ec: 1.2.1.18 malonate-semialdehyde ec: 1.2.1.69 fluoroacetaldehyde dehydrogenase dehydrogenase (acetylating) ec: 1.2.1.71 succinylglutamate-semialdehyde 60 ec: 1.2.1.19 aminobutyraldehyde dehydrogenasd 20 dehydrogenase 49 Other exmplary enzymes and pathways are disclosed herein (see Examples). Furthermore, it is understood that enzymes can be utilized for carry out reactions for which the substrate is not the natural substrate. While the activity for the non-natural substrate may be lower than the natural 5 substrate, it is understood that such enzymes can be utilized, either as naturally occurring or modified using the directed evolution or adaptive evolution, as disclosed herein (see also Examples). BDO production through any of the pathways disclosed herein are based, in part, on the identification of the appropriate enzymes for conversion of precursors to BDO. A number of 10 specific enzymes for several of the reaction steps have been identified. For those transformations where enzymes specific to the reaction precursors have not been identified, enzyme candidates have been identified that are best suited for catalyzing the reaction steps. Enzymes have been shown to operate on a broad range of substrates, as discussed below. In addition, advances in the field of protein engineering also make it feasible to alter enzymes to act efficiently on 15 substrates, even if not a natural substrate. Described below are several examples of broad specificity enzymes from diverse classes suitable for a BDO pathway as well as methods that have been used for evolving enzymes to act on non-natural substrates. A key class of enzymes in BDO pathways is the oxidoreductases that interconvert ketones or aldehydes to alcohols (1.1.1). Numerous exemplary enzymes in this class can operate on a wide 20 range of substrates. An alcohol dehydrogenase (1.1.1.1) purified from the soil bacterium Brevibacterium sp KU 1309 (Hirano et al., J. Biosc. Bioeng. 100:318-322 (2005)) was shown to operate on a plethora of aliphatic as well as aromatic alcohols with high activities. Table 2 shows the activity of the enzyme and its Km on different alcohols. The enzyme is reversible and has very high activity on several aldehydes also (Table 3). 25 Table 2. Relative activities of an alcohol dehydrogenase from Brevibacterium sp KU to oxidize various alcohols. Substrate Relative Activity Km (0%) (mM) 2-Phenylethanol 100* 0.025 (S)-2-Phenylpropanol 156 0.157 (R)-2-Phenylpropanol 63 0.020 Bynzyl alcohol 199 0.012 3-Phenylpropanol 135 0.033 Ethanol 76 1-Butanol 111 1-Octanol 101 50 1-Dodecanol 68 1-Phenylethanol 46 2-Propanol 54 *The activity of 2-phenylethanol, corresponding to 19.2 U/mg, was taken as 100%. Table 3. Relative activities of an alcohol dehydrogenase from Brevibacterium sp KU 1309 to 5 reduce various carbonyl compounds. Substrate Relative Activity Km (%) (mM) Phenylacetaldehyde 100 0.261 2-Phenylpropionaldehyde 188 0.864 1-Octylaldehyde 87 Acetophenone 0 Lactate dehydrogenase (1.1.1.27) from Ralstonia eutropha is another enzyme that has been demonstrated to have high activities on several 2-oxoacids such as 2-oxobutyrate, 2 10 oxopentanoate and 2-oxoglutarate (a C5 compound analogous to 2-oxoadipate) (Steinbuchel and Schlegel, Eur. J. Biochem. 130:329-334 (1983)). Column 2 in Table 4 demonstrates the activities of IdhA from R. eutropha (formerly A. eutrophus) on different substrates (Steinbuchel and Schlegel, supra, 1983). Table 4. The in vitro activity of R. eutropha IdhA (Steinbuchel and Schlegel, supra, 1983) on 15 different substrates and compared with that on pyruvate. Substrate Activity (%) of L(+)-lactate L(+)-lactate D(-)-lactate dehydrogenase dehydrogenase dehydrogenase from A. from rabbit from L. eutrophus muscle leichmanii Glyoxylate 8.7 23.9 5.0 Pyruvate 100.0 100.0 100.0 2-Oxobutyrate 107.0 18.6 1.1 2-Oxovalerate 125.0 0.7 0.0 3-Methyl-2- 28.5 0.0 0.0 oxobutyrate 3-Methyl-2- 5.3 0.0 0.0 oxovalerate 4-Methyl-2- 39.0 1.4 1.1 oxopentanoate Oxaloacetate 0.0 33.1 23.1 2-Oxoglutarate 79.6 0.0 0.0 3-Fluoropyruvate 33.6 74.3 40.0 Oxidoreductases that can convert 2-oxoacids to their acyl-CoA counterparts (1.2.1) have been shown to accept multiple substrates as well. For example, branched-chain 2-keto-acid 51 dehydrogenase complex (BCKAD), also known as 2-oxoisovalerate dehydrogenase (1.2.1.25), participates in branched-chain amino acid degradation pathways, converting 2-keto acids derivatives of valine, leucine and isoleucine to their acyl-CoA derivatives and CO 2 . In some organisms including Rattus norvegicus (Paxton et al., Biochem. J. 234:295-303 (1986)) and 5 Saccharomyces cerevisiae (Sinclair et al., Biochem. Mol Biol. Int. 32:911-922 (1993), this complex has been shown to have a broad substrate range that includes linear oxo-acids such as 2-oxobutanoate and alpha-ketoglutarate, in addition to the branched-chain amino acid precursors. Members of yet another class of enzymes, namely aminotransferases (2.6.1), have been reported 10 to act on multiple substrates. Aspartate aminotransferase (aspAT) from Pyrococcusfursious has been identified, expressed in E. coli and the recombinant protein characterized to demonstrate that the enzyme has the highest activities towards aspartate and alpha-ketoglutarate but lower, yet significant activities towards alanine, glutamate and the aromatic amino acids (Ward et al., Archaea 133-141 (2002)). In another instance, an aminotransferase indentified from Leishmania 15 mexicana and expressed in E. coli (Vernal et al., FEMS Microbiol. Lett. 229:217-222 (2003)) was reported to have a broad substrate specificity towards tyrosine (activity considered 100% on tyrosine), phenylalanine (90%), tryptophan (85%), aspartate (30%), leucine (25%) and methionine (25%), respectively (Vernal et al., Mol. Biochem. Parasitol 96:83-92 (1998)). Similar broad specificity has been reported for a tyrosine aminotransferase from Trypanosoma 20 cruzi, even though both of these enzymes have a sequence homology of only 6%. The latter enzyme can accept leucine, methionine as well as tyrosine, phenylalanine, tryptophan and alanine as efficient amino donors (Nowicki et al., Biochim. Biophys. Acta 1546: 268-281 (2001)). CoA transferases (2.8.3) have been demonstrated to have the ability to act on more than one 25 substrate. Specifically, a CoA transferase was purified from Clostridium acetobutylicum and was reported to have the highest activities on acetate, propionate, and butyrate. It also had significant activities with valerate, isobutyrate, and crotonate (Wiesenborn et al., Appl. Environ. Microbiol. 55:323-329 (1989)). In another study, the E. coli enzyme acyl-CoA:acetate-CoA transferase, also known as acetate-CoA transferase (EC 2.8.3.8), has been shown to transfer the 30 CoA moiety to acetate from a variety of branched and linear acyl-CoA substrates, including isobutyrate (Matthies and Schink, App. Environm. Microbiol. 58:1435-1439 (1992)), valerate (Vanderwinkel et al., Biochem. Biophys. Res Commun. 33:902-908 (1968b)) and butanoate (Vanderwinkel et al., Biochem. Biophys. Res Commun. 33:902-908(1968a).

52 Other enzyme classes additionally support broad substrate specificity for enzymes. Some isomerases (5.3.3) have also been proven to operate on multiple substrates. For example, L rhamnose isomerase from Pseudomonas stutzeri catalyzes the isomerization between various aldoalses and ketoses (Yoshida et al., J. Mol. Biol. 365:1505-1516 (2007)). These include 5 isomerization between L-rhamnose and L-rhamnulose, L-mannose and L-fructose, L-xylose and L-xylulose, D-ribose and D-ribulose, and D-allose and D-psicose. In yet another class of enzymes, the phosphotransferases (2.7.1), the homoserine kinase (2.7.1.39) from E. coli that converts L-homoserine to L-homoserine phosphate, was found to phosphorylate numerous homoserine analogs. In these substrates, the carboxyl functional group 10 at the R-position had been replaced by an ester or by a hydroxymethyl group (Huo and Viola, Biochemistry 35:16180-16185 (1996)). Table 5 demonstrates the broad substrate specificity of this kinase. Table 5. The substrate specificity of homoserine kinase. Substrate kcat % kcat Km (mM) kcat/Km L-homoserine 18.3 0.1 100 0.14 0.04 184 17 D-homoserine 8.3 1.1 32 31.8 7.2 0.26 0.03 L-aspartate 0- 2.1 ± 0.1 8.2 0.28 0.02 7.5 0.3 semialdehyde L-2-amino-1,4- 2.0 ±0.5 7.9 11.6 6.5 0.17 0.06 butanediol L-2-amino-5- 2.5 ± 0.4 9.9 1.1 0.5 2.3 0.3 hydroxyvalerate L-homoserine methyl 14.7 ± 2.6 80 4.9 2.0 3.0 0.6 ester L-homoserine ethyl 13.6 ±0.8 74 1.9 0.5 7.2 1.7 ester L-homoserine 13.6 ± 1.4 74 1.2 0.5 11.3 1.1 isopropyl ester L-homoserine n- 14.0 ± 0.4 76 3.5 0.4 4.0 1.2 propyl ester L-homoserine isobutyl 16.4 ± 0.8 84 6.9 1.1 2.4 0.3 ester L-homserine n-butyl 29.1 ± 1.2 160 5.8 0.8 5.0 0.5 ester 15 Another class of enzymes useful in BDO pathways is the acid-thiol ligases (6.2.1). Like enzymes in other classes, certain enzymes in this class have been determined to have broad substrate specificity. For example, acyl CoA ligase from Pseudomonas putida has been 20 demonstrated to work on several aliphatic substrates including acetic, propionic, butyric, valeric, 53 hexanoic, heptanoic, and octanoic acids and on aromatic compounds such as phenylacetic and phenoxyacetic acids (Fernandez-Valverde et al., Appl. Environ. Microbiol. 59:1149-1154 (1993)). A related enzyme, malonyl CoA synthetase (6.3.4.9) from Rhizobium trifolii could convert several diacids, namely, ethyl-, propyl-, allyl-, isopropyl-, dimethyl-, cyclopropyl-, 5 cyclopropylmethylene-, cyclobutyl-, and benzyl-malonate into their corresponding monothioesters (Pohl et al., J. Am. Chem. Soc. 123:5822-5823 (2001)). Similarly, decarboxylases (4.1.1) have also been found with broad substrate ranges. Pyruvate decarboxylase (PDC), also termed keto-acid decarboxylase, is a key enzyme in alcoholic fermentation, catalyzing the decarboxylation of pyruvate to acetaldehyde. The enzyme isolated 10 from Saccharomyces cerevisiae has a broad substrate range for aliphatic 2-keto acids including 2-ketobutyrate, 2-ketovalerate, and 2-phenylpyruvate (Li and Jordan, Biochemistry 38:10004 10012 (1999)). Similarly, benzoylformate decarboxylase has a broad substrate range and has been the target of enzyme engineering studies. The enzyme from Pseudomonas putida has been extensively studied and crystal structures of this enzyme are available (Polovnikova et al., 15 Biochemistry 42:1820-1830 (2003); Hasson et al., Biochemistry 37:9918-9930 (1998)). Branched chain alpha-ketoacid decarboxylase (BCKA) has been shown to act on a variety of compounds varying in chain length from 3 to 6 carbons (Oku and Kaneda, J. Biol. Chem. 263:18386-18396 (1998); Smit et al., Appl. Environ. Microbiol. 71:303-311 (2005b)). The enzyme in Lactococcus lactis has been characterized on a variety of branched and linear 20 substrates including 2-oxobutanoate, 2-oxohexanoate, 2-oxopentanoate, 3-methyl-2 oxobutanoate, 4-methyl-2-oxobutanoate and isocaproate (Smit et al., Appl. Environ. Microbiol. 71:303-311 (2005a). Interestingly, enzymes known to have one dominant activity have also been reported to catalyze a very different function. For example, the cofactor-dependent phosphoglycerate mutase 25 (5.4.2.1) from Bacillus stearothermophilus and Bacillus subtilis is known to function as a phosphatase as well (Rigden et al., Protein Sci. 10:1835-1846 (2001)). The enzyme from B. stearothermophilus is known to have activity on several substrates, including 3 phosphoglycerate, alpha-napthylphosphate, p-nitrophenylphosphate, AMP, fructose-6 phosphate, ribose-5-phosphate and CMP. 30 In contrast to these examples where the enzymes naturally have broad substrate specificities, numerous enzymes have been modified using directed evolution to broaden their specificity towards their non-natural substrates. Alternatively, the substrate preference of an enzyme has also been changed using directed evolution. Therefore, it is feasible to engineer a given enzyme 54 for efficient function on a natural, for example, improved efficiency, or a non-natural substrate, for example, increased efficiency. For example, it has been reported that the enantioselectivity of a lipase from Pseudomonas aeruginosa was improved significantly (Reetz et al., Agnew. Chem. Int. Ed Engl. 36:2830-2832 (1997)). This enzyme hydrolyzed p-nitrophenyl 2 5 methyldecanoate with only 2% enantiomeric excess (ee) in favor of the (S)-acid. However, after four successive rounds of error-prone mutagenesis and screening, a variant was produced that catalyzed the requisite reaction with 81% ee (Reetz et al., Agnew. Chem. Int. Ed Engl. 36:2830 2832 (1997)). Directed evolution methods have been used to modify an enzyme to function on an array of non 10 natural substrates. The substrate specificity of the lipase in P. aeruginosa was broadened by randomization of amino acid residues near the active site. This allowed for the acceptance of alpha-substituted carboxylic acid esters by this enzyme (Reetz et al., Agnew. Chem. Int. Ed Engl. 44:4192-4196 (2005)). In another successful modification of an enzyme, DNA shuffling was employed to create an Escherichia coli aminotransferase that accepted p-branched 15 substrates, which were poorly accepted by the wild-type enzyme (Yano et al., Proc. Nat. Acad. Sci. U.S.A. 95:5511-5515 (1998)). Specifically, at the end of four rounds of shuffling, the activity of aspartate aminotransferase for valine and 2-oxovaline increased by up to five orders of magnitude, while decreasing the activity towards the natural substrate, aspartate, by up to 30 fold. Recently, an algorithm was used to design a retro-aldolase that could be used to catalyze 20 the carbon-carbon bond cleavage in a non-natural and non-biological substrate, 4-hydroxy-4-(6 methoxy-2-naphthyl)-2-butanone (Jiang et al., Science 319:1387-1391 (2008)). These algorithms used different combinations of four different catalytic motifs to design new enzyme, and 20 of the selected designs for experimental characterization had four-fold improved rates over the uncatalyzed reaction (Jiang et al., Science 319:1387-1391 (2008)). Thus, not only are 25 these engineering approaches capable of expanding the array of substrates on which an enzyme can act, but they allow the design and construction of very efficient enzymes. For example, a method of DNA shuffling (random chimeragenesis on transient templates or RACHITT) was reported to lead to an engineered monooxygenase that had an improved rate of desulfurization on complex substrates as well as 20-fold faster conversion of a non-natural substrate (Coco et 30 al., Nat. Biotechnol. 19:354-359 (2001)). Similarly, the specific activity of a sluggish mutant triosephosphate isomerase enzyme was improved up to 19-fold from 1.3 fold (Hermes et al., Proc. Nat. Acad. Sci. U.S.A. 87:696-700 1990)). This enhancement in specific activity was accomplished by using random mutagenesis over the whole length of the protein and the improvement could be traced back to mutations in six amino acid residues.

55 The effectiveness of protein engineering approaches to alter the substrate specificity of an enzyme for a desired substrate has also been demonstrated in several studies. Isopropylmalate dehydrogenase from Thermus thermophilus was modified by changing residues close to the active site so that it could now act on malate and D-lactate as substrates (Fujita et al., Biosci. 5 Biotechnol. Biochem. 65:2695-2700 (2001)). In this study as well as in others, it was pointed out that one or a few residues could be modified to alter the substrate specificity. For example, the dihydroflavonol 4-reductase for which a single amino acid was changed in the presumed substrate-binding region could preferentially reduce dihydrokaempferol (Johnson et al., Plant. J. 25:325-333 (2001)). The substrate specificity of a very specific isocitrate dehydrogenase from 10 Escherichia coli was changed form isocitrate to isopropylmalate by changing one residue in the active site (Doyle et al., Biochemistry 40:4234-4241 (2001)). Similarly, the cofactor specificity of a NAD*-dependent 1,5-hydroxyprostaglandin dehydrogenase was altered to NADP* by changing a few residues near the N-terminal end (Cho et al., Arch. Biochem. Biophys. 419:139 146 (2003)). Sequence analysis and molecular modeling analysis were used to identify the key 15 residues for modification, which were further studied by site-directed mutagenesis. Numerous examples exist spanning diverse classes of enzymes where the function of enzyme was changed to favor one non-natural substrate over the natural substrate of the enzyme. A fucosidase was evolved from a galactosidase in E. coli by DNA shuffling and screening (Zhang et al., Proc. Natl Acad. Sci. U.S.A. 94:4504-4509 (1997)). Similarly, aspartate aminotransferase 20 from E. coli was converted into a tyrosine aminotransferase using homology modeling and site directed mutagenesis (Onuffer and Kirsch, Protein Sci., 4:1750-1757 (1995)). Site-directed mutagenesis of two residues in the active site of benzoylformate decarboxylase from P. putida reportedly altered the affinity (Km) towards natural and non-natural substrates (Siegert et al., Protein Eng Des Sel 18:345-357 (2005)). Cytochrome c peroxidase (CCP) from Saccharomyces 25 cerevisiae was subjected to directed molecular evolution to generate mutants with increased activity against the classical peroxidase substrate guaiacol, thus changing the substrate specificity of CCP from the protein cytochrome c to a small organic molecule. After three rounds of DNA shuffling and screening, mutants were isolated which possessed a 300-fold increased activity against guaiacol and up to 1000-fold increased specificity for this substrate 30 relative to that for the natural substrate (Iffland et al., Biochemistry 39:10790-10798 (2000)). In some cases, enzymes with different substrate preferences than either of the parent enzymes have been obtained. For example, biphenyl-dioxygenase-mediated degradation of polychlorinated biphenyls was improved by shuffling genes from two bacteria, Pseudomonas 56 pseudoalcaligens and Burkholderia cepacia (Kumamaru et al., Nat. Biotechnol. 16:663-666 (1998)). The resulting chimeric biphenyl oxygenases showed different substrate preferences than both the parental enzymes and enhanced the degradation activity towards related biphenyl compounds and single aromatic ring hydrocarbons such as toluene and benzene which were 5 originally poor substrates for the enzyme. In addition to changing enzyme specificity, it is also possible to enhance the activities on substrates for which the enzymes naturally have low activities. One study demonstrated that amino acid racemase from P. putida that had broad substrate specificity (on lysine, arginine, alanine, serine, methionine, cysteine, leucine and histidine among others) but low activity 10 towards tryptophan could be improved significantly by random mutagenesis (Kino et al., Appl. Microbiol. Biotechnol. 73:1299-1305 (2007)). Similarly, the active site of the bovine BCKAD was engineered to favor alternate substrate acetyl-CoA (Meng and Chuang, Biochemistry 33:12879-12885 (1994)). An interesting aspect of these approaches is that even if random methods have been applied to generate these mutated enzymes with efficacious activities, the 15 exact mutations or structural changes that confer the improvement in activity can be identified. For example, in the aforementioned study, the mutations that facilitated improved activity on tryptophan was traced back to two different positions. Directed evolution has also been used to express proteins that are difficult to express. For example, by subjecting horseradish peroxidase to random mutagenesis and gene recombination, 20 mutants were identified that had more than 14-fold higher activity than the wild type (Lin et al., Biotechnol. Prog. 15:467-471 (1999)). Another example of directed evolution shows the extensive modifications to which an enzyme can be subjected to achieve a range of desired functions. The enzyme lactate dehydrogenase from Bacillus stearothermophilus was subjected to site-directed mutagenesis, and three amino 25 acid substitutions were made at sites that were believed to determine the specificity towards different hydroxyacids (Clarke et al., Biochem. Biophys. Res. Commun. 148:15-23 (1987)). After these mutations, the specificity for oxaloacetate over pyruvate was increased to 500 in contrast to the wild type enzyme that had a catalytic specificity for pyruvate over oxaloacetate of 1000. This enzyme was further engineered using site-directed mutagenesis to have activity 30 towards branched-chain substituted pyruvates (Wilks et al., Biochemistry 29:8587-8591 (1990)). Specifically, the enzyme had a 55-fold improvement in Kcat for alpha-ketoisocaproate. Three structural modifications were made in the same enzyme to change its substrate specificity from 57 lactate to malate. The enzyme was highly active and specific towards malate (Wilks et al., Science 242:1541-1544 (1988)). The same enzyme from B. stearothermophilus was subsequently engineered to have high catalytic activity towards alpha-keto acids with positively charged side chains, such as those containing ammonium groups (Hogan et al., Biochemistry 5 34:4225-4230 (1995)). Mutants with acidic amino acids introduced at position 102 of the enzyme favored binding of such side chain ammonium groups. The results obtained proved that the mutants showed up to 25-fold improvements in kcat/Km values for omega-amino-alpha-keto acid substrates. Interestingly, this enzyme was also structurally modified to function as a phenyllactate dehydrogenase instead of a lactate dehydrogenase (Wilks et al., Biochemistry 10 31:7802-7806 1992). Restriction sites were introduced into the gene for the enzyme which allowede a region of the gene to be excised. This region coded for a mobile surface loop of the polypeptide (residues 98-110) which normally seals the active site from bulk solvent and is a major determinant of substrate specificity. The variable length and sequence loops were inserted so that hydroxyacid dehydrogenases with altered substrate specificities were generated. With 15 one longer loop construction, activity with pyruvate was reduced one-million-fold but activity with phenylpyruvate was largely unaltered. A switch in specificity (kcat/Km) of 390,000-fold was achieved. The 1700:1 selectivity of this enzyme for phenylpyruvate over pyruvate is that required in a phenyllactate dehydrogenase. The studies described above indicate that various approaches of enzyme engineering can be used to obtain enzymes for the BDO pathways as 20 disclosed herein. As disclosed herein, biosynthetic pathways to 1,4-butanediol from a number of central metabolic intermediates are can be utilized, including acetyl-CoA, succinyl-CoA, alpha-ketoglutarate, glutamate, 4-aminobutyrate, and homoserine. Acetyl-CoA, succinyl-CoA and alpha ketoglutarate are common intermediates of the tricarboxylic acid (TCA) cycle, a series of 25 reactions that is present in its entirety in nearly all living cells that utilize oxygen for cellular respiration and is present in truncated forms in a number of anaerobic organisms. Glutamate is an amino acid that is derived from alpha-ketoglutarate via glutamate dehydrogenase or any of a number of transamination reactions (see Figure 8B). 4-aminobutyrate can be formed by the decarboxylation of glutamate (see Figure 8B) or from acetoacetyl-CoA via the pathway 30 disclosed in Figure 9C. Acetoacetyl-CoA is derived from the condensation of two acetyl-CoA molecules by way of the enzyme, acetyl-coenzyme A acetyltransferase, or equivalently, acetoacetyl-coenzyme A thiolase. Homoserine is an intermediate in threonine and methionine metabolism, formed from oxaloacetate via aspartate. The conversion of oxaloacetate to homoserine requires one NADH, two NADPH, and one ATP.

58 Pathways other than those exemplified above also can be employed to generate the biosynthesis of BDO in non-naturally occurring microbial organisms. In one embodiment, biosynthesis can be achieved using a L-homoserine to BDO pathway (see Figure 13). This pathway has a molar yield of 0.90 mol/mol glucose, which appears restricted by the availability of reducing 5 equivalents. A second pathway synthesizes BDO from acetoacetyl-CoA and is capable of achieving the maximum theoretical yield of 1.091 mol/mol glucose (see Figure 9). Implementation of either pathway can be achieved by introduction of two exogenous enzymes into a host organism such as E. coli, and both pathways can additionally complement BDO production via succinyl-CoA. Pathway enzymes, thermodynamics, theoretical yields and overall 10 feasibility are described further below. A homoserine pathway also can be engineered to generate BDO-producing microbial organisms. Homoserine is an intermediate in threonine and methionine metabolism, formed from oxaloacetate via aspartate. The conversion of oxaloacetate to homoserine requires one NADH, two NADPH, and one ATP (Figure 2). Once formed, homoserine feeds into biosynthetic 15 pathways for both threonine and methionine. In most organisms, high levels of threonine or methionine feedback to repress the homoserine biosynthesis pathway (Caspi et al., Nucleic Acids Res. 34:D511-D516 (1990)). The transformation of homoserine to 4-hydroxybutyrate (4-HB) can be accomplished in two enzymatic steps as described herein. The first step of this pathway is deamination of homoserine 20 by a putative ammonia lyase. In step 2, the product alkene, 4-hydroxybut-2-enoate is reduced to 4-HB by a putative reductase at the cost of one NADH. 4-HB can then be converted to BDO. Enzymes available for catalyzing the above transformations are disclosed herein. For example, the ammonia lyase in step 1 of the pathway closely resembles the chemistry of aspartate ammonia-lyase (aspartase). Aspartase is a widespread enzyme in microorganisms, and has been 25 characterized extensively (Viola, R.E., Mol. Biol. 74:295-341 (2008)). The crystal structure of the E. coli aspartase has been solved (Shi et al., Biochemistry 36:9136-9144 (1997)), so it is therefore possible to directly engineer mutations in the enzyme's active site that would alter its substrate specificity to include homoserine. The oxidoreductase in step 2 has chemistry similar to several well-characterized enzymes including fumarate reductase in the E. coli TCA cycle. 30 Since the thermodynamics of this reaction are highly favorable, an endogenous reductase with broad substrate specificity will likely be able to reduce 4-hydroxybut-2-enoate. The yield of this pathway under anaerobic conditions is 0.9 mol BDO per mol glucose.

59 The succinyl-CoA pathway was found to have a higher yield due to the fact that it is more energetically efficient. The conversion of one oxaloacetate molecule to BDO via the homoserine pathway will require the expenditure of 2 ATP equivalents. Because the conversion of glucose to two oxaloacetate molecules can generate a maximum of 3 ATP molecules assuming PEP 5 carboxykinase to be reversible, the overall conversion of glucose to BDO via homoserine has a negative energetic yield. As expected, if it is assumed that energy can be generated via respiration, the maximum yield of the homoserine pathway increases to 1.05 mol/mol glucose which is 96% of the succinyl-CoA pathway yield. The succinyl-CoA pathway can channel some of the carbon flux through pyruvate dehydrogenase and the oxidative branch of the TCA cycle to 10 generate both reducing equivalents and succinyl-CoA without an energetic expenditure. Thus, it does not encounter the same energetic difficulties as the homoserine pathway because not all of the flux is channeled through oxaloacetate to succinyl-CoA to BDO. Overall, the homoserine pathway demonstrates a high-yielding route to BDO. An acetoacetate pathway also can be engineered to generate BDO-producing microbial 15 organisms. Acetoacetate can be formed from acetyl-CoA by enzymes involved in fatty acid metabolism, including acetyl-CoA acetyltransferase and acetoacetyl-CoA transferase. Biosynthetic routes through acetoacetate are also particularly useful in microbial organisms that can metabolize single carbon compounds such as carbon monoxide, carbon dioxide or methanol to form acetyl-CoA. 20 A three step route from acetoacetyl-CoA to 4-aminobutyrate (see Figure 9C) can be used to synthesize BDO through acetoacetyl-CoA. 4-Aminobutyrate can be converted to succinic semialdehyde as shown in Figure 8B. Succinic semialdehyde, which is one reduction step removed from succinyl-CoA or one decarboxylation step removed from a-ketoglutarate, can be converted to BDO following three reductions steps (Figure 1). Briefly, step 1 of this pathway 25 involves the conversion of acetoacetyl-CoA to acetoacetate by, for example, the E. coli acetoacetyl-CoA transferase encoded by the atoA and atoD genes (Hanai et al., Appl. Environ. Microbiol. 73: 7814-7818 (2007)). Step 2 of the acetoacetyl-CoA biopathway entails conversion of acetoacetate to 3-aminobutanoate by an o-aminotransferase. The o-amino acid:pyruvate aminotransferase (o-APT) from Alcaligens denitrificans was overexpressed in E. 30 coli and shown to have a high activity toward 3-aminobutanoate in vitro (Yun et al., Appl. Environ. Microbiol. 70:2529-2534 (2004)).

60 In step 2, a putative aminomutase shifts the amine group from the 3- to the 4- position of the carbon backbone. An aminomutase performing this function on 3-aminobutanoate has not been characterized, but an enzyme from Clostridium sticklandii has a very similar mechanism. The enzyme, D-lysine-5,6-aminomutase, is involved in lysine biosynthesis. 5 The synthetic route to BDO from acetoacetyl-CoA passes through 4-aminobutanoate, a metabolite in E. coli that is normally formed from decarboxylation of glutamate. Once formed, 4-aminobutanoate can be converted to succinic semialdehyde by 4-aminobutanoate transaminase (2.6.1.19), an enzyme which has been biochemically characterized. One consideration for selecting candidate enzymes in this pathway is the stereoselectivity of the 10 enzymes involved in steps 2 and 3. The o-ABT in Alcaligens denitrificans is specific to the L stereoisomer of 3-aminobutanoate, while D-lysine-5,6-aminomutase likely requires the D stereoisomer. If enzymes with complementary stereoselectivity are not initially found or engineered, a third enzyme can be added to the pathway with racemase activity that can convert L-3-aminobutanoate to D-3-aminobutanoate. While amino acid racemases are widespread, 15 whether these enzymes can function on o-amino acids is not known. The maximum theoretical molar yield of this pathway under anaerobic conditions is 1.091 mol/mol glucose. In order to generate flux from acetoacetyl-CoA to BDO it was necessary to assume that acetyl-CoA:acetoacetyl-CoA transferase is reversible. The function of this enzyme in E. coli is to metabolize short-chain fatty acids by first converting them into thioesters. 20 While the operation of acetyl-CoA:acetoacetyl-CoA transferase in the acetate-consuming direction has not been demonstrated experimentally in E. coli, studies on similar enzymes in other organisms support the assumption that this reaction is reversible. The enzyme butyryl CoA:acetate:CoA transferase in gut microbes Roseburia sp. and F. prasnitzii operates in the acetate utilizing direction to produce butyrate (Duncan et al., Appl. Environ. Microbiol 68:5186 25 5190 (2002)). Another very similar enzyme, acetyl:succinate CoA-transferase in Trypanosoma brucei, also operates in the acetate utilizing direction. This reaction has a A,,G close to equilibrium, so high concentrations of acetate can likely drive the reaction in the direction of interest. At the maximum theoretical BDO production rate of 1.09 mol/mol glucose simulations predict that E. coli can generate 1.098 mol ATP per mol glucose with no fermentation 30 byproducts. This ATP yield should be sufficient for cell growth, maintenance, and production. The acetoacetatyl-CoA biopathway is a high-yielding route to BDO from acetyl-CoA.

61 Therefore, in addition to any of the various modifications exemplified previously for establishing 4-HB biosynthesis in a selected host, the BDO producing microbial organisms can include any of the previous combinations and permutations of 4-HB pathway metabolic modifications as well as any combination of expression for CoA-independent aldehyde 5 dehydrogenase, CoA-dependent aldehyde dehydrogenase or an alcohol dehydrogenase or other enzymes disclosed herein to generate biosynthetic pathways for GBL and/or BDO. Therefore, the BDO producers of the invention can have exogenous expression of, for example, one, two, three, four, five, six, seven, eight, nine, or up to all enzymes corresponding to any of the 4-HB pathway and/or any of the BDO pathway enzymes disclosed herein. 10 Design and construction of the genetically modified microbial organisms is carried out using methods well known in the art to achieve sufficient amounts of expression to produce BDO. In particular, the non-naturally occurring microbial organisms of the invention can achieve biosynthesis of BDO resulting in intracellular concentrations between about 0.1-200 mM or more, such as about 0.1-25 mM or more, as discussed above. For example, the intracellular 15 concentration of BDO is between about 3-20mM, particularly between about 5-15 mM and more particularly between about 8-12 mM, including about 10 mM or more. Intracellular concentrations between and above each of these exemplary ranges also can be achieved from the non-naturally occurring microbial organisms of the invention. As with the 4-HB producers, the BDO producers also can be sustained, cultured or fermented under anaerobic conditions. 20 The invention further provides a method for the production of 4-HB. The method includes culturing a non-naturally occurring microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway comprising at least one exogenous nucleic acid encoding 4 hydroxybutanoate dehydrogenase, CoA-independent succinic semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, 25 glutamate:succinic semialdehyde transaminase, a-ketoglutarate decarboxylase, or glutamate decarboxylase under substantially anaerobic conditions for a sufficient period of time to produce monomeric 4-hydroxybutanoic acid (4-HB). The method can additionally include chemical conversion of 4-HB to GBL and to BDO or THF, for example. Additionally provided is a method for the production of 4-HB. The method includes culturing a 30 non-naturally occurring microbial organism having a 4-hydroxybutanoic acid (4-HB) biosynthetic pathway including at least one exogenous nucleic acid encoding 4 hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic 62 semialdehyde dehydrogenase or a-ketoglutarate decarboxylase under substantially anaerobic conditions for a sufficient period of time to produce monomeric 4-hydroxybutanoic acid (4-HB). The 4-HB product can be secreted into the culture medium. Further provided is a method for the production of BDO. The method includes culturing a non 5 naturally occurring microbial biocatalyst or microbial organism, comprising a microbial organism having 4-hydroxybutanoic acid (4-HB) and 1,4-butanediol (BDO) biosynthetic pathways, the pathways including at least one exogenous nucleic acid encoding 4 hydroxybutanoate dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, 4-hydroxybutyrate:CoA transferase, 4-hydroxybutyrate kinase, 10 phosphotranshydroxybutyrylase, a-ketoglutarate decarboxylase, aldehyde dehydrogenase, alcohol dehydrogenase or an aldehyde/alcohol dehydrogenase for a sufficient period of time to produce 1,4-butanediol (BDO). The BDO product can be secreted into the culture medium. Additionally provided are methods for producing BDO by culturing a non-naturally occurring microbial organism having a BDO pathway of the invention. The BDO pathway can comprise 15 at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO pathway comprising 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl-CoA oxidoreductase (deaminating), 4 aminobutyryl-CoA transaminase, or 4-hydroxybutyryl-CoA dehydrogenase (see Example VII 20 and Table 17). Alternatively, the BDO pathway can compre at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO pathway comprising 4-aminobutyrate CoA transferase, 4-aminobutyryl-CoA hydrolase, 4-aminobutyrate-CoA ligase, 4-aminobutyryl 25 CoA reductase (alcohol forming), 4-aminobutyryl-CoA reductase, 4-aminobutan-1-ol dehydrogenase, 4-aminobutan- 1-ol oxidoreductase (deaminating) or 4-aminobutan- 1-ol transaminase (see Example VII and Table 18). In addition, the invention provides a method for producing BDO, comprising culturing a non naturally occurring microbial organism having a BDO pathway, the pathway comprising at least 30 one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO pathway comprising 4-aminobutyrate kinase, 4-aminobutyraldehyde dehydrogenase 63 (phosphorylating), 4-aminobutan- 1 -ol dehydrogenase, 4-aminobutan- 1 -ol oxidoreductase (deaminating), 4-aminobutan- 1 -ol transaminase, [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase (deaminating), [(4-aminobutanolyl)oxy]phosphonic acid transaminase, 4 hydroxybutyryl-phosphate dehydrogenase, or 4-hydroxybutyraldehyde dehydrogenase 5 (phosphorylating) (see Example VII and Table 19). The invention further provides a method for producing BDO, comprising culturing a non naturally occurring microbial organism having a BDO pathway, the pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO 10 pathway comprising alpha-ketoglutarate 5-kinase, 2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating), 2,5-dioxopentanoic acid reductase, alpha-ketoglutarate CoA transferase, alpha-ketoglutaryl-CoA hydrolase, alpha-ketoglutaryl-CoA ligase, alpha ketoglutaryl-CoA reductase, 5-hydroxy-2-oxopentanoic acid dehydrogenase, alpha-ketoglutaryl CoA reductase (alcohol forming), 5-hydroxy-2-oxopentanoic acid decarboxylase, or 5-hydroxy 15 2-oxopentanoic acid dehydrogenase (decarboxylation)(see Example VIII and Table 20). The invention additionally provides a method for producing BDO, comprising culturing a non naturally occurring microbial organism having a BDO pathway, the pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO 20 pathway comprising glutamate CoA transferase, glutamyl-CoA hydrolase, glutamyl-CoA ligase, glutamate 5-kinase, glutamate-5-semialdehyde dehydrogenase (phosphorylating), glutamyl-CoA reductase, glutamate-5-semialdehyde reductase, glutamyl-CoA reductase (alcohol forming), 2 amino-5-hydroxypentanoic acid oxidoreductase (deaminating), 2-amino-5-hydroxypentanoic acid transaminase, 5-hydroxy-2-oxopentanoic acid decarboxylase, 5-hydroxy-2-oxopentanoic 25 acid dehydrogenase (decarboxylation)(see Example IX and Table 21). The invention additionally includes a method for producing BDO, comprising culturing a non naturally occurring microbial organism having a BDO pathway, the pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO 30 pathway comprising 3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxybutyryl-CoA dehydratase, vinylacetyl-CoA A-isomerase, or 4-hydroxybutyryl-CoA dehydratase (see Example X and Table 22).

64 Also provided is a method for producing BDO, comprising culturing a non-naturally occurring microbial organism having a BDO pathway, the pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO pathway 5 comprising homoserine deaminase, homoserine CoA transferase, homoserine-CoA hydrolase, homoserine-CoA ligase, homoserine-CoA deaminase, 4-hydroxybut-2-enoyl-CoA transferase, 4 hydroxybut-2-enoyl-CoA hydrolase, 4-hydroxybut-2-enoyl-CoA ligase, 4-hydroxybut-2-enoate reductase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyryl-CoA hydrolase, 4 hydroxybutyryl-CoA ligase, or 4-hydroxybut-2-enoyl-CoA reductase (see Example XI and 10 Table 23). The invention additionally provides a method for producing BDO, comprising culturing a non naturally occurring microbial organism having a BDO pathway, the pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO 15 pathway comprising succinyl-CoA reductase (alcohol forming), 4-hydroxybutyryl-CoA hydrolase, 4-hydroxybutyryl-CoA ligase, 4-hydroxybutanal dehydrogenase (phosphorylating). Such a BDO pathway can further comprise succinyl-CoA reductase, 4-hydroxybutyrate dehydrogenase, 4-hydroxybutyryl-CoA transferase, 4-hydroxybutyrate kinase, phosphotrans-4 hydroxybutyrylase, 4-hydroxybutyryl-CoA reductase, 4-hydroxybutyryl-CoA reductase (alcohol 20 forming), or 1,4-butanediol dehydrogenase. Also provided is a method for producing BDO, comprising culturing a non-naturally occurring microbial organism having a BDO pathway, the pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO, under conditions and for a sufficient period of time to produce BDO, the BDO pathway 25 comprising glutamate dehydrogenase, 4-aminobutyrate oxidoreductase (deaminating), 4 aminobutyrate transaminase, glutamate decarboxylase, 4-hydroxybutyryl-CoA hydrolase, 4 hydroxybutyryl-CoA ligase, 4-hydroxybutanal dehydrogenase (phosphorylating). The invention additionally provides methods of producing a desired product using the genetically modified organisms disclosed herein that allow improved production of a desired 30 product such as BDO by increasing the product or decreasing undesirable byproducts. Thus, the invention provides a method for producing 1,4-butanediol (BDO), comprising culturing the non naturally occurring microbial organisms disclosed herein under conditions and for a sufficient 65 period of time to produce BDO. In one embodiment, the invention provides a method of producing BDO using a non-naturally occurring microbial organism, comprising a microbial organism having a 1,4-butanediol (BDO) pathway comprising at least one exogenous nucleic acid encoding a BDO pathway enzyme expressed in a sufficient amount to produce BDO. In 5 one embodiment, the microbial organism is genetically modified to express exogenous succinyl CoA synthetase (see Example XII). For example, the succinyl-CoA synthetase can be encoded by an Escherichia coli sucCD genes. In another embodiment, the microbial organism is genetically modified to express exogenous alpha-ketoglutarate decarboxylase (see Example XIII). For example, the alpha-ketoglutarate 10 decarboxylase can be encoded by the Mycobacterium bovis sucA gene. In still another embodiment, the microbial organism is genetically modified to express exogenous succinate semialdehyde dehydrogenase and 4-hydroxybutyrate dehydrogenase and optionally 4 hydroxybutyryl-CoA/acetyl-CoA transferase (see Example XIII). For example, the succinate semialdehyde dehydrogenase (CoA-dependent), 4-hydroxybutyrate dehydrogenase and 4 15 hydroxybutyryl-CoA/acetyl-CoA transferase can be encoded by Porphyromonas gingivalis W83 genes. In an additional embodiment, the microbial organism is genetically modified to express exogenous butyrate kinase and phosphotransbutyrylase (see Example XIII). For example, the butyrate kinase and phosphotransbutyrylase can be encoded by Clostridium acetobutilicum buk1 and ptb genes. 20 In yet another embodiment, the microbial organism is genetically modified to express exogenous 4-hydroxybutyryl-CoA reductase (see Example XIII). For example, the 4-hydroxybutyryl-CoA reductase can be encoded by Clostridium beijerinckii ald gene. Additionally, in an embodiment of the invention, the microbial organism is genetically modified to express exogenous 4 hydroxybutanal reductase (see Example XIII). For example, the 4-hydroxybutanal reductase can 25 be encoded by Geobacillus the rmoglucosidasius adhi gene. In another embodiment, the microbial organism is genetically modified to express exogenous pyruvate dehydrogenase subunits (see Example XIV). For example, the exogenous pyruvate dehydrogenase can be NADH insensitive. The pyruvate dehydrogenase subunit can be encoded by the Klebsiella pneumonia lpdA gene. In a particular embodiment, the pyruvate dehydrogenase subunit genes 30 of the microbial organism can be under the control of a pyruvate formate lyase promoter. In still another embodiment, the microbial organism is genetically modified to disrupt a gene encoding an aerobic respiratory control regulatory system (see Example XV). For example, the 66 disruption can be of the arcA gene. Such an organism can further comprise disruption of a gene encoding malate dehydrogenase. In a further embodiment, the microbial organism is genetically modified to express an exogenous NADH insensitive citrate synthase(see Example XV). For example, the NADH insensitive citrate synthase can be encoded by gitA, such as an R163L 5 mutant of gitA. In still another embodiment, the microbial organism is genetically modified to express exogenous phosphoenolpyruvate carboxykinase (see Example XVI). For example, the phosphoenolpyruvate carboxykinase can be encoded by an Haemophilus influenza phosphoenolpyruvate carboxykinase gene. It is understood that strains exemplified herein for improved production of BDO can similarly be used, with appropriate modifications, to produce 10 other desired products, for example, 4-hydroxybutyrate or other desired products disclosed herein. The invention additionally provides a method for producing 4-hydroxybutanal by culturing a non-naturally occurring microbial organism, comprising a 4-hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4-hydroxybutanal pathway enzyme 15 expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising succinyl-CoA reductase (aldehyde forming); 4-hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase (see Figure 58, steps A-C-D). The invention also provides a method for producing 4-hydroxybutanal by culturing a non-naturally occurring microbial organism, comprising a 4-hydroxybutanal pathway comprising at least one exogenous nucleic 20 acid encoding a 4-hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising alpha-ketoglutarate decarboxylase; 4-hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase (Figure 58, steps B-C-D). The invention further provides a method for producing 4-hydroxybutanal by culturing a non naturally occurring microbial organism, comprising a 4-hydroxybutanal pathway comprising at 25 least one exogenous nucleic acid encoding a 4-hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising succinate reductase; 4-hydroxybutyrate dehydrogenase, and 4-hydroxybutyrate reductase (see Figure 62, steps F-C-D). In yet another embodiment, the invention provides a method for producing 4-hydroxybutanal by culturing a non-naturally occurring microbial organism, 30 comprising a 4-hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4-hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4 hydroxybutanal, the 4-hydroxybutanal pathway comprising alpha-ketoglutarate decarboxylase, or glutamate dehydrogenase or glutamate transaminase and glutamate decarboxylase and 4- 67 aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase (see Figure 62, steps B or ((J or K)-L-(M or N))-C-D). The invention also provides a method for producing 4-hydroxybutanal by culturing a non 5 naturally occurring microbial organism, comprising a 4-hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4-hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, the 4-hydroxybutanal pathway comprising alpha-ketoglutarate reductase; 5-hydroxy-2-oxopentanoate dehydrogenase; and 5-hydroxy-2 oxopentanoate decarboxylase (see Figure 62, steps X-Y-Z). The invention furthur provides a 10 method for producing 4-hydroxybutyryl-CoA by culturing a non-naturally occurring microbial organism, comprising a 4-hydroxybutyryl-CoA pathway comprising at least one exogenous nucleic acid encoding a 4-hydroxybutyryl-CoA pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutyryl-CoA, the 4-hydroxybutyryl-CoA pathway comprising alpha-ketoglutarate reductase; 5-hydroxy-2-oxopentanoate dehydrogenase; and 5-hydroxy-2 15 oxopentanoate dehydrogenase (decarboxylation) (see Figure 62, steps X-Y-AA). The invention additionally provides a method for producing putrescine by culturing a non naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising succinate reductase; 4 20 aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase (see Figure 63, steps F-M/N-C-D/E). In still another embodiment, the invention provides a method for producing putrescine by culturing a non-naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a 25 sufficient amount to produce putrescine, the putrescine pathway comprising alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4 aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase (see Figure 63, steps B-M/N-C-D/E). The invention additionally provides a method for producing putrescine by culturing a non-naturally occurring microbial organism, comprising a putrescine 30 pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising glutamate dehydrogenase or glutamate transaminase; glutamate decarboxylase; 4-aminobutyrate 68 reductase; and putrescine dehydrogenase or putrescine transaminase (see Figure 63, steps J/K-L C-D/E). The invention provides in another embodiment a method for producing putrescine by culturing a non-naturally occurring microbial organism, comprising a putrescine pathway comprising at 5 least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate transaminase; 5-amino-2-oxopentanoate decarboxylase; and putrescine dehydrogenase or putrescine transaminase (see Figure 63, steps O-P/Q-R-D/E). Also provided is a method for producing 10 putrescine by culturing a non-naturally occurring microbial organism, comprising a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, the putrescine pathway comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate dehydrogenase or 5-amino-2 oxopentanoate transaminase; ornithine dehydrogenase or ornithine transaminase; and ornithine 15 decarboxylase (see Figure 63, steps O-P/Q-S/T-U). It is understood that a microbial organism comprising any of the pathways disclosed herein can be used to produce a a desired product or intermediate, including 4-HB, 4-HBal, BDO or putrescine. It is understood that, in methods of the invention, any of the one or more exogenous nucleic acids can be introduced into a microbial organism to produce a non-naturally occurring 20 microbial organism of the invention. The nucleic acids can be introduced so as to confer, for example, a 4-HB, BDO, THF or GBL biosynthetic pathway onto the microbial organism. Alternatively, encoding nucleic acids can be introduced to produce an intermediate microbial organism having the biosynthetic capability to catalyze some of the required reactions to confer 4-HB, BDO, THF or GBL biosynthetic capability. For example, a non-naturally occurring 25 microbial organism having a 4-HB biosynthetic pathway can comprise at least two exogenous nucleic acids encoding desired enzymes, such as the combination of 4-hydroxybutanoate dehydrogenase and a-ketoglutarate decarboxylase; 4-hydroxybutanoate dehydrogenase and CoA-independent succinic semialdehyde dehydrogenase; 4-hydroxybutanoate dehydrogenase and CoA-dependent succinic semialdehyde dehydrogenase; CoA-dependent succinic 30 semialdehyde dehydrogenase and succinyl-CoA synthetase; succinyl-CoA synthetase and glutamate decarboxylase, and the like. Thus, it is understood that any combination of two or more enzymes of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention. Similarly, it is understood that any combination of three or more 69 enzymes of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention, for example, 4-hydroxybutanoate dehydrogenase, a-ketoglutarate decarboxylase and CoA-dependent succinic semialdehyde dehydrogenase; CoA-independent succinic semialdehyde dehydrogenase and succinyl-CoA synthetase; 4-hydroxybutanoate 5 dehydrogenase, CoA-dependent succinic semialdehyde dehydrogenase and glutamate:succinic semialdehyde transaminase, and so forth, as desired, so long as the combination of enzymes of the desired biosynthetic pathway results in production of the corresponding desired product. Similarly, for example, with respect to any one or more exogenous nucleic acids introduced to confer BDO production, a non-naturally occurring microbial organism having a BDO 10 biosynthetic pathway can comprise at least two exogenous nucleic acids encoding desired enzymes, such as the combination of 4-hydroxybutanoate dehydrogenase and a-ketoglutarate decarboxylase; 4-hydroxybutanoate dehydrogenase and 4-hydroxybutyryl CoA:acetyl-CoA transferase; 4-hydroxybutanoate dehydrogenase and butyrate kinase; 4-hydroxybutanoate dehydrogenase and phosphotransbutyrylase; 4-hydroxybutyryl CoA:acetyl-CoA transferase and 15 aldehyde dehydrogenase; 4-hydroxybutyryl CoA:acetyl-CoA transferase and alcohol dehydrogenase; 4-hydroxybutyryl CoA:acetyl-CoA transferase and an aldehyde/alcohol dehydrogenase, 4-aminobutyrate-CoA transferase and 4-aminobutyryl-CoA transaminase; 4 aminobutyrate kinase and 4-aminobutan-1-ol oxidoreductase (deaminating), and the like. Thus, it is understood that any combination of two or more enzymes of a biosynthetic pathway can be 20 included in a non-naturally occurring microbial organism of the invention. Similarly, it is understood that any combination of three or more enzymes of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention, for example, 4 hydroxybutanoate dehydrogenase, a-ketoglutarate decarboxylase and 4-hydroxybutyryl CoA:acetyl-CoA transferase; 4-hydroxybutanoate dehydrogenase, butyrate kinase and 25 phosphotransbutyrylase; 4-hydroxybutanoate dehydrogenase, 4-hydroxybutyryl CoA:acetyl CoA transferase and aldehyde dehydrogenase; 4-hydroxybutyryl CoA:acetyl-CoA transferase, aldehyde dehydrogenase and alcohol dehydrogenase; butyrate kinase, phosphotransbutyrylase and an aldehyde/alcohol dehydrogenase; 4-aminobutyryl-CoA hydrolase, 4-aminobutyryl-CoA reductase and 4-amino butan-1-ol transaminase; 3-hydroxybutyryl-CoA dehydrogenase, 3 30 hydroxybutyryl-CoA dehydratase and 4-hydroxybutyryl-CoA dehydratase, and the like. Similarly, any combination of four, five or more enzymes of a biosynthetic pathway as disclosed herein can be included in a non-naturally occurring microbial organism of the invention, as desired, so long as the combination of enzymes of the desired biosynthetic pathway results in production of the corresponding desired product.

70 Any of the non-naturally occurring microbial organisms described herein can be cultured to produce and/or secrete the biosynthetic products of the invention. For example, the 4-HB producers can be cultured for the biosynthetic production of 4-HB. The 4-HB can be isolated or be treated as described below to generate GBL, THF and/or BDO. Similarly, the BDO 5 producers can be cultured for the biosynthetic production of BDO. The BDO can be isolated or subjected to further treatments for the chemical synthesis of BDO family compounds, as disclosed herein. The growth medium can include, for example, any carbohydrate source which can supply a source of carbon to the non-naturally occurring microorganism. Such sources include, for 10 example, sugars such as glucose, sucrose, xylose, arabinose, galactose, mannose, fructose and starch. Other sources of carbohydrate include, for example, renewable feedstocks and biomass. Exemplary types of biomasses that can be used as feedstocks in the methods of the invention include cellulosic biomass, hemicellulosic biomass and lignin feedstocks or portions of feedstocks. Such biomass feedstocks contain, for example, carbohydrate substrates useful as 15 carbon sources such as glucose, sucrose, xylose, arabinose, galactose, mannose, fructose and starch. Given the teachings and guidance provided herein, those skilled in the art will understand that renewable feedstocks and biomass other than those exemplified above also can be used for culturing the microbial organisms of the invention for the production of 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine and other compounds of the invention. 20 Accordingly, given the teachings and guidance provided herein, those skilled in the art will understand that a non-naturally occurring microbial organism can be produced that secretes the biosynthesized compounds of the invention when grown on a carbon source such as a carbohydrate. Such compounds include, for example, 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine and any of the intermediates metabolites in the 4-HB, 4-HBal, 4-HBCoA, BDO or 25 putrescine pathways and/or the combined 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathways. All that is required is to engineer in one or more of the enzyme activities shown in Figure to achieve biosynthesis of the desired compound or intermediate including, for example, inclusion of some or all of the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathways. Accordingly, the invention provides a non-naturally occurring microbial organism 30 that secretes 4-HB when grown on a carbohydrate, secretes BDO when grown on a carbohydrate and/or secretes any of the intermediate metabolites shown in Figures 1, 8-13, 58, 62 or 63 when grown on a carbohydrate. A BDO producing microbial organisms of the invention can initiate synthesis from, for example, succinate, succinyl-CoA, a-ketogluterate, succinic semialdehyde, 71 4-HB, 4-hydroxybutyrylphosphate, 4-hydroxybutyryl-CoA (4-HB-CoA) and/or 4 hydroxybutyraldehyde. In some embodiments, culture conditions include anaerobic or substantially anaerobic growth or maintenance conditions. Exemplary anaerobic conditions have been described previously and 5 are well known in the art. Exemplary anaerobic conditions for fermentation processes are described below in the Examples. Any of these conditions can be employed with the non naturally occurring microbial organisms as well as other anaerobic conditions well known in the art. Under such anaerobic conditions, the 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine producers can synthesize monomeric 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine, 10 respectively, at intracellular concentrations of 5-10 mM or more as well as all other concentrations exemplified previously. A number of downstream compounds also can be generated for the 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine producing non-naturally occurring microbial organisms of the invention. With respect to the 4-HB producing microbial organisms of the invention, monomeric 4-HB and 15 GBL exist in equilibrium in the culture medium. The conversion of 4-HB to GBL can be efficiently accomplished by, for example, culturing the microbial organisms in acid pH medium. A pH less than or equal to 7.5, in particular at or below pH 5.5, spontaneously converts 4-HB to GBL. The resultant GBL can be separated from 4-HB and other components in the culture using a 20 variety of methods well known in the art. Such separation methods include, for example, the extraction procedures exemplified in the Examples as well as methods which include continuous liquid-liquid extraction, pervaporation, membrane filtration, membrane separation, reverse osmosis, electrodialysis, distillation, crystallization, centrifugation, extractive filtration, ion exchange chromatography, size exclusion chromatography, adsorption chromatography, and 25 ultrafiltration. All of the above methods are well known in the art. Separated GBL can be further purified by, for example, distillation. Another down stream compound that can be produced from the 4-HB producing non-naturally occurring microbial organisms of the invention includes, for example, BDO. This compound can be synthesized by, for example, chemical hydrogenation of GBL. Chemical hydrogenation 30 reactions are well known in the art. One exemplary procedure includes the chemical reduction of 4-HB and/or GBL or a mixture of these two components deriving from the culture using a 72 heterogeneous or homogeneous hydrogenation catalyst together with hydrogen, or a hydride based reducing agent used stoichiometrically or catalytically, to produce 1,4-butanediol. Other procedures well known in the art are equally applicable for the above chemical reaction and include, for example, WO No. 82/03854 (Bradley, et al.), which describes the 5 hydrogenolysis of gamma-butyrolactone in the vapor phase over a copper oxide and zinc oxide catalyst. British Pat. No. 1,230,276, which describes the hydrogenation of gamma-butyrolactone using a copper oxide-chromium oxide catalyst. The hydrogenation is carried out in the liquid phase. Batch reactions also are exemplified having high total reactor pressures. Reactant and product partial pressures in the reactors are well above the respective dew points. British Pat. 10 No. 1,314,126, which describes the hydrogenation of gamma-butyrolactone in the liquid phase over a nickel-cobalt-thorium oxide catalyst. Batch reactions are exemplified as having high total pressures and component partial pressures well above respective component dew points. British Pat. No. 1,344,557, which describes the hydrogenation of gamma-butyrolactone in the liquid phase over a copper oxide-chromium oxide catalyst. A vapor phase or vapor-containing mixed 15 phase is indicated as suitable in some instances. A continuous flow tubular reactor is exemplified using high total reactor pressures. British Pat. No. 1,512,751, which describes the hydrogenation of gamma-butyrolactone to 1,4-butanediol in the liquid phase over a copper oxide-chromium oxide catalyst. Batch reactions are exemplified with high total reactor pressures and, where determinable, reactant and product partial pressures well above the 20 respective dew points. U.S. Pat. No. 4,301,077, which describes the hydrogenation to 1,4 butanediol of gamma-butyrolactone over a Ru-Ni-Co-Zn catalyst. The reaction can be conducted in the liquid or gas phase or in a mixed liquid-gas phase. Exemplified are continuous flow liquid phase reactions at high total reactor pressures and relatively low reactor productivities. U.S. Pat. No. 4,048,196, which describes the production of 1,4-butanediol by the 25 liquid phase hydrogenation of gamma-butyrolactone over a copper oxide-zinc oxide catalyst. Further exemplified is a continuous flow tubular reactor operating at high total reactor pressures and high reactant and product partial pressures. And U.S. Patent No. 4,652,685, which describes the hydrogenation of lactones to glycols. A further downstream compound that can be produced form the 4-HB producing microbial 30 organisms of the invention includes, for example, THF. This compound can be synthesized by, for example, chemical hydrogenation of GBL. One exemplary procedure well known in the art applicable for the conversion of GBL to THF includes, for example, chemical reduction of 4-HB and/or GBL or a mixture of these two components deriving from the culture using a 73 heterogeneous or homogeneous hydrogenation catalyst together with hydrogen, or a hydride based reducing agent used stoichiometrically or catalytically, to produce tetrahydrofuran. Other procedures well know in the art are equally applicable for the above chemical reaction and include, for example, U.S. Patent No. 6,686,310, which describes high surface area sol-gel route 5 prepared hydrogenation catalysts. Processes for the reduction of maleic acid to tetrahydrofuran (THF) and 1,4-butanediol (BDO) and for the reduction of gamma butyrolactone to tetrahydrofuran and 1,4-butanediol also are described. The culture conditions can include, for example, liquid culture procedures as well as fermentation and other large scale culture procedures. As described further below in the 10 Examples, particularly useful yields of the biosynthetic products of the invention can be obtained under anaerobic or substantially anaerobic culture conditions. Suitable purification and/or assays to test for the production of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine can be performed using well known methods. Suitable replicates such as triplicate cultures can be grown for each engineered strain to be tested. For example, product and 15 byproduct formation in the engineered production host can be monitored. The final product and intermediates, and other organic compounds, can be analyzed by methods such as HPLC (High Performance Liquid Chromatography), GC-MS (Gas Chromatography-Mass Spectroscopy) and LC-MS (Liquid Chromatography-Mass Spectroscopy) or other suitable analytical methods using routine procedures well known in the art. The release of product in the fermentation broth can 20 also be tested with the culture supernatant. Byproducts and residual glucose can be quantified by HPLC using, for example, a refractive index detector for glucose and alcohols, and a UV detector for organic acids (Lin et al., Biotechnol. Bioeng. 90:775-779 (2005)), or other suitable assay and detection methods well known in the art. The individual enzyme or protein activities from the exogenous DNA sequences can also be assayed using methods well known in the art. 25 The 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine product can be separated from other components in the culture using a variety of methods well known in the art. Such separation methods include, for example, extraction procedures as well as methods that include continuous liquid-liquid extraction, pervaporation, membrane filtration, membrane separation, reverse osmosis, electrodialysis, distillation, crystallization, centrifugation, extractive filtration, ion 30 exchange chromatography, size exclusion chromatography, adsorption chromatography, and ultrafiltration. All of the above methods are well known in the art.

74 The invention further provides a method of manufacturing 4-HB. The method includes fermenting a non-naturally occurring microbial organism having a 4-hydroxybutanoic acid (4 HB) biosynthetic pathway comprising at least one exogenous nucleic acid encoding 4 hydroxybutanoate dehydrogenase, CoA-independent succinic semialdehyde dehydrogenase, 5 succinyl-CoA synthetase, CoA-dependent succinic semialdehyde dehydrogenase, glutamate:succinic semialdehyde transaminase, a-ketoglutarate decarboxylase, or glutamate decarboxylase under substantially anaerobic conditions for a sufficient period of time to produce monomeric 4-hydroxybutanoic acid (4-HB), the process comprising fed-batch fermentation and batch separation; fed-batch fermentation and continuous separation, or continuous fermentation 10 and continuous separation. The culture and chemical hydrogenations described above also can be scaled up and grown continuously for manufacturing of 4-HB, 4-HlBal, 4-HBCoA, GBL, BDO and/or THF or putrescine. Exemplary growth procedures include, for example, fed-batch fermentation and batch separation; fed-batch fermentation and continuous separation, or continuous fermentation 15 and continuous separation. All of these processes are well known in the art. Employing the 4 HB producers allows for simultaneous 4-HB biosynthesis and chemical conversion to GBL, BDO and/or THF by employing the above hydrogenation procedures simultaneous with continuous cultures methods such as fermentation. Other hydrogenation procedures also are well known in the art and can be equally applied to the methods of the invention. 20 Fermentation procedures are particularly useful for the biosynthetic production of commercial quantities of 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine. Generally, and as with non continuous culture procedures, the continuous and/or near-continuous production of 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine will include culturing a non-naturally occurring 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine producing organism of the invention in sufficient nutrients 25 and medium to sustain and/or nearly sustain growth in an exponential phase. Continuous culture under such conditions can be include, for example, 1 day, 2, 3, 4, 5, 6 or 7 days or more. Additionally, continuous culture can include 1 week, 2, 3, 4 or 5 or more weeks and up to several months. Alternatively, organisms of the invention can be cultured for hours, if suitable for a particular application. It is to be understood that the continuous and/or near-continuous 30 culture conditions also can include all time intervals in between these exemplary periods. It is further understood that the time of culturing the microbial organism of the invention is for a sufficient period of time to produce a sufficient amount of product for a desired purpose.

75 Fermentation procedures are well known in the art. Briefly, fermentation for the biosynthetic production of 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine or other 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine derived products, including intermediates, of the invention can be utilized in, for example, fed-batch fermentation and batch separation; fed-batch fermentation and 5 continuous separation, or continuous fermentation and continuous separation. Examples of batch and continuous fermentation procedures well known in the art are exemplified further below in the Examples. In addition to the above fermentation procedures using the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producers of the invention for continuous production of substantial quantities of 4 10 HB, 4-HBal, 4-HBCoA, BDO or putrescine, including monomeric 4-HB, respectively, the 4-HB producers also can be, for example, simultaneously subjected to chemical synthesis procedures to convert the product to other compounds or the product as described previously for the chemical conversion of monomeric 4-HB to, for example, GBL, BDO and/or THF. The BDO producers can similarly be, for example, simultaneously subjected to chemical synthesis 15 procedures as described previously for the chemical conversion of BDO to, for example, THF, GBL, pyrrolidones and/or other BDO family compounds. In addition, the products of the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producers can be separated from the fermentation culture and sequentially subjected to chemical conversion to convert the product to other compounds, if desired, as disclosed herein. 20 Briefly, hydrogenation of GBL in the fermentation broth can be performed as described by Frost et al., Biotechnology Progress 18: 201-211 (2002). Another procedure for hydrogenation during fermentation include, for example, the methods described in, for example, U.S. Patent No. 5,478,952. This method is further exemplified in the Examples below. Therefore, the invention additionally provides a method of manufacturing y-butyrolactone 25 (GBL), tetrahydrofuran (THF) or 1,4-butanediol (BDO). The method includes fermenting a non-naturally occurring microbial organism having 4-hydroxybutanoic acid (4-HB) and/or 1,4 butanediol (BDO) biosynthetic pathways, the pathways comprise at least one exogenous nucleic acid encoding 4-hydroxybutanoate dehydrogenase, CoA-independent succinic semialdehyde dehydrogenase, succinyl-CoA synthetase, CoA-dependent succinic semialdehyde 30 dehydrogenase, 4-hydroxybutyrate:CoA transferase, glutamate:succinic semialdehyde transaminase, a-ketoglutarate decarboxylase, glutamate decarboxylase, 4-hydroxybutanoate kinase, phosphotransbutyrylase, CoA-independent 1,4-butanediol semialdehyde dehydrogenase, 76 CoA-dependent 1,4-butanediol semialdehyde dehydrogenase, CoA-independent 1,4-butanediol alcohol dehydrogenase or CoA-dependent 1,4-butanediol alcohol dehydrogenase, under substantially anaerobic conditions for a sufficient period of time to produce 1,4-butanediol (BDO), GBL or THF, the fermenting comprising fed-batch fermentation and batch separation; 5 fed-batch fermentation and continuous separation, or continuous fermentation and continuous separation. In addition to the biosynthesis of 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine and other products of the invention as described herein, the non-naturally occurring microbial organisms and methods of the invention also can be utilized in various combinations with each other and 10 with other microbial organisms and methods well known in the art to achieve product biosynthesis by other routes. For example, one alternative to produce BDO other than use of the 4-HB producers and chemical steps or other than use of the BDO producer directly is through addition of another microbial organism capable of converting 4-HB or a 4-HB product exemplified herein to BDO. 15 One such procedure includes, for example, the fermentation of a 4-HB producing microbial organism of the invention to produce 4-HB, as described above and below. The 4-HB can then be used as a substrate for a second microbial organism that converts 4-HB to, for example, BDO, GBL and/or THF. The 4-HB can be added directly to another culture of the second organism or the original culture of 4-HB producers can be depleted of these microbial organisms 20 by, for example, cell separation, and then subsequent addition of the second organism to the fermentation broth can utilized to produce the final product without intermediate purification steps. One exemplary second organism having the capacity to biochemically utilize 4-HB as a substrate for conversion to BDO, for example, is Clostridium acetobutylicum (see, for example, Jewell et al., Current Microbiology, 13:215-19 (1986)). 25 Thus, such a procedure includes, for example, the fermentation of a microbial organism that produces a 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway intermediate. The 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine pathway intermediate can then be used as a substrate for a second microbial organism that converts the 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine pathway intermediate to 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine. The 4-HB, 4-HlBal, 4 30 HBCoA, BDO or putrescine pathway intermediate can be added directly to another culture of the second organism or the original culture of the 4-HB, 4-HlBal, 4-HBCoA BDO or putrescine pathway intermediate producers can be depleted of these microbial organisms by, for example, 77 cell separation, and then subsequent addition of the second organism to the fermentation broth can be utilized to produce the final product without intermediate purification steps. In other embodiments, the non-naturally occurring microbial organisms and methods of the invention can be assembled in a wide variety of subpathways to achieve biosynthesis of, for 5 example, 4-HB and/or BDO as described. In these embodiments, biosynthetic pathways for a desired product of the invention can be segregated into different microbial organisms and the different microbial organisms can be co-cultured to produce the final product. In such a biosynthetic scheme, the product of one microbial organism is the substrate for a second microbial organism until the final product is synthesized. For example, the biosynthesis of BDO 10 can be accomplished as described previously by constructing a microbial organism that contains biosynthetic pathways for conversion of one pathway intermediate to another pathway intermediate or the product, for example, a substrate such as endogenous succinate through 4 HB to the final product BDO. Alternatively, BDO also can be biosynthetically produced from microbial organisms through co-culture or co-fermentation using two organisms in the same 15 vessel. A first microbial organism being a 4-HB producer with genes to produce 4-HB from succinic acid, and a second microbial organism being a BDO producer with genes to convert 4 HB to BDO. For example, the biosynthesis of 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine can be accomplished by constructing a microbial organism that contains biosynthetic pathways for conversion of one pathway intermediate to another pathway intermediate or the product. 20 Alternatively, 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine also can be biosynthetically produced from microbial organisms through co-culture or co-fermentation using two organisms in the same vessel, where the first microbial organism produces a 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine intermediate and the second microbial organism converts the intermediate to 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine. 25 Given the teachings and guidance provided herein, those skilled in the art will understand that a wide variety of combinations and permutations exist for the non-naturally occurring microbial organisms and methods of the invention together with other microbial organisms, with the co culture of other non-naturally occurring microbial organisms having subpathways and with combinations of other chemical and/or biochemical procedures well known in the art to produce 30 4-HB, BDO, GBL and THF products of the invention. It is understood that, in methods of the invention, any of the one or more exogenous nucleic acids can be introduced into a microbial organism to produce a non-naturally occurring 78 microbial organism of the invention. The nucleic acids can be introduced so as to confer, for example, a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathway onto the microbial organism. Alternatively, encoding nucleic acids can be introduced to produce an intermediate microbial organism having the biosynthetic capability to catalyze some of the 5 required reactions to confer 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic capability. For example, a non-naturally occurring microbial organism having a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathway can comprise at least two exogenous nucleic acids encoding desired enzymes or proteins, such as the combination of enzymes as disclosed herein (see Examples and Figures 1, 8-13, 58, 62 and 63), and the like. Thus, it is 10 understood that any combination of two or more enzymes or proteins of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention. Similarly, it is understood that any combination of three or more enzymes or proteins of a biosynthetic pathway can be included in a non-naturally occurring microbial organism of the invention, for example,], and so forth, as desired and disclosed herein, so long as the combination of enzymes and/or 15 proteins of the desired biosynthetic pathway results in production of the corresponding desired product. Similarly, any combination of four or more enzymes or proteins of a biosynthetic pathway as disclosed herein can be included in a non-naturally occurring microbial organism of the invention, as desired, so long as the combination of enzymes and/or proteins of the desired biosynthetic pathway results in production of the corresponding desired product. 20 To generate better producers, metabolic modeling can be utilized to optimize growth conditions. Modeling can also be used to design gene knockouts that additionally optimize utilization of the pathway (see, for example, U.S. patent publications US 2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466, and U.S. Patent No. 7,127,379). Modeling analysis allows reliable predictions of the effects on 25 cell growth of shifting the metabolism towards more efficient production of 4-HB, 4-HBal, 4 HBCoA, BDO or putrescine. One computational method for identifying and designing metabolic alterations favoring biosynthesis of a desired product is the OptKnock computational framework (Burgard et al., Biotechnol. Bioeng. 84:647-657 (2003)). OptKnock is a metabolic modeling and simulation 30 program that suggests gene deletion or disruption strategies that result in genetically stable microorganisms which overproduce the target product. Specifically, the framework examines the complete metabolic and/or biochemical network of a microorganism in order to suggest genetic manipulations that force the desired biochemical to become an obligatory byproduct of 79 cell growth. By coupling biochemical production with cell growth through strategically placed gene deletions or other functional gene disruption, the growth selection pressures imposed on the engineered strains after long periods of time in a bioreactor lead to improvements in performance as a result of the compulsory growth-coupled biochemical production. Lastly, 5 when gene deletions are constructed there is a negligible possibility of the designed strains reverting to their wild-type states because the genes selected by OptKnock are to be completely removed from the genome. Therefore, this computational methodology can be used to either identify alternative pathways that lead to biosynthesis of a desired product or used in connection with the non-naturally occurring microbial organisms for further optimization of biosynthesis of 10 a desired product. Briefly, OptKnock is a term used herein to refer to a computational method and system for modeling cellular metabolism. The OptKnock program relates to a framework of models and methods that incorporate particular constraints into flux balance analysis (FBA) models. These constraints include, for example, qualitative kinetic information, qualitative regulatory 15 information, and/or DNA microarray experimental data. OptKnock also computes solutions to various metabolic problems by, for example, tightening the flux boundaries derived through flux balance models and subsequently probing the performance limits of metabolic networks in the presence of gene additions or deletions. OptKnock computational framework allows the construction of model formulations that allow an effective query of the performance limits of 20 metabolic networks and provides methods for solving the resulting mixed-integer linear programming problems. The metabolic modeling and simulation methods referred to herein as OptKnock are described in, for example, U.S. publication 2002/0168654, filed January 10, 2002, in International Patent No. PCT/US02/00660, filed January 10, 2002, and U.S. publication 2009/0047719, filed August 10, 2007. 25 Another computational method for identifying and designing metabolic alterations favoring biosynthetic production of a product is a metabolic modeling and simulation system termed SimPheny@. This computational method and system is described in, for example, U.S. publication 2003/0233218, filed June 14, 2002, and in International Patent Application No. PCT/US03/18838, filed June 13, 2003. SimPheny@ is a computational system that can be used 30 to produce a network model in silico and to simulate the flux of mass, energy or charge through the chemical reactions of a biological system to define a solution space that contains any and all possible functionalities of the chemical reactions in the system, thereby determining a range of allowed activities for the biological system. This approach is referred to as constraints-based 80 modeling because the solution space is defined by constraints such as the known stoichiometry of the included reactions as well as reaction thermodynamic and capacity constraints associated with maximum fluxes through reactions. The space defined by these constraints can be interrogated to determine the phenotypic capabilities and behavior of the biological system or of 5 its biochemical components. These computational approaches are consistent with biological realities because biological systems are flexible and can reach the same result in many different ways. Biological systems are designed through evolutionary mechanisms that have been restricted by fundamental constraints that all livi ng systems must face. Therefore, constraints-based modeling strategy 10 embraces these general realities. Further, the ability to continuously impose further restrictions on a network model via the tightening of constraints results in a reduction in the size of the solution space, thereby enhancing the precision with which physiological performance or phenotype can be predicted. Given the teachings and guidance provided herein, those skilled in the art will be able to apply 15 various computational frameworks for metabolic modeling and simulation to design and implement biosynthesis of a desired compound in host microbial organisms. Such metabolic modeling and simulation methods include, for example, the computational systems exemplified above as SimPheny@ and OptKnock. For illustration of the invention, some methods are described herein with reference to the OptKnock computation framework for modeling and 20 simulation. Those skilled in the art will know how to apply the identification, design and implementation of the metabolic alterations using OptKnock to any of such other metabolic modeling and simulation computational frameworks and methods well known in the art. The methods described above will provide one set of metabolic reactions to disrupt. Elimination of each reaction within the set or metabolic modification can result in a desired product as an 25 obligatory product during the growth phase of the organism. Because the reactions are known, a solution to the bilevel OptKnock problem also will provide the associated gene or genes encoding one or more enzymes that catalyze each reaction within the set of reactions. Identification of a set of reactions and their corresponding genes encoding the enzymes participating in each reaction is generally an automated process, accomplished through 30 correlation of the reactions with a reaction database having a relationship between enzymes and encoding genes.

81 Once identified, the set of reactions that are to be disrupted in order to achieve production of a desired product are implemented in the target cell or organism by functional disruption of at least one gene encoding each metabolic reaction within the set. One particularly useful means to achieve functional disruption of the reaction set is by deletion of each encoding gene. However, 5 in some instances, it can be beneficial to disrupt the reaction by other genetic aberrations including, for example, mutation, deletion of regulatory regions such as promoters or cis binding sites for regulatory factors, or by truncation of the coding sequence at any of a number of locations. These latter aberrations, resulting in less than total deletion of the gene set can be useful, for example, when rapid assessments of the coupling of a product are desired or when 10 genetic reversion is less likely to occur. To identify additional productive solutions to the above described bilevel OptKnock problem which lead to further sets of reactions to disrupt or metabolic modifications that can result in the biosynthesis, including growth-coupled biosynthesis of a desired product, an optimization method, termed integer cuts, can be implemented. This method proceeds by iteratively solving 15 the OptKnock problem exemplified above with the incorporation of an additional constraint referred to as an integer cut at each iteration. Integer cut constraints effectively prevent the solution procedure from choosing the exact same set of reactions identified in any previous iteration that obligatorily couples product biosynthesis to growth. For example, if a previously identified growth-coupled metabolic modification specifies reactions 1, 2, and 3 for disruption, 20 then the following constraint prevents the same reactions from being simultaneously considered in subsequent solutions. The integer cut method is well known in the art and can be found described in, for example, Burgard et al., Biotechnol. Prog. 17:791-797 (2001). As with all methods described herein with reference to their use in combination with the OptKnock computational framework for metabolic modeling and simulation, the integer cut method of 25 reducing redundancy in iterative computational analysis also can be applied with other computational frameworks well known in the art including, for example, SimPheny@. The methods exemplified herein allow the construction of cells and organisms that biosynthetically produce a desired product, including the obligatory coupling of production of a target biochemical product to growth of the cell or organism engineered to harbor the identified 30 genetic alterations. Therefore, the computational methods described herein allow the identification and implementation of metabolic modifications that are identified by an in silico method selected from OptKnock or SimPheny@. The set of metabolic modifications can include, for example, addition of one or more biosynthetic pathway enzymes and/or functional 82 disruption of one or more metabolic reactions including, for example, disruption by gene deletion. As discussed above, the OptKnock methodology was developed on the premise that mutant microbial networks can be evolved towards their computationally predicted maximum-growth 5 phenotypes when subjected to long periods of growth selection. In other words, the approach leverages an organism's ability to self-optimize under selective pressures. The OptKnock framework allows for the exhaustive enumeration of gene deletion combinations that force a coupling between biochemical production and cell growth based on network stoichiometry. The identification of optimal gene/reaction knockouts requires the solution of a bilevel optimization 10 problem that chooses the set of active reactions such that an optimal growth solution for the resulting network overproduces the biochemical of interest (Burgard et al., Biotechnol. Bioeng. 84:647-657 (2003)). An in silico stoichiometric model of . coli metabolism can be employed to identify essential genes for metabolic pathways as exemplified previously and described in, for example, U.S. 15 patent publications US 2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466, and in U.S. Patent No. 7,127,379. As disclosed herein, the OptKnock mathematical framework can be applied to pinpoint gene deletions leading to the growth-coupled production of a desired product. Further, the solution of the bilevel OptKnock problem provides only one set of deletions. To enumerate all meaningful 20 solutions, that is, all sets of knockouts leading to growth-coupled production formation, an optimization technique, termed integer cuts, can be implemented. This entails iteratively solving the OptKnock problem with the incorporation of an additional constraint referred to as an integer cut at each iteration, as discussed above. The methods exemplified above and further illustrated in the Examples below allow the 25 construction of cells and organisms that biosynthetically produce, including obligatory couple production of a target biochemical product to growth of the cell or organism engineered to harbor the identified genetic alterations. In this regard, metabolic alterations have been identified that result in the biosynthesis of 4-HB and 1,4-butanediol. Microorganism strains constructed with the identified metabolic alterations produce elevated levels of 4-HB, 4-HBal, 4 30 HBCoA, BDO or putrescine compared to unmodified microbial organisms. These strains can be beneficially used for the commercial production of 4-HB, BDO, THF, GBL, 4-HBal, 4-HBCoA 83 or putrescine, for example, in continuous fermentation process without being subjected to the negative selective pressures. Therefore, the computational methods described herein allow the identification and implementation of metabolic modifications that are identified by an in silico method selected 5 from OptKnock or SimPheny@. The set of metabolic modifications can include, for example, addition of one or more biosynthetic pathway enzymes and/.or functional disruption of one or more metabolic reactions including, for example, disruption by gene deletion. It is understood that modifications which do not substantially affect the activity of the various embodiments of this invention are also included within the definition of the invention provided 10 herein. Accordingly, the following examples are intended to illustrate but not limit the present invention. Any of the non-naturally occurring microbial organisms described herein can be cultured to produce and/or secrete the biosynthetic products of the invention. For example, the 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine producers can be cultured for the biosynthetic production 15 of 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine. For the production of 4-HB, 4-HlBal, 4-HBCoA, BDO or putrescine, the recombinant strains are cultured in a medium with carbon source and other essential nutrients. It is highly desirable to maintain anaerobic conditions in the fermenter to reduce the cost of the overall process. Such conditions can be obtained, for example, by first sparging the medium with nitrogen and then 20 sealing the flasks with a septum and crimp-cap. For strains where growth is not observed anaerobically, microaerobic conditions can be applied by perforating the septum with a small hole for limited aeration. Exemplary anaerobic conditions have been described previously and are well-known in the art. Exemplary aerobic and anaerobic conditions are described, for example, in U.S. publication 2009/0047719, filed August 10, 2007. Fermentations can be 25 performed in a batch, fed-batch or continuous manner, as disclosed herein. If desired, the pH of the medium can be maintained at a desired pH, in particular neutral pH, such as a pH of around 7 by addition of a base, such as NaOH or other bases, or acid, as needed to maintain the culture medium at a desirable pH. The growth rate can be determined by measuring optical density using a spectrophotometer (600 nm), and the glucose uptake rate by 30 monitoring carbon source depletion over time.

84 In addition to renewable feedstocks such as those exemplified above, the 4-HB, 4-HBal, 4 HBCoA, BDO or putrescine producing microbial organisms of the invention also can be modified for growth on syngas as its source of carbon. In this specific embodiment, one or more proteins or enzymes are expressed in the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine 5 producing organisms to provide a metabolic pathway for utilization of syngas or other gaseous carbon source. Synthesis gas, also known as syngas or producer gas, is the major product of gasification of coal and of carbonaceous materials such as biomass materials, including agricultural crops and residues. Syngas is a mixture primarily of H 2 and CO and can be obtained from the gasification 10 of any organic feedstock, including but not limited to coal, coal oil, natural gas, biomass, and waste organic matter. Gasification is generally carried out under a high fuel to oxygen ratio. Although largely H 2 and CO, syngas can also include CO 2 and other gases in smaller quantities. Thus, synthesis gas provides a cost effective source of gaseous carbon such as CO and, additionally,

CO

2 15 The Wood-Ljungdahl pathway catalyzes the conversion of CO and H 2 to acetyl-CoA and other products such as acetate. Organisms capable of utilizing CO and syngas also generally have the capability of utilizing CO 2 and C0 2

/H

2 mixtures through the same basic set of enzymes and transformations encompassed by the Wood-Ljungdahl pathway. H 2 -dependent conversion of

CO

2 to acetate by microorganisms was recognized long before it was revealed that CO also 20 could be used by the same organisms and that the same pathways were involved. Many acetogens have been shown to grow in the presence of CO 2 and produce compounds such as acetate as long as hydrogen is present to supply the necessary reducing equivalents (see for example, Drake, Acetogenesis, pp. 3-60 Chapman and Hall, New York, (1994)). This can be summarized by the following equation: 25 2 C02 + 4 H 2 + n ADP + n Pi -> CH 3 COOH + 2 H 2 0 +n ATP Hence, non-naturally occurring microorganisms possessing the Wood-Ljungdahl pathway can utilize CO 2 and H 2 mixtures as well for the production of acetyl-CoA and other desired products. The Wood-Ljungdahl pathway is well known in the art and consists of 12 reactions which can 30 be separated into two branches: (1) methyl branch and (2) carbonyl branch. The methyl branch 85 converts syngas to methyl-tetrahydrofolate (methyl-THF) whereas the carbonyl branch converts methyl-THF to acetyl-CoA. The reactions in the methyl branch are catalyzed in order by the following enzymes or proteins: ferredoxin oxidoreductase, formate dehydrogenase, formyltetrahydrofolate synthetase, methenyltetrahydrofolate cyclodehydratase, 5 methylenetetrahydrofolate dehydrogenase and methylenetetrahydrofolate reductase. The reactions in the carbonyl branch are catalyzed in order by the following enzymes or proteins: methyltetrahydrofolate:corrinoid protein methyltransferase (for example, AcsE), corrinoid iron sulfur protein, nickel-protein assembly protein (for example, AcsF), ferredoxin, acetyl-CoA synthase, carbon monoxide dehydrogenase and nickel-protein assembly protein (for example, 10 CooC). Following the teachings and guidance provided herein for introducing a sufficient number of encoding nucleic acids to generate a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway, those skilled in the art will understand that the same engineering design also can be performed with respect to introducing at least the nucleic acids encoding the Wood-Ljungdahl enzymes or proteins absent in the host organism. Therefore, introduction of one or more 15 encoding nucleic acids into the microbial organisms of the invention such that the modified organism contains the complete Wood-Ljungdahl pathway will confer syngas utilization ability. Additionally, the reductive (reverse) tricarboxylic acid cycle is and/or hydrogenase activities can also be used for the conversion of CO, C02 and/or H2 to acetyl-CoA and other products such as acetate. Organisms capable of fixing carbon via the reductive TCA pathway can utilize one or 20 more of the following enzymes: ATP citrate-lyase, citrate lyase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate:ferredoxin oxidoreductase, succinyl-CoA synthetase, succinyl-CoA transferase, fumarate reductase, fumarase, malate dehydrogenase, NAD(P)H:ferredoxin oxidoreductase, carbon monoxide dehydrogenase, and hydrogenase. Specifically, the reducing equivalents extracted from CO and/or H2 by carbon monoxide 25 dehydrogenase and hydrogenase are utilized to fix C02 via the reductive TCA cycle into acetyl CoA or acetate. Acetate can be converted to acetyl-CoA by enzymes such as acetyl-CoA transferase, acetate kinase/phosphotransacetylase, and acetyl-CoA synthetase. Acetyl-CoA can be converted to the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine precursors, glyceraldehyde-3 phosphate, phosphoenolpyruvate, and pyruvate, by pyruvate:ferredoxin oxidoreductase and the 30 enzymes of gluconeogenesis. Following the teachings and guidance provided herein for introducing a sufficient number of encoding nucleic acids to generate a 4-HB, 4-HBal, 4 HBCoA, BDO or putrescine pathway, those skilled in the art will understand that the same engineering design also can be performed with respect to introducing at least the nucleic acids encoding the reductive TCA pathway enzymes or proteins absent in the host organism.

86 Therefore, introduction of one or more encoding nucleic acids into the microbial organisms of the invention such that the modified organism contains the complete reductive TCA pathway will confer syngas utilization ability. Accordingly, given the teachings and guidance provided herein, those skilled in the art will 5 understand that a non-naturally occurring microbial organism can be produced that secretes the biosynthesized compounds of the invention when grown on a carbon source such as a carbohydrate. Such compounds include, for example, 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine and any of the intermediate metabolites in the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway. All that is required is to engineer in one or more of the required enzyme or 10 protein activities to achieve biosynthesis of the desired compound or intermediate including, for example, inclusion of some or all of the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine biosynthetic pathways. Accordingly, the invention provides a non-naturally occurring microbial organism that produces and/or secretes 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine when grown on a carbohydrate or other carbon source and produces and/or secretes any of the 15 intermediate metabolites shown in the 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway when grown on a carbohydrate or other carbon source. The 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine producing microbial organisms of the invention can initiate synthesis from an intermediate in a 4-HB, 4-HBal, 4-HBCoA, BDO or putrescine pathway, as disclosed herein. To generate better producers, metabolic modeling can be utilized to optimize growth conditions. 20 Modeling can also be used to design gene knockouts that additionally optimize utilization of the pathway (see, for example, U.S. patent publications US 2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466, and U.S. Patent No. 7,127,379). Modeling analysis allows reliable predictions of the effects on cell growth of shifting the metabolism towards more efficient production of 4-HB, 4-HBal, 4 25 HBCoA, BDO or putrescine. One computational method for identifying and designing metabolic alterations favoring biosynthesis of a desired product is the OptKnock computational framework (Burgard et al., Biotechnol. Bioeng. 84:647-657 (2003)). OptKnock is a metabolic modeling and simulation program that suggests gene deletion strategies that result in genetically stable microorganisms 30 which overproduce the target product. Specifically, the framework examines the complete metabolic and/or biochemical network of a microorganism in order to suggest genetic manipulations that force the desired biochemical to become an obligatory byproduct of cell 87 growth. By coupling biochemical production with cell growth through strategically placed gene deletions or other functional gene disruption, the growth selection pressures imposed on the engineered strains after long periods of time in a bioreactor lead to improvements in performance as a result of the compulsory growth-coupled biochemical production. Lastly, 5 when gene deletions are constructed there is a negligible possibility of the designed strains reverting to their wild-type states because the genes selected by OptKnock are to be completely removed from the genome. Therefore, this computational methodology can be used to either identify alternative pathways that lead to biosynthesis of a desired product or used in connection with the non-naturally occurring microbial organisms for further optimization of biosynthesis of 10 a desired product. Briefly, OptKnock is a term used herein to refer to a computational method and system for modeling cellular metabolism. The OptKnock program relates to a framework of models and methods that incorporate particular constraints into flux balance analysis (FBA) models. These constraints include, for example, qualitative kinetic information, qualitative regulatory 15 information, and/or DNA microarray experimental data. OptKnock also computes solutions to various metabolic problems by, for example, tightening the flux boundaries derived through flux balance models and subsequently probing the performance limits of metabolic networks in the presence of gene additions or deletions. OptKnock computational framework allows the construction of model formulations that allow an effective query of the performance limits of 20 metabolic networks and provides methods for solving the resulting mixed-integer linear programming problems. The metabolic modeling and simulation methods referred to herein as OptKnock are described in, for example, U.S. publication 2002/0168654, filed January 10, 2002, in International Patent No. PCT/US02/00660, filed January 10, 2002, and U.S. publication 2009/0047719, filed August 10, 2007. 25 Another computational method for identifying and designing metabolic alterations favoring biosynthetic production of a product is a metabolic modeling and simulation system termed SimPheny@. This computational method and system is described in, for example, U.S. publication 2003/0233218, filed June 14, 2002, and in International Patent Application No. PCT/US03/18838, filed June 13, 2003. SimPheny@ is a computational system that can be used 30 to produce a network model in silico and to simulate the flux of mass, energy or charge through the chemical reactions of a biological system to define a solution space that contains any and all possible functionalities of the chemical reactions in the system, thereby determining a range of allowed activities for the biological system. This approach is referred to as constraints-based 88 modeling because the solution space is defined by constraints such as the known stoichiometry of the included reactions as well as reaction thermodynamic and capacity constraints associated with maximum fluxes through reactions. The space defined by these constraints can be interrogated to determine the phenotypic capabilities and behavior of the biological system or of 5 its biochemical components. These computational approaches are consistent with biological realities because biological systems are flexible and can reach the same result in many different ways. Biological systems are designed through evolutionary mechanisms that have been restricted by fundamental constraints that all living systems must face. Therefore, constraints-based modeling strategy 10 embraces these general realities. Further, the ability to continuously impose further restrictions on a network model via the tightening of constraints results in a reduction in the size of the solution space, thereby enhancing the precision with which physiological performance or phenotype can be predicted. Given the teachings and guidance provided herein, those skilled in the art will be able to apply 15 various computational frameworks for metabolic modeling and simulation to design and implement biosynthesis of a desired compound in host microbial organisms. Such metabolic modeling and simulation methods include, for example, the computational systems exemplified above as SimPheny@ and OptKnock. For illustration of the invention, some methods are described herein with reference to the OptKnock computation framework for modeling and 20 simulation. Those skilled in the art will know how to apply the identification, design and implementation of the metabolic alterations using OptKnock to any of such other metabolic modeling and simulation computational frameworks and methods well known in the art. The methods described above will provide one set of metabolic reactions to disrupt. Elimination of each reaction within the set or metabolic modification can result in a desired product as an 25 obligatory product during the growth phase of the organism. Because the reactions are known, a solution to the bilevel OptKnock problem also will provide the associated gene or genes encoding one or more enzymes that catalyze each reaction within the set of reactions. Identification of a set of reactions and their corresponding genes encoding the enzymes participating in each reaction is generally an automated process, accomplished through 30 correlation of the reactions with a reaction database having a relationship between enzymes and encoding genes.

89 Once identified, the set of reactions that are to be disrupted in order to achieve production of a desired product are implemented in the target cell or organism by functional disruption of at least one gene encoding each metabolic reaction within the set. One particularly useful means to achieve functional disruption of the reaction set is by deletion of each encoding gene. However, 5 in some instances, it can be beneficial to disrupt the reaction by other genetic aberrations including, for example, mutation, deletion of regulatory regions such as promoters or cis binding sites for regulatory factors, or by truncation of the coding sequence at any of a number of locations. These latter aberrations, resulting in less than total deletion of the gene set can be useful, for example, when rapid assessments of the coupling of a product are desired or when 10 genetic reversion is less likely to occur. To identify additional productive solutions to the above described bilevel OptKnock problem which lead to further sets of reactions to disrupt or metabolic modifications that can result in the biosynthesis, including growth-coupled biosynthesis of a desired product, an optimization method, termed integer cuts, can be implemented. This method proceeds by iteratively solving 15 the OptKnock problem exemplified above with the incorporation of an additional constraint referred to as an integer cut at each iteration. Integer cut constraints effectively prevent the solution procedure from choosing the exact same set of reactions identified in any previous iteration that obligatorily couples product biosynthesis to growth. For example, if a previously identified growth-coupled metabolic modification specifies reactions 1, 2, and 3 for disruption, 20 then the following constraint prevents the same reactions from being simultaneously considered in subsequent solutions. The integer cut method is well known in the art and can be found described in, for example, Burgard et al., Biotechnol. Prog. 17:791-797 (2001). As with all methods described herein with reference to their use in combination with the OptKnock computational framework for metabolic modeling and simulation, the integer cut method of 25 reducing redundancy in iterative computational analysis also can be applied with other computational frameworks well known in the art including, for example, SimPheny@. The methods exemplified herein allow the construction of cells and organisms that biosynthetically produce a desired product, including the obligatory coupling of production of a target biochemical product to growth of the cell or organism engineered to harbor the identified 30 genetic alterations. Therefore, the computational methods described herein allow the identification and implementation of metabolic modifications that are identified by an in silico method selected from OptKnock or SimPheny@. The set of metabolic modifications can include, for example, addition of one or more biosynthetic pathway enzymes and/or functional 90 disruption of one or more metabolic reactions including, for example, disruption by gene deletion. As discussed above, the OptKnock methodology was developed on the premise that mutant microbial networks can be evolved towards their computationally predicted maximum-growth 5 phenotypes when subjected to long periods of growth selection. In other words, the approach leverages an organism's ability to self-optimize under selective pressures. The OptKnock framework allows for the exhaustive enumeration of gene deletion combinations that force a coupling between biochemical production and cell growth based on network stoichiometry. The identification of optimal gene/reaction knockouts requires the solution of a bilevel optimization 10 problem that chooses the set of active reactions such that an optimal growth solution for the resulting network overproduces the biochemical of interest (Burgard et al., Biotechnol. Bioeng. 84:647-657 (2003)). An in silico stoichiometric model of . coli metabolism can be employed to identify essential genes for metabolic pathways as exemplified previously and described in, for example, U.S. 15 patent publications US 2002/0012939, US 2003/0224363, US 2004/0029149, US 2004/0072723, US 2003/0059792, US 2002/0168654 and US 2004/0009466, and in U.S. Patent No. 7,127,379. As disclosed herein, the OptKnock mathematical framework can be applied to pinpoint gene deletions leading to the growth-coupled production of a desired product. Further, the solution of the bilevel OptKnock problem provides only one set of deletions. To enumerate all meaningful 20 solutions, that is, all sets of knockouts leading to growth-coupled production formation, an optimization technique, termed integer cuts, can be implemented. This entails iteratively solving the OptKnock problem with the incorporation of an additional constraint referred to as an integer cut at each iteration, as discussed above. As disclosed herein, a nucleic acid encoding a desired activity of a 4-HB, 4-HBal, 4-HBCoA, 25 BDO or putrescine pathway can be introduced into a host organism. In some cases, it can be desirable to modify an activity of a 4-HB, 4-HBal, 4-HBCoA BDO or putrescine pathway enzyme or protein to increase production of 4-HB, 4-HBal, 4-HBCoA BDO or putrescine. For example, known mutations that increase the activity of a protein or enzyme can be introduced into an encoding nucleic acid molecule. Additionally, optimization methods can be applied to 30 increase the activity of an enzyme or protein and/or decrease an inhibitory activity, for example, decrease the activity of a negative regulator.

91 One such optimization method is directed evolution. Directed evolution is a powerful approach that involves the introduction of mutations targeted to a specific gene in order to improve and/or alter the properties of an enzyme. Improved and/or altered enzymes can be identified through the development and implementation of sensitive high-throughput screening assays that allow 5 the automated screening of many enzyme variants (for example, >104). Iterative rounds of mutagenesis and screening typically are performed to afford an enzyme with optimized properties. Computational algorithms that can help to identify areas of the gene for mutagenesis also have been developed and can significantly reduce the number of enzyme variants that need to be generated and screened. Numerous directed evolution technologies have been developed 10 (for reviews, see Hibbert et al., Biomol.Eng 22:11-19 (2005); Huisman and Lalonde, In Biocatalysis in the pharmaceutical and biotechnology industries pgs. 717-742 (2007), Patel (ed.), CRC Press; Otten and Quax. Biomol.Eng 22:1-9 (2005).; and Sen et al., Appl Biochem.Biotechnol 143:212-223 (2007)) to be effective at creating diverse variant libraries, and these methods have been successfully applied to the improvement of a wide range of properties 15 across many enzyme classes. Enzyme characteristics that have been improved and/or altered by directed evolution technologies include, for example: selectivity/specificity, for conversion of non-natural substrates; temperature stability, for robust high temperature processing; pH stability, for bioprocessing under lower or higher pH conditions; substrate or product tolerance, so that high product titers can be achieved; binding (Km), including broadening substrate binding 20 to include non-natural substrates; inhibition (Ki), to remove inhibition by products, substrates, or key intermediates; activity (kcat), to increases enzymatic reaction rates to achieve desired flux; expression levels, to increase protein yields and overall pathway flux; oxygen stability, for operation of air sensitive enzymes under aerobic conditions; and anaerobic activity, for operation of an aerobic enzyme in the absence of oxygen. 25 A number of exemplary methods have been developed for the mutagenesis and diversification of genes to target desired properties of specific enzymes. Such methods are well known to those skilled in the art. Any of these can be used to alter and/or optimize the activity of a 4-HB, 4 HBal, 4-HBCoA, BDO or putrescine pathway enzyme or protein. Such methods include, but are not limited to EpPCR, which introduces random point mutations by reducing the fidelity of 30 DNA polymerase in PCR reactions (Pritchard et al., J Theor.Biol. 234:497-509 (2005)); Error prone Rolling Circle Amplification (epRCA), which is similar to epPCR except a whole circular plasmid is used as the template and random 6-mers with exonuclease resistant thiophosphate linkages on the last 2 nucleotides are used to amplify the plasmid followed by transformation into cells in which the plasmid is re-circularized at tandem repeats (Fujii et al., Nucleic Acids 92 Res. 32:e145 (2004); and Fujii et al., Nat. Protoc. 1:2493-2497 (2006)); DNA or Family Shuffling, which typically involves digestion of two or more variant genes with nucleases such as Dnase I or EndoV to generate a pool of random fragments that are reassembled by cycles of annealing and extension in the presence of DNA polymerase to create a library of chimeric 5 genes (Stemmer, Proc Natl Acad Sci USA 91:10747-10751 (1994); and Stemmer, Nature 370:389-391 (1994)); Staggered Extension (StEP), which entails template priming followed by repeated cycles of 2 step PCR with denaturation and very short duration of annealing/extension (as short as 5 sec) (Zhao et al., Nat. Biotechnol. 16:258-261 (1998)); Random Priming Recombination (RPR), in which random sequence primers are used to generate many short DNA 10 fragments complementary to different segments of the template (Shao et al., Nucleic Acids Res 26:681-683 (1998)). Additional methods include Heteroduplex Recombination, in which linearized plasmid DNA is used to form heteroduplexes that are repaired by mismatch repair (Volkov et al, Nucleic Acids Res. 27:e18 (1999); and Volkov et al., Methods Enzymol. 328:456-463 (2000)); Random 15 Chimeragenesis on Transient Templates (RACHITT), which employs Dnase I fragmentation and size fractionation of single stranded DNA (ssDNA) (Coco et al., Nat. Biotechnol. 19:354-359 (2001)); Recombined Extension on Truncated templates (RETT), which entails template switching of unidirectionally growing strands from primers in the presence of unidirectional ssDNA fragments used as a pool of templates (Lee et al., J. Molec. Catalysis 26:119-129 20 (2003)); Degenerate Oligonucleotide Gene Shuffling (DOGS), in which degenerate primers are used to control recombination between molecules; (Bergquist and Gibbs, Methods Mol.Biol 352:191-204 (2007); Bergquist et al., Biomol.Eng 22:63-72 (2005); Gibbs et al., Gene 271:13-20 (2001)); Incremental Truncation for the Creation of Hybrid Enzymes (ITCHY), which creates a combinatorial library with 1 base pair deletions of a gene or gene fragment of interest 25 (Ostermeier et al., Proc. Natl. Acad. Sci. USA 96:3562-3567 (1999); and Ostermeier et al., Nat. Biotechnol. 17:1205-1209 (1999)); Thio-Incremental Truncation for the Creation of Hybrid Enzymes (THIO-ITCHY), which is similar to ITCHY except that phosphothioate dNTPs are used to generate truncations (Lutz et al., Nucleic Acids Res 29:E16 (2001)); SCRATCHY, which combines two methods for recombining genes, ITCHY and DNA shuffling (Lutz et al., Proc. 30 Natl. Acad. Sci. USA 98:11248-11253 (2001)); Random Drift Mutagenesis (RNDM), in which mutations made via epPCR are followed by screening/selection for those retaining usable activity (Bergquist et al., Biomol. Eng. 22:63-72 (2005)); Sequence Saturation Mutagenesis (SeSaM), a random mutagenesis method that generates a pool of random length fragments using random incorporation of a phosphothioate nucleotide and cleavage, which is used as a template 93 to extend in the presence of "universal" bases such as inosine, and replication of an inosine containing complement gives random base incorporation and, consequently, mutagenesis (Wong et al., Biotechnol. J. 3:74-82 (2008); Wong et al., Nucleic Acids Res. 32:e26 (2004); and Wong et al., Anal. Biochem. 341:187-189 (2005)); Synthetic Shuffling, which uses overlapping 5 oligonucleotides designed to encode "all genetic diversity in targets" and allows a very high diversity for the shuffled progeny (Ness et al., Nat. Biotechnol. 20:1251-1255 (2002)); Nucleotide Exchange and Excision Technology NexT, which exploits a combination of dUTP incorporation followed by treatment with uracil DNA glycosylase and then piperidine to perform endpoint DNA fragmentation (Muller et al., Nucleic Acids Res. 33:el 17 (2005)). 10 Further methods include Sequence Homology-Independent Protein Recombination (SHIPREC), in which a linker is used to facilitate fusion between two distantly related or unrelated genes, and a range of chimeras is generated between the two genes, resulting in libraries of single-crossover hybrids (Sieber et al., Nat. Biotechnol. 19:456-460 (2001)); Gene Site Saturation MutagenesisTM (GSSMTM), in which the starting materials include a supercoiled double stranded DNA (dsDNA) 15 plasmid containing an insert and two primers which are degenerate at the desired site of mutations (Kretz et al., Methods Enzymol. 388:3-11 (2004)); Combinatorial Cassette Mutagenesis (CCM), which involves the use of short oligonucleotide cassettes to replace limited regions with a large number of possible amino acid sequence alterations (Reidhaar-Olson et al. Methods Enzymol. 208:564-586 (1991); and Reidhaar-Olson et al. Science 241:53-57 (1988)); 20 Combinatorial Multiple Cassette Mutagenesis (CMCM), which is essentially similar to CCM and uses epPCR at high mutation rate to identify hot spots and hot regions and then extension by CMCM to cover a defined region of protein sequence space (Reetz et al., Angew. Chem. Int. Ed Engl. 40:3589-3591 (2001)); the Mutator Strains technique, in which conditional ts mutator plasmids, utilizing the mutD5 gene, which encodes a mutant subunit of DNA polymerase III, to 25 allow increases of 20 to 4000-X in random and natural mutation frequency during selection and block accumulation of deleterious mutations when selection is not required (Selifonova et al., Appl. Environ. Microbiol. 67:3645-3649 (2001)); Low et al., J. Mol. Biol. 260:359-3680 (1996)). Additional exemplary methods include Look-Through Mutagenesis (LTM), which is a 30 multidimensional mutagenesis method that assesses and optimizes combinatorial mutations of selected amino acids (Rajpal et al., Proc. Natl. Acad. Sci. USA 102:8466-8471 (2005)); Gene Reassembly, which is a DNA shuffling method that can be applied to multiple genes at one time or to create a large library of chimeras (multiple mutations) of a single gene (Tunable 94 GeneReassemblyTM (TGRTM) Technology supplied by Verenium Corporation), in Silico Protein Design Automation (PDA), which is an optimization algorithm that anchors the structurally defined protein backbone possessing a particular fold, and searches sequence space for amino acid substitutions that can stabilize the fold and overall protein energetics, and generally works 5 most effectively on proteins with known three-dimensional structures (Hayes et al., Proc. Natl. Acad. Sci. USA 99:15926-15931 (2002)); and Iterative Saturation Mutagenesis (ISM), which involves using knowledge of structure/function to choose a likely site for enzyme improvement, performing saturation mutagenesis at chosen site using a mutagenesis method such as Stratagene QuikChange (Stratagene; San Diego CA), screening/selecting for desired properties, and, using 10 improved clone(s), starting over at another site and continue repeating until a desired activity is achieved (Reetz et al., Nat. Protoc. 2:891-903 (2007); and Reetz et al., Angew. Chem. Int. Ed Engl. 45:7745-7751 (2006)). Any of the aforementioned methods for mutagenesis can be used alone or in any combination. Additionally, any one or combination of the directed evolution methods can be used in 15 conjunction with adaptive evolution techniques, as described herein. It is understood that modifications which do not substantially affect the activity of the various embodiments of this invention are also provided within the definition of the invention provided herein. Accordingly, the following examples are intended to illustrate but not limit the present invention. 20 EXAMPLE I Biosynthesis of 4-Hydroxybutanoic Acid This example describes exemplary biochemical pathways for 4-HB production. Previous reports of 4-HB synthesis in microbes have focused on this compound as an intermediate in production of the biodegradable plastic poly-hydroxyalkanoate (PHA) (U.S. 25 Patent No. 6,117,658). The use of 4-HB/3-HB copolymers over poly-3-hydroxybutyrate polymer (PHB) can result in plastic that is less brittle (Saito and Doi, Intl. J Biol. Macromol. 16:99-104 (1994)). The production of monomeric 4-HB described herein is a fundamentally distinct process for several reasons: (1) the product is secreted, as opposed to PHA which is produced intracellularly and remains in the cell; (2) for organisms that produce 30 hydroxybutanoate polymers, free 4-HB is not produced, but rather the Coenzyme A derivative is used by the polyhydroxyalkanoate synthase; (3) in the case of the polymer, formation of the granular product changes thermodynamics; and (4) extracellular pH is not an issue for 95 production of the polymer, whereas it will affect whether 4-HB is present in the free acid or conjugate base state, and also the equilibrium between 4-HB and GBL. 4-HB can be produced in two enzymatic reduction steps from succinate, a central metabolite of the TCA cycle, with succinic semialdehyde as the intermediate (Figure 1). The first of these 5 enzymes, succinic semialdehyde dehydrogenase, is native to many organisms including E. coli, in which both NADH- and NADPH-dependent enzymes have been found (Donnelly and Cooper, Eur. J. Biochem. 113:555-561 (1981); Donnelly and Cooper, J. Bacteriol. 145:1425 1427 (1981); Marek and Henson, J. Bacteriol. 170:991-994 (1988)). There is also evidence supporting succinic semialdehyde dehydrogenase activity in S. cerevisiae (Ramos et al., Eur. J. 10 Biochem. 149:401-404 (1985)), and a putative gene has been identified by sequence homology. However, most reports indicate that this enzyme proceeds in the direction of succinate synthesis, as shown in Figure 1 (Donnelly and Cooper, supra; Lutke-Eversloh and Steinbuchel, FEMS Microbiol. Lett. 181:63-71 (1999)), participating in the degradation pathway of 4-HB and gamma-aminobutyrate. Succinic semialdehyde also is natively produced by certain microbial 15 organisms such as E. coli through the TCA cycle intermediate a-ketogluterate via the action of two enzymes: glutamate:succinic semialdehyde transaminase and glutamate decarboxylase. An alternative pathway, used by the obligate anaerobe Clostridium kluyveri to degrade succinate, activates succinate to succinyl-CoA, then converts succinyl-CoA to succinic semialdehyde using an alternative succinic semialdehyde dehydrogenase which is known to function in this direction 20 (Sohling and Gottschalk, Eur. J. Biochem. 212:121-127 (1993)). However, this route has the energetic cost of ATP required to convert succinate to succinyl-CoA. The second enzyme of the pathway, 4-hydroxybutanoate dehydrogenase, is not native to E. coli or yeast but is found in various bacteria such as C. kluyveri and Ralstonia eutropha (Lutke Eversloh and Steinbuchel, supra; Sohling and Gottschalk, J. Bacteriol. 178:871-880 (1996); 25 Valentin et al., Eur. J. Biochem. 227:43-60 (1995); Wolff and Kenealy, Protein Expr. Purif 6:206-212 (1995)). These enzymes are known to be NADH-dependent, though NADPH dependent forms also exist. An additional pathway to 4-HB from alpha-ketoglutarate was demonstrated in E. coli resulting in the accumulation of poly(4-hydroxybutyric acid) (Song et al., Wei Sheng Wu Xue.Bao. 45:382-386 (2005)). The recombinant strain required the 30 overexpression of three heterologous genes, PHA synthase (R. eutropha), 4-hydroxybutyrate dehydrogenase (R. eutropha) and 4-hydroxybutyrate:CoA transferase (C. kluyveri), along with two native E. coli genes: glutamate:succinic semialdehyde transaminase and glutamate decarboxylase. Steps 4 and 5 in Figure 1 can alternatively be carried out by an alpha- 96 ketoglutarate decarboxylase such as the one identified in Euglena gracilis (Shigeoka et al., Biochem. J. 282(Pt2):319-323 (1992); Shigeoka and Nakano, Arch. Biochem. Biophys. 288:22 28 (1991); Shigeoka and Nakano, Biochem J. 292(Pt 2):463-467 (1993)). However, this enzyme has not previously been applied to impact the production of 4-HB or related polymers in any 5 organism. The microbial production capabilities of 4-hydroxybutyrate were explored in two microbes, Escherichia coli and Saccharomyces cerevisiae, using in silico metabolic models of each organism. Potential pathways to 4-HB proceed via a succinate, succinyl-CoA, or alpha ketoglutarate intermediate as shown in Figure 1. 10 A first step in the 4-HB production pathway from succinate involves the conversion of succinate to succinic semialdehyde via an NADH- or NADPH-dependant succinic semialdehyde dehydrogenase. In E. coli, gabD is an NADP-dependant succinic semialdehyde dehydrogenase and is part of a gene cluster involved in 4-aminobutyrate uptake and degradation (Niegemann et al.,. Arch. Microbiol. 160:454-460 (1993); Schneider et al., J. Bacteriol. 184:6976-6986 (2002)). 15 sad is believed to encode the enzyme for NAD-dependant succinic semialdehyde dehydrogenase activity (Marek and Henson, supra). S. cerevisiae contains only the NADPH-dependant succinic semialdehyde dehydrogenase, putatively assigned to UGA2 , which localizes to the cytosol (Huh et al., Nature 425:686-691 (2003)). The maximum yield calculations assuming the succinate pathway to 4-HB in both E. coli and S. cerevisiae require only the assumption that a 20 non-native 4-HB dehydrogenase has been added to their metabolic networks. The pathway from succinyl-CoA to 4-hydroxybutyrate was described in U.S. Patent No. 6,117,658 as part of a process for making polyhydroxyalkanoates comprising 4-hydroxybutyrate monomer units. Clostridium k/uyveri is one example organism known to possess CoA dependant succinic semialdehyde dehydrogenase activity (Sohling and Gottschalk, supra; 25 Sohling and Gottschalk, supra). In this study, it is assumed that this enzyme, from C. k/uyveri or another organism, is expressed in E. coli or S cerevisiae along with a non-native or heterologous 4-HB dehydrogenase to complete the pathway from succinyl-CoA to 4-HB. The pathway from alpha-ketoglutarate to 4-HB was demonstrated in E. coli resulting in the accumulation of poly(4-hydroxybutyric acid) to 30% of dry cell weight (Song et al., supra). As 30 E. coli and S. cerevisiae natively or endogenously possess both glutamate:succinic semialdehyde transaminase and glutamate decarboxylase (Coleman et al., J. Biol. Chem. 276:244-250 (2001)), 97 the pathway from AKG to 4-HB can be completed in both organisms by assuming only that a non-native 4-HB dehydrogenase is present. EXAMPLE II Biosynthesis of 1,4-Butanediol from Succinate and Alpha-ketoglutarate 5 This example illustrates the construction and biosynthetic production of 4-HB and BDO from microbial organisms. Pathways for 4-HB and BDO are disclosed herein. There are several alternative enzymes that can be utilized in the pathway described above. The native or endogenous enzyme for conversion of succinate to succinyl-CoA (Step 1 in Figure 1) can be replaced by a CoA transferase such as that encoded by the cat] gene C. kluyveri (Sohling 10 and Gottschalk, Eur.J Biochem. 212:121-127 (1993)), which functions in a similar manner to Step 9. However, the production of acetate by this enzyme may not be optimal, as it might be secreted rather than being converted back to acetyl-CoA. In this respect, it also can be beneficial to eliminate acetate formation in Step 9. As one alternative to this CoA transferase, a mechanism can be employed in which the 4-HB is first phosphorylated by ATP and then 15 converted to the CoA derivative, similar to the acetate kinase/phosphotransacetylase pathway in E. coli for the conversion of acetate to acetyl-CoA. The net cost of this route is one ATP, which is the same as is required to regenerate acetyl-CoA from acetate. The enzymes phosphotransbutyrylase (ptb) and butyrate kinase (bk) are known to carry out these steps on the non-hydroxylated molecules for butyrate production in C. acetobutylicum (Cary et al., Appl 20 Environ Microbiol 56:1576-1583 (1990); Valentine, R. C. and R. S. Wolfe, J Biol Chem. 235:1948-1952 (1960)). These enzymes are reversible, allowing synthesis to proceed in the direction of 4-HB. BDO also can be produced via a-ketoglutarate in addition to or instead of through succinate. A described previously, and exemplified further below, one pathway to accomplish product 25 biosynthesis is with the production of succinic semialdehyde via a-ketoglutarate using the endogenous enzymes (Figure 1, Steps 4-5). An alternative is to use an a-ketoglutarate decarboxylase that can perform this conversion in one step (Figure 1, Step 8; Tian et al., Proc Nati Acad Sci U S.A 102:10670-10675 (2005)). For the construction of different strains of BDO-producing microbial organisms, a list of 30 applicable genes was assembled for corroboration. Briefly, one or more genes within the 4-HB and/or BDO biosynthetic pathways were identified for each step of the complete BDO producing pathway shown in Figure 1, using available literature resources, the NCBI genetic 98 database, and homology searches. The genes cloned and assessed in this study are presented below in in Table 6, along with the appropriate references and URL citations to the polypeptide sequence. As discussed further below, some genes were synthesized for codon optimization while others were cloned via PCR from the genomic DNA of the native or wild-type organism. 5 For some genes both approaches were used, and in this case the native genes are indicated by an "n" suffix to the gene identification number when used in an experiment. Note that only the DNA sequences differ; the proteins are identical. Table 6. Genes expressed in host BDO-producting microbial organisms. Gene ID Reaction Gene Source Enzyme name Link to protein sequence Reference number number name organism (Fig. 1) 0001 9 Cat2 Clostridium 4-hydroxybutyrate www.ncbi.nlm.nihsgov/entrez/ 1 kluyveri coenzyme A viewer.fcgi?db=nuccore&id= DSM 555 transferase 1228100 0002 12/13 adhE Clostridium Aldehyde/ alcohol www.ncbi.nlm.nih.gov/entrez/ 2 acetobutylicu dehydrogenase viewer.fcgi?db=protein&val= m ATCC 824 15004739 0003 12/13 adhE2 Clostridium Aldehyde/ alcohol www.ncbi.nlm.nih.gov/entrez/ 2 acetobutylicu dehydrogenase viewer.fcgi?val=NP_149325. m ATCC 824 1 0004 1 Cati Clostridium Succinate www.ncbi.nlm.nih.gov/entrez/ 1 kluyveri coenzyme A viewer.fcgi?db=nuccore&id= DSM 555 transferase 1228100 0008 6 sucD Clostridium Succinic www.ncbi.nlm.nih.gov/entrez/ 1 kluyveri semialdehyde viewer.fcgi?db=nuccore&id= DSM 555 dehydrogenase 1228100 (CoA-dependent) 0009 7 4-HBd Ralstonia 4-hydroxybutyrate www.ncbi.nlm.nih.gov/entrez/ 2 eutropha H16 dehydrogenase viewer.fcgi?val=YP_726053. (NAD-dependent) 1 0010 7 4-HBd Clostridium 4-hydroxybutyrate www.ncbi.nlm.nih.gov/entrez/ 1 kluyveri dehydrogenase viewer.fcgi?db=nuccore&id= DSM 555 (NAD-dependent) 1228100 0011 12/13 adhE E. coli Aldehyde/ alcohol www.shigen.nig.ac.jp/ecoli/pe dehydrogenase c/genes.List.DetailAction.do?f romListFlag=true&featureTyp e=1&orfld=1219 0012 12/13 yqhD E. coli Aldehyde/ alcohol www.shigen.nig.ac.jp/ecoli/pe dehydrogenase c/genes.List.DetailAction.do 0013 13 bdhB Clostridium Butanol www.ncbi.nlm.nihsgov/entrez/ 2 acetobutylicu dehydrogenase II viewer.fcgi?val=NP_349891. m ATCC 824 1 0020 11 ptb Clostridium Phospho- www.ncbi.nlm.nih.gov/entrez/ 2 acetobutylicu transbutyrylase viewer.fcgi?db=protein&id= 1 m ATCC 824 5896327 0021 10 buk1 Clostridium Butyrate kinase I www.ncbi.nlm.nih.gov/entrez/ 2 acetobutylicu viewer.fcgi?db=protein&id=2 m ATCC 824 0137334 0022 10 buk2 Clostridium Butyrate kinase II www.ncbi.nlm.nih.gov/entrez/ 2 acetobutylicu viewer.fcgi?db=protein&id=2 m ATCC 824 0137415 99 0023 13 adhEm isolated from Alcohol (37)d} metalibrary dehydrogenase of anaerobic sewage digester microbial consortia 0024 13 adhE Clostridium Alcohol www.genome.jp/dbget thermocellum dehydrogenase bin/www bget?cth:Cthe_0423 0025 13 ald Clostridium Coenzyme A- www.ncbi.nlm.nih.gov/entrez/ (31)d} beijerinckii acylating aldehyde viewer.fcgi?db=protein&id=4 dehydrogenase 9036681 0026 13 bdhA Clostridium Butanol www.ncbi.nlm.nih.gov/entrez/ 2 acetobutylicu dehydrogenase viewer.fcgi?val=NP_349892. m ATCC 824 1 0027 12 bld Clostridium Butyraldehyde www.ncbi.nlm.nih.gov/entrez/ 4 saccharoperb dehydrogenase viewer.fcgi?db=protein&id=3 utylacetonicu 1075383 m 0028 13 bdh Clostridium Butanol www.ncbi.nlm.nih.gov/entrez/ 4 saccharoperb dehydrogenase viewer.fcgi?db=protein&id=1 utylacetonicu 24221917 m 0029 12/13 adhE Clostridium Aldehyde/ alcohol www.genome.jp/dbget tetani dehydrogenase bin/www bget?ctc:CTC01366 0030 12/13 adhE Clostridium Aldehyde/ alcohol www.genome.jp/dbget perfringens dehydrogenase bin/www bget?cpe:CPE2531 0031 12/13 adhE Clostridium Aldehyde/ alcohol www.genome.jp/dbget difficile dehydrogenase bin/www bget?cdf:CD2966 0032 8 sucA Mycobacteriu a-ketoglutarate www.ncbi.nlm.nih.gov/entrez/ 5 m bovis decarboxylase viewer.fcgi?val=YP_977400. BCG, Pasteur 1 0033 9 cat2 Clostridium 4-hydroxybutyrate www.ncbi.nlm.nih.gov/entrez/ aminobutyric coenzyme A viewer.fcgi?db=protein&val= um transferase 6249316 0034 9 cat2 Porphyromon 4-hydroxybutyrate www.ncbi.nlm.nih.gov/entrez/ as gingivalis coenzyme A viewer.fcgi?db=protein&val= W83 transferase 34541558 0035 6 sucD Porphyromon Succinic www.ncbi.nlm.nih.gov/entrez/ as gingivalis semialdehyde viewer.fcgi?val=NP_904963. W83 dehydrogenase 1 (CoA-dependent) 0036 7 4-HBd Porphyromon NAD-dependent www.ncbi.nlm.nih.gov/entrez/ as gingivalis 4-hydroxybutyrate viewer.fcgi?val=NP_904964. W83 dehydrogenase 1 0037 7 gbd Uncultured 4-hydroxybutyrate www.ncbi.nlm.nih.gov/entrez/ 6 bacterium dehydrogenase viewer.fcgi?db=nuccore&id= 5916168 0038 1 sucCD E. coli Succinyl-CoA www.shigen.nig.ac.jp/ecoli/pe synthetase c/genes.List.DetailAction.do 'Sohling and Gottschalk, Eur. J. Biochem. 212:121-127 (1993); Sohling and Gottschalk, J. Bacteriol. 178:871-880 (1996) 2Nolling et al,, J., J. Bacteriol. 183:4823-4838 (2001) 5 3 Pohlmann et al., Nat. Biotechnol. 24:1257-1262 (2006) 4 Kosaka et al., Biosci. Biotechnol. Biochem. 71:58-68 (2007) 5 Brosch et al., Proc. Nati. Acad. Sci. U.S.A. 104:5596-5601 (2007) 6 Henne et al., Appl. Environ. Microbiol. 65:3901-3907 (1999) 100 Expression Vector Construction for BDO pathway. Vector backbones and some strains were obtained from Dr. Rolf Lutz of Expressys (www.expressys.de/). The vectors and strains are based on the pZ Expression System developed by Dr. Rolf Lutz and Prof. Hermann Bujard (Lutz, R. and H. Bujard, Nucleic Acids Res 25:1203-1210 (1997)). Vectors obtained were 5 pZE13lue, pZA33luc, pZS* l3luc and pZE22luc and contained the luciferase gene as a stuffer fragment. To replace the luciferase stuffer fragment with a lacZ-alpha fragment flanked by appropriate restriction enzyme sites, the luciferase stuffer fragment was first removed from each vector by digestion with EcoRI and XbaI. The lacZ-alpha fragment was PCR amplified from pUC19 with the following primers: 10 lacZalpha-RI 5'GACGAATTCGCTAGCAAGAGGAGAAGTCGACATGTCCAATTCACTGGCCGTCG TTTTAC3' lacZalpha 3'BB 5'-GACCCTAGGAAGCTTTCTAGAGTCGACCTATGCGGCATCAGAGCAGA-3'. 15 This generated a fragment with a 5' end of EcoRI site, NheI site, a Ribosomal Binding Site, a SalI site and the start codon. On the 3' end of the fragment contained the stop codon, XbaI, HindlIl, and AvrII sites. The PCR product was digested with EcoRI and AvrII and ligated into the base vectors digested with EcoRI and Xbal (XbaI and AvrII have compatible ends and generate a non-site). Because NheI and XbaI restriction enzyme sites generate compatible ends 20 that can be ligated together (but generate a NheI/XbaI non-site that is not digested by either enzyme), the genes cloned into the vectors could be "Biobricked" together (http://openwetware.org/wiki/Synthetic Biology:BioBricks). Briefly, this method allows joining an unlimited number of genes into the vector using the same 2 restriction sites (as long as the sites do not appear internal to the genes), because the sites between the genes are destroyed after 25 each addition. All vectors have the pZ designation followed by letters and numbers indication the origin of replication, antibiotic resistance marker and promoter/regulatory unit. The origin of replication is the second letter and is denoted by E for ColEl, A for p15A and S for pSC101 -based origins. The first number represents the antibiotic resistance marker (1 for Ampicillin, 2 for Kanamycin, 30 3 for Chloramphenicol, 4 for Spectinomycin and 5 for Tetracycline). The final number defines the promoter that regulated the gene of interest (1 for PLtetO-1, 2 for PLaco-, 3 for PA11aco-1, and 4 for Piac/a-). The MCS and the gene of interest follows immediately after. For the work 101 discussed here we employed two base vectors, pZA33 and pZE13, modified for the biobricks insertions as discussed above. Once the gene(s) of interest have been cloned into them, resulting plasmids are indicated using the four digit gene codes given in Table 6; e.g., pZA33-XXXX YYYY-... 5 Host Strain Construction. The parent strain in all studies described here is E. coli K-12 strain MG1655. Markerless deletion strains in adhE, gabD, and aldA were constructed under service contract by a third party using the redET method (Datsenko, K. A. and B. L. Wanner, Proc Nati Acad Sci U S.A 97:6640-6645 (2000)). Subsequent strains were constructed via bacteriophage P1 mediated transduction (Miller, J. Experiments in Molecular Genetics, Cold Spring Harbor 10 Laboratories, New York (1973)). Strain C600Z1 (laciq, PN25-tetR, SpR, lacYl, leuB6,mcrB+, supE44, thi-1, thr-1, tonA21) was obtained from Expressys and was used as a source of a lacIq allele for P1 transduction. Bacteriophage Pivir was grown on the C600Z1 E. coli strain, which has the spectinomycin resistance gene linked to the lacIq. The P1 lysate grown on C600Z1 was used to infect MG1655 with selection for spectinomycin resistance. The spectinomycin resistant 15 colonies were then screened for the linked lacIq by determining the ability of the transductants to repress expression of a gene linked to a PAI1aco-1 promoter. The resulting strain was designated MG1655 lacIq. A similar procedure was used to introduce lacIQ into the deletion strains. Production of 4-HB From Succinate. For construction of a 4-HB producer from succinate, genes encoding steps from succinate to 4-HB and 4-HB-CoA (1, 6, 7, and 9 in Figure 20 1) were assembled onto the pZA33 and pZE13 vectors as described below. Various combinations of genes were assessed, as well as constructs bearing incomplete pathways as controls (Tables 7 and 8). The plasmids were then transformed into host strains containing lacIQ, which allow inducible expression by addition of isopropyl P-D-1-thiogalactopyranoside (IPTG). Both wild-type and hosts with deletions in genes encoding the native succinic 25 semialdehyde dehydrogenase (step 2 in Figure 1) were tested. Activity of the heterologous enzymes were first tested in in vitro assays, using strain MG1655 lacIQ as the host for the plasmid constructs containing the pathway genes. Cells were grown aerobically in LB media (Difco) containing the appropriate antibiotics for each construct, and induced by addition of IPTG at 1 mM when the optical density (OD600) reached approximately 30 0.5. Cells were harvested after 6 hours, and enzyme assays conducted as discussed below. In Vitro Enzyme Assays. To obtain crude extracts for activity assays, cells were harvested by centrifugation at 4,500 rpm (Beckman-Coulter, Allegera X-15R) for 10 min. The pellets were 102 resuspended in 0.3 mL BugBuster (Novagen) reagent with benzonase and lysozyme, and lysis proceeded for 15 minutes at room temperature with gentle shaking. Cell-free lysate was obtained by centrifugation at 14,000 rpm (Eppendorf centrifuge 5402) for 30 min at 4'C. Cell protein in the sample was determined using the method of Bradford et al., Anal. Biochem. 72:248-254 5 (1976), and specific enzyme assays conducted as described below. Activities are reported in Units/mg protein, where a unit of activity is defined as the amount of enzyme required to convert 1 pmol of substrate in 1 min. at room temperature. In general, reported values are averages of at least 3 replicate assays. Succinyl-CoA transferase (Cat1) activity was determined by monitoring the formation of acetyl 10 CoA from succinyl-CoA and acetate, following a previously described procedure Sohling and Gottschalk, J. Bacteriol. 178:871-880 (1996). Succinyl-CoA synthetase (SucCD) activity was determined by following the formation of succinyl-CoA from succinate and CoA in the presence of ATP. The experiment followed a procedure described by Cha and Parks, J. Biol. Chem. 239:1961-1967 (1964). CoA-dependent succinate semialdehyde dehydrogenase (SucD) activity 15 was determined by following the conversion of NAD to NADH at 340 nm in the presence of succinate semialdehyde and CoA (Sohling and Gottschalk, Eur. J. Biochem. 212:121-127 (1993)). 4-HB dehydrogenase (4-HBd) enzyme activity was determined by monitoring the oxidation of NADH to NAD at 340 nm in the presence of succinate semialdehyde. The experiment followed a published procedure Gerhardt et al. Arch. Microbiol. 174:189-199 20 (2000). 4-HB CoA transferase (Cat2) activity was determined using a modified procedure from Scherf and Buckel, Appl. Environ. Microbiol. 57:2699-2702 (1991). The formation of 4-HB CoA or butyryl-CoA formation from acetyl-CoA and 4-HB or butyrate was determined using HPLC. Alcohol (ADH) and aldehyde (ALD) dehydrogenase was assayed in the reductive direction 25 using a procedure adapted from several literature sources (Durre et al., FEMS Microbiol Rev. 17:251-262 (1995); Palosaari and Rogers, J. Bacteriol. 170:2971-2976 (1988) and Welch et al., Arch. Biochem. Biophys. 273:309-318 (1989). The oxidation of NADH is followed by reading absorbance at 340 nM every four seconds for a total of 240 seconds at room temperature. The reductive assays were performed in 100 mM MOPS (adjusted to pH 7.5 with KOH), 0.4 mM 30 NADH, and from 1 to 50 1tl of cell extract. The reaction is started by adding the following reagents: 100 1tl of 100 mM acetaldehyde or butyraldehyde for ADH, or 100 il of 1 mM acetyl CoA or butyryl-CoA for ALD. The Spectrophotometer is quickly blanked and then the kinetic read is started. The resulting slope of the reduction in absorbance at 340 nM per minute, along 103 with the molar extinction coefficient of NAD(P)H at 340 nM (6000) and the protein concentration of the extract, can be used to determine the specific activity. The enzyme activity of PTB is measured in the direction of butyryl-CoA to butyryl-phosphate as described in Cary et al. J. Bacteriol. 170:4613-4618 (1988). It provides inorganic phosphate for 5 the conversion, and follows the increase in free CoA with the reagent 5,5' -dithiobis-(2 nitrobenzoic acid), or DTNB. DTNB rapidly reacts with thiol groups such as free CoA to release the yellow-colored 2-nitro-5-mercaptobenzoic acid (TNB), which absorbs at 412 nm with a molar extinction coefficient of 14,140 M cm- . The assay buffer contained 150 mM potassium phosphate at pH 7.4, 0.1 mM DTNB, and 0.2 mM butyryl-CoA, and the reaction was 10 started by addition of 2 to 50 pL cell extract. The enzyme activity of BK is measured in the direction of butyrate to butyryl-phosphate formation at the expense of ATP. The procedure is similar to the assay for acetate kinase previously described Rose et al., J. Biol. Chem. 211:737 756 (1954). However we have found another acetate kinase enzyme assay protocol provided by Sigma to be more useful and sensitive. This assay links conversion of ATP to ADP by acetate 15 kinase to the linked conversion of ADP and phosphoenol pyruvate (PEP) to ATP and pyruvate by pyruvate kinase, followed by the conversion of pyruvate and NADH to lactate and NAD+ by lactate dehydrogenase. Substituting butyrate for acetate is the only major modification to allow the assay to follow BK enzyme activity. The assay mixture contained 80 mM triethanolamine buffer at pH 7.6, 200 mM sodium butyrate, 10 mM MgCl2, 0.1 mM NADH, 6.6 mM ATP, 1.8 20 mM phosphoenolpyruvate. Pyruvate kinase, lactate dehydrogenase, and myokinase were added according to the manufacturer's instructions. The reaction was started by adding 2 to 50 pL cell extract, and the reaction was monitored based on the decrease in absorbance at 340 nm indicating NADH oxidation. Analysis of CoA Derivatives by HPLC. An HPLC based assay was developed to monitor 25 enzymatic reactions involving coenzyme A (CoA) transfer. The developed method allowed enzyme activity characterization by quantitative determination of CoA, acetyl CoA (AcCoA), butyryl CoA (BuCoA) and 4-hydroxybutyrate CoA (4-HBCoA) present in in-vitro reaction mixtures. Sensitivity down to low pM was achieved, as well as excellent resolution of all the CoA derivatives of interest. 30 Chemical and sample preparation was performed as follows. Briefly, CoA, AcCoA, BuCoA and all other chemicals, were obtained from Sigma-Aldrich. The solvents, methanol and acetonitrile, were of HPLC grade. Standard calibration curves exhibited excellent linearity in the 0.01- 104 1mg/mL concentration range. Enzymatic reaction mixtures contained 100mM Tris HCl buffer (pH 7), aliquots were taken at different time points, quenched with formic acid (0.04% final concentration) and directly analyzed by HPLC. HPLC analysis was performed using an Agilent 1100 HPLC system equipped with a binary 5 pump, degasser, thermostated autosampler and column compartment, and diode array detector (DAD), was used for the analysis. A reversed phase column, Kromasil 100 5um C18, 4.6x150mm (Peeke Scientific), was employed. 25mM potassium phosphate (pH 7) and methanol or acetonitrile, were used as aqueous and organic solvents at 1mL/min flow rate. Two methods were developed: a short one with a faster gradient for the analysis of well-resolved CoA, AcCoA 10 and BuCoA, and a longer method for distinguishing between closely eluting AcCoA and 4 HBCoA. Short method employed acetonitrile gradient (0min - 5%, 6min - 30%, 6.5min - 5%, 10min - 5%) and resulted in the retention times 2.7, 4.1 and 5.5min for CoA, AcCoA and BuCoA, respectively. In the long method methanol was used with the following linear gradient: 0min - 5%, 20 min - 35%, 20.5min - 5%, 25min - 5%. The retention times for CoA, AcCoA, 15 4-HBCoA and BuCoA were 5.8, 8.4, 9.2 and 16.0 min, respectively. The injection volume was 5pL, column temperature 30'C, and UV absorbance was monitored at 260nm. The results demonstrated activity of each of the four pathway steps (Table 7), though activity is clearly dependent on the gene source, position of the gene in the vector, and the context of other genes with which it is expressed. For example, gene 0035 encodes a succinic semialdehyde 20 dehydrogenase that is more active than that encoded by 0008, and 0036 and 00 1On are more active 4-HB dehydrogenase genes than 0009. There also seems to be better 4-HB dehydrogenase activity when there is another gene preceding it on the same operon.

105 Table 7. In vitro enzyme activities in cell extracts from MG1655 lacIQ containing the plasmids expressing genes in the 4-HB-CoA pathway. Activities are reported in Units/mg protein, where a unit of activity is defined as the amount of enzyme required to convert 1 pmol of substrate in 1 min. at room temperature. Sample # pZE13 (a) pZA33 (b) OD600 Cell Prot (c) Cat1 SucD 4HBd Cat2 1 cat1 (0004) 2.71 6.43 1.232 0.00 2 cat1 (0004)-sucD (0035) 2.03 5.00 0.761 2.57 3 cat1 (0004)-sucD (0008) 1.04 3.01 0.783 0.01 4 sucD (0035) 2.31 6.94 2.32 5 sucD (0008) 1.10 4.16 0.05 6 4hbd (0009) 2.81 7.94 0.003 0.25 7 4hbd (0036) 2.63 7.84 3.31 8 4hbd(OO10n) 2.00 5.08 2.57 9 cat1 (0004)-sucD (0035) 4hbd (0009) 2.07 5.04 0.600 1.85 0.01 10 cat1 (0004)-sucD (0035) 4hbd (0036) 2.08 5.40 0.694 1.73 0.41 11 cat1 (0004)-sucD (0035) 4hbd (OO10n) 2.44 4.73 0.679 2.28 0.37 12 cat1 (0004)-sucD (0008) 4hbd (0009) 1.08 3.99 0.572 -0.01 0.02 13 cat1 (0004)-sucD (0008) 4hbd (0036) 0.77 2.60 0.898 -0.01 0.04 14 cat1 (0004)-sucD (0008) 4hbd (OO10n) 0.63 2.47 0.776 0.00 0.00 15 cat2 (0034) 2.56 7.86 1.283 16 cat2(0034)-4hbd(0036) 3.13 8.04 24.86 0.993 17 cat2(0034)-4hbd(OO10n) 2.38 7.03 7.45 0.675 18 4hbd(0036)-cat2(0034) 2.69 8.26 2.15 7.490 5 19 4hbd(OO10n)-cat2(0034) 2.44 6.59 0.59 4.101 Genes expressed from Plac on pZE13, a high-copy plasmid with colE1 origin and ampicillin resistance. Gene identification numbers are as given in Table 6 Genes expressed from Plac on pZA33, a medium-copy plasmid with pACYC origin and chloramphenicol resistance. 10 (c) Cell protein given as mg protein per mL extract. Recombinant strains containing genes in the 4-HB pathway were then evaluated for the ability to produce 4-HB in vivo from central metabolic intermediates. Cells were grown anaerobically in LB medium to OD600 of approximately 0.4, then induced with 1 mM IPTG. One hour later, sodium succinate was added to 10 mM, and samples taken for analysis following an additional 15 24 and 48 hours. 4-HB in the culture broth was analyzed by GC-MS as described below. The results indicate that the recombinant strain can produce over 2 mM 4-HB after 24 hours, compared to essentially zero in the control strain (Table 8).

106 Table 8. Production of 4-HB from succinate in E. coli strains harboring plasmids expressing various combinations of 4-HB pathway genes. 24 Hours 48 Hours Sample# Host Strain pZE13 pZA33 OD6OO 4HB, gM 4HB norm. (a) OD6OO 4HB,gM 4HBnorm.(a) 1 MG1655 aclq cat1 (0004)-sucD (0035) 4hbd(0009) 0.47 487 1036 1.04 1780 1711 2 MG1655 aclq cat1 (0004)-sucD (0035) 4hbd(0027) 0.41 111 270 0.99 214 217 3 MG1655 aclq cat1 (0004)-sucD (0035) 4hbd(0036) 0.47 863 1835 0.48 2152 4484 4 MG1655 aclq cat1 (0004)-sucD (0035) 4hbd(OO10n) 0.46 956 2078 0.49 2221 4533 5 MG1655 aclq cat1 (0004)-sucD (0008) 4hbd (0009) 0.38 493 1296 0.37 1338 3616 6 MG1655 aclq cat1 (0004)-sucD (0008) 4hbd(0027) 0.32 26 81 0.27 87 323 7 MG1655 aclq cat1 (0004)-sucD (0008) 4hbd(0036) 0.24 506 2108 0.31 1448 4672 8 MG1655 aclq cat1 (0004)-sucD (0008) 4hbd(OO10n) 0.24 78 324 0.56 233 416 9 MG1655 Iaclq gabD cat1 (0004)-sucD (0035) 4hbd (0009) 0.53 656 1237 1.03 1643 1595 10 MG1655 aclq gabD cat1 (0004)-sucD (0035) 4hbd (0027) 0.44 92 209 0.98 214 218 11 MG1655 acq gabD cat1 (0004)-sucD (0035) 4hbd(0036) 0.51 1072 2102 0.97 2358 2431 12 MG1655 aclq gabD cat1 (0004)-sucD (0035) 4hbd (OO10n) 0.51 981 1924 0.97 2121 2186 13 MG1655 Iaclq gabD cat1 (0004)-sucD (0008) 4hbd (0009) 0.35 407 1162 0.77 1178 1530 14 MG1655 Iaclq gabD cat1 (0004)-sucD (0008) 4hbd (0027) 0.51 19 36 1.07 50 47 15 MG1655 acq gabD cat1 (0004)-sucD (0008) 4hbd(0036) 0.35 584 1669 0.78 1350 1731 16 MG1655 Iaclq gabD cat1 (0004)-sucD (0008) 4hbd (OO10n) 0.32 74 232 0.82 232 283 17 MG1655 Iaclq vector only vector only 0.8 1 2 1.44 3 2 18 MG1655 Iaclq gabD vector only vector only 0.89 1 2 1.41 7 5 (a) Normalized 4-HB concentration, ptM/OD600 units 5 An alternate to using a CoA transferase (cat1) to produce succinyl-CoA from succinate is to use the native E. coli sucCD genes, encoding succinyl-CoA synthetase. This gene cluster was cloned onto pZE13 along with candidate genes for the remaining steps to 4-HB to create pZE13 0038-0035-0036. Production of 4-HB from Glucose. Although the above experiments demonstrate a functional 10 pathway to 4-HB from a central metabolic intermediate (succinate), an industrial process would require the production of chemicals from low-cost carbohydrate feedstocks such as glucose or sucrose. Thus, the next set of experiments was aimed to determine whether endogenous succinate produced by the cells during growth on glucose could fuel the 4-HB pathway. Cells were grown anaerobically in M9 minimal medium (6.78 g/L Na 2

HPO

4 , 3.0 g/L KH 2

PO

4 , 0.5 g/L 15 NaCl, 1.0 g/L NH 4 Cl, 1 mM MgSO 4 , 0.1 mM CaCl 2 ) supplemented with 20 g/L glucose, 100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the buffering capacity, 10 tg/mL thiamine, and the appropriate antibiotics. 0.25 mM IPTG was added when OD600 reached approximately 0.2, and samples taken for 4-HB analysis every 24 hours following induction. In all cases 4-HB plateaued after 24 hours, with a maximum of about 1 mM in the 20 best strains (Figure 3a), while the succinate concentration continued to rise (Figure 3b). This indicates that the supply of succinate to the pathway is likely not limiting, and that the bottleneck may be in the activity of the enzymes themselves or in NADH availability. 0035 and 0036 are clearly the best gene candidates for CoA-dependent succinic semialdehyde dehydrogenase and 4-HB dehydrogenase, respectively. The elimination of one or both of the 107 genes encoding known (gabD) or putative (aldA) native succinic semialdehyde dehydrogenases had little effect on performance. Finally, it should be noted that the cells grew to a much lower OD in the 4-HB-producing strains than in the controls (Figure 3c). An alternate pathway for the production of 4-HB from glucose is via a-ketoglutarate. We 5 explored the use of an a.-ketoglutarate decarboxylase from Mycobacterium tuberculosis Tian et al., Proc. Natl. Acad. Sci. USA 102:10670-10675 (2005) to produce succinic semialdehyde directly from a-ketoglutarate (step 8 in Figure 1). To demonstrate that this gene (0032) was functional in vivo, we expressed it on pZE13 in the same host as 4-HB dehydrogenase (gene 0036) on pZA33. This strain was capable of producing over 1.0 mM 4-HB within 24 hours 10 following induction with 1 mM IPTG (Figure 4). Since this strain does not express a CoA dependent succinic semialdehyde dehydrogenase, the possibility of succinic semialdehyde production via succinyl-CoA is eliminated. It is also possible that the native genes responsible for producing succinic semialdehyde could function in this pathway (steps 4 and 5 in Figure 1); however, the amount of 4-HB produced when the pZE13-0032 plasmid was left out of the host 15 is the negligible. Production of BDO from 4-HB. The production of BDO from 4-HB required two reduction steps, catalyzed by dehydrogenases. Alcohol and aldehyde dehydrogenases (ADH and ALD, respectively) are NAD+/H and/or NADP+/H-dependent enzymes that together can reduce a carboxylic acid group on a molecule to an alcohol group, or in reverse, can perform the 20 oxidation of an alcohol to a carboxylic acid. This biotransformation has been demonstrated in wild-type Clostridium acetobutylicum (Jewell et al., Current Microbiology, 13:215-19 (1986)), but neither the enzymes responsible nor the genes responsible were identified. In addition, it is not known whether activation to 4-HB-CoA is first required (step 9 in Figure 1), or if the aldehyde dehydrogenase (step 12) can act directly on 4-HB. We developed a list of candidate 25 enzymes from C. acetobutylicum and related organisms based on known activity with the non hydroxylated analogues to 4-HB and pathway intermediates, or by similarity to these characterized genes (Table 6). Since some of the candidates are multifunctional dehydrogenases, they could potentially catalyze both the NAD(P)H-dependent reduction of the acid (or CoA-derivative) to the aldehyde, and of the aldehyde to the alcohol. Before beginning 30 work with these genes in E. coli, we first validated the result referenced above using C. acetobutylicum ATCC 824. Cells were grown in Schaedler broth (Accumedia, Lansing, MI) supplemented with 10 mM 4-HB, in an anaerobic atmosphere of 10% C0 2 , 10% H 2 , and 80% N 2 at 30"C. Periodic culture samples were taken, centrifuged, and the broth analyzed for BDO by 108 GC-MS as described below. BDO concentrations of 0.1 mM, 0.9 mM, and 1.5 mM were detected after 1 day, 2 days, and 7 days incubation, respectively. No BDO was detected in culture grown without 4-HB addition. To demonstrate that the BDO produced was derived from glucose, we grew the best BDO producing strain MG1655 lacIQ pZE13-0004-0035-0002 5 pZA33-0034-0036 in M9 minimal medium supplemented with 4 g/L uniformly labeled 3

C

glucose. Cells were induced at OD of 0.67 with 1 mM IPTG, and a sample taken after 24 hours. Analysis of the culture supernatant was performed by mass spectrometry. Gene candidates for the 4-HB to BDO conversion pathway were next tested for activity when expressed in the E. coli host MG1655 lacIQ. Recombinant strains containing each gene 10 candidate expressed on pZA33 were grown in the presence of 0.25 mM IPTG for four hours at 37'C to fully induce expression of the enzyme. Four hours after induction, cells were harvested and assayed for ADH and ALD activity as described above. Since 4-HB-CoA and 4 hydroxybutyraldehyde are not available commercially, assays were performed using the non hydroxylated substrates (Table 9). The ratio in activity between 4-carbon and 2-carbon 15 substrates for C. acetobutylicum adhE2 (0002) and E. coli adhE (0011) were similar to those previously reported in the literature a Atsumi et al., Biochim. Biophys. Acta. 1207:1-11 (1994). Table 9. In vitro enzyme activities in cell extracts from MG1655 lacIQ containing pZA33 expressing gene candidates for aldehyde and alcohol dehydrogenases. Activities are expressed in imol min-' mg cell protein 1 . N.D., not determined. Aldehyde dehydrogenase Alcohol dehydrogenase Gene Substrate Butyryl-CoA Acetyl-CoA Butyraldehyde Acetaldehyde 0002 0.0076 0.0046 0.0264 0.0247 0003n 0.0060 0.0072 0.0080 0.0075 0011 0.0069 0.0095 0.0265 0.0093 0013 N.D. N.D. 0.0130 0.0142 0023 0.0089 0.0137 0.0178 0.0235 0025 0 0.0001 N.D. N.D. 0026 0 0.0005 0.0024 0.0008 20 For the BDO production experiments, cat2 from Porphyromonas gingivalis W83 (gene 0034) was included on pZA33 for the conversion of 4-HB to 4-HB-CoA, while the candidate dehydrogenase genes were expressed on pZE13. The host strain was MG1655 lacIQ. Along with the alcohol and aldehyde dehydrogenase candidates, we also tested the ability of CoA-dependent 25 succinic semialdehyde dehydrogenases (sucD) to function in this step, due to the similarity of the substrates. Cells were grown to an OD of about 0.5 in LB medium supplemented with 10 mM 4-HB, induced with 1 mM IPTG, and culture broth samples taken after 24 hours and 109 analyzed for BDO as described below. The best BDO production occurred using adhE2 from C. acetobutylicum, sucD from C. kluyveri, or sucD from P. gingivalis (Figure 5). Interestingly, the absolute amount of BDO produced was higher under aerobic conditions; however, this is primarily due to the lower cell density achieved in anaerobic cultures. When normalized to cell 5 OD, the BDO production per unit biomass is higher in anaerobic conditions (Table 10). Table 10. Absolute and normalized BDO concentrations from cultures of cells expressing adhE2 from C. acetobutylicum, sucD from C. kluyveri, or sucD from P. gingivalis (data from experiments 2, 9, and 10 in Figure 3), as well as the negative control (experiment 1). Gene jConditions BDO OD BDO/OD 10 expressed (M) (600nm) none Aerobic 0 13.4 0 none Microaerobic 0.5 6.7 0.09 none Anaerobic 2.2 1.26 1.75 0002 Aerobic 138.3 9.12 15.2 0002 Microaerobic 48.2 5.52 8.73 0002 Anaerobic 54.7 1.35 40.5 0008n Aerobic 255.8 5.37 47.6 0008n Microaerobic 127.9 3.05 41.9 15 ______ 0008n Anaerobic 60.8 0.62 98.1 0035 Aerobic 21.3 14.0 1.52 0035 Microaerobic 13.1 4.14 3.16 0035 Anaerobic 21.3 1.06 20.1 As discussed above, it may be advantageous to use a route for converting 4-HB to 4-HB-CoA that does not generate acetate as a byproduct. To this aim, we tested the use of 20 phosphotransbutyrylase (ptb) and butyrate kinase (bk) from C. acetobutylicum to carry out this conversion via steps 10 and 11 in Figure 1. The native ptb/bk operon from C. acetobutylicum (genes 0020 and 0021) was cloned and expressed in pZA33. Extracts from cells containing the resulting construct were taken and assayed for the two enzyme activities as described herein. The specific activity of BK was approximately 65 U/mg, while the specific activity of PTB was 25 approximately 5 U/mg. One unit (U) of activity is defined as conversion of 1 PM substrate in 1 minute at room temperature. Finally, the construct was tested for participation in the conversion of 4-HB to BDO. Host strains were transformed with the pZA33-0020-0021 construct described and pZE13-0002, and compared to use of cat2 in BDO production using the aerobic procedure used above in Figure 5. The BK/PTB strain produced 1 mM BDO, compared to 2 mM when 110 using cat2 (Table 11). Interestingly, the results were dependent on whether the host strain contained a deletion in the native adhE gene. Table 11. Absolute and normalized BDO concentrations from cultures of cells expressing adhE2 from C. acetobutylicum in pZE13 along with either cat2 from P. gingivalis (0034) or the 5 PTB/BK genes from C. acetobutylicum on pZA33. Host strains were either MG1655 lacI or MG1655 AadhE lacIQ. Genes Host Strain BDO BDO/OD (riM) (600nm) B 0034 MG1655 lacI 0.827 19.9 0.042 0020+0021 MG1655 lacI 0.007 9.8 0.0007 0034 MG1655 AadhE 2.084 12.5 0.166 lacJI_____ ____ 0020+0021 MG1655 AadhE 0.975 18.8 0.052 ___________ lacJI__ __ _ Production of BDO from Glucose. The final step of pathway corroboration is to express both the 4-HB and BDO segments of the pathway in E. coli and demonstrate production of BDO in 10 glucose minimal medium. New plasmids were constructed so that all the required genes fit on two plamids. In general, cat1, adhE, and sucD genes were expressed from pZE13, and cat2 and 4-HBd were expressed from pZA33. Various combinations of gene source and gene order were tested in the MG1655 lacI background. Cells were grown anaerobically in M9 minimal medium (6.78 g/L Na 2

HPO

4 , 3.0 g/L KH 2

PO

4 , 0.5 g/L NaCl, 1.0 g/L NH 4 Cl, 1 mM MgSO 4 , 0.1 15 mM CaCl 2 ) supplemented with 20 g/L glucose, 100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the buffering capacity, 10 pg/mL thiamine, and the appropriate antibiotics. 0.25 mM IPTG was added approximately 15 hours following inoculation, and culture supernatant samples taken for BDO, 4-HB, and succinate analysis 24 and 48 hours following induction. The production of BDO appeared to show a dependency on gene order (Table 12). 20 The highest BDO production, over 0.5 mM, was obtained with cat2 expressed first, followed by 4-HBd on pZA33, and cat1 followed by P. gingivalis sucD on pZE13. The addition of C. acetobutylicum adhE2 in the last position on pZE13 resulted in slight improvement. 4-HB and succinate were also produced at higher concentrations.

111 Table 12. Production of BDO, 4-HB, and succinate in recombinant E. coli strains expressing combinations of BDO pathway genes, grown in minimal medium supplemented with 20 g/L glucose. Concentrations are given in mM. 24 Hours 48 Hours Sample pZE13 pZA33 Induction OD OD600nm Su 4HB BDO OD600nm Su 4HB BDO 1 catl(0004)-sucD(0035) Ahbd (0036)-cat2(0034) 0.92 1.29 5.44 1.37 0.240 1.24 6.42 1.49 0.280 2 cat1(0004)-sucD(0008N) 4hbd (0036)-cat2(0034) 0.36 1.11 6.90 1.24 0.011 1.06 7.63 1.33 0.011 3 adhE(0002)-catl(0004)-sucD(0035) 4hbd (0036)-cat2(0034) 0.20 0.44 0.34 1.84 0.050 0.60 1.93 2.67 0.119 4 catl(0004)-sucD(0035)-adhE(0002) 4hbd (0036)-cat2(0034) 1.31 1.90 9.02 0.73 0.073 1.95 9.73 0.82 0.077 5 adhE(0002)-catl(0004)-sucD(0008N) 4hbd (0036)-cat2(0034) 0.17 0.45 1.04 1.04 0.008 0.94 7.13 1.02 0.017 6 catl(0004)-sucD(0008N)-adhE(0002) 4hbd (0036)-cat2(0034) 1.30 1.77 10.47 0.25 0.004 1.80 11.49 0.28 0.003 7 catl(0004)-sucD(0035) cat2(0034)-4hbd(0036) 1.09 1.29 5.63 2.15 0.461 1.38 6.66 2.30 0.520 8 catl(0004)-sucD(0008N) cat2(0034)-4hbd(0036) 1.81 2.01 11.28 0.02 0.000 2.24 11.13 0.02 0.000 9 adhE(0002)-catl(0004)-sucD(0035) cat2(0034)-4hbd(0036) 0.24 1.99 2.02 2.32 0.106 0.89 4.85 2.41 0.186 10 catl(0004)-sucD(0035)-adhE(0002) cat2(0034)-4hbd(0036) 0.98 1.17 5.30 2.08 0.569 1.33 6.15 2.14 0.640 11 adhE(0002)-catl(0004)-sucD(0008N) cat2(0034)-4hbd(0036) 0.20 0.53 1.38 2.30 0.019 0.91 8.10 1.49 0.034 12 catl(0004)-sucD(0008N)-adhE(0002) cat2(0034)-4hbd(0036) 2.14 2.73 12.07 0.16 0.000 3.10 11.79 0.17 0.002 13 vectoronly vectoronly 2.11 2.62 9.03 0.01 0.000 3.00 12.05 0.01 0.000 5 Analysis of BDO, 4-HB and succinate by GCMS. BDO, 4-HB and succinate in fermentation and cell culture samples were derivatized by silylation and quantitatively analyzed by GCMS using methods adapted from literature reports ((Simonov et al., J. Anal Chem.59:965-971 (2004)). The developed method demonstrated good sensitivity down to 1p M, linearity up to at least 25mM, as well as excellent selectivity and reproducibility. 10 Sample preparation was performed as follows: lOOgL filtered (0.2pm or 0.45pm syringe filters) samples, e.g. fermentation broth, cell culture or standard solutions, were dried down in a Speed Vac Concentrator (Savant SVC-100H) for approximately 1 hour at ambient temperature, followed by the addition of 20pL 10mM cyclohexanol solution, as an internal standard, in dimethylformamide. The mixtures were vortexed and sonicated in a water bath (Branson 3510) 15 for 15 min to ensure homogeneity. 100 gL silylation derivatization reagent, N,O bis(trimethylsilyl)triflouro-acetimide (BSTFA) with 1% trimethylchlorosilane, was added, and the mixture was incubated at 70 9 C for 30 min. The derivatized samples were centrifuged for 5 min, and the clear solutions were directly injected into GCMS. All the chemicals and reagents were from Sigma-Aldrich, with the exception of BDO which was purchased from J.T.Baker. 20 GCMS was performed on an Agilent gas chromatograph 6890N, interfaced to a mass-selective detector (MSD) 5973N operated in electron impact ionization (El) mode has been used for the analysis. A DB-5MS capillary column (J&W Scientific, Agilent Technologies), 30m x 0.25mm i.d. x 0.25 gm film thickness, was used. The GC was operated in a split injection mode introducing 1pL of sample at 20:1 split ratio. The injection port temperature was 2502C. Helium 25 was used as a carrier gas, and the flow rate was maintained at 1.0 mL/min. A temperature gradient program was optimized to ensure good resolution of the analytes of interest and minimum matrix interference. The oven was initially held at 80 9 C for 1min, then ramped to 112 1202C at 22C/min, followed by fast ramping to 3202C at 1002C/min and final hold for 6min at 3202C. The MS interface transfer line was maintained at 2802C. The data were acquired using 'lowmass' MS tune settings and 30-400 m/z mass-range scan. The total analysis time was 29 min including 3 min solvent delay. The retention times corresponded to 5.2, 10.5, 14.0 and 18.2 5 min for BSTFA-derivatized cyclohexanol, BDO, 4-HB and succinate, respectively. For quantitative analysis, the following specific mass fragments were selected (extracted ion chromatograms): m/z 157 for internal standard cyclohexanol, 116 for BDO, and 147 for both 4 HB and succinate. Standard calibration curves were constructed using analyte solutions in the corresponding cell culture or fermentation medium to match sample matrix as close as possible. 10 GCMS data were processed using Environmental Data Analysis ChemStation software (Agilent Technologies). The results indicated that most of the 4-HB and BDO produced were labeled with 1 3 C (Figure 6, right-hand sides). Mass spectra from a parallel culture grown in unlabeled glucose are shown for comparison (Figure 6, left-hand sides). Note that the peaks seen are for fragments of the 15 derivatized molecule containing different numbers of carbon atoms from the metabolite. The derivatization reagent also contributes some carbon and silicon atoms that naturally-occurring label distribution, so the results are not strictly quantitative. Production of BDO from 4-HB using alternate pathways. The various alternate pathways were also tested for BDO production. This includes use of the native E. coli SucCD enzyme to 20 convert succinate to succinyl-CoA (Table 13, rows 2-3), use of a-ketoglutarate decarboxylase in the a-ketoglutarate pathway (Table 13, row 4), and use of PTB/BK as an alternate means to generate the CoA-derivative of 4HB (Table 13, row 1). Strains were constructed containing plasmids expressing the genes indicated in Table 13, which encompass these variants. The results show that in all cases, production of 4-HB and BDO occurred (Table 13). 25 Table 13. Production of BDO, 4-HB, and succinate in recombinant E. coli strains genes for different BDO pathway variants, grown anaerobically in minimal medium supplemented with 20 g/L glucose, and harvested 24 hours after induction with 0.1 mM IPTG. Concentrations are given in mM. Genes on pZE13 Genes on pZA33 Succinate 4-HB BDO 0002+0004+0035 0020n-0021n-0036 0.336 2.91 0.230 0038+0035 0034-0036 0.814 2.81 0.126 0038+0035 0036-0034 0.741 2.57 0.114 0035+0032 0034-0036 5.01 0.538 0.154 113 EXAMPLE III Biosynthesis of 4-Hydroxybutanoic Acid, y-Butyrolactone and 1,4-Butanediol This Example describes the biosynthetic production of 4-hydroxybutanoic acid, y-butyrolactone and 1,4-butanediol using fermentation and other bioprocesses. 5 Methods for the integration of the 4-HB fermentation step into a complete process for the production of purified GBL, 1,4-butanediol (BDO) and tetrahydrofuran (THF) are described below. Since 4-HB and GBL are in equilibrium, the fermentation broth will contain both compounds. At low pH this equilibrium is shifted to favor GBL. Therefore, the fermentation can operate at pH 7.5 or less, generally pH 5.5 or less. After removal of biomass, the product 10 stream enters into a separation step in which GBL is removed and the remaining stream enriched in 4-HB is recycled. Finally, GBL is distilled to remove any impurities. The process operates in one of three ways: 1) fed-batch fermentation and batch separation; 2) fed-batch fermentation and continuous separation; 3) continuous fermentation and continuous separation. The first two of these modes are shown schematically in Figure 7. The integrated fermentation procedures 15 described below also are used for the BDO producing cells of the invention for biosynthesis of BDO and subsequent BDO family products. Fermentation protocol to produce 4-HB/GBL (batch): The production organism is grown in a 1OL bioreactor sparged with an N 2

/CO

2 mixture, using 5 L broth containing 5 g/L potassium phosphate, 2.5 g/L ammonium chloride, 0.5 g/L magnesium sulfate, and 30 g/L corn steep 20 liquor, and an initial glucose concentration of 20 g/L. As the cells grow and utilize the glucose, additional 70% glucose is fed into the bioreactor at a rate approximately balancing glucose consumption. The temperature of the bioreactor is maintained at 30 degrees C. Growth continues for approximately 24 hours, until 4-HB reaches a concentration of between 20-200 g/L, with the cell density being between 5 and 10 g/L. The pH is not controlled, and will typically decrease to 25 pH 3-6 by the end of the run. Upon completion of the cultivation period, the fermenter contents are passed through a cell separation unit (e.g., centrifuge) to remove cells and cell debris, and the fermentation broth is transferred to a product separations unit. Isolation of 4-HB and/or GBL would take place by standard separations procedures employed in the art to separate organic products from dilute aqueous solutions, such as liquid-liquid extraction using a water immiscible 30 organic solvent (e.g., toluene) to provide an organic solution of 4-HB/GBL. The resulting solution is then subjected to standard distillation methods to remove and recycle the organic solvent and to provide GBL (boiling point 204-205'C) which is isolated as a purified liquid.

114 Fermentation protocol to produce 4-HB/GBL (fully continuous): The production organism is first grown up in batch mode using the apparatus and medium composition described above, except that the initial glucose concentration is 30-50 g/L. When glucose is exhausted, feed medium of the same composition is supplied continuously at a rate between 0.5 5 L/hr and 1 L/hr, and liquid is withdrawn at the same rate. The 4-HB concentration in the bioreactor remains constant at 30-40 g/L, and the cell density remains constant between 3-5 g/L. Temperature is maintained at 30 degrees C, and the pH is maintained at 4.5 using concentrated NaOH and HCl, as required. The bioreactor is operated continuously for one month, with samples taken every day to assure consistency of 4-HB concentration. In continuous mode, 10 fermenter contents are constantly removed as new feed medium is supplied. The exit stream, containing cells, medium, and products 4-HB and/or GBL, is then subjected to a continuous product separations procedure, with or without removing cells and cell debris, and would take place by standard continuous separations methods employed in the art to separate organic products from dilute aqueous solutions, such as continuous liquid-liquid extraction using a water 15 immiscible organic solvent (e.g., toluene) to provide an organic solution of 4-HB/GBL. The resulting solution is subsequently subjected to standard continuous distillation methods to remove and recycle the organic solvent and to provide GBL (boiling point 204-205'C) which is isolated as a purified liquid. GBL Reduction Protocol: Once GBL is isolated and purified as described above, it will then 20 be subjected to reduction protocols such as those well known in the art (references cited) to produce 1,4-butanediol or tetrahydrofuran (THF) or a mixture thereof. Heterogeneous or homogeneous hydrogenation catalysts combined with GBL under hydrogen pressure are well known to provide the products 1,4-butanediol or tetrahydrofuran (THF) or a mixture thereof. It is important to note that the 4-HB/GBL product mixture that is separated from the fermentation 25 broth, as described above, may be subjected directly, prior to GBL isolation and purification, to these same reduction protocols to provide the products 1,4-butanediol or tetrahydrofuran or a mixture thereof. The resulting products, 1,4-butanediol and THF are then isolated and purified by procedures well known in the art. Fermentation and hydrogenation protocol to produce BDO or THF directly (batch): Cells 30 are grown in a 10L bioreactor sparged with an N 2 /C0 2 mixture, using 5 L broth containing 5 g/L potassium phosphate, 2.5 g/L ammonium chloride, 0.5 g/L magnesium sulfate, and 30 g/L corn steep liquor, and an initial glucose concentration of 20 g/L. As the cells grow and utilize the glucose, additional 70% glucose is fed into the bioreactor at a rate approximately balancing 115 glucose consumption. The temperature of the bioreactor is maintained at 30 degrees C. Growth continues for approximately 24 hours, until 4-HB reaches a concentration of between 20-200 g/L, with the cell density being between 5 and 10 g/L. The pH is not controlled, and will typically decrease to pH 3-6 by the end of the run. Upon completion of the cultivation period, 5 the fermenter contents are passed through a cell separation unit (e.g., centrifuge) to remove cells and cell debris, and the fermentation broth is transferred to a reduction unit (e.g., hydrogenation vessel), where the mixture 4-HB/GBL is directly reduced to either 1,4-butanediol or THF or a mixture thereof. Following completion of the reduction procedure, the reactor contents are transferred to a product separations unit. Isolation of 1,4-butanediol and/or THF would take 10 place by standard separations procedures employed in the art to separate organic products from dilute aqueous solutions, such as liquid-liquid extraction using a water immiscible organic solvent (e.g., toluene) to provide an organic solution of 1,4-butanediol and/or THF. The resulting solution is then subjected to standard distillation methods to remove and recycle the organic solvent and to provide 1,4-butanediol and/or THF which are isolated as a purified 15 liquids. Fermentation and hydrogenation protocol to produce BDO or THF directly (fully continuous): The cells are first grown up in batch mode using the apparatus and medium composition described above, except that the initial glucose concentration is 30-50 g/L. When glucose is exhausted, feed medium of the same composition is supplied continuously at a rate 20 between 0.5 L/hr and 1 L/hr, and liquid is withdrawn at the same rate. The 4-HB concentration in the bioreactor remains constant at 30-40 g/L, and the cell density remains constant between 3 5 g/L. Temperature is maintained at 30 degrees C, and the pH is maintained at 4.5 using concentrated NaOH and HCl, as required. The bioreactor is operated continuously for one month, with samples taken every day to assure consistency of 4-HB concentration. In 25 continuous mode, fermenter contents are constantly removed as new feed medium is supplied. The exit stream, containing cells, medium, and products 4-HB and/or GBL, is then passed through a cell separation unit (e.g., centrifuge) to remove cells and cell debris, and the fermentation broth is transferred to a continuous reduction unit (e.g., hydrogenation vessel), where the mixture 4-HB/GBL is directly reduced to either 1,4-butanediol or THF or a mixture 30 thereof. Following completion of the reduction procedure, the reactor contents are transferred to a continuous product separations unit. Isolation of 1,4-butanediol and/or THF would take place by standard continuous separations procedures employed in the art to separate organic products from dilute aqueous solutions, such as liquid-liquid extraction using a water immiscible organic solvent (e.g., toluene) to provide an organic solution of 1,4-butanediol and/or THF. The 116 resulting solution is then subjected to standard continuous distillation methods to remove and recycle the organic solvent and to provide 1,4-butanediol and/or THF which are isolated as a purified liquids. Fermentation protocol to produce BDO directly (batch): The production organism is 5 grown in a 1OL bioreactor sparged with an N 2

/CO

2 mixture, using 5 L broth containing 5 g/L potassium phosphate, 2.5 g/L ammonium chloride, 0.5 g/L magnesium sulfate, and 30 g/L corn steep liquor, and an initial glucose concentration of 20 g/L. As the cells grow and utilize the glucose, additional 70% glucose is fed into the bioreactor at a rate approximately balancing glucose consumption. The temperature of the bioreactor is maintained at 30 degrees C. Growth 10 continues for approximately 24 hours, until BDO reaches a concentration of between 20-200 g/L, with the cell density generally being between 5 and 10 g/L. Upon completion of the cultivation period, the fermenter contents are passed through a cell separation unit (e.g., centrifuge) to remove cells and cell debris, and the fermentation broth is transferred to a product separations unit. Isolation of BDO would take place by standard separations procedures 15 employed in the art to separate organic products from dilute aqueous solutions, such as liquid liquid extraction using a water immiscible organic solvent (e.g., toluene) to provide an organic solution of BDO. The resulting solution is then subjected to standard distillation methods to remove and recycle the organic solvent and to provide BDO (boiling point 228-229'C) which is isolated as a purified liquid. 20 Fermentation protocol to produce BDO directly (fully continuous): The production organism is first grown up in batch mode using the apparatus and medium composition described above, except that the initial glucose concentration is 30-50 g/L. When glucose is exhausted, feed medium of the same composition is supplied continuously at a rate between 0.5 L/hr and 1 L/hr, and liquid is withdrawn at the same rate. The BDO concentration in the 25 bioreactor remains constant at 30-40 g/L, and the cell density remains constant between 3-5 g/L. Temperature is maintained at 30 degrees C, and the pH is maintained at 4.5 using concentrated NaOH and HCl, as required. The bioreactor is operated continuously for one month, with samples taken every day to assure consistency of BDO concentration. In continuous mode, fermenter contents are constantly removed as new feed medium is supplied. The exit stream, 30 containing cells, medium, and the product BDO, is then subjected to a continuous product separations procedure, with or without removing cells and cell debris, and would take place by standard continuous separations methods employed in the art to separate organic products from dilute aqueous solutions, such as continuous liquid-liquid extraction using a water immiscible 117 organic solvent (e.g., toluene) to provide an organic solution of BDO. The resulting solution is subsequently subjected to standard continuous distillation methods to remove and recycle the organic solvent and to provide BDO (boiling point 228-229'C) which is isolated as a purified liquid (mpt 20'C). 5 EXAMPLE IV Exemplary BDO Pathways This example describes exemplary enzymes and corresponding genes for 1,4-butandiol (BDO) synthetic pathways. 10 Exemplary BDO synthetic pathways are shown in Figures 8-13. The pathways depicted in Figures 8-13 are from common central metabolic intermediates to 1,4-butanediol. All transformations depicted in Figures 8-13 fall into the 18 general categories of transformations shown in Table 14. Below is described a number of biochemically characterized candidate genes in each category. Specifically listed are genes that can be applied to catalyze the 15 appropriate transformations in Figures 9-13 when cloned and expressed in a host organism. The top three exemplary genes for each of the key steps in Figures 9-13 are provided in Tables 15-23 (see below). Exemplary genes were provided for the pathways depicted in Figure 8 are described herein. Table 14. Enzyme types required to convert common central metabolic intermediates into 1,4 20 butanediol. The first three digits of each label correspond to the first three Enzyme Commission number digits which denote the general type of transformation independent of substrate specificity. Label Function 1,1.1.a Oxidoreductase (ketone to hydroxyl or aldehyde to alcohol) 1.1.1.c Oxidoreductase (2 step, acyl-CoA to alcohol) 1.2.1.b Oxidoreductase (acyl-CoA to aldehyde) 1.2.1.c Oxidoreductase (2-oxo acid to acyl-CoA, decarboxylation) 1.2.1 .d Oxidoreductase (phosphorylating/dephosphorylating) 1.3.1.a Oxidoreductase operating on CH-CH donors 1.4.1.a Oxidoreductase operating on amino acids 2.3.1.a Acyltransferase (transferring phosphate group) 2.6. 1.a Aminotransferase 2.7.2.a Phosphotransferase, carboxyl group acceptor 2.8.3.a Coenzyme-A transferase 3.1.2.a Thiolester hydrolase (CoA specific) 4.1.1.a Carboxy-lyase 118 4.2. 1.a Hydro-lyase 4.3. 1.a Ammonia-lyase 5.3.3.a Isomerase 5.4.3.a Aminomutase 6.2.1.a Acid-thiol ligase 5 1.1.a - Oxidoreductase (aldehyde to alcohol or ketone to hydroxyl) Aldehyde to alcohol. Exemplary genes encoding enzymes that catalyze the conversion of an aldehyde to alcohol, that is, alcohol dehydrogenase or equivalently aldehyde reductase, include alrA encoding a medium-chain alcohol dehydrogenase for C2-C14 (Tani et al. Appl.Environ.Microbiol. 66:5231-5235 (2000)), ADH2 from Saccharomyces cerevisiae (Atsumi 10 et al. Nature 451:86-89 (2008)), yqhD from E. coli which has preference for molecules longer than C(3) (Sulzenbacher et al. Journal of Molecular Biology 342:489-502 (2004)), and bdh I and bdh II from C. acetobutylicum which converts butyryaldehyde into butanol (Walter et al. Journal of Bacteriology 174:7149-7158 (1992)). The protein sequences for each of these exemplary gene products, if available, can be found using the following GenBank accession 15 numbers: Gene Accession No. GI No. Organism alrA BAB12273.1 9967138 Acinetobacter sp. Strain M-1 ADH2 NP_014032.1 6323961 Saccharymyces cerevisiae yqhD NP_417484.1 16130909 Escherichia coli bdh I NP_349892.1 15896543 Clostridium acetobutylicum bdh II NP_349891.1 15896542 Clostridium acetobutylicum Enzymes exhibiting 4-hydroxybutyrate dehydrogenase activity (EC 1.1.1.61) also fall into this category. Such enzymes have been characterized in Ralstonia eutropha (Bravo et al. J.Forensic Sci. 49:379-387 (2004), Clostridium kluyveri (Wolff et al. Protein Expr.Purif 6:206-212 (1995)) and Arabidopsis thaliana (Breitkreuz et al. J.Biol. Chem. 278:41552-41556 (2003)). Gene Accession No. GI No. Organism 4hbd YP_726053.1 113867564 Ralstonia eutropha H16 4hbd L21902.1 146348486 Clostridium kluyveri DSM 555 4hbd Q94B07 75249805 Arabidopsis thaliana 20 Another exemplary enzyme is 3-hydroxyisobutyrate dehydrogenase which catalyzes the reversible oxidation of 3-hydroxyisobutyrate to methylmalonate semialdehyde. This enzyme participates in valine, leucine and isoleucine degradation and has been identified in bacteria, 119 eukaryotes, and mammals. The enzyme encoded by P84067 from Thermus thermophilus HB8 has been structurally characterized (Lokanath et al. JMol Biol 352:905-17 (2005)). The reversibility of the human 3-hydroxyisobutyrate dehydrogenase was demonstrated using isotopically-labeled substrate (Manning et al. Biochem J 231:481-484 (1985)). Additional genes 5 encoding this enzyme include 3hidh in Homo sapiens (Hawes et al. Methods Enzymol. 324:218 228 (2000)) and Oryctolagus cuniculus (Chowdhury et al. Biosci.Biotechnol Biochem. 60:2043 2047 (1996); Hawes et al. Methods Enzymol. 324:218-228 (2000)), mmsb in Pseudomonas aeruginosa, and dhat in Pseudomonas putida (Aberhart et al. J Chem.Soc. [Perkin 1] 6:1404 1406 (1979); Chowdhury et al. Biosci.Biotechnol Biochem. 67:438-441 (2003); Chowdhury et 10 al. Biosci.Biotechnol Biochem. 60:2043-2047 (1996)). Gene Accession No. GI No. Organism P84067 P84067 75345323 Thermus thermophilus mmsb P28811.1 127211 Pseudomonas aeruginosa dhat Q59477.1 2842618 Pseudomonas putida 3hidh P31937.2 12643395 Homo sapiens 3hidh P32185.1 416872 Oryctolagus cuniculus Several 3-hydroxyisobutyrate dehydrogenase enzymes have also been shown to convert malonic semialdehyde to 3-hydroxyproprionic acid (3-HP). Three gene candidates exhibiting this activity are mmsB from Pseudomonas aeruginosa PAO1(62), mmsB from Pseudomonas putida 15 KT2440 (Liao et al., US Publication 2005/0221466) and mmsB from Pseudomonas putida E23 (Chowdhury et al., Biosci.Biotechnol.Biochem. 60:2043-2047 (1996)). An enzyme with 3 hydroxybutyrate dehydrogenase activity in Alcaligenesfaecalis M3A has also been identified (Gokam et al., US Patent No. 7,393,676; Liao et al., US Publication No. 2005/0221466). Additional gene candidates from other organisms including Rhodobacter spaeroides can be 20 inferred by sequence similarity. Gene Accession No. GI No. Organism mmsB AAA25892.1 151363 Pseudomonas aeruginosa mmsB NP_252259.1 15598765 Pseudomonas aeruginosa PA01 mmsB NP_746775.1 26991350 Pseudomonas putida KT2440 mmsB JC7926 60729613 Pseudomonas putida E23 orfBl AAL26884 16588720 Rhodobacter spaeroides The conversion of malonic semialdehyde to 3-HP can also be accomplished by two other enzymes: NADH-dependent 3-hydroxypropionate dehydrogenase and NADPH-dependent 120 malonate semialdehyde reductase. An NADH-dependent 3-hydroxypropionate dehydrogenase is thought to participate in beta-alanine biosynthesis pathways from propionate in bacteria and plants (Rathinasabapathi, B. Journal of Plant Pathology 159:671-674 (2002); Stadtman, E. R. JAm.Chem.Soc. 77:5765-5766 (1955)). This enzyme has not been associated with a gene in any 5 organism to date. NADPH-dependent malonate semialdehyde reductase catalyzes the reverse reaction in autotrophic C0 2 -fixing bacteria. Although the enzyme activity has been detected in Metallosphaera sedula, the identity of the gene is not known (Alber et al. J.Bacteriol. 188:8551 8559 (2006)). Ketone to hydroxyl. There exist several exemplary alcohol dehydrogenases that convert a ketone 10 to a hydroxyl functional group. Two such enzymes from E. coli are encoded by malate dehydrogenase (mdh) and lactate dehydrogenase (ldhA). In addition, lactate dehydrogenase from Ralstonia eutropha has been shown to demonstrate high activities on substrates of various chain lengths such as lactate, 2-oxobutyrate, 2-oxopentanoate and 2-oxoglutarate (Steinbuchel and. Schlegel, Eur.J.Biochem. 130:329-334 (1983)). Conversion of alpha-ketoadipate into 15 alpha-hydroxyadipate can be catalyzed by 2-ketoadipate reductase, an enzyme reported to be found in rat and in human placenta (Suda et al. Arch.Biochem.Biophys. 176:610-620 (1976); Suda et al. Biochem.Biophys.Res.Commun. 77:586-591 (1977)). An additional candidate for this step is the mitochondrial 3-hydroxybutyrate dehydrogenase (bdh) from the human heart which has been cloned and characterized (Marks et al. J.Biol.Chem. 267:15459-15463 (1992)). This 20 enzyme is a dehydrogenase that operates on a 3-hydroxyacid. Another exemplary alcohol dehydrogenase converts acetone to isopropanol as was shown in C. beijerinckii (Ismaiel et al. J.Bacteriol. 175:5097-5105 (1993)) and T. brockii (Lamed et al. Biochem. J. 195:183-190 (1981); Peretz and Burstein Biochemistry 28:6549-6555 (1989)). Gene Accession No. GI No. Organism mdh AAC76268.1 1789632 Escherichia coli ldhA NP_415898.1 16129341 Escherichia coli ldh YP_725182.1 113866693 Ralstonia eutropha bdh AAA58352.1 177198 Homo sapiens adh AAA23199.2 60592974 Clostridium beijerinckii NRRL B593 adh P14941.1 113443 Thermoanaerobacter brockii HTD4 Exemplary 3-hydroxyacyl dehydrogenases which convert acetoacetyl-CoA to 3-hydroxybutyryl 25 CoA include hbd from C. acetobutylicum (Boynton et al. Journal of Bacteriology 178:3015 3024 (1996)), hbd from C. beijerinckii (Colby et al. Appl Environ.Microbiol 58:3297-3302 121 (1992)), and a number of similar enzymes from Metallosphaera sedula (Berg et al. Archaea. Science 318:1782-1786 (2007)). Gene Accession No. GI No. Organism hbd NP_349314.1 15895965 Clostridium acetobutylicum hbd AAM14586.1 20162442 Clostridium beijerinckii Msed_1423 YP_001191505 146304189 Metallosphaera sedula Msed_0399 YP_001190500 146303184 Metallosphaera sedula Msed_0389 YP_001190490 146303174 Metallosphaera sedula Msed_1993 YP_001192057 146304741 Metallosphaera sedula 1.1.1.c - Oxidoredutase (2 step, acyl-CoA to alcohol) Exemplary 2-step oxidoreductases that convert an acyl-CoA to alcohol include those that 5 transform substrates such as acetyl-CoA to ethanol (for example, adhE from E. coli (Kessler et al. FEBS.Lett. 281:59-63 (1991)) and butyryl-CoA to butanol (for example, adhE2 from C. acetobutylicum (Fontaine et al. J.Bacteriol. 184:821-830 (2002)). In addition to reducing acetyl CoA to ethanol, the enzyme encoded by adhE in Leuconostoc mesenteroides has been shown to oxide the branched chain compound isobutyraldehyde to isobutyryl-CoA (Kazahaya et al. 10 J.Gen.Appl.Microbiol. 18:43-55 (1972); Koo et al. Biotechnol Lett. 27:505-510 (2005)). Gene Accession No. GI No. Organism adhE NP_415757.1 16129202 Escherichia coli adhE2 AAK09379.1 12958626 Clostridium acetobutylicum adhE AAV66076.1 55818563 Leuconostoc mesenteroides Another exemplary enzyme can convert malonyl-CoA to 3-HP. An NADPH-dependent enzyme with this activity has characterized in Chloroflexus aurantiacus where it participates in the 3 hydroxypropionate cycle (Hugler et al., J.Bacteriol. 184:2404-2410 (2002); Strauss and Fuchs, Eur.J.Biochem. 215:633-643 (1993)). This enzyme, with a mass of 300 kDa, is highly substrate 15 specific and shows little sequence similarity to other known oxidoreductases (Hugler et al., J.Bacteriol. 184:2404-2410 (2002)). No enzymes in other organisms have been shown to catalyze this specific reaction; however there is bioinformatic evidence that other organisms may have similar pathways (Klatt et al., Environ.Microbiol 9:2067-2078 (2007)). Enzyme candidates in other organisms including Roseiflexus castenholzii, Erythrobacter sp. NAP] and 20 marine gamma proteobacterium HTCC2080 can be inferred by sequence similarity.

122 Gene Accession No. GI No. Organism mcr AAS20429.1 42561982 Chloroflexus aurantiacus Rcas_2929 YP_001433009.1 156742880 Roseiflexus castenholzii NAP]_02720 ZP_01039179.1 85708113 Erythrobacter sp. NAP] MGP2080_00535 ZP_01626393.1 119504313 marine gamma proteobacterium HTCC2080 Longer chain acyl-CoA molecules can be reduced by enzymes such as the jojoba (Simmondsia chinensis) FAR which encodes an alcohol-forming fatty acyl-CoA reductase. Its overexpression in E. coli resulted in FAR activity and the accumulation of fatty alcohol (Metz et al. Plant 5 Physiology 122:635-644) 2000)). Gene Accession No. GI No. Organism FAR AAD38039.1 5020215 Simmondsia chinensis 1.2.1.b - Oxidoreductase (acyl-CoA to aldehyde) Several acyl-CoA dehydrogenases are capable of reducing an acyl-CoA to its corresponding aldehyde. Exemplary genes that encode such enzymes include the Acinetobacter calcoaceticus acr1 encoding a fatty acyl-CoA reductase (Reiser and Somerville, J. Bacteriology 179:2969 10 2975 (1997)), the Acinetobacter sp. M-1 fatty acyl-CoA reductase (Ishige et al. Appl.Environ.Microbiol. 68:1192-1195 (2002)), and a CoA- and NADP- dependent succinate semialdehyde dehydrogenase encoded by the sucD gene in Clostridium kluyveri (Sohling and Gottschalk J Bacteriol 178:871-80 (1996); Sohling and Gottschalk J Bacteriol. 178:871-880 (1996)). SucD of P. gingivalis is another succinate semialdehyde dehydrogenase (Takahashi et 15 al. J.Bacteriol. 182:4704-4710 (2000)). The enzyme acylating acetaldehyde dehydrogenase in Pseudomonas sp, encoded by bphG, is yet another as it has been demonstrated to oxidize and acylate acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde and formaldehyde (Powlowski et al. J Bacteriol. 175:377-385 (1993)). Gene Accession No. GI No. Organism acr1 YP_047869.1 50086359 Acinetobacter calcoaceticus acri AAC45217 1684886 Acinetobacter baylyi acr1 BAB85476.1 18857901 Acinetobacter sp. Strain M-1 sucD P38947.1 730847 Clostridium kluyveri sucD NP_904963.1 34540484 Porphyromonas gingivalis bphG BAA03892.1 425213 Pseudomonas sp 123 An additional enzyme type that converts an acyl-CoA to its corresponding aldehyde is malonyl CoA reductase which transforms malonyl-CoA to malonic semialdehyde. Malonyl-CoA reductase is a key enzyme in autotrophic carbon fixation via the 3-hydroxypropionate cycle in thermoacidophilic archael bacteria (Berg et al. Science 318:1782-1786 (2007); Thauer, R. K. 5 Science 318:1732-1733 (2007)). The enzyme utilizes NADPH as a cofactor and has been characterized in Metallosphaera and Sulfolobus spp (Alber et al. J.Bacteriol. 188:8551-8559 (2006); Hugler et al. J.Bacteriol. 184:2404-2410 (2002)). The enzyme is encoded by Msed_0709 in Metallosphaera sedula (Alber et al. J.Bacteriol. 188:8551-8559 (2006); Berg et al. Science 318:1782-1786 (2007)). A gene encoding a malonyl-CoA reductase from Sulfolobus 10 tokodaii was cloned and heterologously expressed in E. coli (Alber et al. J.Bacteriol. 188:8551 8559 (2006)). Although the aldehyde dehydrogenase functionality of these enzymes is similar to the bifunctional dehydrogenase from Chloroflexus aurantiacus, there is little sequence similarity. Both malonyl-CoA reductase enzyme candidates have high sequence similarity to aspartate-semialdehyde dehydrogenase, an enzyme catalyzing the reduction and concurrent 15 dephosphorylation of aspartyl-4-phosphate to aspartate semialdehyde. Additional gene candidates can be found by sequence homology to proteins in other organisms including Sulfolobus solfataricus and Sulfolobus acidocaldarius. Gene Accession No. GI No. Organism Msed_0709 YP_001190808.1 146303492 Metallosphaera sedula mcr NP_378167.1 15922498 Sulfolobus tokodaii asd-2 NP_343563.1 15898958 Sulfolobus solfataricus Saci_2370 YP_256941.1 70608071 Sulfolobus acidocaldarius 1.2.1.c - Oxidoreductase (2-oxo acid to acyl-CoA, decarboxylation) 20 Enzymes in this family include 1) branched-chain 2-keto-acid dehydrogenase, 2) alpha ketoglutarate dehydrogenase, and 3) the pyruvate dehydrogenase multienzyme complex (PDHC). These enzymes are multi-enzyme complexes that catalyze a series of partial reactions which result in acylating oxidative decarboxylation of 2-keto-acids. Each of the 2-keto-acid dehydrogenase complexes occupies key positions in intermediary metabolism, and enzyme 25 activity is typically tightly regulated (Fries et al. Biochemistry 42:6996-7002 (2003)). The enzymes share a complex but common structure composed of multiple copies of three catalytic components: alpha-ketoacid decarboxylase (El), dihydrolipoamide acyltransferase (E2) and dihydrolipoamide dehydrogenase (E3). The E3 component is shared among all 2-keto-acid dehydrogenase complexes in an organism, while the El and E2 components are encoded by 124 different genes. The enzyme components are present in numerous copies in the complex and utilize multiple cofactors to catalyze a directed sequence of reactions via substrate channeling. The overall size of these dehydrogenase complexes is very large, with molecular masses between 4 and 10 million Da (that is, larger than a ribosome). 5 Activity of enzymes in the 2-keto-acid dehydrogenase family is normally low or limited under anaerobic conditions in E. coli. Increased production of NADH (or NADPH) could lead to a redox-imbalance, and NADH itself serves as an inhibitor to enzyme function. Engineering efforts have increased the anaerobic activity of the E. coli pyruvate dehydrogenase complex (Kim et al. Appl.Environ.Microbiol. 73:1766-1771 (2007); Kim et al. J.Bacteriol. 190:3851 10 3858 ) 2008); Zhou et al. Biotechnol.Lett. 30:335-342 (2008)). For example, the inhibitory effect of NADH can be overcome by engineering an H322Y mutation in the E3 component (Kim et al. J.Bacteriol. 190:3851-3858 (2008)). Structural studies of individual components and how they work together in complex provide insight into the catalytic mechanisms and architecture of enzymes in this family (Aevarsson et al. Nat.Struct.Biol. 6:785-792 (1999); Zhou 15 et al. Proc.Natl.Acad.Sci. U.S.A. 98:14802-14807 (2001)). The substrate specificity of the dehydrogenase complexes varies in different organisms, but generally branched-chain keto-acid dehydrogenases have the broadest substrate range. Alpha-ketoglutarate dehydrogenase (AKGD) converts alpha-ketoglutarate to succinyl-CoA and is the primary site of control of metabolic flux through the TCA cycle (Hansford, R. G. 20 Curr. Top.Bioenerg. 10:217-278 (1980)). Encoded by genes sucA, sucB and lpd in E. coli, AKGD gene expression is downregulated under anaerobic conditions and during growth on glucose (Park et al. Mol.Microbiol. 15:473-482 (1995)). Although the substrate range of AKGD is narrow, structural studies of the catalytic core of the E2 component pinpoint specific residues responsible for substrate specificity (Knapp et al. J.Mol.Biol. 280:655-668 (1998)). The Bacillus 25 subtilis AKGD, encoded by odhAB (El and E2) and pdhD (E3, shared domain), is regulated at the transcriptional level and is dependent on the carbon source and growth phase of the organism (Resnekov et al. Mol.Gen.Genet. 234:285-296 (1992)). In yeast, the LPD1 gene encoding the E3 component is regulated at the transcriptional level by glucose (Roy and Dawes J.Gen.Microbiol. 133:925-933 (1987)). The El component, encoded by KGD1, is also regulated 30 by glucose and activated by the products of HAP2 and HAP3 (Repetto and Tzagoloff Mol. Cell Biol. 9:2695-2705 (1989)). The AKGD enzyme complex, inhibited by products NADH and succinyl-CoA, is well-studied in mammalian systems, as impaired function of has been linked to 125 several neurological diseases (Tretter and dam-Vizi Philos. Trans.R.Soc.Lond B Biol.Sci. 360:2335-2345 (2005)). Gene Accession No. GI No. Organism sucA NP_415254.1 16128701 Escherichia coli str. K12 substr. MG1655 sucB NP_415255.1 16128702 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1 16128109 Escherichia coli str. K12 substr. MG1655 odhA P23129.2 51704265 Bacillus subtilis odhB P16263.1 129041 Bacillus subtilis pdhD P21880.1 118672 Bacillus subtilis KGD1 NP_012141.1 6322066 Saccharomyces cerevisiae KGD2 NP_010432.1 6320352 Saccharomyces cerevisiae LPD1 NP_116635.1 14318501 Saccharomyces cerevisiae Branched-chain 2-keto-acid dehydrogenase complex (BCKAD), also known as 2-oxoisovalerate dehydrogenase, participates in branched-chain amino acid degradation pathways, converting 2 5 keto acids derivatives of valine, leucine and isoleucine to their acyl-CoA derivatives and C0 2 . The complex has been studied in many organisms including Bacillus subtilis (Wang et al. Eur.J.Biochem. 213:1091-1099 (1993)), Rattus norvegicus (Namba et al. J.Biol.Chem. 244:4437-4447 (1969)) and Pseudomonas putida (Sokatch J.Bacteriol. 148:647-652 (1981)). In Bacillus subtilis the enzyme is encoded by genes pdhD (E3 component), bfmBB (E2 10 component), bfmBAA and bfmBAB (El component) (Wang et al. Eur.J.Biochem. 213:1091-1099 (1993)). In mammals, the complex is regulated by phosphorylation by specific phosphatases and protein kinases. The complex has been studied in rat hepatocites (Chicco et al. J.Biol. Chem. 269:19427-19434 (1994)) and is encoded by genes Bckdha (El alpha), Bckdhb (El beta), Dbt (E2), and Dld (E3). The El and E3 components of the Pseudomonas putida BCKAD complex 15 have been crystallized (Aevarsson et al. Nat.Struct.Biol. 6:785-792 (1999); Mattevi Science 255:1544-1550 (1992)) and the enzyme complex has been studied (Sokatch et al. J.Bacteriol. 148:647-652 (1981)). Transcription of the P. putida BCKAD genes is activated by the gene product of bkdR (Hester et al. Eur.J.Biochem. 233:828-836 (1995)). In some organisms including Rattus norvegicus (Paxton et al. Biochem.J. 234:295-303 (1986)) and Saccharomyces 20 cerevisiae (Sinclair et al. Biochem.Mol.Biol.Int. 31:911-922 (1993)), this complex has been shown to have a broad substrate range that includes linear oxo-acids such as 2-oxobutanoate and alpha-ketoglutarate, in addition to the branched-chain amino acid precursors. The active site of the bovine BCKAD was engineered to favor alternate substrate acetyl-CoA (Meng and Chuang, Biochemistry 33:12879-12885 (1994)).

126 Gene Accession No. GI No. Organism bfmBB NP_390283.1 16079459 Bacillus subtilis bfmBAA NP_390285.1 16079461 Bacillus subtilis bfmBAB NP_390284.1 16079460 Bacillus subtilis pdhD P21880.1 118672 Bacillus subtilis lpdV P09063.1 118677 Pseudomonas putida bkdB P09062.1 129044 Pseudomonas putida bkdAl NP_746515.1 26991090 Pseudomonas putida bkdA2 NP_746516.1 26991091 Pseudomonas putida Bckdha NP_036914.1 77736548 Rattus norvegicus Bckdhb NP_062140.1 158749538 Rattus norvegicus Dbt NP_445764.1 158749632 Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus The pyruvate dehydrogenase complex, catalyzing the conversion of pyruvate to acetyl-CoA, has also been extensively studied. In the E. coli enzyme, specific residues in the El component are responsible for substrate specificity (Bisswanger, H. J Biol Chem. 256:815-822 (1981); Bremer, J. Eur.J Biochem. 8:535-540 (1969); Gong et al. J Biol Chem. 275:13645-13653 (2000)). As 5 mentioned previously, enzyme engineering efforts have improved the E. coli PDH enzyme activity under anaerobic conditions (Kim et al. Appl.Environ.Microbiol. 73:1766-1771 (2007); Kim J.Bacteriol. 190:3851-3858 (2008); Zhou et al. Biotechnol.Lett. 30:335-342 (2008)). In contrast to the E. coli PDH, the B. subtilis complex is active and required for growth under anaerobic conditions (Nakano J.Bacteriol. 179:6749-6755 (1997)). The Klebsiella pneumoniae 10 PDH, characterized during growth on glycerol, is also active under anaerobic conditions (Menzel et al. J.Biotechnol. 56:135-142 (1997)). Crystal structures of the enzyme complex from bovine kidney (Zhou et al. Proc.Natl.Acad.Sci. U.S.A. 98:14802-14807 (2001)) and the E2 catalytic domain from Azotobacter vinelandii are available (Mattevi et al. Science 255:1544 1550 (1992)). Some mammalian PDH enzymes complexes can react on alternate substrates 15 such as 2-oxobutanoate, although comparative kinetics of Rattus norvegicus PDH and BCKAD indicate that BCKAD has higher activity on 2-oxobutanoate as a substrate (Paxton et al. Biochem.J. 234:295-303 (1986)). Gene Accession No. GI No. Organism aceE NP_414656.1 16128107 Escherichia coli str. K12 substr. MG1655 aceF NP_414657.1 16128108 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1 16128109 Escherichia coli str. K12 substr. MG1655 pdhA P21881.1 3123238 Bacillus subtilis pdhB P21882.1 129068 Bacillus subtilis pdhC P21883.2 129054 Bacillus subtilis 127 pdhD P21880.1 118672 Bacillus subtilis aceE YP_001333808.1 152968699 Klebsiella pneumonia MGH78578 aceF YP_001333809.1 152968700 Klebsiella pneumonia MGH78578 lpdA YP_001333810.1 152968701 Klebsiella pneumonia MGH78578 Pdhal NP_001004072.2 124430510 Rattus norvegicus Pdha2 NP_446446.1 16758900 Rattus norvegicus Dat NP_112287.1 78365255 Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus As an alternative to the large multienzyme 2-keto-acid dehydrogenase complexes described above, some anaerobic organisms utilize enzymes in the 2-ketoacid oxidoreductase family (OFOR) to catalyze acylating oxidative decarboxylation of 2-keto-acids. Unlike the dehydrogenase complexes, these enzymes contain iron-sulfur clusters, utilize different cofactors, 5 and use ferredoxin or flavodixin as electron acceptors in lieu of NAD(P)H. While most enzymes in this family are specific to pyruvate as a substrate (POR) some 2-keto-acid:ferredoxin oxidoreductases have been shown to accept a broad range of 2-ketoacids as substrates including alpha-ketoglutarate and 2-oxobutanoate (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2002); Zhang et al. J.Biochem. 120:587-599 (1996)). One such enzyme is the OFOR from the 10 thermoacidophilic archaeon Sulfolobus tokodaii 7, which contains an alpha and beta subunit encoded by gene ST2300 (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2002); Zhang et al. J.Biochem. 120:587-599 (1996)). A plasmid-based expression system has been developed for efficiently expressing this protein in E. coli ( Fukuda et al. Eur.J.Biochem. 268:5639 5646 (2001)) and residues involved in substrate specificity were determined (Fukuda and 15 Wakagi Biochim.Biophys.Acta 1597:74-80 (2002)). Two OFORs from Aeropyrum pernix str. K1 have also been recently cloned into E. coli, characterized, and found to react with a broad range of 2-oxoacids (Nishizawa et al. FEBS Lett. 579:2319-2322 (2005)). The gene sequences of these OFOR candidates are available, although they do not have GenBank identifiers assigned to date. There is bioinformatic evidence that similar enzymes are present in all archaea, some 20 anaerobic bacteria and amitochondrial eukarya (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2005)). This class of enzyme is also interesting from an energetic standpoint, as reduced ferredoxin could be used to generate NADH by ferredoxin-NAD reductase (Petitdemange et al. Biochim.Biophys.Acta 421:334-337 (1976)). Also, since most of the enzymes are designed to operate under anaerobic conditions, less enzyme engineering may be 25 required relative to enzymes in the 2-keto-acid dehydrogenase complex family for activity in an anaerobic environment.

128 Gene Accession No. GI No. Organism ST2300 NP_378302.1 15922633 Sulfolobus tokodaii 7 1.2.1.d - Oxidoreductase (phosphorylating/dephosphorylating) Exemplary enzymes in this class include glyceraldehyde 3-phosphate dehydrogenase which 5 converts glyceraldehyde-3-phosphate into D-glycerate 1,3-bisphosphate (for example, E. coli gapA (Branlant and Branlant Eur.J.Biochem. 150:61-66(1985)), aspartate-semialdehyde dehydrogenase which converts L-aspartate-4-semialdehyde into L-4-aspartyl-phosphate (for example, E. coli asd (Biellmann et al. Eur.J.Biochem. 104:53-58 (1980)), N-acetyl-gamma glutamyl-phosphate reductase which converts N-acetyl-L-glutamate-5-semialdehyde into N 10 acetyl-L-glutamyl-5-phosphate (for example, E. coli argC (Parsot et al. Gene 68:275-283 (1988)), and glutamate-5-semialdehyde dehydrogenase which converts L-glutamate-5 semialdehyde into L-glutamyl-5-phospate (for example, E. coli proA (Smith et al. J.Bacteriol. 157:545-551 (1984)). Gene Accession No. GI No. Organism gapA POA9B2.2 71159358 Escherichia coli asd NP_417891.1 16131307 Escherichia coli argC NP_418393.1 16131796 Escherichia coli proA NP_414778.1 16128229 Escherichia coli 15 1.3.1.a - Oxidoreductase operating on CH-CH donors An exemplary enoyl-CoA reductase is the gene product of bcd from C. acetobutylicum (Atsumi et al. Metab Eng (2007); Boynton et al. Journal of Bacteriology 178:3015-3024 (1996), which naturally catalyzes the reduction of crotonyl-CoA to butyryl-CoA. Activity of this enzyme can be enhanced by expressing bcd in conjunction with expression of the C. acetobutylicum etfAB 20 genes, which encode an electron transfer flavoprotein. An additional candidate for the enoyl CoA reductase step is the mitochondrial enoyl-CoA reductase from E. gracilis (Hoffmeister et al. Journal of Biological Chemistry 280:4329-4338 (2005)). A construct derived from this sequence following the removal of its mitochondrial targeting leader sequence was cloned in E. coli resulting in an active enzyme (Hoffmeister et al., supra, (2005)). This approach is well 25 known to those skilled in the art of expressing eukarytotic genes, particularly those with leader sequences that may target the gene product to a specific intracellular compartment, in prokaryotic organisms. A close homolog of this gene, TDE0597, from the prokaryote 129 Treponema denticola represents a third enoyl-CoA reductase which has been cloned and expressed in E. coli (Tucci and Martin FEBS Letters 581:1561-1566 (2007)). Gene Accession No. GI No. Organism bcd NP_349317.1 15895968 Clostridium acetobutylicum etfA NP_349315.1 15895966 Clostridium acetobutylicum etfB NP_349316.1 15895967 Clostridium acetobutylicum TER Q5EU90.1 62287512 Euglena gracilis TDE0597 NP_971211.1 42526113 Treponema denticola Exemplary 2-enoate reductase (EC 1.3.1.31) enzymes are known to catalyze the NADH dependent reduction of a wide variety of a, 3-unsaturated carboxylic acids and aldehydes 5 (Rohdich et al. J.Biol.Chem. 276:5779-5787 (2001)). 2-Enoate reductase is encoded by enr in several species of Clostridia (Giesel and Simon Arch Microbiol. 135(1): p. 51-57 (2001) including C. tyrobutyricum, and C. thermoaceticum (now called Moorella thermoaceticum) (Rohdich et al., supra, (2001)). In the recently published genome sequence of C. kluyveri, 9 coding sequences for enoate reductases have been reported, out of which one has been 10 characterized (Seedorf et al. Proc Nat/ Acad Sci U. S. A. 105(6):2128-33 (2008)). The enr genes from both C. tyrobutyricum and C. thermoaceticum have been cloned and sequenced and show 59% identity to each other. The former gene is also found to have approximately 75% similarity to the characterized gene in C. kluyveri (Giesel and Simon Arch Microbiol 135(1):51-57 (1983)). It has been reported based on these sequence results that enr is very similar to the dienoyl CoA 15 reductase in E. coli (fadH) (163 Rohdich et al., supra (2001)). The C. thermoaceticum enr gene has also been expressed in an enzymatically active form in E. coli (163 Rohdich et al., supra (2001)). Gene Accession No. GI No. Organism fadH NP_417552.1 16130976 Escherichia coli enr ACA54153.1 169405742 Clostridium botulinum A3 str enr CAA71086.1 2765041 Clostridium tyrobutyricum enr CAA76083.1 3402834 Clostridium kluyveri enr YP_430895.1 83590886 Moorella thermoacetica 1.4.1.a - Oxidoreductase operating on amino acids 20 Most oxidoreductases operating on amino acids catalyze the oxidative deamination of alpha amino acids with NAD+ or NADP+ as acceptor. Exemplary oxidoreductases operating on amino acids include glutamate dehydrogenase (deaminating), encoded by gdhA, leucine 130 dehydrogenase (deaminating), encoded by ldh, and aspartate dehydrogenase (deaminating), encoded by nadX. The gdhA gene product from Escherichia coli (Korber et al. J.Mol.Biol. 234:1270-1273 (1993); McPherson and Wootton Nucleic.Acids Res. 11:5257-5266 (1983)), gdh from Thermotoga maritima (Kort et al. Extremophiles 1:52-60 (1997); Lebbink, et al. 5 J.Mol.Biol. 280:287-296 (1998)); Lebbink et al. J.Mol.Biol. 289:357-369 (1999)), and gdhA1 from Halobacterium salinarum (Ingoldsby et al. Gene 349:237-244 (2005)) catalyze the reversible interconversion of glutamate to 2-oxoglutarate and ammonia, while favoring NADP(H), NAD(H), or both, respectively. The ldh gene of Bacillus cereus encodes the LeuDH protein that has a wide of range of substrates including leucine, isoleucine, valine, and 2 10 aminobutanoate (Ansorge and Kula Biotechnol Bioeng. 68:557-562 (2000); Stoyan et al. J.Biotechnol 54:77-80 (1997)). The nadX gene from Thermotoga maritime encoding for the aspartate dehydrogenase is involved in the biosynthesis of NAD (Yang et al. J.Biol.Chem. 278:8804-8808 (2003)). Gene Accession No. GI No. Organism gdhA P00370 118547 Escherichia coli gdh P96110.4 6226595 Thermotoga maritima gdhA1 NP_279651.1 15789827 Halobacterium salinarum ldh P0A393 61222614 Bacillus cereus nadX NP_229443.1 15644391 Thermotoga maritima The lysine 6-dehydrogenase (deaminating), encoded by lysDH gene, catalyze the oxidative 15 deamination of the s -amino group of L-lysine to form 2-aminoadipate-6-semialdehyde, which in turn nonenzymatically cyclizes to form A1-piperideine-6-carboxylate (Misono and Nagasaki J.Bacteriol. 150:398-401 (1982)). The lysDH gene from Geobacillus stearothermophilus encodes a thermophilic NAD-dependent lysine 6-dehydrogenase (Heydari et al. Apple Environ.Microbiol 70:937-942 (2004)). In addition, the lysDH gene from Aeropyrum pernix K1 20 is identified through homology from genome projects. Gene Accession No. GI No. Organism lysDH AB052732 13429872 Geobacillus stearothermophilus lysDH NP_147035.1 14602185 Aeropyrumpernix K] ldh P0A393 61222614 Bacillus cereus 2.3.1.a - Acyltransferase (transferring phosphate group) Exemplary phosphate transferring acyltransferases include phosphotransacetylase, encoded by pta, and phosphotransbutyrylase, encoded by ptb. The pta gene from E. coli encodes an enzyme 131 that can convert acetyl-CoA into acetyl-phosphate, and vice versa (Suzuki, T. Biochim.Biophys.Acta 191:559-569 (1969)). This enzyme can also utilize propionyl-CoA instead of acetyl-CoA forming propionate in the process (Hesslinger et al. Mol.Microbiol 27:477-492 (1998)). Similarly, the ptb gene from C. acetobutylicum encodes an enzyme that 5 can convert butyryl-CoA into butyryl-phosphate (Walter et al. Gene 134(1): p. 107-11 (1993)); Huang et al. J Mol Microbiol Biotechnol 2(1): p. 33-38 (2000). Additional ptb genes can be found in butyrate-producing bacterium L2-50 (Louis et al. J.Bacteriol. 186:2099-2106 (2004)) and Bacillus megaterium (Vazquez et al. Curr.Microbiol 42:345-349 (2001)). Gene Accession No. GI No. Organism pta NP_416800.1 16130232 Escherichia coli ptb NP_349676 15896327 Clostridium acetobutylicum ptb AAR19757.1 38425288 butyrate-producing bacterium L2-50 ptb CAC07932.1 10046659 Bacillus megaterium 10 2.6.1.a - Aminotransferase Aspartate aminotransferase transfers an amino group from aspartate to alpha-ketoglutarate, forming glutamate and oxaloacetate. This conversion is catalyzed by, for example, the gene products of aspC from Escherichia coli (Yagi et al. FEBS Lett. 100:81-84 (1979); Yagi et al. Methods Enzymol. 113:83-89 (1985)), AAT2 from Saccharomyces cerevisiae (Yagi et al. J 15 Biochem. 92:35-43 (1982)) and ASP5 from Arabidopsis thaliana (48, 108, 225 48. de la et al. Plant J 46:414-425 (2006); Kwok and Hanson J Exp.Bot. 55:595-604 (2004); Wilkie and Warren Protein Expr.Purif 12:381-389 (1998)). Valine aminotransferase catalyzes the conversion of valine and pyruvate to 2-ketoisovalerate and alanine. The E. coli gene, avtA, encodes one such enzyme (Whalen and Berg J.Bacteriol. 150:739-746 (1982)). This gene 20 product also catalyzes the amination of a-ketobutyrate to generate a-aminobutyrate, although the amine donor in this reaction has not been identified (Whalen and Berg J.Bacteriol. 158:571-574 (1984)). The gene product of the E. coli serC catalyzes two reactions, phosphoserine aminotransferase and phosphohydroxythreonine aminotransferase (Lam and Winkler J.Bacteriol. 172:6518-6528 (1990)), and activity on non-phosphorylated substrates could not be 25 detected (Drewke et al. FEBS.Lett. 390:179-182 (1996)). Gene Accession No. GI No. Organism aspC NP_415448.1 16128895 Escherichia coli AAT2 P23542.3 1703040 Saccharomyces cerevisiae ASP5 P46248.2 20532373 Arabidopsis thaliana 132 avtA YP_026231.1 49176374 Escherichia coli serC NP_415427.1 16128874 Escherichia coli Cargill has developed a beta-alanine/alpha-ketoglutarate aminotransferase for producing 3-HP from beta-alanine via malonyl-semialdehyde (PCT/US2007/076252 (Jessen et al)). The gene product of SkPYD4 in Saccharomyces kluyveri was also shown to preferentially use beta alanine as the amino group donor (Andersen et al. FEBS.J. 274:1804-1817 (2007)). SkUGA1 5 encodes a homologue of Saccharomyces cerevisiae GABA aminotransferase, UGA1 (Ramos et al. Eur.J.Biochem. 149:401-404 (1985)), whereas SkPYD4 encodes an enzyme involved in both P-alanine and GABA transamination (Andersen et al. FEBS.J. 274:1804-1817 (2007)). 3 Amino-2-methylpropionate transaminase catalyzes the transformation from methylmalonate semialdehyde to 3-amino-2-methylpropionate. The enzyme has been characterized in Rattus 10 norvegicus and Sus scrofa and is encoded by Abat (Kakimoto et al. Biochim.Biophys.Acta 156:374-380 (1968); Tamaki et al. Methods Enzymol. 324:376-389 (2000)). Enzyme candidates in other organisms with high sequence homology to 3-amino-2-methylpropionate transaminase include Gta-1 in C. elegans and gabT in Bacillus subtilus. Additionally, one of the native GABA aminotransferases in E. coli, encoded by gene gabT, has been shown to have broad 15 substrate specificity (Liu et al. Biochemistry 43:10896-10905 (2004); Schulz et al. Apple Environ Microbiol 56:1-6 (1990)). The gene product of puuE catalyzes the other 4-aminobutyrate transaminase in E. coli (Kurihara et al. J.Biol. Chem. 280:4602-4608 (2005)). Gene Accession No. GI No. Organism SkyPYD4 ABF5 8893.1 98626772 Saccharomyces kluyveri SkUGA1 ABF58894.1 98626792 Saccharomyces kluyveri UGA1 NP_011533.1 6321456 Saccharomyces cerevisiae Abat P50554.3 122065191 Rattus norvegicus Abat P80147.2 120968 Sus scrofa Gta-1 Q21217.1 6016091 Caenorhabditis elegans gabT P94427.1 6016090 Bacillus subtilus gabT P22256.1 120779 Escherichia coli K12 puuE NP 415818.1 16129263 Escherichia coli K12 The X-ray crystal structures of E. coli 4-aminobutyrate transaminase unbound and bound to the inhibitor were reported (Liu et al. Biochemistry 43:10896-10905 (2004)). The substrates 20 binding and substrate specificities were studied and suggested. The roles of active site residues were studied by site-directed mutagenesis and X-ray crystallography (Liu et al. Biochemistry 44:2982-2992 (2005)). Based on the structural information, attempt was made to engineer E.

133 coli 4-aminobutyrate transaminase with novel enzymatic activity. These studies provide a base for evolving transaminase activity for BDO pathways. 2.7.2.a - Phosphotransferase, carboxyl group acceptor Exemplary kinases include the E. coli acetate kinase, encoded by ackA (Skarstedt and Silverstein 5 J.Biol.Chem. 251:6775-6783 (1976)), the C. acetobutylicum butyrate kinases, encoded by buk1 and buk2 (Walter et al. Gene 134(1):107-111 (1993) (Huang et al. J Mol Microbiol Biotechnol 2(1):33-38 (2000)], and the E. coli gamma-glutamyl kinase, encoded by proB (Smith et al. J.Bacteriol. 157:545-551 (1984)). These enzymes phosphorylate acetate, butyrate, and glutamate, respectively. The ackA gene product from E. coli also phosphorylates propionate 10 (Hesslinger et al. Mol.Microbiol 27:477-492 (1998)). Gene Accession No. GI No. Organism ackA NP_416799.1 16130231 Escherichia coli buki NP_349675 15896326 Clostridium acetobutylicum buk2 Q97111 20137415 Clostridium acetobutylicum proB NP_414777.1 16128228 Escherichia coli 2.8.3.a - Coenzyme-A transferase In the CoA-transferase family, E. coli enzyme acyl-CoA:acetate-CoA transferase, also known as acetate-CoA transferase (EC 2.8.3.8), has been shown to transfer the CoA moiety to acetate from 15 a variety of branched and linear acyl-CoA substrates, including isobutyrate (Matthies and Schink Apple Environ Microbiol 58:1435-1439 (1992)), valerate (Vanderwinkel et al. Biochem.Biophys.Res Commun. 33:902-908 (1968)) and butanoate (Vanderwinkel, supra (1968)). This enzyme is encoded by atoA (alpha subunit) and atoD (beta subunit) in E. coli sp. K12 (Korolev et al. Acta Crystallogr.D Biol Crystallogr. 58:2116-2121 (2002); Vanderwinkel, 20 supra (1968)) and actA and cg0592 in Corynebacterium glutamicum ATCC 13032 (Duncan et al. Apple Environ Microbiol 68:5186-5190 (2002)). Additional genes found by sequence homology include atoD and atoA in Escherichia coli UT189. Gene Accession No. GI No. Organism atoA P76459.1 2492994 Escherichia coli K12 atoD P76458.1 2492990 Escherichia coli K12 actA YP_226809.1 62391407 Corynebacterium glutamicum ATCC 13032 cg0592 YP 224801.1 62389399 Corynebacterium glutamicum ATCC 13032 atoA ABE07971.1 91073090 Escherichia coli UT189 atoD ABE07970.1 91073089 Escherichia coli UT189 134 Similar transformations are catalyzed by the gene products of cat], cat2, and cat3 of Clostridium kluyveri which have been shown to exhibit succinyl-CoA, 4-hydroxybutyryl-CoA, and butyryl-CoA acetyltransferase activity, respectively (Seedorf et al. Proc Natl Acad Sci U.SA 105(6):2128-2133 (2008); Sohling and Gottschalk J Bacteriol 178(3):871-880 (1996)]. Gene Accession No. GI No. Organism cat] P38946.1 729048 Clostridium kluyveri cat2 P38942.2 1705614 Clostridium kluyveri cat3 EDK35586.1 146349050 Clostridium kluyveri 5 The glutaconate-CoA-transferase (EC 2.8.3.12) enzyme from anaerobic bacterium Acidaminococcusfermentans reacts with diacid glutaconyl-CoA and 3-butenoyl-CoA (Mack and Buckel FEBS Lett. 405:209-212 (1997)). The genes encoding this enzyme are gctA and gctB. This enzyme has reduced but detectable activity with other CoA derivatives including glutaryl CoA, 2-hydroxyglutaryl-CoA, adipyl-CoA and acrylyl-CoA (Buckel et al. Eur.J.Biochem. 10 118:315-321 (1981)). The enzyme has been cloned and expressed in E. coli (Mac et al. Eur.J.Biochem. 226:41-51 (1994)). Gene Accession No. GI No. Organism gctA CAA57199.1 559392 Acidaminococcusfermentans gctB CAA57200.1 559393 Acidaminococcus fermentans 3.1.2.a - Thiolester hydrolase (CoA specific) In the CoA hydrolase family, the enzyme 3-hydroxyisobutyryl-CoA hydrolase is specific for 3 15 HIBCoA and has been described to efficiently catalyze the desired transformation during valine degradation (Shimomura et al. JBiol Chem 269:14248-14253 (1994)). Genes encoding this enzyme include hibch of Rattus norvegicus (Shimomura et al., supra (1994); Shimomura et al. Methods Enzymol. 324:229-240 (2000) and Homo sapiens (Shimomura et al., supra, 2000). Candidate genes by sequence homology include hibch of Saccharomyces cerevisiae and 20 BC_2292 of Bacillus cereus. Gene Accession No. GI No. Organism hibch Q5XIE6.2 146324906 Rattus norvegicus hibch Q6NVY1.2 146324905 Homo sapiens hibch P28817.2 2506374 Saccharomyces cerevisiae BC_2292 Q81DR3 81434808 Bacillus cereus 135 The conversion of adipyl-CoA to adipate can be carried out by an acyl-CoA hydrolase or equivalently a thioesterase. The top E. coli gene candidate is tesB (Naggert et al. J Biol Chem. 266(17):11044-11050 (1991)] which shows high similarity to the human acot8 which is a dicarboxylic acid acetyltransferase with activity on adipyl-CoA (Westin et al. J Biol Chem 5 280(46): 38125-38132 (2005). This activity has also been characterized in the rat liver (Deana, Biochem Int. 26(4): p. 767-773 (1992)). Gene Accession No. GI No. Organism tesB NP_414986 16128437 Escherichia coli acot8 CAA15502 3191970 Homo sapiens acot8 NP_570112 51036669 Rattus norvegicus Other potential E. coli thiolester hydrolases include the gene products of tesA (Bonner and Bloch, J Biol Chem. 247(10):3123-3133 (1972)), ybgC (Kuznetsova et al., FEMS Microbiol Rev. 29(2):263-279 (2005); Zhuang et al., FEBS Lett. 516(1-3):161-163 (2002)) paal (Song et al., J 10 Biol Chem. 281(16):11028-11038 (2006)), and ybdB (Leduc et al,, J Bacteriol. 189(19):7112 7126 (2007)). Gene Accession No. GI No. Organism tesA NP_415027 16128478 Escherichia coli ybgC NP_415264 16128711 Escherichia coli paal NP 415914 16129357 Escherichia coli ybdB NP_415129 16128580 Escherichia coli Several eukaryotic acetyl-CoA hydrolases (EC 3.1.2.1) have broad substrate specificity. The enzyme from Rattus norvegicus brain (Robinson et al. Biochem.Biophys. Res.Commun. 71:959 965 (1976)) can react with butyryl-CoA, hexanoyl-CoA and malonyl-CoA. Gene Accession No. GI No. Organism acotL2 NP_570103.1 18543355 Rattus norvegicus 15 4.1.1.a - Carboxy-lyase An exemplary carboxy-lyase is acetolactate decarboxylase which participates in citrate catabolism and branched-chain amino acid biosynthesis, converting 2-acetolactate to acetoin. In Lactococcus lactis the enzyme is composed of six subunits, encoded by gene aldB, and is 20 activated by valine, leucine and isoleucine (Goupil et al. Appl.Environ.Microbiol. 62:2636-2640 (1996); Goupil-Feuillerat et al. J.Bacteriol. 182:5399-5408 (2000)). This enzyme has been overexpressed and characterized in E. coli (Phalip et al. FEBS Lett. 351:95-99 (1994)). In other 136 organisms the enzyme is a dimer, encoded by aldC in Streptococcus thermophilus (Monnet et al. Lett.Appl.Microbiol. 36:399-405 (2003)), aldB in Bacillus brevis (Diderichsen et al. J.Bacteriol. 172:4315-4321 (1990); Najmudin et al. Acta Crystallogr.D.Biol.Crystallogr. 59:1073-1075 (2003)) and budA from Enterobacter aerogenes (Diderichsen et al. J.Bacteriol. 172:4315-4321 5 (1990)). The enzyme from Bacillus brevis was cloned and overexpressed in Bacillus subtilis and characterized crystallographically (Najmudin et al. Acta Crystallogr.D.Biol. Crystallogr. 59:1073-1075 (2003)). Additionally, the enzyme from Leuconostoc lactis has been purified and characterized but the gene has not been isolated (O'Sullivan et al. FEMS Microbiol.Lett. 194:245-249 (2001)). Gene Accession No. GI No. Organism aldB NP_267384.1 15673210 Lactococcus lactis aldC Q8L208 75401480 Streptococcus thermophilus aldB P23616.1 113592 Bacillus brevis budA P05361.1 113593 Enterobacter aerogenes 10 Aconitate decarboxylase catalyzes the final step in itaconate biosynthesis in a strain of Candida and also in the filamentous fungus Aspergillus terreus (Bonnarme et al. J Bacteriol. 177:3573 3578 (1995); Willke and Vorlop Appl Microbiol Biotechnol 56:289-295 (2001)). Although itaconate is a compound of biotechnological interest, the aconitate decarboxylase gene or protein sequence has not been reported to date. 15 4-oxalocronate decarboxylase has been isolated from numerous organisms and characterized. Genes encoding this enzyme include dmpH and dmpE in Pseudomonas sp. (strain 600) (Shingler et al. J Bacteriol. 174:711-724 (1992)), xylII and xylIII from Pseudomonas putida (Kato and Asano Arch.Microbiol 168:457-463 (1997); Lian and Whitman J.Am. Chem.Soc. 116:10403-10411 (1994); Stanley et al. Biochemistry 39:3514 (2000)) and ReutB5691 and 20 ReutB5692 from Ralstonia eutropha JMP134 (Hughes et al. J Bacteriol. 158:79-83 (1984)). The genes encoding the enzyme from Pseudomonas sp. (strain 600) have been cloned and expressed in E. coli (Shingler et al. J Bacteriol. 174:711-724 (1992)). Gene Accession No. GI No. Organism dmpH CAA43228.1 45685 Pseudomonas sp. CF600 dmpE CAA43225.1 45682 Pseudomonas sp. CF600 xy/II YP_709328.1 111116444 Pseudomonas putida xy/III YP_709353.1 111116469 Pseudomonas putida ReutB5691 YP_299880.1 73539513 Ralstonia eutropha JMP134 ReutB5692 YP_299881.1 73539514 Ralstonia eutropha JMP134 137 An additional class of decarboxylases has been characterized that catalyze the conversion of cinnamate (phenylacrylate) and substituted cinnamate derivatives to the corresponding styrene derivatives. These enzymes are common in a variety of organisms and specific genes encoding these enzymes that have been cloned and expressed in E. coli are: pad 1 from Saccharomyces 5 cerevisae (Clausen et al. Gene 142:107-112 (1994)), pdc from Lactobacillus plantarum (Barthelmebs et al. Apple Environ Microbiol 67:1063-1069 (2001); Qi et al. Metab Eng 9:268 276 (2007); Rodriguez et al. J.Agric.Food Chem. 56:3068-3072 (2008)), pofK (pad) from Klebsiella oxytoca (Hashidoko et al. Biosci.Biotech.Biochem. 58:217-218 (1994); Uchiyama et al. Biosci.Biotechnol.Biochem. 72:116-123 (2008)), Pedicoccus pentosaceus (Barthelmebs et al. 10 Appl Environ Microbiol 67:1063-1069 (2001)), and padC from Bacillus subtilis and Bacillus pumilus (Lingen et al. Protein Eng 15:585-593 (2002)). A ferulic acid decarboxylase from Pseudomonasfluorescens also has been purified and characterized (Huang et al. J.Bacteriol. 176:5912-5918 (1994)). Importantly, this class of enzymes have been shown to be stable and do not require either exogenous or internally bound co-factors, thus making these enzymes ideally 15 suitable for biotransformations (Sariaslani, Annu.Rev.Microbiol. 61:51-69 (2007)). Gene Accession No. GI No. Organism pad] AB368798 188496948 Saccharomyces cerevisae BAG32372.1 188496949 pdc U63827 1762615, 1762616 Lactobacillus plantarum AAC45282.1 pofK (pad) AB330293, 149941607, Klebsiella oxytoca BAF65031.1 149941608 padC AF017117 2394281, 2394282 Bacillus subtilis AAC46254.1 pad AJ276891 11322456, 11322458 Pedicoccus pentosaceus CAC16794.1 pad AJ278683 11691809, 11691810 Bacillus pumilus CAC18719.1 Additional decarboxylase enzymes can form succinic semialdehyde from alpha-ketoglutarate. These include the alpha-ketoglutarate decarboxylase enzymes from Euglena gracilis (Shigeoka et al. Biochem.J. 282( Pt 2):319-323 (1992); Shigeoka and Nakano Arch.Biochem.Biophys. 288:22-28 (1991); Shigeoka and Nakano Biochem.J. 292 ( Pt 2):463-467 (1993)), whose 20 corresponding gene sequence has yet to be determined, and from Mycobacterium tuberculosis (Tian et al. Proc Natl Acad Sci U.S.A. 102:10670-10675 (2005)). In addition, glutamate decarboxylase enzymes can convert glutamate into 4-aminobutyrate such as the products of the E. coli gadA and gadB genes (De Biase et al. Protein.Expr.Purif 8:430-438 (1993)).

138 Gene Accession No. GI No. Organism kgd 050463.4 160395583 Mycobacterium tuberculosis gadA NP_417974 16131389 Escherichia coli gadB NP 416010 16129452 Escherichia coli Keto-acid decarboxylases Pyruvate decarboxylase (PDC, EC 4.1.1.1), also termed keto-acid decarboxylase, is a key enzyme in alcoholic fermentation, catalyzing the decarboxylation of pyruvate to acetaldehyde. 5 This enzyme has a broad substrate range for aliphatic 2-keto acids including 2-ketobutyrate, 2 ketovalerate, 3-hydroxypyruvate and 2-phenylpyruvate (Berg et al. Science 318:1782-1786 (2007)). The PDC from Zymomonas mobilus, encoded by pdc, has been a subject of directed engineering studies that altered the affinity for different substrates (Siegert et al. Protein Eng Des Sel 18:345-357 (2005)). The PDC from Saccharomyces cerevisiae has also been 10 extensively studied, engineered for altered activity, and functionally expressed in E. coli (Killenberg-Jabs et al. Eur.J.Biochem. 268:1698-1704 (2001); Li and Jordan Biochemistry 38:10004-10012 (1999); ter Schure et al. Appl.Environ.Microbiol. 64:1303-1307 (1998)). The crystal structure of this enzyme is available (Killenberg-Jabs Eur.J.Biochem. 268:1698-1704 (2001)). Other well-characterized PDC candidates include the enzymes from Acetobacter 15 pasteurians (Chandra et al. Arch.Microbiol. 176:443-451 (2001)) and Kluyveromyces lactis (Krieger et al. Eur.J.Biochem. 269:3256-3263 (2002)). Gene Accession No. GI No. Organism pdc P06672.1 118391 Zymomonas mobilus pdc1 P06169 30923172 Saccharomyces cerevisiae pdc Q8L388 75401616 Acetobacter pasteurians pdcl Q12629 52788279 Kluyveromyces lactis Like PDC, benzoylformate decarboxylase (EC 4.1.1.7) has a broad substrate range and has been the target of enzyme engineering studies. The enzyme from Pseudomonas putida has been extensively studied and crystal structures of this enzyme are available (Hasson et al. 20 Biochemistry 37:9918-9930 (1998); Polovnikova et al. Biochemistry 42:1820-1830 (2003)). Site-directed mutagenesis of two residues in the active site of the Pseudomonas putida enzyme altered the affinity (Km) of naturally and non-naturally occuring substrates (Siegert Protein Eng Des Sel 18:345-357 (2005)). The properties of this enzyme have been further modified by directed engineering (Lingen et al. Protein Eng 15:585-593 (2002)); Lingen Chembiochem 25 4:721-726 (2003)). The enzyme from Pseudomonas aeruginosa, encoded by mdlC, has also 139 been characterized experimentally (Barrowman et al. FEMS Microbiology Letters 34:57-60 (1986)). Additional gene candidates from Pseudomonas stutzeri, Pseudomonasfluorescens and other organisms can be inferred by sequence homology or identified using a growth selection system developed in Pseudomonas putida (Henning et al. Appl.Environ.Microbiol. 72:75 10 5 7517 (2006)). Gene Accession No. GI No. Organism mdlC P20906.2 3915757 Pseudomonas putida mdlC Q9HUR2.1 81539678 Pseudomonas aeruginosa dpgB ABN80423.1 126202187 Pseudomonas stutzeri ilvB-1 YP_260581.1 70730840 Pseudomonasfluorescens 4.2.1.a - Hydro-lyase The 2-(hydroxymethyl)glutarate dehydratase of Eubacterium barkeri is an exemplary hydro lyase. This enzyme has been studied in the context of nicotinate catabolism and is encoded by 10 hmd (Alhapel et al. Proc Natl Acad Sci U S A 103:12341-12346 (2006)). Similar enzymes with high sequence homology are found in Bacteroides capillosus, Anaerotruncus colihominis, and Natranaerobius thermophilius. Gene Accession No. GI No. Organism hnd ABC88407.1 86278275 Eubacterium barkeri BACCAP_02294 ZP_02036683.1 154498305 Bacteroides capillosus ATCC 29799 ANACOL_02527 ZP_02443222.1 167771169 Anaerotruncus colihominis DSM 17241 NtherDRAFT_2368 ZP_02852366.1 169192667 Natranaerobius thermophilus JW/NM WN-LF A second exemplary hydro-lyase is fumarate hydratase, an enzyme catalyzing the dehydration of malate to fumarate. A wealth of structural information is available for this enzyme and 15 researchers have successfully engineered the enzyme to alter activity, inhibition and localization (Weaver, T. Acta Crystallogr.D Biol Crystallogr. 61:1395-1401 (2005)). Additional fumarate hydratases include those encoded byfumC from Escherichia coli (Estevez et al. Protein Sci. 11:1552-1557 (2002); Hong and Lee Biotechnol.Bioprocess Eng. 9:252-255 (2004); Rose and Weaver Proc Natl Acad Sci U S.A 101:3393-3397 (2004)), Campylobacterjejuni (Smith et al. 20 Int.J Biochem.Cell Biol 31:961-975 (1999)) and Thermus thermophilus (Mizobata et al. Arch.Biochem.Biophys. 355:49-55 (1998)), andfumH from Rattus norvegicus (Kobayashi et al. J Biochem. 89:1923-1931(1981)). Similar enzymes with high sequence homology includefum1 from Arabidopsis thaliana and fumC from Corynebacterium glutamicum.

140 Gene Accession No. GI No. Organism fumC P05042.1 120601 Escherichia coli K12 fumC 069294.1 9789756 Campylobacterjejuni fumC P84127 75427690 Thermus thermophilus fumH P14408.1 120605 Rattus norvegicus fum1 P93033.2 39931311 Arabidopsis thaliana fumC Q8NRN8.1 39931596 Corynebacterium glutamicum Citramalate hydrolyase, also called 2-methylmalate dehydratase, converts 2-methylmalate to mesaconate. 2-Methylmalate dehydratase activity was detected in Clostridium tetanomorphum, Morganella morganii, Citrobacter amalonaticus in the context of the glutamate degradation VI pathway (Kato and Asano Arch.Microbiol 168:457-463 (1997)); however the genes encoding 5 this enzyme have not been sequenced to date. The gene product of crt from C. acetobutylicum catalyzes the dehydration of 3-hydroxybutyryl CoA to crotonyl-CoA (Atsumi et al. Metab Eng.; 29 (2007)); Boynton et al. Journal of Bacteriology 178:3015-3024 (1996)). The enoyl-CoA hydratases, phaA and phaB, of P. putida are believed to carry out the hydroxylation of double bonds during phenylacetate catabolism; 10 (Olivera et al. Proc Natl Acad Sci U S A 95(11):6419-6424 (1998)). The paaA and paaB from P. fluorescens catalyze analogous transformations (14 Olivera et al., supra, 1998). Lastly, a number of Escherichia coli genes have been shown to demonstrate enoyl-CoA hydratase functionality including maoC (Park and Lee J Bacteriol 185(18):5391-5397 (2003)), paaF (Park and Lee Biotechnol Bioeng. 86(6):681-686 (2004a)); Park and Lee Appl Biochem 15 Biotechnol. 113-116: 335-346 (2004b)); Ismail et al. Eur J Biochem 2 7 0(1 4 ):p. 3047-3054 (2003), and paaG (Park and Lee, supra, 2004; Park and Lee supra, 2004b; Ismail et al., supra, 2003). Gene Accession No. GI No. Organism maoC NP_415905.1 16129348 Escherichia coli paaF NP_415911.1 16129354 Escherichia coli paaG NP_415912.1 16129355 Escherichia coli crt NP_349318.1 15895969 Clostridium acetobutylicum paaA NP_745427.1 26990002 Pseudomonas putida paaB NP_745426.1 26990001 Pseudomonasputida 141 phaA ABF82233.1 106636093 Pseudomonasfluorescens phaB ABF82234.1 106636094 Pseudomonasfluorescens The E. coli genes fadA andfadB encode a multienzyme complex that exhibits ketoacyl-CoA thiolase, 3-hydroxyacyl-CoA dehydrogenase, and enoyl-CoA hydratase activities (Yang et al. 5 Biochemistry 30(27): p. 6788-6795 (1991); Yang et al. JBiol Chem 265(18): p. 10424-10429 (1990); Yang et al. J Biol Chem 266(24): p. 16255 (1991); Nakahigashi and Inokuchi Nucleic Acids Res 18(16): p. 4937 (1990)). The fadI andfadJ genes encode similar functions and are naturally expressed only anaerobically (Campbell et al. Mol Microbiol 47(3): p. 793-805 (2003). A method for producing poly [(R)-3-hydroxybutyrate] in E. coli that involves activating fadB (by 10 knocking out a negative regulator, fadR) and co-expressing a non-native ketothiolase (phaA from Ralstonia eutropha) has been described previously (Sato et al. J Biosci Bioeng 103(1): 38 44 (2007)). This work clearly demonstrates that a P-oxidation enzyme, in particular the gene product of fadB which encodes both 3-hydroxyacyl-CoA dehydrogenase and enoyl-CoA hydratase activities, can function as part of a pathway to produce longer chain molecules from 15 acetyl-CoA precursors. Gene Accession No. GI No. Organism fadA YP_026272.1 49176430 Escherichia coli fadB NP_418288.1 16131692 Escherichia coli fadI NP_416844.1 16130275 Escherichia coli fadJ NP_416843.1 16130274 Escherichia coli fadR NP_415705.1 16129150 Escherichia coli 4.3.1.a - Ammonia-lyase Aspartase (EC 4.3.1.1), catalyzing the deamination of aspartate to fumarate, is a widespread enzyme in microorganisms, and has been characterized extensively (Viola, R. E. 20 Adv.Enzymol.Relat Areas Mol.Biol 74:295-341 (2000)). The crystal structure of the E. coli aspartase, encoded by aspA, has been solved (Shi et al. Biochemistry 36:9136-9144 (1997)). The E. coli enzyme has also been shown to react with alternate substrates aspartatephenylmethylester, asparagine, benzyl-aspartate and malate (Ma et al. Ann N. Y.Acad Sci 672:60-65 (1992)). In a separate study, directed evolution was been employed on this 25 enzyme to alter substrate specificity (Asano et al. Biomol.Eng 22:95-101 (2005)). Enzymes with aspartase functionality have also been characterized in Haemophilus influenzae (Sjostrom et al.

142 Biochim.Biophys.Acta 1324:182-190 (1997)), Pseudomonas fluorescens (Takagi et al. J.Biochem. 96:545-552 (1984)), Bacillus subtilus (Sjostrom et al. Biochim.Biophys.Acta 1324:182-190 (1997)) and Serratia marcescens (Takagi and Kisumi J Bacteriol. 161:1-6 (1985)). Gene Accession No. GI No. Organism aspA NP_418562 90111690 Escherichia coli K12 subsp. MG1655 aspA P44324.1 1168534 Haemophilus influenzae aspA P07346.1 114273 Pseudomonasfluorescens ansB P26899.1 114271 Bacillus subtilus aspA P33109.1 416661 Serratia marcescens 5 3-methylaspartase (EC 4.3.1.2), also known as beta-methylaspartase or 3-methylaspartate ammonia-lyase, catalyzes the deamination of threo-3-methylasparatate to mesaconate. The 3 methylaspartase from Clostridium tetanomorphum has been cloned, functionally expressed in E. coli, and crystallized (Asuncion et al. Acta Crystallogr.D Biol Crystallogr. 57:731-733 (2001); Asuncion et al. J Biol Chem. 277:8306-8311 (2002); Botting et al. Biochemistry 27:2953-2955 10 (1988); Goda et al. Biochemistry 31:10747-10756 (1992). In Citrobacter amalonaticus, this enzyme is encoded by BAA28709 (Kato and Asano Arch.Microbiol 168:457-463 (1997)). 3 Methylaspartase has also been crystallized from E. coli YG1002 (Asano and Kato FEMS Microbiol Lett. 118:255-258 (1994)) although the protein sequence is not listed in public databases such as GenBank. Sequence homology can be used to identify additional candidate 15 genes, including CTC_02563 in C. tetani and ECsO761 in Escherichia coli 0157:H7. Gene Accession No. GI No. Organism MAL AAB24070.1 259429 Clostridium tetanomorphum BAA28709 BAA28709.1 3184397 Citrobacter amalonaticus CTC_02563 NP_783085.1 28212141 Clostridium tetani ECs0761 BAB34184.1 13360220 Escherichia coli 0157:H7 str. Sakai Ammonia-lyase enzyme candidates that form enoyl-CoA products include beta-alanyl-CoA ammonia-lyase (EC 4.3.1.6), which deaminates beta-alanyl-CoA, and 3-aminobutyryl-CoA ammonia-lyase (EC 4.3.1.14). Two beta-alanyl-CoA ammonia lyases have been identified and characterized in Clostridium propionicum (Herrmann et al. FEBS J. 272:813-821 (2005)). No 20 other beta-alanyl-CoA ammonia lyases have been studied to date, but gene candidates can be identified by sequence similarity. One such candidate is MXAN_4385 in Myxococcus xanthus.

143 Gene Accession No. GI No. Organism ac12 CAG29275.1 47496504 Clostridium propionicum acli CAG29274.1 47496502 Clostridium propionicum MXAN_4385 YP_632558.1 108756898 Myxococcus xanthus 5.3.3.a - Isomerase The 4-hydroxybutyryl-CoA dehydratases from both Clostridium aminobutyrium and C. kluyveri 5 catalyze the reversible conversion of 4-hydroxybutyryl-CoA to crotonyl-CoA and posses an intrinsic vinylacetyl-CoA A-isomerase activity (Scherf and Buckel Eur.J Biochem. 215:421-429 (1993); Scherf et al. Arch.Microbiol 161:239-245 (1994)). Both native enzymes were purified and characterized, including the N-terminal amino acid sequences (Scherf and Buckel, supra, 1993; Scherf et al., supra, 1994). The abfD genes from C. aminobutyrium and C. kluyveri match 10 exactly with these N-terminal amino acid sequences, thus are encoding the 4-hydroxybutyryl CoA dehydratases/vinylacetyl-CoA A-isomerase. In addition, the abfD gene from Porphyromonas gingivalis ATCC 33277 is identified through homology from genome projects. Gene Accession No. GI No. Organism abfD YP_001396399.1 153955634 ClostridiumkluyveriDSM555 abfD P55792 84028213 Clostridium aminobutyricum abfD YP_001928843 188994591 Porphyromonas gingivalis ATCC 33277 5.4.3.a - Aminomutase 15 Lysine 2,3-aminomutase (EC 5.4.3.2) is an exemplary aminomutase that converts lysine to (3S) 3,6-diaminohexanoate, shifting an amine group from the 2- to the 3- position. The enzyme is found in bacteria that ferment lysine to acetate and butyrate, including as Fusobacterium nuleatum (kamA) (Barker et al. J.Bacteriol. 152:201-207 (1982)) and Clostridium subterminale (kamA) (Chirpich et al. J.Biol.Chem. 245:1778-1789 (1970)). The enzyme from Clostridium 20 subterminale has been crystallized (Lepore et al. Proc.Natl.Acad.Sci. U.S.A 102:13819-13824 (2005)). An enzyme encoding this function is also encoded by yodO in Bacillus subtilus (Chen et al. Biochem.J. 348 Pt 3:539-549 (2000)). The enzyme utilizes pyridoxal 5'-phosphate as a cofactor, requires activation by S-Adenosylmethoionine, and is stereoselective, reacting with the only with L-lysine. The enzyme has not been shown to react with alternate substrates.

144 Gene Accession No. GI No. Organism yodO 034676.1 4033499 Bacillus subtilus kamA Q9XBQ8.1 75423266 Clostridium subterminale kamA Q8RHX4 81485301 Fusobacterium nuleatum subsp. nuleatum A second aminomutase, beta-lysine 5,6-aminomutase (EC 5.4.3.3), catalyzes the next step of lysine fermentation to acetate and butyrate, which transforms (3S)-3,6-diaminohexanoate to (3S,5S)-3,5-diaminohexanoate, shifting a terminal amine group from the 6- to the 5- position. 5 This enzyme also catalyzes the conversion of lysine to 2,5-diaminohexanoate and is also called lysine-5,6-aminomutase (EC 5.4.3.4). The enzyme has been crystallized in Clostridium sticklandii (kamD, kamE) (Berkovitch et al. Proc.Natl.Acad.Sci. U.S.A 101:15870-15875 (2004)). The enzyme from Porphyromonas gingivalis has also been characterized (Tang et al. Biochemistry 41:8767-8776 (2002)). Gene Accession No. GI No. Organism kamD AAC79717.1 3928904 Clostridium sticklandii kamE AAC79718.1 3928905 Clostridium sticklandii kamD NC_002950.2 34539880, 34540809 Porphyromonas gingivalis W83 kamE NC_002950.2 34539880, 34540810 Porphyromonas gingivalis W83 10 Ornithine 4,5-aminomutase (EC 5.4.3.5) converts D-ornithine to 2,4-diaminopentanoate, also shifting a terminal amine to the adjacent carbon. The enzyme from Clostridium sticklandii is encoded by two genes, oraE and oraS, and has been cloned, sequenced and expressed in E. coli (Chen et al. J.Biol. Chem. 276:44744-44750 (2001)). This enzyme has not been characterized in other organisms to date. Gene Accession No. GI No. Organism oraE AAK72502 17223685 Clostridium sticklandii oraS AAK72501 17223684 Clostridium sticklandii 15 Tyrosine 2,3-aminomutase (EC 5.4.3.6) participates in tyrosine biosynthesis, reversibly converting tyrosine to 3-amino-3-(4-hdyroxyphenyl)propanoate by shifting an amine from the 2 to the 3- position. In Streptomyces globisporus the enzyme has also been shown to react with tyrosine derivatives (Christenson et al. Biochemistry 42:12708-12718 (2003)). Sequence information is not available. 20 Leucine 2,3-aminomutase (EC 5.4.3.7) converts L-leucine to beta-leucine during leucine degradation and biosynthesis. An assay for leucine 2,3-aminomutase detected activity in many 145 organisms (Poston, J. M. Methods Enzymol. 166:130-135 (1988)) but genes encoding the enzyme have not been identified to date. Cargill has developed a novel 2,3-aminomutase enzyme to convert L-alanine to 3-alanine, thus creating a pathway from pyruvate to 3-HP in four biochemical steps (Liao et al., U.S. 5 Publication No. 2005-0221466). 6.2.1.a - Acid-thiol ligase An exemplary acid-thiol ligase is the gene products of sucCD of E. coli which together catalyze the formation of succinyl-CoA from succinate with the concaminant consumption of one ATP, a reaction which is reversible in vivo (Buck et al. Biochemistry 24(22): p. 6245-6252 (1985)). 10 Additional exemplary CoA-ligases include the rat dicarboxylate-CoA ligase for which the sequence is yet uncharacterized (Vamecq et al. Biochem J. 230(3): p. 683-693 (1985)), either of the two characterized phenylacetate-CoA ligases from P. chrysogenum (Lamas-Maceiras et al. Biochem J 395(1):147-155 (2006); Wang et al. Biochem Biophys Res Commun, 360(2):453-458 (2007)), the phenylacetate-CoA ligase from Pseudomonas putida (Martinez-Blanco et al. J Biol 15 Chem. 265(12):7084-7090 (1990)), and the 6-carboxyhexanoate-CoA ligase from Bacillus subtilis (Bower et al. J Bacteriol 178(14):4122-4130 (1996)). Gene Accession No. GI No. Organism sucC NP_415256.1 16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia coli phl CAJ15517.1 77019264 Penicillium chrysogenum phlB ABS19624.1 152002983 Penicillium chrysogenum paaF AAC24333.2 22711873 Pseudomonas putida bioW NP_390902.2 50812281 Bacillus subtilis EXAMPLE V Exemplary BDO Pathway from Succinyl-CoA 20 This example describes exemplary BDO pathways from succinyl-CoA. BDO pathways from succinyl-CoA are described herein and have been described previously (see U.S. application serial No. 12/049,256, filed March 14, 2008, and PCT application serial No. US08/57168, filed March 14, 2008, each of which is incorporated herein by reference). Additional pathways are shown in Figure 8A. Enzymes of such exemplary BDO pathways are 25 listed in Table 15, along with exemplary genes encoding these enzymes.

146 Briefly, succinyl-CoA can be converted to succinic semialdehyde by succinyl-CoA reductase (or succinate semialdehyde dehydrogenase) (EC 1.2.1.b). Succinate semialdehyde can be converted to 4-hydroxybutyrate by 4-hydroxybutyrate dehydrogenase (EC 1.1.1. a), as previously described. Alternatively, succinyl-CoA can be converted to 4-hydroxybutyrate by succinyl-CoA 5 reductase (alcohol forming) (EC 1.1.1 .c). 4-Hydroxybutyrate can be converted to 4 hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA transferase (EC 2.8.3.a), as previously described, or by 4-hydroxybutyryl-CoA hydrolase (EC 3.1.2.a) or 4-hydroxybutyryl-CoA ligase (or 4-hydroxybutyryl-CoA synthetase) (EC 6.2. 1.a). Alternatively, 4-hydroxybutyrate can be converted to 4-hydroxybutyryl-phosphate by 4-hydroxybutyrate kinase (EC 2.7.2.a), as 10 previously described. 4-Hydroxybutyryl-phosphate can be converted to 4-hydroxybutyryl-CoA by phosphotrans-4-hydroxybutyrylase (EC 2.3.1.a), as previously described. Alternatively, 4 hydroxybutyryl-phosphate can be converted to 4-hydroxybutanal by 4-hydroxybutanal dehydrogenase (phosphorylating) (EC 1.2.1 .d). 4-Hydroxybutyryl-CoA can be converted to 4 hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or 4-hydroxybutanal dehydrogenase) (EC 15 1.2.1.b). Alternatively, 4-hydroxybutyryl-CoA can be converted to 1,4-butanediol by 4 hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1. 1.c). 4-Hydroxybutanal can be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a), as previously described.

147 0 o c CD CD N C 0 0 0 -~CD

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7Z- ~ 0 0 0 n 0n u cl E n n u 04, OC) O) OC 148 StC CI -C 9 R a t o0 0 zt IZ - -0 z G -Z

C

C4 CA G G I-)l pc 'CCf CC '7C & 7 7 C-. a 0 O 0 149 CO4 - - - Ec CO CO oG~- -o -I G - tI- ) OCD O O O O OO- ~ oooo 4k 4 150 o o o 0 t c , o .) - ~ - 32a . C od Ct CC ,. .2Q 2~ 3oo C - Ct - C 0 xx - - C .o C ..- e O O O0 t o 0 Ct de - 3. -C -S o t Co oo C oo oo C 151 EXAMPLE VI Additional Exemplary BDO Pathways from Alpha-ketoglutarate This example describes exemplary BDO pathways from alpha-ketoglutarate. BDO pathways from succinyl-CoA are described herein and have been described previously (see 5 U.S. application serial No. 12/049,256, filed March 14, 2008, and PCT application serial No. US08/57168, filed March 14, 2008, each of which is incorporated herein by reference). Additional pathways are shown in Figure 8B. Enzymes of such exemplary BDO pathways are listed in Table 16, along with exemplary genes encoding these enzymes. Briefly, alpha-ketoglutarate can be converted to succinic semialdehyde by alpha-ketoglutarate 10 decarboxylase (EC 4.1.1 .a), as previously described. Alternatively, alpha-ketoglutarate can be converted to glutamate by glutamate dehydrogenase (EC 1.4. 1.a). 4-Aminobutyrate can be converted to succinic semialdehyde by 4-aminobutyrate oxidoreductase (deaminating) (EC 1.4.1.a) or 4-aminobutyrate transaminase (EC 2.6.1.a). Glutamate can be converted to 4 aminobutyrate by glutamate decarboxylase (EC 4.1.1.a). Succinate semialdehyde can be 15 converted to 4-hydroxybutyrate by 4-hydroxybutyrate dehydrogenase (EC 1.1.1.a), as previously described. 4-Hydroxybutyrate can be converted to 4-hydroxybutyryl-CoA by 4-hydroxybutyryl CoA transferase (EC 2.8.3.a), as previously described, or by 4-hydroxybutyryl-CoA hydrolase (EC 3.1.2.a), or 4-hydroxybutyryl-CoA ligase (or 4-hydroxybutyryl-CoA synthetase) (EC 6.2.1 .a). 4-Hydroxybutyrate can be converted to 4-hydroxybutyryl-phosphate by 4 20 hydroxybutyrate kinase (EC 2.7.2.a). 4-Hydroxybutyryl-phosphate can be converted to 4 hydroxybutyryl-CoA by phosphotrans-4-hydroxybutyrylase (EC 2.3.1.a), as previously described. Alternatively, 4-hydroxybutyryl-phosphate can be converted to 4-hydroxybutanal by 4-hydroxybutanal dehydrogenase (phosphorylating) (EC 1.2.1 .d). 4-Hydroxybutyryl-CoA can be converted to 4-hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or 4-hydroxybutanal 25 dehydrogenase) (EC 1.2.1.b), as previously described. 4-Hydroxybutyryl-CoA can be converted to 1,4-butanediol by 4-hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c). 4 Hydroxybutanal can be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a), as previously described.

152 u 0 0n 0 r-- oLn Ln Ln ~ -~ E O n ~ cl .7'~ C4 C t 01 7 S 5 -5 o7 7-1 7:1-1 -C 70 OC) OCt OC0 153 71 71 71 7 o o o 0 c~ c~ 0 0 .,71 ~~ 710 o~ ~ ~ t0 t0 ~0 ~--0 c Z- -Z -Z Z -Z -Z -Z t 0 0 0n 0 10 CA -0 r0-- r--- *0 OC *- CD m no nL CA -0 0,! -, 7t -7 -Z - n0 42 4 000 0 0 0 154 0 0 0 0 0 0 0 -~ ~0 -~ 00 .~ -~ ~-~0 ~ 0 0 0 ~ ~0 0 .0 0 0 0 0 0 0 0 ~ 0 0 0 0 ~ 0 0 ~ 0~ ~ 0 ~ 0 0 ~ 0 0 ~- 0 ~ ~- ~-~- '.0 ~ t1~(~] 'C I A . I I ~ & Cl (N 0 ~ 0 0 . 0 0 ~ ~ 0 ~ c~ 0 -~ z c~- 0 ~ ~ 0 ~ 0 -~ 0 -~0~0 -~ 0 0 0 0 0 ~toQ) 0 0 0 ~0 0 0 0

'C

155 Z -Z -Z 0 00 m 0 O C .-- 0 CA M CD OC0 0 ~ C m 0 ~- - ~7Z CO0 0 -0-0 - 00 .- .- - ~ C4 -zt -n - n * C4 C4 0 n -0-0 ~ 041 7N oR O 4 ~ o. o. n 156 -e ~) -~ - COt CO CO CO ot A Cfl~n z k b .~ ~ k ~ ~Lfl In z 5 Cfl 30 o N - - C o ~t ~ I I CO CL COO 2 -e - -e -5 CO CO -z CO CO CO -z z 0 t CO 30 157 EXAMPLE VII BDO Pathways from 4-Aminobutyrate This example describes exemplary BDO pathwayd from 4-aminobutyrate. 5 Figure 9A depicts exemplary BDO pathways in which 4-aminobutyrate is converted to BDO. Enzymes of such an exemplary BDO pathway are listed in Table 17, along with exemplary genes encoding these enzymes. Briefly, 4-aminobutyrate can be converted to 4-aminobutyryl-CoA by 4-aminobutyrate CoA transferase (EC 2.8.3.a), 4-aminobutyryl-CoA hydrolase (EC 3.1.2.a), or 4-aminobutyrate-CoA 10 ligase (or 4-aminobutyryl-CoA synthetase) (EC 6.2.1.a). 4-aminobutyryl-CoA can be converted to 4-oxobutyryl-CoA by 4-aminobutyryl-CoA oxidoreductase (deaminating) (EC 1.4. 1.a) or 4 aminobutyryl-CoA transaminase (EC 2.6.1.a). 4-oxobutyryl-CoA can be converted to 4 hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA dehydrogenase (EC 1.1.1 .a). 4-hydroxybutyryl CoA can be converted to 1,4-butanediol by 4-hydroxybutyryl-CoA reductase (alcohol forming) 15 (EC 1.1.1.c). Alternatively, 4-hydroxybutyryl-CoA can be converted to 4-hydroxybutanal by 4 hydroxybutyryl-CoA reductase (or 4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). 4 hydroxybutanal can be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a).

158 000 S0 C 0 0 I6 -n r- 0-L 0 - z -I 0Z .04 4 0 4 - o - o ) E ~ - .- e .2 .0 . 2 '03~ i 5 - -8 z Ci 00 eZ 3t . C -- 'C CC' feC 5 C] 2 - ON ? 7<7 < 7<. 7 C- 0 e o d W*Q Q * x ~ ~ -1 Pc Q. .

159 Z A Ln) 7t rC CA, ~~nL CO N C I - C C G) G ItC 5n C CO 4G 4 G4 e oo e e e ok I Ik Cl Cl 160 00 0 - - 0 0 00 0 -C c) 0n 71 A 4 QD 4 ~ .i ci ;i cJci 1 71I 4-~-C 161 Enzymes for another exemplary BDO pathway converting 4-aminobutyrate to BDO is shown in Figure 9A. Enzymes of such an exemplary BDO pathway are listed in Table 18, along with exemplary genes encoding these enzymes. Briefly, 4-aminobutyrate can be converted to 4-aminobutyryl-CoA by 4-aminobutyrate CoA 5 transferase (EC 2.8.3.a), 4-aminobutyryl-CoA hydrolase (EC 3.1.2.a) or 4-aminobutyrate-CoA ligase (or 4-aminobutyryl-CoA synthetase) (EC 6.2.1 .a). 4-aminobutyryl-CoA can be converted to 4-aminobutan-1-ol by 4-aminobutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c). Alternatively, 4-aminobutyryl-CoA can be converted to 4-aminobutanal by 4-aminobutyryl-CoA reductase (or 4-aminobutanal dehydrogenase) (EC 1.2.1 .b), and 4-aminobutanal converted to 4 10 aminobutan-1-ol by 4-aminobutan-1-ol dehydrogenase (EC 1.1.1.a). 4-aminobutan-1-ol can be converted to 4-hydroxybutanal by 4-aminobutan-1-ol oxidoreductase (deaminating) (EC 1.4. 1.a) or 4-aminobutan-1-ol transaminase (EC 2.6.1.a). 4-hydroxybutanal can be converted to 1,4 butanediol by 1,4-butanediol dehydrogenase (EC 1.1. 1.a).

162 n u 7:1ux 00 0-4 CL0 .0 - 0 Cl n . C c C- C 2 C Ln C-- r- n G -z o Col 4 4 0 N Q.C 163 o A I - 000 on CDN C.C4 4~ N1 kC -C oHc o ze ;e si - - - - C - - a a30 .o .. o .. oC OO K < o oo CC 00 ct . ~ t 164 o -z CD CD ku - .k. ...-. E m 08 C 00 o e- . eo , e n - C CAl CI 3 cto nn 1 O z z 0 0 o O Cz C0 ce c 165 Figure 9B depicts exemplary BDO pathway in which 4-aminobutyrate is converted to BDO. Enzymes of such an exemplary BDO pathway are listed in Table 19, along with exemplary genes encoding these enzymes. Briefly, 4-aminobutyrate can be converted to [(4-aminobutanolyl)oxy] phosphonic acid by 4 5 aminobutyrate kinase (EC 2.7.2.a). [(4-aminobutanolyl)oxy] phosphonic acid can be converted to 4-aminobutanal by 4-aminobutyraldehyde dehydrogenase (phosphorylating) (EC 1.2. 1.d). 4 aminobutanal can be converted to 4-aminobutan-1-ol by 4-aminobutan-1-ol dehydrogenase (EC 1.1.1.a). 4-aminobutan-1-ol can be converted to 4-hydroxybutanal by 4-aminobutan-1-ol oxidoreductase (deaminating) (EC 1.4.1.a) or 4-aminobutan-1-ol transaminase (EC 2.6.1.a). 10 Alternatively, [(4-aminobutanolyl)oxy] phosphonic acid can be converted to [(4 oxobutanolyl)oxy] phosphonic acid by [(4-aminobutanolyl)oxy]phosphonic acid oxidoreductase (deaminating) (EC 1.4.1.a) or [(4-aminobutanolyl)oxy]phosphonic acid transaminase (EC 2.6.1 .a). [(4-oxobutanolyl)oxy] phosphonic acid can be converted to 4-hydroxybutyryl phosphate by 4-hydroxybutyryl-phosphate dehydrogenase (EC 1.1.1 .a). 4-hydroxybutyryl 15 phosphate can be converted to 4-hydroxybutanal by 4-hydroxybutyraldehyde dehydrogenase (phosphorylating) (EC 1.2.1.d). 4-hydroxybutanal can be converted to 1,4-butanediol by 1,4 butanediol dehydrogenase (EC 1.1.1. a).

166 7 0 -& 0E 0 f 4 C4 -z 0z -Z -Z -Z-Z - Z -- -Z o 4 ro 8 m 0 -z Tk A CA4A r/C k e Q ::N k C N 0~ QOO N | N |0 | | ;o C O ' NN 711 4Cl t - 3 . ? - ot N *~CC e -z o tD 167 e 2 2 2 G G0 N N~ - - 00 N 0 00 N 0,, 0 a x 0,, 'O o - -o -- 0 C- Cflos-c O ON '2s '2 t I O ,2 o 0 s-s"'O ~ O~ CC ) 0, ON 168 t 7 8 1 1* t Z -Z OC o 00 OC O It I u7 7 4 7 k- .~~tr~ o C. NZ C] 3 NC 30 -,O k - oC)e OO nC c e - Cz~ 169 C) -e C) -e C) C) CO CO CO C) cn C.) CO C.) C) ot A CO k ;~ b.~ .~ 'm ~z k 'U C.

~ Cl Cfl 30 o N 5 - - C o ~t ~ I I ~- Cl 7 7 A -C) CO t CO C)C) CO 3~ COO 2 -e 'C) - -e C) CO CO -z t CO CO Ct -z z 0 -e ~t -~ t 0 ~cO C 0~ ON 0 170 Figure 9C shows an exemplary pathway through acetoacetate. EXAMPLE VIII Exemplary BDO Pathways from Alpha-ketoglutarate This example describes exemplary BDO pathways from alpha-ketoglutarate. 5 Figure 10 depicts exemplary BDO pathways in which alpha-ketoglutarate is converted to BDO. Enzymes of such an exemplary BDO pathway are listed in Table 20, along with exemplary genes encoding these enzymes. Briefly, alpha-ketoglutarate can be converted to alpha-ketoglutaryl-phosphate by alpha ketoglutarate 5-kinase (EC 2.7.2.a). Alpha-ketoglutaryl-phosphate can be converted to 2,5 10 dioxopentanoic acid by 2,5-dioxopentanoic semialdehyde dehydrogenase (phosphorylating) (EC 1.2.1.d). 2,5-dioxopentanoic acid can be converted to 5-hydroxy-2-oxopentanoic acid by 2,5 dioxopentanoic acid reductase (EC 1.1.1 .a). Alternatively, alpha-ketoglutarate can be converted to alpha-ketoglutaryl-CoA by alpha-ketoglutarate CoA transferase (EC 2.8.3.a), alpha ketoglutaryl-CoA hydrolase (EC 3.1.2.a) or alpha-ketoglutaryl-CoA ligase (or alpha 15 ketoglutaryl-CoA synthetase) (EC 6.2.1.a). Alpha-ketoglutaryl-CoA can be converted to 2,5 dioxopentanoic acid by alpha-ketoglutaryl-CoA reductase (or 2,5-dioxopentanoic acid dehydrogenase) (EC 1.2.1.b). 2,5-Dioxopentanoic acid can be converted to 5-hydroxy-2 oxopentanoic acid by 5-hydroxy-2-oxopentanoic acid dehydrogenase. Alternatively, alpha ketoglutaryl-CoA can be converted to 5-hydroxy-2-oxopentanoic acid by alpha-ketoglutaryl 20 CoA reductase (alcohol forming) (EC 1.1.1.c). 5-hydroxy-2-oxopentanoic acid can be converted to 4-hydroxybutanal by 5-hydroxy-2-oxopentanoic acid decarboxylase (EC 4.1.1.a). 4 hydroxybutanal can be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a). 5-hydroxy-2-oxopentanoic acid can be converted to 4-hydroxybutyryl-CoA by 5 hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation) (EC 1.2.1.c). 25 171 I-)e 2 0 -3 0 Z - - - Ct - ot e , o- c . 0- L-, r- 00 -T 2 ooo O A o C,-A 2 . 333 o ON in N 30 ] ON1 NZ N C ] l3 ell- - - 1- cf 4 4 ON G G 00 I I I I . ~ ~- C g- C ot 8 O N Or- N N x0 C ) 5N I 172 Z 0Z C 06 00 0 oto C4 -c qcl 4 44 C4 C4 C4 C4C4C 2 2 2 446 -,4 ~C 0 0 173 s-i -te 000 -e . e e 8 8 4 -; OCo _ z 0CJ k oo C-C as 30, 10 -8 N -7'i ei N ONO CC up e C )C N0 c 174 4 E; O O - Z A. .) > .t S 3 F3 Lr)L 0 tn o o C z - o o cno 4-oo Cl Cl CCAciOCC z $$ . a 8 o -'8 k - k k - k83 e - os o a C. a . now no 175 EXAMPLE IX Exemplary BDO Pathways from Glutamate This example describes exemplary BDO pathways from glutamate. Figure 11 depicts exemplary BDO pathways in which glutamate is converted to BDO. Enzymes 5 of such an exemplary BDO pathway are listed in Table 21, along with exemplary genes encoding these enzymes. Briefly, glutamate can be converted to glutamyl-CoA by glutamate CoA transferase (EC 2.8.3.a), glutamyl-CoA hydrolase (EC 3.1.2.a) or glutamyl-CoA ligase (or glutamyl-CoA synthetase) (EC 6.2. 1.a). Alternatively, glutamate can be converted to glutamate-5-phosphate by 10 glutamate 5-kinase (EC 2.7.2.a). Glutamate-5-phosphate can be converted to glutamate-5 semialdehyde by glutamate-5-semialdehyde dehydrogenase (phosphorylating) (EC 1.2.1 .d). Glutamyl-CoA can be converted to glutamate-5-semialdehyde by glutamyl-CoA reductase (or glutamate-5-semialdehyde dehydrogenase) (EC 1.2. 1.b). Glutamate-5-semialdehyde can be converted to 2-amino-5-hydroxypentanoic acid by glutamate-5-semialdehyde reductase (EC 15 1.1.1.a). Alternatively, glutamyl-CoA can be converted to 2-amino-5-hydroxypentanoic acid by glutamyl-CoA reductase (alcohol forming) (EC 1.1.1.c). 2-Amino-5-hydroxypentanoic acid can be converted to 5-hydroxy-2-oxopentanoic acid by 2-amino-5-hydroxypentanoic acid oxidoreductase (deaminating) (EC 1.4. 1.a) or 2-amino-5-hydroxypentanoic acid transaminase (EC 2.6.1.a). 5-Hydroxy-2-oxopentanoic acid can be converted to 4-hydroxybutanal by 5 20 hydroxy-2-oxopentanoic acid decarboxylase (EC 4.1.1 .a). 4-Hydroxybutanal can be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a). Alternatively, 5-hydroxy-2 oxopentanoic acid can be converted to 4-hydroxybutyryl-CoA by 5-hydroxy-2-oxopentanoic acid dehydrogenase (decarboxylation) (EC 1.2.1.c).

176 00 CCA 00 CA ~ - o m Ln CtI - 6Z o.o . % 6 -cl d a i c e al o u u oo 'CA N x Ifl Ifl Oo 4 Q C m -C 0-a o o 0 Ud 177 J CZ1 cn 1 Ln C) C IZ- -Z C~C I~- -Z CA) otO010 0-0 C 0 m CA Aq. Aq. Oq. CoA ot x C4 U z

C.

G 30 - o t - * . 30 . N N 7l CA cn7 ONl CC

CC

178 I Ln - - ~ ~- -' -~ .- ~ c C.) n) 44 .2n 48 k 7 C- 0 n - i t 179 on o n Ou e -. o e -o an od ccd- 4 ooZnZnn -o NN N 1 O N N N - re Ln n CD CD OCOD N in in o oo o CD N 0 g OO4a Cl~C C4q C n < C k n n Ln 0 . . o z . zo o C'l - 8tn3 E fm ~ ~ 0t n O N tn O tO CC -a- ~- x C ~C 8~ C<91 180 EXAMPLE X Exemplary BDO from Acetoacetyl-CoA This example describes an exemplary BDO pathway from acetoacetyl-CoA. Figure 12 depicts exemplary BDO pathways in which acetoacetyl-CoA is converted to BDO. 5 Enzymes of such an exemplary BDO pathway are listed in Table 22, along with exemplary genes encoding these enzymes. Briefly, acetoacetyl-CoA can be converted to 3-hydroxybutyryl-CoA by 3-hydroxybutyryl-CoA dehydrogenase (EC 1.1.1.a). 3-Hydroxybutyryl-CoA can be converted to crotonoyl-CoA by 3 hydroxybutyryl-CoA dehydratase (EC 4.2.1 .a). Crotonoyl-CoA can be converted to vinylacetyl 10 CoA by vinylacetyl-CoA A-isomerase (EC 5.3.3.3). Vinylacetyl-CoA can be converted to 4 hydroxybutyryl-CoA by 4-hydroxybutyryl-CoA dehydratase (EC 4.2.1.a). 4-Hydroxybutyryl CoA can be converted to 1,4-butanediol by 4-hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1.1.c). Alternatively, 4-hydroxybutyryl-CoA can be converted to 4-hydroxybutanal by 4 hydroxybutyryl-CoA reductase (or 4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). 4 15 Hydroxybutanal can be converted to 1,4-butanediol by 1,4-butanediol dehydrogenase (EC 1.1.1.a).

181 00 7 lt - C; L CD A 0 0 CDCD C QO 0 0 0 0 Z - o ~ -< - ~ 00 - - ~ -~ - -~ 0 n n 7 N QO- ~ -~ ~ ell C - l 182 000 00 NN m 7 D C CDL "CII C Ln OC Ln -C 7 ~ ~ t n 183 EXAMPLE XI Exemplary BDO Pathway from Homoserine This example describes an exemplary BDO pathway from homoserine. Figure 13 depicts exemplary BDO pathways in which homoserine is converted to BDO. 5 Enzymes of such an exemplary BDO pathway are listed in Table 23, along with exemplary genes encoding these enzymes. Briefly, homoserine can be converted to 4-hydroxybut-2-enoate by homoserine deaminase (EC 4.3.1.a). Alternatively, homoserine can be converted to homoserine-CoA by homoserine CoA transferase (EC 2.8.3.a), homoserine-CoA hydrolase (EC 3.1.2.a) or homoserine-CoA ligase (or 10 homoserine-CoA synthetase) (EC 6.2.1.a). Homoserine-CoA can be converted to 4-hydroxybut 2-enoyl-CoA by homoserine-CoA deaminase (EC 4.3.1.a). 4-Hydroxybut-2-enoate can be converted to 4-hydroxybut-2-enoyl-CoA by 4-hydroxybut-2-enoyl-CoA transferase (EC 2.8.3.a), 4-hydroxybut-2-enoyl-CoA hydrolase (EC 3.1.2.a), or 4-hydroxybut-2-enoyl-CoA ligase (or 4 hydroxybut-2-enoyl-CoA synthetase) (EC 6.2.1.a). Alternatively, 4-hydroxybut-2-enoate can be 15 converted to 4-hydroxybutyrate by 4-hydroxybut-2-enoate reductase (EC 1.3.1 .a). 4 Hydroxybutyrate can be converted to 4-hydroxybutyryl-coA by 4-hydroxybutyryl-CoA transferase (EC 2.8.3.a), 4-hydroxybutyryl-CoA hydrolase (EC 3.1.2.a), or 4-hydroxybutyryl CoA ligase (or 4-hydroxybutyryl-CoA synthetase) (EC 6.2.1.a). 4-Hydroxybut-2-enoyl-CoA can be converted to 4-hydroxybutyryl-CoA by 4-hydroxybut-2-enoyl-CoA reductase (EC 20 1.3.1.a). 4-Hydroxybutyryl-CoA can be converted to 1,4-butanediol by 4-hydroxybutyryl-CoA reductase (alcohol forming) (EC 1.1.1 .c). Alternatively, 4-hydroxybutyryl-CoA can be converted to 4-hydroxybutanal by 4-hydroxybutyryl-CoA reductase (or 4-hydroxybutanal dehydrogenase) (EC 1.2.1.b). 4-Hydroxybutanal can be converted to 1,4-butanediol by 1,4 butanediol dehydrogenase (EC 1.1.1. a).

184 Z0 000 0~ 0 04 Z) Z)V r-r-C 000 0 -Z 040 185 00 0 -~ -Ln 0- Z q~ - ~ - ~ -~ m - ,Z CA O 00 a) 7< 4 17'i 0 o -i 186 O N 00 0 0 ,2. Us -Z -- a -C -z 1. G d G C ,- ~ C, o a aQ ts Q) Cl -e 2 o5 o - N N N CC

C-

187 0 0 060 00 000 m 0n -n -n Ln- > -I 00 07 1 0 0 rq 0 0Z -a ~~-6 >,0 (CA 06 r 00'.

188 0 - t YA -G - G -- - - -o0 o k ke Nk

CC

O - ONOOONC O OC OC tl tC l <C I< < 3 CON N 7 uN N 8, 000 0 189 EXAMPLE XII BDO Producing Strains Expressing Succinyl-CoA Synthetase This example desribes increased production of BDO in BDO producing strains expressing 5 succinyl-CoA synthetase. As discussed above, succinate can be a precursor for production of BDO by conversion to succinyl-CoA (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/0075351). Therefore, the host strain was genetically modified to overexpress the E. coli sucCD genes, which encode succinyl-CoA synthetase. The nucleotide 10 sequence of the E. coli sucCD operon is shown in Figure 14A, and the amino acid sequences for the encoded succinyl-CoA synthetase subunits are shown in Figures 14B and 14C. Briefly, the E. coli sucCD genes were cloned by PCR from E. coli chromosomal DNA and introduced into multicopy plasmids pZS* 13, pZA13, and pZE33 behind the PA1lacO-1 promoter (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997)) using standard molecular biology procedures. 15 The E. coli sucCD genes, which encode the succinyl-CoA synthetase, were overexpressed. The results showed that introducing into the strains sucCD to express succinyl-CoA synthetase improved BDO production in various strains compared to either native levels of expression or expression of cat], which is a succinyl-CoA/acetyl-CoA transferase. Thus, BDO production was improved by overexpressing the native E. coli sucCD genes encoding succinyl-CoA 20 synthetase. EXAMPLE XIII Expression of Heterologous Genes Encoding BDO Pathway Enzymes This example describes the expression of various non-native pathway enzymes to provide improved production of BDO. 25 Alpha-ketoglutarate decarboxylase. The Mycobacterium bovis sucA gene encoding alpha ketoglutarate decarboxylase was expressed in host strains. Overexpression of M. bovis sucA improved BDO production (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/0075351). The nucleotide and amino acid sequences of M. bovis sucA and the encoded alpha-ketoglutarate decarboxylase are shown in Figure 15. 30 To construct the M. bovis sucA expressing strains, fragments of the sucA gene encoding the alpha-ketoglutarate decarboxylase were amplified from the genomic DNA of Mycobacterium bovis BCG (ATCC 19015; American Type Culture Collection, Manassas VA) using primers 190 shown below. The full-length gene was assembled by ligation reaction of the four amplified DNA fragments, and cloned into expression vectors pZS*13 and pZE23 behind the PA1aco-1 promoter (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997)). The nucleotide sequence of the assembled gene was verified by DNA sequencing. 5 Primers for fragment 1: 5'-ATGTACCGCAAGTTCCGC-3' (SEQ ID NO:) 5'-CAATTTGCCGATGCCCAG-3' (SEQ ID NO:) Primers for fragment 2: 5'-GCTGACCACTGAAGACTTTG-3' (SEQ ID NO:) 10 5'-GATCAGGGCTTCGGTGTAG-3' (SEQ ID NO:) Primers for fragment 3: 5'-TTGGTGCGGGCCAAGCAGGATCTGCTC-3' (SEQ ID NO:) 5'-TCAGCCGAACGCCTCGTCGAGGATCTCCTG-3' (SEQ ID NO:) Primers for fragment 4: 15 5'-TGGCCAACATAAGTTCACCATTCGGGCAAAAC-3' (SEQ ID NO:) 5'-TCTCTTCAACCAGCCATTCGTTTTGCCCG-3' (SEQ ID NO:) Functional expression of the alpha-ketoglutarate decarboxylase was demonstrated using both in vitro and in vivo assays. The SucA enzyme activity was measured by following a previously reported method (Tian et al., Proc. Natl. Acad. Sci. USA 102:10670-10675 (2005)). The 20 reaction mixture contained 50 mM potassium phosphate buffer, pH 7.0, 0.2 mM thiamine pyrophosphate, 1 mM MgCl 2 , 0.8 mM ferricyanide, 1 mM alpha-ketoglutarate and cell crude lysate. The enzyme activity was monitored by the reduction of ferricyanide at 430 nm. The in vivo function of the SucA enzyme was verified using E. coli whole-cell culture. Single colonies of E. coli MG1655 lacIq transformed with plasmids encoding the SucA enzyme and the 4 25 hydroxybutyrate dehydrogenase (4Hbd) was inoculated into 5 mL of LB medium containing appropriate antibiotics. The cells were cultured at 37 0 C overnight aerobically. A 200 uL of this overnight culture was introduced into 8 mL of M9 minimal medium (6.78 g/L Na 2

HPO

4 , 3.0 g/L

KH

2

PO

4 , 0.5 g/L NaCl, 1.0 g/L NH 4 Cl, 1 mM MgSO 4 , 0.1 mM CaCl 2 ) supplemented with 20 g/L glucose, 100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the buffering 30 capacity, 10 tg/mL thiamine, and the appropriate antibiotics. Microaerobic conditions were 191 established by initially flushing capped anaerobic bottles with nitrogen for 5 minutes, then piercing the septum with a 23G needle following inoculation. The needle was kept in the bottle during growth to allow a small amount of air to enter the bottles. The protein expression was induced with 0.2 mM isopropyl -D-1-thiogalactopyranoside (IPTG) when the culture reached 5 mid-log growth phase. As controls, E. coli MG1655 lacI" strains transformed with only the plasmid encoding the 4-hydroxybutyrate dehydrogenase and only the empty vectors were cultured under the same condition (see Table 23). The accumulation of 4-hydroxybutyrate (4HB) in the culture medium was monitored using LCMS method. Only the E. coli strain expressing the Mycobacterium alpha-ketoglutarate decarboxylase produced significant amount 10 of 4HB (see Figure 16). Table 24. Three strains containing various plasmid controls and encoding sucA and 4 hydroxybutyrate dehydrogenase. Host pZE13 pZA33 1 MG1655 Iaclq vector vector 2 MG1655 Iaclq vector 4hbd 3 MG1655 Iaclq sucA 4hbd A separate experiment demonstrated that the alpha-ketoglutarate decarboxylase pathway 15 functions independently of the reductive TCA cycle. E. coli strain ECKh-401 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA) was used as the host strain (see Table 25). All the three constructs contained the gene encoding 4HB dehydrogenase (4Hbd). Construct 1 also contained the gene encoding the alpha-ketoglutarate decarboxylase (sucA). Construct 2 contained the genes encoding the succinyl-CoA synthetase (sucCD) and the CoA-dependent 20 succinate semialdehyde dehydrogenase (sucD), which are required for the synthesis of 4HB via the reductive TCA cycle. Construct 3 contains all the genes from 1 and 2. The three E. coli strains were cultured under the same conditions as described above except the second culture was under the micro-aerobic condition. By expressing the SucA enzyme, construct 3 produced more 4HB than construct 2, which relies on the reductive TCA cycle for 4HB synthesis (see 25 Figure 17). Further support for the contribution of alpha-ketoglutarate decarboxylase to production of 4HB and BDO was provided by flux analysis experiments. Cultures of ECKh-432, which contains both sucCD-sucD and sucA on the chromosome, were grown in M9 minimal medium containing a mixture of 1-13C-glucose (60%) and U-13C-glucose (40%). The biomass was harvested, the 30 protein isolated and hydrolyzed to amino acids, and the label distribution of the amino acids 192 analyzed by gas chromatography-mass spectrometry (GCMS) as described previously (Fischer and Sauer, Eur. J. Biochem. 270:880-891 (2003)). In addition, the label distribution of the secreted 4HB and BDO was analyzed by GCMS as described in W02008115840 A2. This data was used to calculate the intracellular flux distribution using established methods (Suthers et al., 5 Metab. Eng. 9:387-405 (2007)). The results indicated that between 56% and 84% of the alpha ketoglutarate was channeled through alpha-ketoglutarate decarboxylase into the BDO pathway. The remainder was oxidized by alpha-ketoglutarate dehydrogenase, which then entered BDO via the succinyl-CoA route. These results demonstrate 4-hydroxybutyrate producing strains that contain the sucA gene from 10 Mycobacterium bovis BCG expressed on a plasmid. When the plasmid encoding this gene is not present, 4-hydroxybutyrate production is negligible when sucD (CoA-dependant succinate semialdehyde dehydrogenase) is not expressed. The M. bovis gene is a close homolog of the Mycobacterium tuberculosis gene whose enzyme product has been previously characterized (Tian et al., supra, 2005). 15 Succinate semialdehyde dehydrogenase (CoA-dependent), 4-hydroxybutyrate dehydrogenase, and 4-hydroxybutyryl-CoA/acetyl-CoA transferase. The genes from Porphyromonas gingivalis W83 can be effective components of the pathway for 1,4-butanediol production (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/0075351). The nucleotide sequence of CoA-dependent succinate semialdehyde 20 dehydrogenase (sucD) from Porphyromonas gingivalis is shown in Figure 18A, and the encoded amino acid sequence is shown in Figure 18B. The nucleotide sequence of 4-hydroxybutyrate dehydrogenase (4hbd) from Porphymonas gingivalis is shown in Figure 19A, and the encoded amino acid seqence is shown in Figure 19B. The nucleotide sequence of 4-hydroxybutyrate CoA transferase (cat2) from Porphyromonas gingivalis is shown in Figure 20A, and the 25 encoded amino acid sequence is shown in Figure 20B. Briefly, the genes from Porphyromonas gingivalis W83 encoding succinate semialdehyde dehydrogenase (CoA-dependent) and 4-hydroxybutyrate dehydrogenase, and in some cases additionally 4-hydroxybutyryl-CoA/acetyl-CoA, were cloned by PCR from P. gingivalis chromosomal DNA and introduced into multicopy plasmids pZS* 13, pZA13, and pZE33 behind 30 the PAlacO-1 promoter (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997)) using standard molecular biology procedures. These plasmids were then introduced into host strains.

193 The Porphyromonas gingivalis W83 genes were introduced into production strains as described above. Some strains included only succinate semialdehyde dehydrogenase (CoA-dependant) and 4-hydroxybutyrate dehydrogenase without 4-hydroxybutyryl-CoA/acetyl-CoA transferase. Butyrate kinase and phosphotransbutyrylase. Butyrate kinase (BK) and phosphotransbutyrylase 5 (PTB) enzymes can be utlized to produce 4-hydroxybutyryl-CoA (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/0075351). In particular, the Clostridium acetobutylicum genes, buki and ptb, can be utilized as part of a functional BDO pathway. Initial experiments involved the cloning and expression of the native C. acetobutylicum PTB 10 (020) and BK (021) genes in E. coli. Where required, the start codon and stop codon for each gene were modified to "ATG" and "TAA," respectively, for more optimal expression in E. coli. The C. acetobutylicum gene sequences (020N and 021N) and their corresponding translated peptide sequences are shown in Figures 21 and 22. The PTB and BK genes exist in C. acetobutylicum as an operon, with the PTB (020) gene 15 expressed first. The two genes are connected by the sequence "atta aagttaagtg gaggaatgtt aac" (SEQ ID NO:) that includes a re-initiation ribosomal binding site for the downstream BK (021) gene. The two genes in this context were fused to lac-controlled promoters in expression vectors for expression in E. coli (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997)). Expression of the two proteins from these vector constructs was found to be low in comparison 20 with other exogenously expressed genes due to the high incidence of codons in the C. acetobutylicum genes that occur only rarely in E. coli. Therefore new 020 and 021 genes were predicted that changed rare codons for alternates that are more highly represented in E. coli gene sequences. This method of codon optimization followed algorithms described previously (Sivaraman et al., Nucleic Acids Res. 36:e16(2008)). This method predicts codon replacements 25 in context with their frequency of occurrence when flanked by certain codons on either side. Alternative gene sequences for 020 (Figure 23) and 021 (Figure 24) were determined in which increasing numbers of rare codons were replaced by more prevalent codons (A<B<C<D) based on their incidence in the neighboring codon context. No changes in actual peptide sequence compared to the native 020 and 021 peptide sequences were introduced in these predicted 30 sequences.

194 The improvement in expression of the BK and PTB proteins resulting from codon optimization is shown in Figure 25A. Expression of the native gene sequences is shown in lane 2, while expression of the 020B-021B and 020C-021C is shown in lanes 3 and 4, respectively. Higher levels of protein expression in the codon-optimized operons 020B-021B (2021B) and 020C 5 021C (2021C) also resulted in increased activity compared to the native operon (2021n) in equivalently-expressed E. coli crude extracts (Figure 25B). The codon optimized operons were expressed on a plasmid in strain ECKh-432 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA gltAR163L fimD:: E coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd) along with the C. acetobutylicum 10 aldehyde dehydrogenase to provide a complete BDO pathway. Cells were cultured in M9 minimal medium containing 20 g/L glucose, using a 23G needle to maintain microaerobic conditions as described above. The resulting conversion of glucose to the final product BDO was measured. Also measured was the accumulation of gamma-butyrylactone (GBL), which is a spontaneously rearranged molecule derived from 4Hb-CoA, the immediate product of the 15 PTB-BK enzyme pair. Figure 26 shows that expression of the native 2021n operon resulted in comparable BDO levels to an alternative enzyme function, Cat2 (034), that is capable of converting 4HB and free CoA to 4HB-CoA. GBL levels of 034 were significantly higher than 2021n, suggesting that the former enzyme has more activity than PTB-BK expressed from the native genes. However levels of both BDO and GBL were higher than either 034 or 2021n 20 when the codon-optimized variants 2021B and 2021C were expressed, indicating that codon optimization of the genes for PTB and BK significantly increases their contributions to BDO synthesis in E coli. These results demonstrate that butyrate kinase (BK) and phosphotransbutyrylase (PTB) enzymes can be employed to convert 4-hydroxybutyrate to 4-hydroxybutyryl-CoA. This eliminates the 25 need for a transferase enzyme such as 4-hydoxybutyryl-CoA/Acetyl-CoA transferase, which would generate one mole of acetate per mol of 4-hydroxybutyryl-CoA produced. The enzymes from Clostridium acetobutylicum are present in a number of engineered strains for BDO production. 4-hydroxybutyryl-CoA reductase. The Clostridium beijerinckii ald gene can be utilized as part 30 of a functional BDO pathway (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/007535 1). The Clostridium beijerinckii ald can also be 195 utilized to lower ethanol production in BDO producing strains. Additionally, a specific codon optimized ald variant (GNM0025B) was found to improve BDO production. The native C. beijerinckii ald gene (025n) and the predicted protein sequence of the enzyme are shown in Figure 27. As was seen for the Clostridium acetobutylicum PTB and BK genes, 5 expression of the native C. beijerinckii ald gene was very low in E. coli. Therefore, four codon optimized variants for this gene were predicted. Figures 28A-28D show alternative gene sequences for 025, in which increasing numbers of rare codons are replaced by more prevalent codons (A<B<C<D) based on their incidence in the neighboring codon context (25A, P=0.05; 25B, P=0.1; 25C, P=0.15; 25D, P=1). No changes in actual peptide sequence compared to the 10 native 025 peptide sequence were introduced in these predictions. Codon optimization significantly increased expression of the C. beijerinckii ald (see Figure 29), which resulted in significantly higher conversion of glucose to BDO in cells expressing the entire BDO pathway (Figure 30A). The native and codon-optimized genes were expressed on a plasmid along with P. gingivalis 15 Cat2, in the host strain ECKh-432 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA gltAR163L AackA fimD:: E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd), thus containing a complete BDO pathway. Cells were cultured microaerobically in M9 minimal medium containing 20 g/L glucose as described above. The relative production of BDO and ethanol by the C. beijerinckii Ald enzyme (expressed from 20 codon-optimized variant gene 025B) was compared with the C. acetobutylicum AdhE2 enzyme (see Figure 30B). The C. acetobutylicum AdhE2 enzyme (002C) produced nearly 4 times more ethanol than BDO. In comparison, the C. beijerinckii Ald (025B) (in conjunction with an endogenous ADH activity) produced equivalent amounts of BDO, yet the ratio of BDO to ethanol production was reversed for this enzyme compared to 002C. This suggests that the C. 25 beijerinckii Ald is more specific for 4HB-CoA over acetyl-coA than the C. acetobutylicum AdhE2, and therefore the former is the preferred enzyme for inclusion in the BDO pathway. The Clostridium beijerinckii ald gene (Toth et al., Appl. Environ. Microbiol. 65:4973-4980 (1999)) was tested as a candidate for catalyzing the conversion of 4-hydroxybutyryl-CoA to 4 hydroxybutanal. Over fifty aldehyde dehydrogenases were screened for their ability to catalyze 30 the conversion of 4-hydroxybutyryl-CoA to 4-hydroxybutyraldehyde. The C. beijerinckii ald gene was chosen for implementation into BDO-producing strains due to the preference of this enzyme for 4-hydroxybutyryl-CoA as a substrate as opposed to acetyl-CoA. This is important 196 because most other enzymes with aldehyde dehydrogenase functionality (for example, adhE2 from C. acetobutylicum (Fontaine et al., J Bacteriol. 184:821-830 (2002)) preferentially convert acetyl-CoA to acetaldehyde, which in turn is converted to ethanol. Utilization of the C. beijerinckii gene lowers the amount of ethanol produced as a byproduct in BDO-producing 5 organisms. Also, a codon-optimized version of this gene expresses very well in E. coli (Sivaraman et al., Nucleic Acids Res. 36:e16 (2008)). 4-hydroxybutanal reductase. 4-hydroxybutanal reductase activity of adh1 from Geobacillus thermoglucosidasius (M1OEXG) was utilized. This led to improved BDO production by increasing 4-hydroxybutanal reductase activity over endogenous levels. 10 Multiple alcohol dehydrogenases were screened for their ability to catalyze the reduction of 4 hydroxybutanal to BDO. Most alcohol dehydrogenases with high activity on butyraldehyde exhibited far lower activity on 4-hydroxybutyraldehyde. One notable exception is the adh1 gene from Geobacillus thermoglucosidasius M1OEXG (Jeon et al., J. Biotechnol. 135:127-133 (2008)) (GNMOO84), which exhibits high activity on both 4-hydroxybutanal and butanal. 15 The native gene sequence and encoded protein sequence if the adhi gene from Geobacillus thermoglucosidasius are shown in Figure 31. The G. thermoglucosidasius ald] gene was expressed in E. coli. The AdhI enzyme (084) expressed very well from its native gene in E. coli (see Figure 32A). In ADH enzyme assays, the E. coli expressed enzyme showed very high reductive activity when 20 butyraldehyde or 4HB-aldehyde were used as the substrates (see Figure 32B). The Km values determined for these substrates were 1.2 mM and 4.0 mM, respectively. These activity values showed that the Adh1 enzyme was the most active on reduction of 4HB-aldehyde of all the candidates tested. The 084 enzyme was tested for its ability to boost BDO production when coupled with the C. 25 beijerinckii ald. The 084 gene was inserted behind the C. beijerinckii ald variant 025B gene to create a synthetic operon that results in coupled expression of both genes. Similar constructs linked 025B with other ADH candidate genes, and the effect of including each ADH with 025B on BDO production was tested. The host strain used was ECKh-459 (AadhE ldhA ApflB AlpdA::fnr-pflB6-K.p.lpdA322 Amdh AarcA gltAR163L fimD:: E. coli sucCD, P. gingivalis 30 sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd fimD:: C. acetobutylicum buki, C. acetobutylicum ptb), which contains the remainder of the BDO pathway on the chromosome.

197 The 084 ADH expressed in conjunction with 025B showed the highest amount of BDO (right arrow in Figure 33) when compared with 025B only (left arrow in Figure 33) and in conjunction with endogenous ADH functions. It also produced more BDO than did other ADH enzymes when paired with 025B, indicated as follows: 026A-C, codon-optimized variants of Clostridium 5 acetobutylicum butanol dehydrogenase; 050, Zymomonas mobilis alcohol dehydrogenase I; 052, Citrobacterfreundii 1,3-propanediol dehydrogenase; 053, Lactobacillus brevis 1,3-propanediol dehydrogenase; 057, Bacteroidesfragilis lactaldehyde reductase; 058, E. coli 1,3-propanediol dehydrogenase; 071, Bacillus subtilis 168 alpha-ketoglutarate semialdehyde dehydrogenase. The constructs labeled "PT51acO" are those in which the genes are driven by the PT51acO 10 promoter. In all other cases, the PAlacO-1 promoter was used. This shows that inclusion of the 084 ADH in the BDO pathway increased BDO production. EXAMPLE XIV BDO Producing Strains Expressing Pyruvate Dehydrogenase This example describes the utilization of pyruvate dehydrogenase (PDH) to enhance BDO 15 production. Heterologous expression of the Klebsiella pneumonia lpdA gene was used to enhance BDO production. Computationally, the NADH-generating conversion of pyruvate to acetyl-CoA is required to reach the maximum theoretical yield of 1,4-butanediol (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/007535 1; WO 20 2008/018930; Kim et al., Appl. Environ. Microbiol. 73:1766-1771 (2007); Kim et al., J. Bacteriol. 190:3851-3858 (2008); Menzel et al., J. Biotechnol. 56:135-142 (1997)). Lack of PDH activity was shown to reduce the maximum anaerobic theoretical yield of BDO by 11% if phosphoenolpyruvate carboxykinase (PEPCK) activity cannot be attained and by 3% if PEPCK activity can be attained. More importantly, however, absence of PDH activity in the OptKnock 25 strain #439, described in WO 2009/023493 and U.S. publication 2009/0047719, which has the knockout of ADHEr, ASPT, LDH_D, MDH and PFLi, would reduce the maximum anaerobic yield of BDO by 54% or by 43% if PEPCK activity is absent or present, respectively. In the presence of an external electron acceptor, lack of PDH activity would reduce the maximum yield of the knockout strain by 10% or by 3% assuming that PEPCK activity is absent or present, 30 respectively. PDH is one of the most complicated enzymes of central metabolism and is comprised of 24 copies of pyruvate decarboxylase (El) and 12 molecules of dihydrolipoyl dehydrogenase (E3), 198 which bind to the outside of the dihydrolipoyl transacetylase (E2) core. PDH is inhibited by high NADH/NAD, ATP/ADP, and Acetyl-CoA/CoA ratios. The enzyme naturally exhibits very low activity under oxygen-limited or anaerobic conditions in organisms such as E. coli due in large part to the NADH sensitivity of E3, encoded by lpdA. To this end, an NADH-insensitive version 5 of the lpdA gene from Klebsiella pneumonia was cloned and expressed to increase the activity of PDH under conditions where the NADH/NAD ratio is expected to be high. Replacement of the native lpdA. The pyruvate dehydrogenase operon of Klebsiella pneumoniae is between 78 and 95% identical at the nucleotide level to the equivalent operon of E. coli. It was shown previously that K. pneumoniae has the ability to grow anaerobically in presence of 10 glycerol (Menzel et al., J. Biotechnol. 56:135-142 (1997); Menzel et al., Biotechnol. Bioeng. 60:617-626 (1998)). It has also been shown that two mutations in the lpdA gene of the operon of E. coli would increase its ability to grow anaerobically (Kim et al.. Apple. Environ. Microbiol. 73:1766-1771 (2007); Kim et al., J. Bacteriol. 190:3851-3858 (2008)). The lpdA gene of K. pneumonia was amplified by PCR using genomic DNA (ATCC700721D) as template and the 15 primers KP-1pdA-Bam (5'-acacgcggatccaacgtcccgg-3')(SEQ ID NO:) and KP-1pdA-Nhe (5' agcggctccgctagccgcttatg-3')(SEQ ID NO:). The resulting fragment was cloned into the vector pCR-BluntII-TOPO (Invitrogen; Carlsbad CA), leading to plasmid pCR-KP-1pdA. The chromosomal gene replacement was performed using a non-replicative plasmid and the sacB gene from Bacillus subtilis as a means of counterselection (Gay et al., J. Bacteriol. 20 153:1424-1431 (1983)). The vector used is pRE118 (ATCC87693) deleted of the oriT and IS sequences, which is 3.6 kb in size and carrrying the kanamycin resistance gene. The sequence was confirmed, and the vector was called pRE1 18-V2 (see Figure 34). The E. coli fragments flanking the lpdA gene were amplified by PCR using the combination of primers: EC-aceF-Pst (5'-aagccgttgctgcagctcttgagc-3')(SEQ ID NO:) + EC-aceF-Bam2 (5' 25 atctccggcggtcggatccgtcg-3')(SEQ ID NO:) and EC-yacH-Nhe (5'-aaagcggctagccacgccgc 3')(SEQ ID NO:) + EC-yacH-Kpn (5'-attacacgaggtacccaacg-3')(SEQ ID NO:). A BamHI-XbaI fragment containing the lpdA gene of K. pneumonia was isolated from plasmid pCR-KP-lpdA and was then ligated to the above E. coli fragments digested with PstI +BamHI and NheI-KpnI respectively, and the pRE1 18-V2 plasmid digested with KpnI and PstI. The resulting plasmid 30 (called pRE118-M2.1 lpdA yac) was subjected to Site Directed Mutagenesis (SDM) using the combination of primers KP-1pdA-HisTyr-F (5'- atgctggcgtacaaaggtgtcc-3')(SEQ ID NO:) and (5'-ggacacctttgtacgccagcat-3')(SEQ ID NO:) for the mutation of the His 322 residue to a Tyr 199 residue or primers KP-1pdA-GluLys-F (5'-atcgcctacactaaaccagaagtgg-3')(SEQ ID NO:) and KP lpdA-GluLys-R (5'-ccacttctggtttagtgtaggcgat-3')(SEQ ID NO:) for the mutation of the residue Glu 354 to Lys residue. PCR was performed with the Polymerase Pfu Turbo (Stratagene; San Diego CA). The sequence of the entire fragment as well as the presence of only the desired 5 mutations was verified. The resulting plasmid was introduced into electro competent cells of E. coli AadhE::Frt-AldhA::Frt by transformation. The first integration event in the chromosome was selected on LB agar plates containing Kanamycin (25 or 50 mg/L). Correct insertions were verified by PCR using 2 primers, one located outside the region of insertion and one in the kanamycin gene (5'-aggcagttccataggatggc-3')(SEQ ID NO:). Clones with the correct insertion 10 were selected for resolution. They were sub-cultured twice in plain liquid LB at the desired temperature and serial dilutions were plated on LB-no salt-sucrose 10% plates. Clones that grew on sucrose containing plates were screened for the loss of the kanamycin resistance gene on LB low salt agar medium and the lpdA gene replacement was verified by PCR and sequencing of the encompassing region. Sequence of the insertion region was verified, and is as described below. 15 One clone (named 4-4-P1) with mutation Glu354Lys was selected. This clone was then transduced with P1 lysate of E. coli APflB::Frt leading to strain ECKh-138 (AadhE AldhA ApflB AlpdA::K.p.lpdA322). The sequence of the ECKh-138 region encompassing the aceF and lpdA genes is shown in Figure 35. The K. pneumonia lpdA gene is underlined, and the codon changed in the Glu354Lys 20 mutant shaded. The protein sequence comparison of the native E. coli lpdA and the mutant K. pneumonia /pdA is shown in Figure 36. To evaluate the benefit of using K. pneumoniae /pdA in a BDO production strain, the host strains AB3 and ECKh-138 were transformed with plasmids expressing the entire BDO pathway from strong, inducible promoters. Specifically, E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd 25 were expressed on the medium copy plasmid pZA33, and P. gingivalis Cat2 and C. acetobutylicum AdhE2 were expressed on the high copy plasmid pZE13. These plasmids have been described in the literature (Lutz and H. Bujard, Nucleic Acids Res 25:1203-1210 (1997)), and their use for BDO pathway expression is described in Example XIII and W02008/115840. Cells were grown anaerobically at 37'C in M9 minimal medium (6.78 g/L Na 2

HPO

4 , 3.0 g/L 30 KH 2

PO

4 , 0.5 g/L NaCl, 1.0 g/L NH 4 Cl, 1 mM MgSO 4 , 0.1 mM CaCl 2 ) supplemented with 20 g/L glucose, 100 mM 3-(N-morpholino)propanesulfonic acid (MOPS) to improve the buffering capacity, 10 tg/mL thiamine, and the appropriate antibiotics. Microaerobic conditions were 200 established by initially flushing capped anaerobic bottles with nitrogen for 5 minutes, then piercing the septum with a 23G needle following inoculation. The needle was kept in the bottle during growth to allow a small amount of air to enter the bottles. 0.25 mM IPTG was added when OD600 reached approximately 0.2 to induce the pathway genes, and samples taken for 5 analysis every 24 hours following induction. The culture supernatants were analyzed for BDO, 4HB, and other by-products as described in Example II and in WO2008/115840. BDO and 4HB production in ECKh- 138 was significantly higher after 48 hours than in AB3 or the host used in previous work, MG1655 AldhA (Figure 37). PDH promoter replacement. It was previously shown that the replacement of the pdhR repressor 10 by a transcriptional fusion containing the Fnr binding site, one of the pflB promoters, and its ribosome binding site (RBS), thus leading to expression of the aceEF-1pd operon by an anaerobic promoter, should increase pdh activity anaerobically (Zhou et al., Biotechnol. Lett. 30:335-342 (2008)). A fusion containing the Fnr binding site, the pflB-p6 promoter and an RBS binding site were constructed by overlapping PCR. Two fragments were amplified, one using 15 the primers aceE-upstream-RC (5'- tgacatgtaacacctaccttctgtgcctgtgccagtggttgctgtgatatagaag 3')(SEQ ID NO:) and pflBp6-Up-Nde (5'- ataataatacatatgaaccatgcgagttacgggcctataagccaggcg 3')(SEQ ID NO:) and the other using primers aceE-EcoRV-EC (5' agtttttcgatatctgcatcagacaccggcacattgaaacgg-3')(SEQ ID NO:) and aceE-upstream (5' ctggcacaggcacagaaggtaggtgttacatgtcagaacgtttacacaatgacgtggatc-3')(SEQ ID NO:). The tw 20 fragments were assembled by overlapping PCR, and the final DNA fragment was digested with the restriction enzymes NdeI and BamHI. This fragment was subsequently introduced upstream of the aceE gene of the E. coli operon using pRE118-V2 as described above. The replacement was done in strains ECKh-138 and ECKh-422. The nucleotide sequence encompassing the 5' region of the aceE gene was verified and is shown in Figure 37. Figure 37 shows the nucleotide 25 sequence of 5' end of the aceE gene fused to the pflB-p6 promoter and ribosome binding site (RBS). The 5' italicized sequence shows the start of the aroP gene, which is transcribed in the opposite direction from the pdh operon. The 3' italicized sequence shows the start of the aceE gene. In upper case: pflB RBS. Underlined: FNR binding site. In bold: pflB-p6 promoter sequence. 30 lpdA promoter replacement. The promoter region containing the fnr binding site, the pflB-p6 promoter and the RBS of the pflB gene was amplified by PCR using chromosomal DNA template and primers aceF-pflBp6-fwd (5'- agacaaatcggttgccgtttgttaagccaggcgagatatgatctatatc 3')(SEQ ID NO:) and lpdA-RBS-B-rev (5'- 201 gagttttgatttcagtactcatcatgtaacacctaccttcttgctgtgatatag-3')(SEQ ID NO:). Plasmid 2-4a was amplified by PCR using primers B-RBS-1pdA fwd (5' ctatatcacagcaagaaggtaggtgttacatgatgagtactgaaatcaaaactc-3')(SEQ ID NO:) and pflBp6-aceF-rev (5'- gatatagatcatatctcgcctggcttaacaaacggcaaccgatttgtct-3')(SEQ ID NO:). The two resulting 5 fragments were assembled using the BPS cloning kit (BPS Bioscience; San Diego CA). The resulting construct was sequenced verified and introduced into strain ECKh-439 using the pRE1 18-V2 method described above. The nucleotide sequence encompassing the aceF-lpdA region in the resulting strain ECKh-456 is shown in Figure 39. The host strain ECKh-439 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA gltAR163L 10 ackA fimD:: E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd), the construction of which is described below, and the pdhR and lpdA promoter replacement derivatives ECKh-455 and ECKh-456, were tested for BDO production. The strains were transformed with pZS * 13 containing P. gingivalis Cat2 and C. beijerinckii Ald to provide a complete BDO pathway. Cells were cultured in M9 minimal medium supplemented 15 with 20 g/L glucose as described above. 48 hours after induction with 0.2 mM IPTG, the concentrations of BDO, 4HB, and pyruvate were as shown in Figure 40. The promoter replacement strains produce slightly more BDO than the isogenic parent. These results demonstrated that expression of pyruvate dehydrogenase increased production of BDO in BDO producing strains. 20 EXAMPLE XV BDO Producing Strains Expressing Citrate Synthase and Aconitase This example describes increasing activity of citrate synthase and aconitase to increase production of BDO. An R163L mutation into gitA was found to improve BDO production. Additionally, an arcA knockout was used to improve BDO production. 25 Computationally, it was determined that flux through citrate synthase (CS) and aconitase (ACONT) is required to reach the maximum theoretical yield of 1,4-butanediol (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/0075351). Lack of CS or ACONT activity would reduce the maximum theoretical yield by 14% under anaerobic conditions. In the presence of an external electron acceptor, the 30 maximum yield is reduced by 9% or by 6% without flux through CS or ACONT assuming the absence or presence of PEPCK activity, respectively. As with pyruvate dehydrogenase (PDH), the importance of CS and ACONT is greatly amplified in the knockout strain background in 202 which ADHEr, ASPT, LDH_D, MDH and PFLi are knocked out (design #439)(see WO 2009/023493 and U.S. publication 2009/0047719, which is incorporated herein by reference). The minimal OptKnock strain design described in WO 2009/023493 and U.S. publication 2009/0047719 had one additional deletion beyond ECKh-138, the mdh gene, encoding malate 5 dehydrogenase. Deletion of this gene is intended to prevent flux to succinate via the reductive TCA cycle. The mdh deletion was performed using the k red homologeous recombination method (Datsenko and Wanner, Proc. Nati. Acad. Sci. USA 97:6640-6645 (2000)). The following oligonucleotides were used to PCR amplify the chloramphenicol resistance gene (CAT) flanked by FRT sites from pKD3: 10 S-mdh-Kan 5' - TAT TGT GCA TAC AGA TGA ATT TTT ATG CAA ACA GTC AGC CCT GAA GAA GGG TGT AGG CTG GAG CTG CTT C -3' (SEQ ID NO:) AS-mdh-Kan 5' - CAA AAA ACC GGA GTC TGT GCT CCG GTT TTT TAT TAT CCG CTA ATC AAT TAC ATA TGA ATA TCC TCC TTA G -3' (SEQ ID NO"). Underlined regions indicate homology to pKD3 plasmid and bold sequence refers to sequence 15 homology upstream and downstream of the mdh ORF. After purification, the PCR product was electroporated into ECKh-138 electrocompetent cells that had been transformed with pRedET (tet) and prepared according to the manufacturer's instructions (www.genebridges.com/gb/pdf/K01%20Q%20E%20BAC%2OModification%20Kit version2.6-2007-screen.pdf). The PCR product was designed so that it integrated into the 20 ECKh-138 genome at a region upstream of the mdh gene, as shown in Figure 41. Recombinants were selected for chloramphenicol resistance and streak purified. Loss of the mdh gene and insertion of CAT was verified by diagnostic PCR. To remove the CAT gene, a temperature sensitive plasmid pCP20 containing a FLP recombinase (Datsenko and Wanner, Proc. Nati. Acad. Sci. USA 97:6640-6645 (2000)) was transformed into the cell at 30'C and 25 selected for ampicillin resistance (AMP). Transformants were grown nonselectively at 42'C overnight to thermally induce FLP synthesis and to cause lose of the plasmid. The culture was then streak purified, and individual colonies were tested for loss of all antibiotic resistances. The majority lost the FRT-flanked resistance gene and the FLP helper plasmid simultaneously. There was also a "FRT" scar leftover. The resulting strain was named ECKh-172. 30 CS and ACONT are not highly active or highly expressed under anaerobic conditions. To this end, the arcA gene, which encodes for a global regulator of the TCA cycle, was deleted. ArcA 203 works during microaerobic conditions to induce the expression of gene products that allow the activity of central metabolism enzymes that are sensitive to low oxygen levels, aceE, pflB and adhE. It was shown that microaerobically, a deletion in arcAlarcB increases the specific activities of ldh, icd, gitA, mdh, and gdh genes (Salmon et al., J. Biol. Chem. 280:15084-15096 5 (2005); Shalel-Levanon et al., Biotechnol. Bioeng. 92(2):147-159 (2005). The upstream and downstream regions of the arcA gene of E. coli MG1655 were amplified by PCR using primers ArcA-up-EcoRI (5'- ataataatagaattcgtttgctacctaaattgccaactaaatcgaaacagg -3')(SEQ ID NO:) with ArcA-up-KpnI (5'-tattattatggtaccaatatcatgcagcaaacggtgcaacattgccg -3')(SEQ ID NO:) and ArcA-down-EcoRI (5'-tgatctggaagaattcatcggctttaccaccgtcaaaaaaaacggcg -3')(SEQ ID NO:) with 10 ArcA-down-PstI (5'-ataaaaccctgcagcggaaacgaagttttatccatttttggttacctg -3')(SEQ ID NO:), respectively. These fragments were subsequently digested with the restriction enzymes EcoRI and KpnI (upstream fragment) and EcoRI and PstI (downstream). They were then ligated into the pRE1 18-V2 plasmid digested with PstI and KpnI, leading to plasmid pRE1 18-AarcA. The sequence of plasmid pRE1 18-AarcA was verified. pRE1 18-AarcA was introduced into electro 15 competent cells of E. coli strain ECKh-172 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh). After integration and resolution on LB-no salt-sucrose plates as described above, the deletion of the arcA gene in the chromosome of the resulting strain ECKh-401 was verified by sequencing and is shown in Figure 42. The gltA gene of E. coli encodes for a citrate synthase. It was previously shown that this gene is 20 inhibited allosterically by NADH, and the amino acids involved in this inhibition have been identified (Pereira et al., J. Biol. Chem. 269(1):412-417 (1994); Stokell et al., J. Biol. Chem. 278(37):35435-35443 (2003)). The gitA gene of E. coli MG1655 was amplified by PCR using primers gltA-up (5'- ggaagagaggctggtacccagaagccacagcagga-3')(SEQ ID NO:) and gltA-PstI (5'-gtaatcactgcgtaagcgccatgccccggcgttaattc -3')(SEQ ID NO:). The amplified fragment was 25 cloned into pRE1 18-V2 after digestion with KpnI and PstL. The resulting plasmid was called pRE1 18-gltA. This plasmid was then subjected to site directed mutagensis (SDM) using primers R163L-f (5'- attgccgcgttcctcctgctgtcga-3')(SEQ ID NO:) and R163L-r (5' cgacagcaggaggaacgcggcaat -3')(SEQ ID NO:) to change the residue Arg 163 to a Lys residue. The sequence of the entire fragment was verified by sequencing. A variation of the k red 30 homologeous recombination method (Datsenko and Wanner, Proc. Nati. Acad. Sci. USA 97:6640-6645 (2000)) was used to replace the native gitA gene with the R163L mutant allele without leaving a Frt scar. The general recombination procedure is the same as used to make the mdh deletion described above. First, the strain ECKh-172 was made streptomycin resistant by 204 introducing an rpsL null mutation using the k red homologeous recombination method. Next, a recombination was done to replace the entire wild-type gltA coding region in this strain with a cassette comprised of a kanamycin resistance gene (kanR) and a wild-type copy of the E. coli rpsL gene. When introduced into an E. coli strain harboring an rpsL null mutation, the cassette 5 causes the cells to change from resistance to the drug streptomycin to streptomycin sensitivity. DNA fragments were then introduced that included each of the mutant versions of the gltA gene along with appropriate homologous ends, and resulting colony growth was tested in the presence of streptomycin. This selected for strains in which the kanR/rpsL cassette had been replaced by the mutant gltA gene. Insertion of the mutant gene in the correct locus was confirmed by PCR 10 and DNA sequencing analyses. The resulting strain was called ECKh-422, and has the genotype AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA gltAR163L. The region encompassing the mutated gltA gene of strain ECKh-422 was verified by sequencing, as shown in Figure 43. Crude extracts of the strains ECKh-401 and the gltAR163L mutant ECKh-422 were then evaluated for citrate synthase activity. Cells were harvested by centrifugation at 4,500 rpm 15 (Beckman-Coulter, Allegera X-15R; Fullerton CA) for 10 min. The pellets were resuspended in 0.3 mL BugBuster (Novagen/EMD; San Diego CA) reagent with benzonase and lysozyme, and lysis proceeded for 15 minutes at room temperature with gentle shaking. Cell-free lysate was obtained by centrifugation at 14,000 rpm (Eppendorf centrifuge 5402; Hamburg Germany) for 30 min at 4'C. Cell protein in the sample was determined using the method of Bradford 20 (Bradford, Anal. Biochem. 72:248-254 (1976)). Citrate synthase activity was determined by following the formation of free coenzyme A (HS CoA), which is released from the reaction of acetyl-CoA with oxaloacetate. The free thiol group of HS-CoA reacts with 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) to form 5-thio-2 nitrobenzoic acid (TNB). The concentration of TNB is then monitored spectrophotometrically 25 by measuring the absorbance at 410 nm (maximum at 412 nm). The assay mixture contained 100 mM Tris/HCl buffer (pH 7.5), 20 mM acetyl-CoA, 10 mM DTNB, and 20 mM oxaloacetate. For the evaluation of NADH inhibition, 0.4 mM NADH was also added to the reaction. The assay was started by adding 5 microliters of the cell extract, and the rate of reaction was measured by following the absorbance change over time. A unit of specific activity 30 is defined as the pmol of product converted per minute per mg protein. Figure 44 shows the citrate synthase activity of wild type gltA gene product and the R163L mutant. The assay was performed in the absence or presence of 0.4 mM NADH.

205 Strains ECKh-401 and ECKh-422 were transformed with plasmids expressing the entire BDO pathway. E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, and M. bovis sucA were expressed on the low copy plasmid pZS* 13, and P. gingivalis Cat2 and C. acetobutylicum AdhE2 were expressed on the medium copy plasmid pZE23. Cultures of these strains were 5 grown microaerobically in M9 minimal medium supplemented with 20 g/L glucose and the appropriate antibiotics as described above. The 4HB and BDO concentrations at 48 hours post induction averaged from duplicate cultures are shown in Figure 45. Both are higher in ECKh 422 than in ECKh-401, demonstrating that the enhanced citrate synthase activity due to the gitA mutation results in increased flux to the BDO pathway. 10 The host strain modifications described in this section were intended to redirect carbon flux through the oxidative TCA cycle, which is consistent with the OptKnock strain design described in WO 2009/023493 and U.S. publication 2009/0047719. To demonstrate that flux was indeed routed through this pathway, 13 C flux analysis was performed using the strain ECKh-432, which is a version of ECKh-422 in which the upstream pathway is integrated into the chromosome (as 15 described in Example XVII). To complete the BDO pathway, P. gingivalis Cat2 and C. beijerinckii Ald were expressed from pZS* 13. Four parallel cultures were grown in M9 minimal medium (6.78 g/L Na 2

HPO

4 , 3.0 g/L KH 2

PO

4 , 0.5 g/L NaCl, 1.0 g/L NH 4 Cl, 1 mM MgSO 4 , 0.1 mM CaCl 2 ) containing 4 g/L total glucose of four different labeling ratios (1~ 3 C, only the first carbon atom in the glucose molecule is labeled with 13C; uniform-' 3 C, all carbon 20 atoms are 1C): 1. 80 mol% unlabeled, 20 mol% uniform-13C 2. 10 mol% unlabeled, 90 mol% uniform- C 3. 90 mol% -" 3 C, 10 mol% uniform-1 3 C 4. 40 mol% 1-" 3 C, 60 mol% uniform-1 3 C 25 Parallel unlabeled cultures were grown in duplicate, from which frequent samples were taken to evaluate growth rate, glucose uptake rate, and product formation rates. In late exponential phase, the labeled cultures were harvested, the protein isolated and hydrolyzed to amino acids, and the label distribution of the amino acids analyzed by gas chromatography- mass spectrometry (GCMS) as described previously (Fischer and Sauer, Eur. J. Biochem. 270:880 30 891 (2003)). In addition, the label distribution of the secreted 4HB and BDO in the broth from the labeled cultures was analyzed by GCMS as described in W02008115840. This data was collectively used to calculate the intracellular flux distribution using established methods 206 (Suthers et al., Metab. Eng. 9:387-405 (2007)). The resulting central metabolic fluxes and associated 95% confidence intervals are shown in Figure 46. Values are molar fluxes normalized to a glucose uptake rate of 1 mmol/hr. The result indicates that carbon flux is routed through citrate synthase in the oxidative direction, and that most of the carbon enters the BDO 5 pathway rather than completing the TCA cycle. Furthermore, it confirms there is essentially no flux between malate and oxaloacetate due to the mdh deletion in this strain. The advantage of using a knockout strain such as strains designed using OptKnock for BDO production (see WO 2009/023493 and U.S. publication 2009/0047719) can be observed by comparing typical fermentation profiles of ECKh-422 with that of the original strain ECKh- 138, 10 in which BDO is produced from succinate via the reductive TCA cycle (see Figure 47). Fermentations were performed with IL initial culture volume in 2L Biostat B+ bioreactors (Sartorius; Cedex France) using M9 minimal medium supplemented with 20 g/L glucose. The temperature was controlled at 37'C, and the pH was controlled at 7.0 using 2 M NH 4 0H or Na 2

CO

3 . Cells were grown aerobically to an OD600 of approximately 10, at which time the 15 cultures were induced with 0.2 mM IPTG. One hour following induction, the air flow rate was reduced to 0.02 standard liters per minute for microaerobic conditions. The agitation rate was set at 700 rpm. Concentrated glucose was fed to maintain glucose concentration in the vessel between 0.5 and 10 g/L. Both strains were transformed with plasmids bearing the entire BDO pathway, as in the examples above. In ECKh-138, acetate, pyruvate, and 4HB dominate the 20 fermentation, while with ECKh-422 BDO is the major product. EXAMPLE XVI BDO Strains Expression Phosphoenolpyruvate Carboxykinase This example describes the utilization of phosphoenolpyruvate carboxykinase (PEPCK) to enhance BDO production. The Haemophilus influenza PEPCK gene was used for heterologous 25 expression. Computationally, it was demonstrated that the ATP-generating conversion of oxaloacetate to phosphoenolpyruvate is required to reach the maximum theoretical yield of 1,4-butanediol (see also W02008/115840, WO 2009/023493, U.S. publication 2009/0047719, U.S. publication 2009/0075351). Lack of PEPCK activity was shown to reduce the maximum theoretical yield of 30 BDO by 12% assuming anaerobic conditions and by 3% assuming an external electron acceptor such as nitrate or oxygen is present.

207 In organisms such as E. coli, PEPCK operates in the gluconeogenic and ATP-consuming direction from oxaloacetate towards phosphoenolpyruvate. It has been hypothesized that kinetic limitations of PEPCK of E. coli prevent it from effectively catalyzing the formation of oxaloacetate from PEP. PEP carboxylase (PPC), which does not generate ATP but is required 5 for efficient growth, is naturally utilized by E. coli to form oxaloacetate from phosphoenolpyruvate. Therefore, three non native PEPCK enzymes (Table 26) were tested for their ability to complement growth of a PPC mutant strain of E. coli in glucose minimal media. Table 26. Sources of phosphoenolpyruvate carboxykinase sequences. PEPCK Source Strain Accession Number, GenBank Reference Sequence Haemophilus influenza NC 000907.1 Actinobacillus succinogenes YP 001343536.1 Mannheimia succiniciproducens YP 089485.1 Growth complementation studies involved plasmid based expression of the candidate genes in 10 Appc mutant E.coli JW3978 obtained from the Keio collection (Baba et al., Molecular Systems Biology 2:2006.0008 (2006)). The genes were cloned behind the PAlacO-1 promoter in the expression vectors pZA23 (medium copy) and pZE13 (high copy). These plasmids have been described previously (Lutz and Bujard, Nucleic Acids Res. 25:1203-1210 (1997)), and their use in expression BDO pathway genes has been described previously in W02008115840. 15 Pre-cultures were grown aerobically in M9 minimal media with 4g/L glucose. All pre-cultures were supplemented with aspartate (2mM) to provide the Appc mutants with a source for generating TCA cycle intermediates independent of PEPCK expression. M9 minimal media was also used in the test conditions with 4g/L glucose, but no aspartate was added and IPTG was added to 0.5 mM. Table 27 shows the results of the growth complementation studies. 20 Table 27. Complementation of Appc mutants with PEPCK from H. influenzae, A. succinogenes and M. succinoproducens when expressed from vectors pZA23 or pZE13. H.influenzae pZA23BB 40 0.950 Appc Control pZA23BB 40 0.03 8 A.succinogenes pZA23BB 40 0.055 M. succinoproducens pZA23BB 40 0.214 A.succinogenes pZE13BB 40 0.041 M. succinoproducens pZE13BB 40 0.024 Appc Control pZE13BB 40 0.042 208 Haemophilus influenza PEPCK was found to complement growth in Appc mutant E. coli best among the genes that were tested in the plasmid based screening. This gene was then integrated into the PPC locus of wild-type E. coli (MG1655) using the SacB counter selection method with pRE118-V2 discussed above (Gay et al., J. Bacteriol. 153:1424-1431 (1983)). PEPCK was 5 integrated retaining the E. coli native PPC promoter, but utilizing the non-native PEPCK terminator. The sequence of this region following replacement of ppc by H. influenzae pepck is shown in Figure 48. The pepck coding region is underlined. Techniques for adaptive evolution were applied to improve the growth rate of the E. coli mutant (Appc::H. inf pepCK). M9 minimal media with 4 g/L glucose and 50mM sodium bicarbonate 10 was used to culture and evolve this strain in an anaerobic environment. The high sodium bicarbonate concentration was used to drive the equilibrium of the PEPCK reaction toward oxaloacetate formation. To maintain exponential growth, the culture was diluted 2-fold whenever an OD600 of 0.5 was achieved. After about 100 generations over 3 weeks of adaptive evolution, anaerobic growth rates improved from about 8h to that of wild type, about 2h. 15 Following evolution, individual colonies were isolated, and growth in anaerobic bottles was compared to that of the initial mutant and wild-type strain (see Figure 49). M9 medium with 4 g/L glucose and 50 mM sodium bicarbonate was used. The ppc/pepck gene replacement procedure described above was then repeated, this time using the BDO-producing strains ECKh-432 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA 20 gltAR163L AackA fimD:: E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. k/uyveri 4hbd) and ECKh-439 as the hosts. These strains contain the TCA cycle enhancements discussed above as well as the upstream pathway integrated in the chromosome. ECKh-439 is a derivative of ECKh-432 that has the ackA gene deleted, which encodes acetate kinase. This deletion was performed using the sacB counterselection method described above. 25 The Appc::H. inf pepCK derivative of ECKh-439, called ECKh-453, was run in a fermentation. The downstream BDO pathway was supplied by pZS*13 containing P. gingivalis Cat2 and C. beijerinckii Ald. This was performed with 1L initial culture volume in 2L Biostat B+ bioreactors (Sartorius) using M9 minimal medium supplemented with 20 g/L glucose and 50 mM NaHCO 3 . The temperature was controlled at 37'C, and the pH was controlled at 7.0 using 30 2 M NH 4 0H or Na 2

CO

3 . Cells were grown aerobically to an OD600 of approximately 2, at which time the cultures were induced with 0.2 mM IPTG. One hour following induction, the air flow rate was reduced to 0.01 standard liters per minute for microaerobic conditions. The 209 agitation rate was initially set at 700 rpm. The aeration rate was gradually increased throughout the fermentation as the culture density increased. Concentrated glucose solution was fed to maintain glucose concentration in the vessel between 0.5 and 10 g/L. The product profile is shown in Figure 50. The observed phenotype, in which BDO and acetate are produced in 5 approximately a one-to-one molar ratio, is highly similar to that predicted in WO 2009/023493 for design #439 (ADHEr, ASPT, LDH_D, MDH, PFLi). The deletion targeting the ASPT reaction was deemed unnecessary as the natural flux through aspartate ammonia-lyase is low. A key feature of OptKnock strains is that production of the metabolite of interest is generally coupled to growth, and further, that, production should occur during exponential growth as well 10 as in stationary phase. The growth coupling potential of ECKh-432 and ECKh-453 was evaluated by growth in microaerobic bottles with frequent sampling during the exponential phase. M9 medium containing 4 g/L glucose and either 10 mM NaHCO 3 (for ECKh-432) or 50 mM NaHCO 3 (for ECKh-453) was used, and 0.2 mM IPTG was included from inoculation. 18G needles were used for microaerobic growth of ECKh-432, while both 18G and 27G needles 15 were tested for ECKh-453. The higher gauge needles result in less aeration. As shown in Figure 51, ECKh-432 does not begin producing BDO until 5 g/L glucose has been consumed, corresponding to the onset of stationary phase. ECKh-453 produces BDO more evenly throughout the experiment. In addition, growth coupling improves as the aeration of the culture is reduced. 20 EXAMPLE XVII Integration of BDO Pathway Encoding Genes at Specific Integration Sites This example describes integration of various BDO pathway genes into the fimD locus to provide more efficient expression and stability. The entire upstream BDO pathway, leading to 4HB, has been integrated into the E. coli 25 chromosome at the fimD locus. The succinate branch of the upstream pathway was integrated into the E. coli chromosome using the k red homologeous recombination method (Datsenko and Wanner, Proc. Nati. Acad. Sci. USA 97:6640-6645 (2000)). The recipient E. coli strain was ECKh-422 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA gltAR163L). A polycistronic DNA fragment containing a promoter, the sucCD gene, the sucD gene and the 30 4hbd gene and a terminator sequence was inserted into the AflIJI site of the pKD3 plasmid. The following primers were used to amplify the operon together with the chloramphenicol marker from the plasmid. The underlined sequences are homologeous to the target insertion site.

210 5'-GTTTGCACGCTATAGCTGAGGTTGTTGTCTTCCAGCAACGTACCGTATACAA TAGGCGTATCACGAGGCCCTTTC-3' (SEQ ID NO:) 5'-GCTACAGCATGTCACACGATCTCAACGGTCGGATGACCAATCTGGCTGGTAT GGGAATTAGCCATGGTCC-3' (SEQ ID NO:) 5 Following DpnI treatment and DNA electrophoresis, the purified PCR product was used to transform E. coli strain harboring plasmid pKD46. The candidate strain was selected on plates containing chloramphenicol. Genomic DNA of the candidate strain was purified. The insertion sequence was amplified and confirmed by DNA sequencing. The chloramphenicol-resistant 10 marker was removed from chromosome by flipase. The nucleotide sequence of the region after insertion and marker removal is shown in Figure 52. The alpha-ketoglutarate branch of the upstream pathway was integrated into the chromosome by homologeous recombination. The plasmid used in this modification was derived from vector pRE1 18-V2, as referenced in Example XIV, which contains a kanamycin-resistant gene, a gene 15 encoding the levansucrase (sacB) and a R6K conditional replication ori. The integration plasmid also contained a polycistronic sequence with a promoter, the sucA gene, the C. kluyveri 4hbd gene, and a terminator being inserted between two 1.5-kb DNA fragments that are homologeous to the flanking regions of the target insertion site. The resulting plasmid was used to transform E. coli strain. The integration candidate was selected on plates containing 20 kanamycin. The correct integration site was verified by PCR. To resolve the antibiotic marker from the chromosome, the cells were selected for growth on medium containing sucrose. The final strain was verified by PCR and DNA sequencing. The nucleotide sequence of the chromosomal region after insertion and marker removal is shown in Figure 53. The resulting upstream pathway integration strain ECKh-432 was transformed with a plasmid 25 harboring the downstream pathway genes. The construct was able to produce BDO from glucose in minimal medium (see Figure 54). EXAMPLE XVIII Use of a Non-Phosphotransferase Sucrose Uptake System to Reduce Pyruvate Byproduct Formation 30 This example describes the utilization of a non-phosphotransferase (PTS) sucrose uptake system to reduce pyruvate as a byproduct in the conversion of sucrose to BDO.

211 Strains engineered for the utilization of sucrose via a phosphotransferase (PTS) system produce significant amounts of pyruvate as a byproduct. Therefore, the use of a non-PTS sucrose system can be used to decrease pyruvate formation because the import of sucrose would not be accompanied by the conversion of phosphoenolpyruvate (PEP) to pyruvate. This will increase 5 the PEP pool and the flux to oxaloacetate through PPC or PEPCK. Insertion of a non-PTS sucrose operon into the rrnC region was performed. To generate a PCR product containing the non-PTS sucrose genes flanked by regions of homology to the rrnC region, two oligos were used to PCR amplify the csc genes from Mach1TM (Invitrogen, Carlsbad, CA). This strain is a descendent of W strain which is an E. coli strain known to be 10 able to catabolize sucrose (Orencio-Trejo et al., Biotechnology Biofuels 1:8 (2008)). The sequence was derived from E. coli W strain KO I1 (accession AY314757) (Shukla et al, Biotechnol. Lett. 26:689-693 (2004)) and includes genes encoding a sucrose permease (cscB), D fructokinase (cscK), sucrose hydrolase (cscA), and a LacI-related sucrose-specific repressor (cscR). The first 53 amino acids of cscR was effectively removed by the placement of the AS 15 primer. The sequences of the oligos were: rrnC 23S del S -CSC 5'-TGT GAG TGA AAG TCA CCT GCC TTA ATA TCT CAA AAC TCA TCT TCG GGT GAC GAA ATA TGG CGT GAC TCG ATA C-3' (SEQ ID NO:) and rmC 23S del AS -CSC 5'-TCT GTA TCA GGC TGA AAA TCT TCT CTC ATC CGC CAA AAC AGC TTC GGC GTT AAG ATG CGC GCT CAA GGA C-3' (SEQ ID NO:). Underlined regions indicate homology to the csc 20 operon, and bold sequence refers to sequence homology upstream and downstream of the rrnC region. The sequence of the entire PCR product is shown in Figure 55. After purification, the PCR product was electroporated into MG1655 electrocompetent cells which had been transformed with pRedET (tet) and prepared according to manufacturer's instructions 25 (www.genebridges.com/gb/pdf/KOO1%20Q%20E%20BAC%20Modification%20Kit version2.6-2007-screen.pdf). The PCR product was designed so that it integrated into genome into the rrnC region of the chromosome. It effectively deleted 191 nucleotides upstream of rrlC (23S rRNA), all of the rrlC rRNA gene and 3 nucleotides downstream of rrlC and replaced it with the sucrose operon, as shown in Figure 56. 30 Transformants were grown on M9 minimal salts medium with 0.4% sucrose and individual colonies tested for presence of the sucrose operon by diagnostic PCR. The entire rrnC::crcAKB region was transferred into the BDO host strain ECKh-432 by P1 transduction (Sambrook et al., 212 Molecular Cloning: A Laboratory Manual, Third Ed., Cold Spring Harbor Laboratory, New York (2001), resulting in ECKh-463 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh AarcA gltAR163L fimD:: E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd rrnC::cscAKB). Recombinants were selected by growth on sucrose and 5 verified by diagnostic PCR. ECKh-463 was transformed with pZS* 13 containing P. gingivalis Cat2 and C. beijerinckii Ald to provide a complete BDO pathway. Cells were cultured in M9 minimal medium (6.78 g/L Na 2

HPO

4 , 3.0 g/L KH 2

PO

4 , 0.5 g/L NaCl, 1.0 g/L NH 4 Cl, 1 mM MgSO 4 , 0.1 mM CaCl 2 ) supplemented with 10 g/L sucrose. 0.2 mM IPTG was present in the culture from the start. 10 Anaerobic conditions were maintained using a bottle with 23G needle. As a control, ECKh-432 containing the same plasmid was cultured on the same medium, except with 10 g/L glucose instead of sucrose. Figure 57 shows average product concentration, normalized to culture OD600, after 48 hours of growth. The data is for 6 replicate cultures of each strain. This demonstrates that BDO production from ECKh-463 on sucrose is similar to that of the parent 15 strain on sucrose. EXAMPLE XIX Summary of BDO Producing Strains This example describes various BDO producting strains. Table 28 summarizes various BDO producing strains disclosed above in Examples XII-XVIII. 20 Table 28. Summary of various BDO production strains. Strain Host Host chromosome Host Description Plasmid-based # Strain 1 AldhA Single deletion E. coli sucCD, P. gingivalis derivative of E. sucD, P. gingivalis 4hbd, P. coli MG1655 gingivalis Cat2, C. acetobutylicum AdhE2 2 AB3 AadhE AldhA ApflB Succinate E. coli sucCD, P. gingivalis producing strain; sucD, P. gingivalis 4hbd, P. derivative of E. gingivalis Cat2, C. coli MG1655 acetobutylicum AdhE2 3 ECKh- AadhE AldhA ApflB Improvement of E. coli sucCD, P. gingivalis 138 AlpdA::K.p.lpdA322 lpdA to increase sucD, P. gingivalis 4hbd, P. pyruvate gingivalis Cat2, C. dehydrogenase acetobutylicum AdhE2 flux 4 ECKh- AadhE AldhA ApflB E. coli sucCD, P. gingivalis 138 AlpdA::K.p.lpdA322 sucD, P. gingivalis 4hbd, C.

213 acetobutylicum buk1, C. acetobutylicum ptb, C. acetobutylicum AdhE2 5 ECKh- AadhE AldhA ApflB Deletions in mdh E. coli sucCD, P. gingivalis 401 AlpdA::K.p.lpdA322 Amdh and arcA to direct sucD, P. gingivalis 4hbd, P. AarcA flux through gingivalis Cat2, C. oxidative TCA acetobutylicum AdhE2 cycle 6 ECKh- AadhE AldhA ApflB M. bovis sucA, E. coli sucCD, 401 AlpdA::K.p.lpdA322 Amdh P. gingivalis sucD, P. AarcA gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2 7 ECKh- AadhE AldhA ApflB Mutation in citrate E. coli sucCD, P. gingivalis 422 AlpdA::K.p.lpdA322 Amdh synthase to sucD, P. gingivalis 4hbd, P. AarcA gltAR163L improve anaerobic gingivalis Cat2, C. activity acetobutylicum AdhE2 8 ECKh- AadhE AldhA ApflB M. bovis sucA, E. coli sucCD, 422 AlpdA::K.p.lpdA322 Amdh P. gingivalis sucD, P. AarcA gltAR163L gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2 9 ECKh- AadhE AldhA ApflB M. bovis sucA, E. coli sucCD, 422 AlpdA::K.p.lpdA322 Amdh P. gingivalis sucD, P. AarcA gltAR163L gingivalis 4hbd, P. gingivalis Cat2, C. beijerinckii Ald 10 ECKh- AadhE AldhA ApflB Succinate branch P. gingivalis Cat2, C. 426 AlpdA::K.p.lpdA322 Amdh of upstream beijerinckii Ald AarcA gltAR1 63L fimD:: E. coli pathway integrated sucCD, P. gingivalis sucD, P. into ECKh-422 gingivalis 4hbd 11 ECKh- AadhE AldhA ApflB Succinate and P. gingivalis Cat2, C. 432 AlpdA::K.p.lpdA322 Amdh alpha-ketoglutarate beijerinckii Ald AarcA gltAR163L fimD:: E. coli upstream pathway sucCD, P. gingivalis sucD, P. branches gingivalis 4hbd fimD:: M. bovis integrated into sucA, C. kluyveri 4hbd ECKh-422 12 ECKh- AadhE AldhA ApflB C. acetobutylicum buk1, C. 432 AlpdA::K.p.lpdA322 Amdh acetobutylicum ptb, C. AarcA gltAR163L fimD:: E. coli beijerinckii Ald sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd 13 ECKh- AadhE AldhA ApflB Acetate kinase P. gingivalis Cat2, C. 439 AlpdA::K.p.lpdA322 Amdh deletion of ECKh- beijerinckii Ald AarcA gltAR163L AackA fimD:: 432 E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd 14 ECKh- AadhE AldhA ApflB Acetate kinase P. gingivalis Cat2, C. 453 AlpdA::K.p.lpdA322 Amdh deletion and beijerinckii Ald AarcA gltAR163L AackA PPC/PEPCK Appc::H.i.ppck fimD:: E. coli replacement of sucCD, P. gingivalis sucD, P. ECKh-432 gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd 15 ECKh- AadhE AldhA ApflB AlpdA::fnr- Replacement of P. gingivalis Cat2, C. 456 pflB6-K.p.lpdA322 Amdh AarcA lpdA promoter beijerinckii Ald gltAR163L fimD:: E. coli with anaerobic promoter in 214 sucCD, P. gingivalis sucD, P. ECKh-432 gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd 16 ECKh- AadhE AldhA ApflB AlpdA:: Replacement of P. gingivalis Cat2, C. 455 K.p.lpdA322 ApdhR:: fnr-pflB6 pdhR and aceEF beijerinckii Ald Amdh AarcA gItAR163L fimD:: promoter with E. coli sucCD, P. gingivalis anaerobic sucD, P. gingivalis 4hbd fimD:: promoter in M. bovis sucA, C. kluyveri 4hbd ECKh-432 17 ECKh- AadhE AldhA ApflB AlpdA:: Integration of C. beijerinckii Ald 459 K.p.lpdA322 Amdh AarcA BK/PTB into gltAR163L fimD:: E. coli ECKh-432 sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd fimD:: C. acetobutylicum buk1, C. acetobutylicum ptb 18 ECKh- AadhE AldhA ApflB AlpdA:: C. beijerinckii Ald, G. 459 K.p.lpdA322 Amdh AarcA thermoglucosidasius adhI gltAR163L fimD:: E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd fimD:: C. acetobutylicum buk1, C. acetobutylicum ptb 19 ECKh- AadhE AldhA ApflB Non-PTS sucrose P. gingivalis Cat2, C. 463 AlpdA::K.p.1pdA322 Amdh genes inserted into beijerinckii Ald AarcA gItAR163L fimD:: E. coli ECKh-432 sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd rrnC::cscAKB 20 ECKh- AadhE AldhA ApflB C. acetobutylicum buk1, C. 463 AlpdA::K.p.1pdA322 Amdh acetobutylicum ptb, C. AarcA gItAR163L fimD:: E. coli beijerinckii Ald sucCD, P. gingivalis sucD, P. gingivalis 4hbd fimD:: M. bovis sucA, C. kluyveri 4hbd rrnC::cscAKB The strains summarized in Table 28 are as follows. Strain 1: Single deletion derivative of E. coli MG1655, with deletion of endogenous idhA; plasmid expression of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2. Strain 2: Host strain AB3, a succinate producing strain, derivative of E. coli MG1655, with deletions of endogenous 5 adhE idhA pflB; plasmid expression of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2. Strain 3: Host strain ECKh-138, deletion of endogenous adhE, idhA, pflB, deletion of endogenous /pdA and chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys mutation at the /pdA locus; plasmid expression of E. coli sucCD, P. gingivalis sucD, P. 10 gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2; strain provides improvement of lpdA to increase pyruvate dehydrogenase flux. Strain 4: Host strain ECKh-138, deletion of 215 endogenous adhE, IdhA, pflB, and /pdA, chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys mutation; plasmid expression E coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, C. acetobutylicum buki, C. acetobutylicum ptb, C. acetobutylicum AdhE2. Strain 5: Host strain ECKh-401, deletion of endogenous adhE, IdhA, pflB, deletion of 5 endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA; plasmid expression of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2; strain has deletions in mdh and arcA to direct flux through oxidative TCA cycle. Strain 6: host strain ECKh-401, deletion of endogenous adhE, IdhA, pflB, deletion of endogenous lpdA and 10 chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA; plasmid expression of M. bovis sucA, E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2. Strain 7: Host strain ECKh-422, deletion of endogenous adhE, idhA, pflB, deletion of endogenous /pdA and chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys 15 mutation at the /pdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gItA with gItA Arg163Leu mutant; plasmid expression of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2; strain has mutation in citrate synthase to improve anaerobic activity. Strain 8: strain ECKh-422, deletion of endogenous adhE, /dhA, pflB, deletion of endogenous /pdA and chromosomal insertion of Klebsiella 20 pneumoniae /pdA with a Glu354Lys mutation at the /pdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of g/tA with g/tA Argl63Leu mutant; plasmid expression of M. bovis sucA, E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. acetobutylicum AdhE2. Strain 9: host strain ECKh-422, deletion of endogenous adhE, /dhA, pflB, deletion of endogenous /pdA and chromosomal insertion of Klebsiella pneumoniae /pdA 25 with a Glu354Lys mutation at the /pdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of g/tA with g/tA Argl63Leu mutant; plasmid expression of M. bovis sucA, E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, P. gingivalis Cat2, C. beijerinckii Ald. Strain 10: host strain ECKh-426, deletion of endogenous adhE, /dhA, pflB, deletion of 30 endogenous /pdA and chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys mutation at the /pdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of g/tA with g/tA Argl63Leu mutant, chromosomal insertion at the fimD locus of E. coli sucCD, P.

216 gingivalis sucD, P. gingivalis 4hbd; plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has succinate branch of upstream pathway integrated into strain ECKh-422 at the fimD locus. Strain 11: host strain ECKh-432, deletion of endogenous adhE, idhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a 5 Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gitA with gitA Arg163Leu mutant, chromosomal insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbd; plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has succinate and alpha-ketoglutarate upstream pathway branches integrated into ECKh 10 422. Strain 12: host strain ECKh-432, deletion of endogenous adhE, idhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gitA with gitA Arg163Leu mutant, chromosomal insertion at thefimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. bovis sucA, 15 C. kluyveri 4hbd; plasmid expression of C. acetobutylicum buki, C. acetobutylicum ptb, C. beijerinckii Ald. Strain 13: host strain ECKh-439, deletion of endogenous adhE, idhA, pflB, deletion of endogenous /pdA and chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys mutation at the /pdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of 20 gitA with gitA Arg163Leu mutant, deletion of endogenous ackA, chromosomal insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at thefimD locus of M. bovis sucA, C. kluyveri 4hbd; plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has acetate kinase deletion in strain ECKh-432. Strain 14: host strain ECKh-453, deletion of endogenous adhE, idhA, pflB, deletion of endogenous /pdA and 25 chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys mutation at the /pdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gitA with gitA Arg 163Leu mutant, deletion of endogenous ackA, deletion of endogenous ppc and insertion of Haemophilus influenza ppck at the ppc locus, chromosomal insertion at thefimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. 30 bovis sucA, C. k/uyveri 4hbd; plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has acetate kinase deletion and PPC/PEPCK replacement in strain ECKh-432. Strain 15: host strain ECKh-456, deletion of endogenous adhE, idhA, pflB, deletion of endogenous /pdA and chromosomal insertion of Klebsiella pneumoniae /pdA with a Glu354Lys 217 mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gItA with gItA Argl63Leu mutant, chromosomal insertion at thefimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbd, replacement of lpdA promoter with fnr binding site, pflB-p6 promoter and 5 RBS of pflB; plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has replacement of lpdA promoter with anaerobic promoter in strain ECKh-432. Strain 16: host strain ECKh-455, deletion of endogenous adhE, IdhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gItA with gItA 10 Argl63Leu mutant, chromosomal insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbdI, replacement of pdhR and aceEF promoter with fnr binding site, pflB-p6 promoter and RBS of pflB; plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has replacement of pdhR and aceEF promoter with anaerobic promoter in ECKh-432. 15 Strain 17: host strain ECKh-459, deletion of endogenous adhE, idhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gItA with gItA Argl63Leu mutant, chromosomal insertion at thefimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. bovis sucA, 20 C. kluyveri 4hbd, chromosomal insertion at thefimD locus of C. acetobutylicum buki, C. acetobutylicum ptb; plasmid expression of C. beijerinckii Ald; strain has integration of BK/PTB into strain ECKh-432. Strain 18: host strain ECKh-459, deletion of endogenous adhE, idhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, 25 chromosomal replacement of gItA with gItA Argl63Leu mutant, chromosomal insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at thefimD locus of M. bovis sucA, C. kluyveri 4hbd, chromosomal insertion at thefimD locus of C. acetobutylicum buki, C. acetobutylicum ptb; plasmid expression of C. beijerinckii Ald, G. thermoglucosidasius adhi. 30 Strain 19: host strain ECKh-463, deletion of endogenous adhE, IdhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gItA with gItA Argl63Leu mutant, chromosomal insertion at thefimD locus of E. coli sucCD, P.

218 gingivalis sucD, P. gingivalis 4hbd, chromosomal insertion at the fimD locus of M. bovis sucA, C. kluyveri 4hbd, insertion at the rrnC locus of non-PTS sucrose operon genes sucrose permease (cscB), D-fructokinase (cscK), sucrose hydrolase (cscA), and a LacI-related sucrose-specific repressor (cscR); plasmid expression of P. gingivalis Cat2, C. beijerinckii Ald; strain has non 5 PTS sucrose genes inserted into strain ECKh-432. Strain 20: host strain ECKh-463 deletion of endogenous adhE, idhA, pflB, deletion of endogenous lpdA and chromosomal insertion of Klebsiella pneumoniae lpdA with a Glu354Lys mutation at the lpdA locus, deletion of endogenous mdh and arcA, chromosomal replacement of gitA with gitA Arg163Leu mutant, chromosomal insertion at the fimD locus of E. coli sucCD, P. gingivalis sucD, P. gingivalis 10 4hbd, chromosomal insertion at thefimD locus of M. bovis sucA, C. kluyveri 4hbd, insertion at the rrnC locus of non-PTS sucrose operon; plasmid expression of C. acetobutylicum buk1, C. acetobutylicum ptb, C. beijerinckii Ald. In addition to the BDO producing strains disclosed herein, including those disclosed in Table 28, it is understood that additional modifications can be incorporated that further increase 15 production of BDO and/or decrease undesirable byproducts. For example, a BDO producing strain, or a strain of Table 28, can incorporate additional knockouts to further increase the production of BDO or decrease an undesirable byproduct. Exemplary knockouts have been described previously (see U.S. publication 2009/0047719). Such knockout strains include, but are not limited to, ADHEr, NADH6; ADHEr, PPCK; ADHEr, SUCD4; ADHEr, ATPS4r; 20 ADHEr, FUM; ADHEr, MDH; ADHEr, PFLi, PPCK; ADHEr, PFLi, SUCD4; ADHEr, ACKr, NADH6; ADHEr, NADH6, PFLi; ADHEr, ASPT, MDH; ADHEr, NADH6, PPCK; ADHEr, PPCK, THD2; ADHEr, ATPS4r, PPCK; ADHEr, MDH, THD2; ADHEr, FUM, PFLi; ADHEr, PPCK, SUCD4; ADHEr, GLCpts, PPCK; ADHEr, GLUDy, MDH; ADHEr, GLUDy, PPCK; ADHEr, FUM, PPCK; ADHEr, MDH, PPCK; ADHEr, FUM, GLUDy; ADHEr, FUM, HEX1; 25 ADHEr, HEXI, PFLi; ADHEr, HEXI, THD2; ADHEr, FRD2, LDH_D, MDH; ADHEr, FRD2, LDH_D, ME2; ADHEr, MDH, PGL, THD2; ADHEr, G6PDHy, MDH, THD2; ADHEr, PFLi, PPCK, THD2; ADHEr, ACKr, AKGD, ATPS4r; ADHEr, GLCpts, PFLi, PPCK; ADHEr, ACKr, ATPS4r, SUCOAS; ADHEr, GLUDy, PFLi, PPCK; ADHEr, ME2, PFLi, SUCD4; ADHEr, GLUDy, PFLi, SUCD4; ADHEr, ATPS4r, LDHD, SUCD4; ADHEr, FUM, HEXI, 30 PFLi; ADHEr, MDH, NADH6, THD2; ADHEr, ATPS4r, MDH, NADH6; ADHEr, ATPS4r, FUM, NADH6; ADHEr, ASPT, MDH, NADH6; ADHEr, ASPT, MDH, THD2; ADHEr, ATPS4r, GLCpts, SUCD4; ADHEr, ATPS4r, GLUDy, MDH; ADHEr, ATPS4r, MDH, PPCK; ADHEr, ATPS4r, FUM, PPCK; ADHEr, ASPT, GLCpts, MDH; ADHEr, ASPT, GLUDy, MDH; ADHEr, ME2, SUCD4, THD2; ADHEr, FUM, PPCK, THD2; ADHEr, MDH, PPCK, 219 THD2; ADHEr, GLUDy, MDH, THD2; ADHEr, HEXI, PFLi, THD2; ADHEr, ATPS4r, G6PDHy, MDH; ADHEr, ATPS4r, MDH, PGL; ADHEr, ACKr, FRD2, LDH_D; ADHEr, ACKr, LDHD, SUCD4; ADHEr, ATPS4r, FUM, GLUDy; ADHEr, ATPS4r, FUM, HEXI; ADHEr, ATPS4r, MDH, THD2; ADHEr, ATPS4r, FRD2, LDH_D; ADHEr, ATPS4r, MDH, 5 PGDH; ADHEr, GLCpts, PPCK, THD2; ADHEr, GLUDy, PPCK, THD2; ADHEr, FUM, HEXI, THD2; ADHEr, ATPS4r, ME2, THD2; ADHEr, FUM, ME2, THD2; ADHEr, GLCpts, GLUDy, PPCK; ADHEr, ME2, PGL, THD2; ADHEr, G6PDHy, ME2, THD2; ADHEr, ATPS4r, FRD2, LDHD, ME2; ADHEr, ATPS4r, FRD2, LDH_D, MDH; ADHEr, ASPT, LDH_D, MDH, PFLi; ADHEr, ATPS4r, GLCpts, NADH6, PFLi; ADHEr, ATPS4r, MDH, 10 NADH6, PGL; ADHEr, ATPS4r, G6PDHy, MDH, NADH6; ADHEr, ACKr, FUM, GLUDy, LDH_D; ADHEr, ACKr, GLUDy, LDHD, SUCD4; ADHEr, ATPS4r, G6PDHy, MDH, THD2; ADHEr, ATPS4r, MDH, PGL, THD2; ADHEr, ASPT, G6PDHy, MDH, PYK; ADHEr, ASPT, MDH, PGL, PYK; ADHEr, ASPT, LDH_D, MDH, SUCOAS; ADHEr, ASPT, FUM, LDH_D, MDH; ADHEr, ASPT, LDH_D, MALS, MDH; ADHEr, ASPT, ICL, LDH_D, MDH; 15 ADHEr, FRD2, GLUDy, LDH_D, PPCK; ADHEr, FRD2, LDHD, PPCK, THD2; ADHEr, ACKr, ATPS4r, LDHD, SUCD4; ADHEr, ACKr, ACS, PPC, PPCK; ADHEr, GLUDy, LDHD, PPC, PPCK; ADHEr, LDHD, PPC, PPCK, THD2; ADHEr, ASPT, ATPS4r, GLCpts, MDH; ADHEr, G6PDHy, MDH, NADH6, THD2; ADHEr, MDH, NADH6, PGL, THD2; ADHEr, ATPS4r, G6PDHy, GLCpts, MDH; ADHEr, ATPS4r, GLCpts, MDH, PGL; ADHEr, 20 ACKr, LDHD, MDH, SUCD4. Table 29 shows the reactions of corresponding genes to be knocked out of a host organism such as E. coli. The corresponding metabolite corresponding to abbreviations in Table 29 are shown in Table 30. Table 29. Corresponding genes to be knocked out to prevent a particular reaction from 25 occurring in E. coli. Genes Encoding the Enzyme(s) Reaction Catalyzing Each Abbreviation Reaction Stoichiometry* Reaction& ACKr [c] ac + atp <==> actp + adp (b3115 or b2296 or ACS [c] ac + atp + coa --> accoa + amp + ppi b4069 ACt6 ac[p] + h[p] <==> ac[c] + h[c] Non-gene associated DHEr [c] etoh + nad <==> acald + h + nadh 12416 or b1478 or [c] acald + coa + nad <==> accoa + h + nadh (b1241 or b0351) AKGD [c] akg + coa + nad --> co2 + nadh + succoa (b0116 and b0726 220 and b0727) ASNS2 [c] asp-L + atp + nh4 --> amp + asn-L + h + ppi b3744 ASPT [c] asp-L --> fum + nh4 b4139 (((b3736 and b3737 and b3738) and (b3731 and b3732 and b3733 and b3734 and b3735 ) ) or ATPS4r adp[c] + (4) h[p] + pi[c] <==> atp[c] + (3) h[c] + h2o[c] ((b3736 and b3737 and b3738) and (b3731 and b3732 and b3733 and b3734 and b3735) and b3739)) CBMK2 [c] atp + co2 + nh4 <==> adp + cbp + (2) h (b0521 or b0323 or b2874) EDA [c] 2ddg6p --> g3p + pyr b1850 ENO [c] 2pg <==> h2o + pep b2779 FBA [c] fdp <==> dhap + g3p (b2097 or b2925 or FBP [c] fdp + h2o --> f6p + pi (b4232 or b3925) for[p] + (2) h[c] + q8[c] --> co2[c] + h[p] + q8h2[c] ((b3892 and b3893 and b3894) or (b1474 FDH2 for[p] + (2) h[c] + mqn8[c] --> co2[c] + h[p] + mql8[c] and b1475 and b1476)) [c] fum + mql8 --> mqn8 + succ (b4151 and b4152 FRD2 [c] 2dmmql8 + fum --> 2dmmq8 + succ and b4153 and [c] dmml8 +fum--> dmm8 + ucc4154) FTHFD [c]: 10fthf + h2o --> for + h + thf b1232 FUM [c] fum + h2o <==> mal-L b1612 or b4122 or G5SD [c] glu5p + h + nadph --> glu5sa + nadp + pi b0243 G6PDHy [c] g6p + nadp <==> 6pgl + h + nadph b1852 ((b2417 and b1101 and b2415 and b2416) or (b1817 and GLCpts glc-D[p] + pep[c] --> g6p[c] + pyr[c] 185 and b24196) o (b2417 and b1621 and b2415 and b2416)) GLU5K [c] atp + glu-L --> adp + glu5p b0242 GLUDy [c] glu-L + h2o + nadp <==> akg + h + nadph + nh4 b1761 (b2904 and b2903 GLYCL [c] gly + nad + thf --> co2 + mlthf + nadh + nh4 and b2905 and b0116) HEX1 [c] atp + glc-D --> adp + g6p + h b2388 ICL [c] icit --> glx + succ b4015 LDHD [c] lac-D + nad <==> h + nadh + pyr (b2133 or b1380) MALS [c] accoa + glx + h2o --> coa + h + mal-L (b4014 or b2976) MDH [c] mal-L + nad <==> h + nadh + oaa b3236 221 ME2 [c] mal-L + nadp --> co2 + nadph + pyr b2463 MTHFC [c] h2o + methf <==> 10fthf + h b0529 [c] h + mqn8 + nadh --> mql8 + nad NADH12 [c] h + nadh + q8 --> nad + q8h2 b1109 [c] 2dmmq8 + h + nadh -- > 2dmmql8 + nad (4) h[c] + nadh[c] + q8[c] -- > (3) h[p] + nad[c] + q8h2[c] (b2276 and b2277 and b2278 and b2279 (4) h[c] + mqn8[c] + nadh[c] --> (3) h[p] + mql8[c] + and b2280 and b2281 NADH6 nad[c] and b2282 and b2283 2dmmq8[c] + (4) h[c] + nadh[c] --> 2dmmql8[c] + (3) and b2284 and b2285 h[p] + nad[c] and b2286 and b2287 and b2288 ) PFK [c] atp + f6p -->adp + fdp + h (b3916 or b1723) (((b0902 and b0903) and b2579) or (b0902 PFLi [c] coa + pyr -- > accoa + for and b0903) or (b0902 and b3114) or (b3951 and b3952)) PGDH [c] :6pgc + nadp --> co2 + nadph + ru5p-D b2029 PGI [c] g6p <==> f6p b4025 PGL [c] 6pgl + h2o --> 6pgc + h b0767 PGM [c] 2pg <==> 3pg (b3612 or b4395 or b0755) PPC [c] :co2 + h2o + pep --> h + oaa + pi b3956 PPCK [c] atp + oaa --> adp + co2 + pep b3403 PRO1z [c] fad + pro-L --> lpyr5c + fadh2 + h 1014 PYK [c] adp + h + pep --> atp + pyr b1854 or b1676) PYRt2 h[p] + pyr[p] <==> h[c] + pyr[c] Non-gene associated RPE [c] : ru5p-D <==> xu5p-D (b4301 or b3386) SO4t2 so4[e] <==> so4[p] (b0241 or b0929 or b1377 or b2215) (b0721 and b0722 SUCD4 [c] q8 + succ --> fum + q8h2 and b0723 and b0724) SUCOAS [c] atp + coa + succ <==> adp + pi + succoa (b0728 and b0729) ((b2422 and b2425 and b2424 and SULabe atp[c] + h2o[c] + so4[p] --> adp[c] + h[c] + pi[c] + 2423) or (b0763 and SUac so4[c] b0764 and b0765) or (b2422 and b2424 and b2423 and b3917)) TAL [c] : g3p + s7p <==> e4p + f6p (b2464 or b0008) THD2 (2) h[p] + nadh[c] + nadp[c] --> (2) h[c] + nad[c] + (b1602 and b1603) nadph[c] THD5 [c] nad + nadph --> nadh + nadp b1603)or (b1602 and TPI [c] dhap <==> g3p b3919 222 Table 30. Metabolite names corresponding to abbreviations used in Table 29. Metabolite Abbreviation Metabolite Name 1 Ofthf 10-Formyltetrahydrofolate lpyr5c 1-Pyrroline-5-carboxylate 2ddg6p 2-Dehydro-3-deoxy-D-gluconate 6-phosphate 2dmmq8 2-Demethylmenaquinone 8 2dmmql8 2-Demethylmenaquinol 8 2pg D-Glycerate 2-phosphate 3pg 3-Phospho-D-glycerate 6pgc 6-Phospho-D-gluconate 6pgl 6-phospho-D-glucono-1,5-lactone ac Acetate acald Acetaldehyde accoa Acetyl-CoA actp Acetyl phosphate adp ADP akg 2-Oxoglutarate amp AMP asn-L L-Asparagine asp-L L-Aspartate atp ATP cbp Carbamoyl phosphate co2 C02 coa Coenzyme A dhap Dihydroxyacetone phosphate e4p D-Erythrose 4-phosphate etoh Ethanol f6p D-Fructose 6-phosphate fad Flavin adenine dinucleotide oxidized fadh2 Flavin adenine dinucleotide reduced fdp D-Fructose 1,6-bisphosphate for Formate fum Fumarate g3p Glyceraldehyde 3-phosphate g6p D-Glucose 6-phosphate glc-D D-Glucose glu5p L-Glutamate 5-phosphate glu5sa L-Glutamate 5-semialdehyde glu-L L-Glutamate glx Glyoxylate gly Glycine h H+ h2o H20 icit Isocitrate lac-D D-Lactate mal-L L-Malate methf 5, 10-Methenyltetrahydrofolate 223 mlthf 5, 10-Methylenetetrahydrofolate mql8 Menaquinol 8 mqn8 Menaquinone 8 nad Nicotinamide adenine dinucleotide nadh Nicotinamide adenine dinucleotide - reduced nadp Nicotinamide adenine dinucleotide phosphate nadph Nicotinamide adenine dinucleotide phosphate - reduced nh4 Ammonium oaa Oxaloacetate pep Phosphoenolpyruvate pi Phosphate ppi Diphosphate pro-L L-Proline pyr Pyruvate q8 Ubiquinone-8 q8h2 Ubiquinol-8 ru5p-D D-Ribulose 5-phosphate s7p Sedoheptulose 7-phosphate so4 Sulfate succ Succinate succoa Succinyl-CoA thf 5,6,7,8-Tetrahydrofolate xu5p-D D-Xylulose 5-phosphate EXAMPLE XX Exemplary Pathways for Producing BDO This example describes exemplary pathways to produce 4-hydroxybutanal (4-HBal) and/or BDO 5 using a carboxylic acid reductase as a BDO pathway enzyme. An exemplary pathway for production of BDO includes use of an NAD+ or NADP+ aryl aldehyde dehydrogenase (E.C.: 1.2.1.29 and 1.2.1.30) to convert 4-hydroxybutyrate to 4 hydroxybutanal and an alcohol dehydrogenase to convert 4-hydroxybutanal to 1,4-butanediol. 4-Hydroxybutyrate can be derived from the tricarboxylic acid cycle intermediates succinyl-CoA 10 and/or alpha-ketoglutarate as shown in Figure 58. Aryl-Aldehyde Dehydrogenase (or Carboxylic Acid Reductase). An aryl-aldehyde dehydrogenase, or equivalently a carboxylic acid reductase, can be found in Nocardia iowensis. Carboxylic acid reductase catalyzes the magnesium, ATP and NADPH-dependent reduction of carboxylic acids to their corresponding aldehydes (Venkitasubramanian et al., J. Biol. Chem. 15 282:478-485 (2007)) and is capable of catalyzing the conversion of 4-hydroxybutyrate to 4 hydroxybutanal. This enzyme, encoded by car, was cloned and functionally expressed in E. coli (Venkitasubramanian et al., J. Biol. Chem. 282:478-485 (2007)). Expression of the npt gene 224 product improved activity of the enzyme via post-transcriptional modification. The npt gene encodes a specific phosphopantetheine transferase (PPTase) that converts the inactive apo enzyme to the active holo-enzyme. The natural substrate of this enzyme is vanillic acid, and the enzyme exhibits broad acceptance of aromatic and aliphatic substrates (Venkitasubramanian et 5 al., in Biocatalysis in the Pharmaceutical and Biotechnology Industires, ed. R.N. Patel, Chapter 15, pp. 425-440, CRC Press LLC, Boca Raton, FL. (2006)). Gene name GI No. GenBank Accession Organism No. car 40796035 AAR91681.1 Nocardia iowensis (sp. NRRL 5646) npt 114848891 ABI83656.1 Nocardia iowensis (sp. NRRL npt 1484891 B18356.15646) Additional car and npt genes can be identified based on sequence homology. GenBank Gene name GI No. Accession No. Organism fadD9 121638475 YP_978699.1 Mycobacterium bovis BCG BCG_2812c 121638674 YP_978898.1 Mycobacterium bovis BCG nfa20150 54023983 YP_118225.1 Nocardia1arcinica IFM nfa40540 54026024 YP_120266.1 Nocardia1arcinica IFM SGR_6790 182440583 YP_001828302.1 Streptomyces griseus subsp. griseus NBRC 13350 SGR_665 182434458 YP_001822177.1 Streptomyces griseus subsp. griseus NBRC 13350 MSMEG_2956 YP887275.1 YP887275.1 Mycobacterium smegmatis MSME 296 YP88775. YP_8725.1MC2 155 MSMEG_5739 YP_889972.1 118469671 Mycobacterium smegmatis MC2 155 MSMEG_2648 YP_886985.1 118471293 Mycobactum smegmatis MAP1040c NP_959974.1 41407138 Mycobacterium avium subsp. paratuberculosis K-10 MAP2899c NP_961833.1 41408997 Mycobacterium avium subsp. paratuberculosis K-10 MMAR_2117 YP_001850422.1 183982131 Mycobacterium marinum M MMAR_2936 YP_001851230.1 183982939 Mycobacterium marinum M MMAR_1916 YP_001850220.1 183981929 Mycobacterium marinum M TpauDRAFT 33060 ZP_04027864.1 227980601 Tsukamurella paurometabola DSM 20162 TpauDRAFT 20920 ZP_04026660.1 ZP_04026660.1 Tsukamurella paurometabola DSM 20162 225 CPCC7001_1320 ZP_05045132.1 254431429 Cyanobium PCC7001 DDBDRAFT 0187729 XP_636931.1 66806417 Dictyostelium discoideum t AX4 An additional enzyme candidate found in Streptomyces griseus is encoded by the griC and griD genes. This enzyme is believed to convert 3-amino-4-hydroxybenzoic acid to 3-amino-4 5 hydroxybenzaldehyde as deletion of either griC or griD led to accumulation of extracellular 3 acetylamino-4-hydroxybenzoic acid, a shunt product of 3-amino-4-hydroxybenzoic acid metabolism (Suzuki, et al., J. Antibiot. 60(6):380-387 (2007)). Co-expression of griC and griD with SGR_665, an enzyme similar in sequence to the Nocardia iowensis npt, can be beneficial. GenBank Gene name GI No. Accession No. Organism griC 182438036 YP_001825755.1 Streptomyces griseus subsp. griseus NBRC 13350 griD 182438037 YP_001825756.1 Streptomyces griseus subsp. griseus NBRC 13350 10 An enzyme with similar characteristics, alpha-aminoadipate reductase (AAR, EC 1.2.1.31), participates in lysine biosynthesis pathways in some fungal species. This enzyme naturally reduces alpha-aminoadipate to alpha-aminoadipate semialdehyde. The carboxyl group is first activated through the ATP-dependent formation of an adenylate that is then reduced by NAD(P)H to yield the aldehyde and AMP. Like CAR, this enzyme utilizes magnesium and 15 requires activation by a PPTase. Enzyme candidates for AAR and its corresponding PPTase are found in Saccharomyces cerevisiae (Morris et al., Gene 98:141-145 (1991)), Candida albicans (Guo et al., Mol. Genet. Genomics 269:271-279 (2003)), and Schizosaccharomyces pombe (Ford et al., Curr. Genet. 28:131-137 (1995)). The AAR from S. pombe exhibited significant activity when expressed in E. coli (Guo et al., Yeast 21:1279-1288 (2004)). The AAR from Penicillium 20 chrysogenum accepts S-carboxymethyl-L-cysteine as an alternate substrate, but did not react with adipate, L-glutamate or diaminopimelate (Hijarrubia et al., J. Biol. Chem. 278:8250-8256 (2003)). The gene encoding the P. chrysogenum PPTase has not been identified to date. GenBank Gene name GI No. Accession No. Organism LYS2 171867 AAA34747.1 Saccharomyces cerevisiae LYS5 1708896 P50113.1 Saccharomyces cerevisiae LYS2 2853226 AAC02241.1 Candida albicans LYS5 28136195 AA026020.1 Candida albicans Lysip 13124791 P40976.3 Schizosaccharomyces pombe 226 Lys7p 1723561 Q10474.1 Schizosaccharomyces pombe Lys2 3282044 CAA74300.1 Penicillium chrysogenum There are several advantages of using carboxylic acid reductase for BDO p.roduction. There are at least two advantages of forming 4-hydroxybutanal from 4-hydroxybutyrate via a carboxylic 5 acid reductase compared to forming 4-hydroxybutanal from an activated version of 4 hydroxybutyrate (for example, 4-hydroxybutyryl-CoA, 4-hydroxybutyryl-Pi) via an acyl-CoA or acyl-phosphate reductase. First, the formation of gamma-butyrolactone (GBL) as a byproduct is greatly reduced. It is believed that the activated versions of 4-hydroxybutyrate cyclize to GBL more readily than unactivated 4-hydroxybutyrate. The use of carboxylic acid reductase 10 eliminates the need to pass through a free activated 4-hydroxybutyrate intermediate, thus reducing the formation of GBL as a byproduct accompanying BDO production. Second, the formation of ethanol as a byproduct is greatly reduced. Ethanol is often formed in varying amounts when an aldehyde- or an alcohol-forming 4-hydroxybutyryl-CoA reductase is used to convert 4-hydroxybutyryl-CoA to 4-hydroxybutanal or 1,4-butanediol, respectively. This is 15 because most, if not all, aldehyde- or alcohol-forming 4-hydroxybutyryl-CoA reductases can accept acetyl-CoA as a substrate in addition to 4-hydroxybutyryl-CoA. Aldehyde-forming enzymes, for example, often catalyze the conversion of acetyl-CoA to acetaldehyde, which is subsequently reduced to ethanol by native or non-native alcohol dehydrogenases. Alcohol forming 4-hydroxybutyryl-CoA reductases that accept acetyl-CoA as a substrate will convert 20 acetyl-CoA directly to ethanol. It appears that carboxylic acid reductase enzymes have far less activity on acetyl-CoA than aldehyde- or alcohol-forming acyl-CoA reductase enzymes, and thus their application for BDO production results in minimal ethanol byproduct formation (see below). EXAMPLE XXI 25 Biosynthesis of 1,4-Butanediol Using A Carboxylic Acid Reductase Enzyme This example describes the generation of a microbial organism that produces 1,4-butanediol using a carboxylic acid reductase enzyme. Escherichia coli is used as a target organism to engineer the pathway for 1,4-butanediol synthesis described in Figure 58. E. coli provides a good host for generating a non-naturally 30 occurring microorganism capable of producing 1,4-butanediol. E. coli is amenable to genetic manipulation and is known to be capable of producing various products, like ethanol, acetic 227 acid, formic acid, lactic acid, and succinic acid, effectively under various oxygenation conditions. Integration of 4-Hydroxybutyrate Pathway Genes into Chromosome: Construction of ECKh 432. _The carboxylic acid reductase enzyme was expressed in a strain of E. coli designated 5 ECKh-432 whose construction is described in Example XVII. This strain contained the components of the BDO pathway, leading to 4HB, integrated into the chromosome of E. coli at thefimD locus. As described in Example XVII, the succinate branch of the upstream pathway was integrated into the E. coli chromosome using the k red homologeous recombination method (Datsenko and 10 Wanner, Proc. Nati. Acad. Sci. USA 97:6640-6645 (2000)). A polycistronic DNA fragment containing a promoter, the sucCD gene of Escherichia coli encoding succinyl-CoA ligase, the sucD gene of Porphyromonas gingivalis encoding succinyl-CoA reductase (aldehyde forming) (step A of Figure 58), the 4hbd gene of Porphyromonas gingivalis encoding 4-hydroxybutyrate dehydrogenase (step C of Figure 58), and a terminator sequence was inserted into the AflIII site 15 of the pKD3 plasmid. As described in Example XVII, the alpha-ketoglutarate branch of the upstream pathway was integrated into the chromosome by homologeous recombination. The plasmid used in this modification was pRE1 18-V2 (pRE1 18 (ATCC87693) deleted of the oriT and IS sequences), which contains a kanamycin-resistant gene, a gene encoding the levansucrase (sacB) and a R6K 20 conditional replication ori. The integration plasmid also contained a polycistronic sequence with a promoter, the sucA gene from Mycobacterium bovis encoding alpha-ketoglutarate decarboxylase (step B of Figure 58), the Clostridium kluyveri 4hbd gene encoding 4 hydroxybutyrate dehydrogenase (step C of Figure 58), and a terminator being inserted between two 1.5-kb DNA fragments that are homologous to the flanking regions of the target insertion 25 site. The resulting plasmid was used to transform E. coli strain. The integration candidate was selected on plates containing kanamycin. The correct integration site was verified by PCR. To resolve the antibiotic marker from the chromosome, the cells were selected for growth on medium containing sucrose. The final strain was verified by PCR and DNA sequencing. The recipient E. coli strain was ECKh-422 (AadhE AldhA ApflB AlpdA::K.p.lpdA322 Amdh 30 AarcA g/tAR163L) whose construction is described in Example XV. ECKh-422 contains a mutation g/tAR163L leading to NADH-insensitivity of citrate synthase encoded by g/tA. It 228 further contains an NADH-insensitive version of the /pdA gene from Klebsiella pneumonia integrated into the chromosome as described below. Replacement of the native /pdA was replaced with a NADH-insensitive /pdA from Klebsiella pneumonie, as described in Example XIV. The resulting vector was designated pRE1 18-V2 (see 5 Figure 34).] Cloning and Expression of Carboxylic Acid Reductase and PPTase. To generate an E. coli strain engineered to produce 1,4-butanediol, nucleic acids encoding a carboxylic acid reductase and phosphopantetheine transferase are expressed in E. coli using well known molecular biology techniques (see, for example, Sambrook, supra, 2001; Ausubel supra, 1999). In particular, the 10 car (AAR91681.1) and npt (ABI83656.1) genes were cloned into the pZS*13 vector (Expressys, Ruelzheim, Germany) under the PA1/lacO promoter. The car gene (GNM_720) was cloned by PCR from Nocardia genomic DNA. Its nucleic acid and protein sequences are shown in Figures 59A and 59B, respectively. A codon-optimized version of the npt gene (GNM_721) was synthesized by GeneArt 15 (Regensburg, Germany). Its nucleic acid and protein sequences are shown in Figures 60A and 60B, respectively. The resulting vector from cloning GNM_720 and GNM_721 into pZS*13 is shown in Figure 61. The plasmid was transformed into ECKh-432 to express the proteins and enzymes required for 1,4-butanediol production. Alternate versions of the plasmid containing only GNM_720 and 20 only GNM_721 were also constructed. Demonstration of 1,4-BDO Production using Carboxylic Acid Reductase. Functional expression of the 1,4-butanediol pathway was demonstrated using E. coli whole-cell culture. A single colony of E. coli ECKh-432 transformed with the pZS* 13 plasmid containing both GNM_720 and GNM_721 was inoculated into 5 mL of LB medium containing appropriate 25 antibiotics. Similarly, single colonies of E. coli ECKh-432 transformed with the pZS* 13 plasmids containing either GNM_720 or GNM_721 were inoculated into additional 5 mL aliquots of LB medium containing appropriate antibiotics. Ten mL micro-aerobic cultures were started by inoculating fresh minimal in vivo conversion medium (see below) containing the appropriate antibiotics with 1% of the first cultures.

229 Recipe of the minimal in vivo conversion medium (for 1000 mL) is as follows: final concentration 1M MOPS/KOH buffer 40 mM Glucose (40%) 1% 5 1OXM9 salts solution iX MgSO4 (1 M) 1 mM trace minerals (x1000) 1x 1M NaHCO3 10 mM 10 Microaerobic conditions were established by initially flushing capped anaerobic bottles with nitrogen for 5 minutes, then piercing the septum with an 18G needle following inoculation. The needle was kept in the bottle during growth to allow a small amount of air to enter the bottles. Protein expression was induced with 0.2 mM IPTG when the culture reached mid-log growth phase. This is considered: time = 0 hr. The culture supernatants were analyzed for BDO, 4HB, 15 and other by-products as described above and in W02008115840 (see Table 31). Table 31. Production of BDO, 4-HB and other products in various strains. mM .. pD600 OD600 PA SA LA 4,H BDQ GL ETOH ECKh-432 720 0.420 2.221 6.36 0.00 0.10 7.71 3.03 0.07 >LLOQ ECKh-432 721 0.323 2.574 1.69 0.00 0.00 12.60 0.00 0.00 >LLOQ ECKh-432 720/721 0.378 2.469 1.70 0.00 0.01 4.23 9.16 0.24 1.52 PA = pyruvate, SA = succinate, LA = lactate, 4HB = 4-hydroxybutyrate, BDO = 1,4-butanediol, 20 GBL = gamma-butyrolactone, Etoh = ethanol, LLOQ = lower limit of quantification These results demonstrate that the carboxylic acid reductase gene, GNM 720, is required for BDO formation in ECKh-432 and its effectiveness is increased when co-expressed with the PPTase, GNM_721. GBL and ethanol were produced in far smaller quantities than BDO in the strains expressing GNM_720 by itself or in combination with GNM_721. 25 Additional Pathways to BDO Employing Carboxylic Acid Reductase. It is expected that carboxylic acid reductase can function as a component of many pathways to 1,4-butanediol from the TCA cycle metabolites: succinate, succinyl-CoA, and alpha-ketoglutarate. Several of these pathways are disclosed in Figure 62. All routes can lead to theoretical BDO yields greater than or equal to 1 mol/mol assuming glucose as the carbon source. Similar high theoretical yields 30 can be obtained from additional substrates including sucrose, xylose, arabinose, synthesis gas, among many others. It is expected that the expression of carboxylic acid reductase alone or in combination with PPTase (that is, to catalyze steps F and D of Figure 62) is sufficient for 1,4- 230 butanediol production from succinate provided that sufficient endogenous alcohol dehydrogenase activity is present to catalyze steps C and E of Figure 62. Candidate enzymes for steps A through Z of Figure 62 are described in section XXIII. EXAMPLE XXII 5 Pathways to Putrescine that Employ Carboxylic Acid Reductase This example describes exemplary putrescine pathways utilizing carboxylic acid reductase. Putrescine, also known as 1,4-diaminobutane or butanediamine, is an organic chemical compound of the formula NH 2

(CH

2

)

4

NH

2 . It can be reacted with adipic acid to yield the polyamide Nylon-4,6, which is marketed by DSM (Heerlen, Netherlands) under the trade name 10 Stanyl

T

M. Putrescine is naturally produced, for example, by the natural breakdown of amino acids in living and dead organisms. E. coli has been engineered to produce putrescine by overexpressing the native ornithine biosynthetic machinery as well as an omithine decarboxylase (Qian, et al., Biotechnol. Bioeng. 104(4):651-662 (2009)). Figure 63 describes a number of additional biosynthetic pathways leading to the production of 15 putrescine from succinate, succinyl-CoA, or alpha-ketoglutarate and employing a carboxylic acid reductase. Note that none of these pathways require formation of an activated version of 4 aminobutyrate such as 4-aminobutyryl-CoA, which can be reduced by an acyl-CoA reductase to 4-aminobutanal but also can readily cyclize to its lactam, 2-pyrrolidinone (Ohsugi, et al., J. Biol. Chem. 256:7642-7651 (1981)). All routes can lead to theoretical putrescine yields greater than 20 or equal to 1 mol/mol assuming glucose as the carbon source. Similar high theoretical yields can be obtained from additional substrates including sucrose, xylose, arabinose, synthesis gas, among many others. Candidate enzymes for steps A through U of Figure 63 are described in Example XXIII. EXAMPLE XXIII 25 Exemplary Enzymes for Production of C4 Compounds This example describes exemplary enzymes for production of C4 compounds such as 1,4 butanediol, 4-hydroxybutanal and putrescine. Enzyme classes. All transformations depicted in Figures 58, 62 and 63 fall into the general categories of transformations shown in Table 32. This example describes a number of 30 biochemically characterized genes in each category. Specifically listed are genes that can be applied to catalyze the appropriate transformations in Figures 58, 62 and 63 when cloned and 231 expressed. The first three digits of each label correspond to the first three Enzyme Commission number digits which denote the general type of transformation independent of substrate specificity. Table 32. Classes of Enzyme Transformations Depicted in Figures 58, 62 and 63. 5 LABEL FUNCTION 1.1.1.a Oxidoreductase (oxo to alcohol) 1.1..c Oxidoreductase (2 step, acyl-CoA to alcohol) 1.2.1.b Oxidoreductase (acyl-CoA to aldehyde) 10 1.2.1.c Oxidoreductase (2-oxo acid to acyl-CoA, decarboxylation) 1.2.1.d Oxidoreductase (phosphonate reductase) 1.2.1.e Acid reductase 15 1.4.1.a Oxidoreductase (aminating) 2.3.1.a Acyltransferase (transferring phosphate group to CoA) 2.6. 1.a Aminotransferase 2.7.2.a Phosphotransferase (carboxy acceptor) 20 2.8.3.a CoA transferase 3.1.2.a CoA hydrolase 4.1.1.a Carboxy-lyase 6.2.1.a CoA synthetase 1.1.1.a Oxidoreductase (oxo to alcohol) Aldehyde to alcohol. Three transformations described in Figures 58, 62 and 63 involve the conversion of an aldehyde to alcohol. These are 4-hydroxybutyrate dehydrogenase (step C, Figures 58 and 62), 1,4-butanediol dehydrogenase (step E, Figures 58 and 62), and 5-hydroxy-2 30 pentanoic acid (step Y, Figure 62). Exemplary genes encoding enzymes that catalyze the conversion of an aldehyde to alcohol, that is, alcohol dehydrogenase or equivalently aldehyde reductase, include alrA encoding a medium-chain alcohol dehydrogenase for C2-C14 (Tani et al. Apple. Environ. Microbiol. 66:5231-5235 (2000)), ADH2 from Saccharomyces cerevisiae (Atsumi et al. Nature 451:86-89 (2008)), yqhD from E. coli, which has preference for molecules 35 longer than C(3) (Sulzenbacher et al. J. Mol. Biol. 342:489-502 (2004)), and bdh I and bdh II from C. acetobutylicum, which converts butyryaldehyde into butanol (Walter et al. J. Bacteriol. 174:7149-7158 (1992)). The protein sequences for each of exemplary gene products can be found using the following GenBank accession numbers: 232 Gene Accession No. GI No. Organism airA BAB 12273.1 9967138 Acinetobacter sp. Strain M-1 ADH2 NP_014032.1 6323961 Saccharymyces cerevisiae yqhD NP_417484.1 16130909 Escherichia coli bdh I NP_349892.1 15896543 Clostridium acetobutylicum bdh II NP 349891.1 15896542 Clostridium acetobutylicum Enzymes exhibiting 4-hydroxybutyrate dehydrogenase activity (EC 1.1.1.61) also fall into this category. Such enzymes have been characterized in Ralstonia eutropha (Bravo et al. J. Forensic 5 Sci. 49:379-387 (2004)), Clostridium k/uyveri (Wolff et al., Protein Expr. Purif 6:206-212 (1995)) and Arabidopsis thaliana (Breitkreuz et al. J. Biol. Chem. 278:41552-41556 (2003)). Gene Accession No. GI No. Organism 4hbd YP_726053.1 113867564 Ralstonia eutropha H16 4hbd EDK35022.1 146348486 Clostridium k/uyveri DSM 555 4hbd Q94B07 75249805 Arabidopsis thaliana The adhi gene from Geobacillus thermoglucosidasius M10EXG (Jeon et al., J. Biotechnol. 135:127-133 (2008)) was shown to exhibit high activity on both 4-hydroxybutanal and butanal 10 (see above). Thus this enzyme exhibits 1,4-butanediol dehydrogenase activity. Gene Accession No. GI No. Organism adh1 AAR91477.1 40795502 Geobacillus thermoglucosidasius M1OEXG Another exemplary enzyme is 3-hydroxyisobutyrate dehydrogenase, which catalyzes the reversible oxidation of 3-hydroxyisobutyrate to methylmalonate semialdehyde. This enzyme participates in valine, leucine and isoleucine degradation and has been identified in bacteria, 15 eukaryotes, and mammals. The enzyme encoded by P84067 from Thermus thermophilus HB8 has been structurally characterized (Lokanath et al. J. Mol. Biol. 352:905-17 (2005)). The reversibility of the human 3-hydroxyisobutyrate dehydrogenase was demonstrated using isotopically-labeled substrate (Manning et al., Biochem. J. 231:481-484 (1985)). Additional genes encoding this enzyme include 3hidh in Homo sapiens (Hawes et al., Methods Enzymol. 20 324:218-228 (2000)) and Oryctolagus cuniculus (Chowdhury et al., Biosci. Biotechnol. Biochem. 60:2043-2047 (1996); Hawes et al. Methods Enzymol. 324:218-228 (2000)), mmsb in Pseudomonas aeruginosa, and dhat in Pseudomonas putida (Aberhart et al., J. Chem. Soc. [Perkin 1] 6:1404-1406 (1979); Chowdhury et al., Biosci. Biotechnol Biochem. 67:438-441 (2003); Chowdhury et al., Biosci. Biotechnol. Biochem. 60:2043-2047 (1996)).

233 Gene Accession No. GI No. Organism P84067 P84067 75345323 Thermus thermophilus mmsb P28811.1 127211 Pseudomonas aeruginosa dhat Q59477.1 2842618 Pseudomonas putida 3hidh P31937.2 12643395 Homo sapiens 3hidh P32185.1 416872 Oryctolagus cuniculus Several 3-hydroxyisobutyrate dehydrogenase enzymes have also been shown to convert malonic semialdehyde to 3-hydroxyproprionic acid (3-HP). Three gene candidates exhibiting this 5 activity are mmsB from Pseudomonas aeruginosa PAO1(62), mmsB from Pseudomonas putida KT2440 (Liao et al., US Publication 2005/0221466) and mmsB from Pseudomonas putida E23 (Chowdhury et al., Biosci. Biotechnol. Biochem. 60:2043-2047 (1996)). An enzyme with 3 hydroxybutyrate dehydrogenase activity in Alcaligenesfaecalis M3A has also been identified (Gokam et al., US Patent No. 7,393,676; Liao et al., US Publication No. 2005/0221466). 10 Additional gene candidates from other organisms including Rhodobacter spaeroides can be inferred by sequence similarity. Gene Accession No. GI No. Organism mmsB AAA25892.1 151363 Pseudomonas aeruginosa mmsB NP_252259.1 15598765 Pseudomonas aeruginosa PA0I mmsB NP_746775.1 26991350 Pseudomonas putida KT2440 mmsB JC7926 60729613 Pseudomonas putida E23 orfBl AAL26884 16588720 Rhodobacter spaeroides The conversion of malonic semialdehyde to 3-HP can also be accomplished by two other enzymes, NADH-dependent 3-hydroxypropionate dehydrogenase and NADPH-dependent 15 malonate semialdehyde reductase. An NADH-dependent 3-hydroxypropionate dehydrogenase is thought to participate in beta-alanine biosynthesis pathways from propionate in bacteria and plants (Rathinasabapathi, J. Plant Pathol. 159:671-674 (2002); Stadtman, J. Am. Chem. Soc. 77:5765-5766 (1955)). This enzyme has not been associated with a gene in any organism to date. NADPH-dependent malonate semialdehyde reductase catalyzes the reverse reaction in 20 autotrophic C0 2 -fixing bacteria. Although the enzyme activity has been detected in Metallosphaera sedula, the identity of the gene is not known (Alber et al. J. Bacteriol. 188:8551-8559 (2006)). 1.1.1.c Oxidoreductase (2 step, acyl-CoA to alcohol). Steps S and W of Figure 62 depict bifunctional reductase enzymes that can form 4 25 hydroxybutyrate and 1,4-butanediol, respectively. Exemplary 2-step oxidoreductases that 234 convert an acyl-CoA to alcohol include those that transform substrates such as acetyl-CoA to ethanol (for example, adhE from E. coli (Kessler et al., FEBS. Lett. 281:59-63 (1991)) and butyryl-CoA to butanol (for example, adhE2 from C. acetobutylicum (Fontaine et al., J.Bacteriol. 184:821-830 (2002)). The C. acetobutylicum adhE2 gene was shown to convert 4 5 hydroxybutyryl-CoA to 1,4-butanediol (see above). In addition to reducing acetyl-CoA to ethanol, the enzyme encoded by adhE in Leuconostoc mesenteroides has been shown to oxidize the branched chain compound isobutyraldehyde to isobutyryl-CoA (Kazahaya et al. J., Gen. Apple. Microbiol. 18:43-55 (1972); Koo et al., Biotechnol. Lett. 27:505-510 (2005)). Gene Accession No. GI No. Organism adhE NP_415757.1 16129202 Escherichia coli adhE2 AAK09379.1 12958626 Clostridium acetobutylicum adhE AAV66076.1 55818563 Leuconostoc mesenteroides 10 Another exemplary enzyme can convert malonyl-CoA to 3-HP. An NADPH-dependent enzyme with this activity has characterized in Chloroflexus aurantiacus, where it participates in the 3 hydroxypropionate cycle (Hugler et al., J. Bacteriol. 184:2404-2410 (2002); Strauss and Fuchs, Eur. J. Biochem. 215:633-643 (1993)). This enzyme, with a mass of 300 kDa, is highly substrate-specific and shows little sequence similarity to other known oxidoreductases (Hugler 15 et al., J. Bacteriol. 184:2404-2410 (2002)). No enzymes in other organisms have been shown to catalyze this specific reaction; however there is bioinformatic evidence that other organisms may have similar pathways (Klatt et al., Environ. Microbiol. 9:2067-2078 (2007)). Enzyme candidates in other organisms including Roseiflexus castenholzii, Erythrobacter sp. NAP] and marine gamma proteobacterium HTCC2080 can be inferred by sequence similarity. Gene Accession No. GI No. Organism mcr AAS20429.1 42561982 Chloroflexus aurantiacus Rcas 2929 YP 001433009.1 156742880 Roseiflexus castenholzii NAP] 02720 ZP 01039179.1 85708113 Erythrobacter sp. NAP] MGP2080_00535 ZP_01626393.1 119504313 marine gamma proteobacterium HTCC2080 20 Longer chain acyl-CoA molecules can be reduced by enzymes such as the jojoba (Simmondsia chinensis) FAR, which encodes an alcohol-forming fatty acyl-CoA reductase. Its overexpression in E. coli resulted in FAR activity and the accumulation of fatty alcohol (Metz et al., Plant Physiol. 122:635-644 2000)).

235 Gene Accession No. GI No. Organism FAR AAD38039.1 5020215 Simmondsia chinensis 1.2.1.b Oxidoreductase (acyl-CoA to aldehyde). Step A of Figures 58, 62 and 63 involves the conversion of succinyl-CoA to succinate 5 semialdehyde by an aldehyde forming succinyl-CoA reductase. Step Q of Figure 62 depicts the conversion of 4-hydroxybutyryl-CoA to 4-hydroxybutanal by an aldehyde-forming 4 hydroxybutyryl-CoA reductase. Several acyl-CoA dehydrogenases are capable of reducing an acyl-CoA to its corresponding aldehyde. Exemplary genes that encode such enzymes include the Acinetobacter calcoaceticus acr1 encoding a fatty acyl-CoA reductase (Reiser and 10 Somerville, J. Bacteriol. 179:2969-2975 (1997)), the Acinetobacter sp. M-1 fatty acyl-CoA reductase (Ishige et al., Appl. Environ. Microbiol. 68:1192-1195 (2002)), and a CoA- and NADP- dependent succinate semialdehyde dehydrogenase encoded by the sucD gene in Clostridium kluyveri (Sohling and Gottschalk, J. Bacteriol. 178:871-80 (1996); Sohling and Gottschalk, J. Bacteriol. 178:871-880 (1996)). SucD of P. gingivalis is another aldehyde 15 forming succinyl-CoA reductase (Takahashi et al., J.Bacteriol. 182:4704-4710 (2000)). The enzyme acylating acetaldehyde dehydrogenase in Pseudomonas sp, encoded by bphG, is yet another as it has been demonstrated to oxidize and acylate acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde and formaldehyde (Powlowski et al., J. Bacteriol. 175:377-385 (1993)). In addition to reducing acetyl-CoA to ethanol, the enzyme encoded by adhE in 20 Leuconostoc mesenteroides has been shown to oxidize the branched chain compound isobutyraldehyde to isobutyryl-CoA (Koo et al., Biotechnol. Lett. 27:505-510 (2005)). Butyraldehyde dehydrogenase catalyzes a similar reaction, conversion of butyryl-CoA to butyraldehyde, in solventogenic organisms such as Clostridium saccharoperbutylacetonicum (Kosaka et al., Biosci. Biotechnol. Biochem. 71:58-68 (2007)). Gene Accession No. GI No. Organism acr1 YP_047869.1 50086359 Acinetobacter calcoaceticus acri AAC45217 1684886 Acinetobacter baylyi acr1 BAB85476.1 18857901 Acinetobacter sp. Strain M-1 sucD P38947.1 730847 Clostridium kluyveri sucD NP_904963.1 34540484 Porphyromonas gingivalis 236 bphG BAA03892.1 425213 Pseudomonas sp adhE AAV66076.1 55818563 Leuconostoc mesenteroides bld AAP42563.1 31075383 Clostridium saccharoperbutylacetonicum An additional enzyme type that converts an acyl-CoA to its corresponding aldehyde is malonyl CoA reductase, which transforms malonyl-CoA to malonic semialdehyde. Malonyl-CoA reductase is a key enzyme in autotrophic carbon fixation via the 3-hydroxypropionate cycle in thermoacidophilic archael bacteria (Berg et al., Science 318:1782-1786 (2007); Thauer, Science 5 318:1732-1733 (2007)). The enzyme utilizes NADPH as a cofactor and has been characterized in Metallosphaera and Sulfolobus spp (Alber et al., J. Bacteriol. 188:8551-8559 (2006); Hugler et al., J. Bacteriol. 184:2404-2410 (2002)). The enzyme is encoded by Msed_0709 in Metallosphaera sedula (Alber et al., J. Bacteriol. 188:8551-8559 (2006); Berg et al., Science 318:1782-1786 (2007)). A gene encoding a malonyl-CoA reductase from Sulfolobus tokodaii 10 was cloned and heterologously expressed in E. coli (Alber et al., J. Bacteriol. 188:8551-8559 (2006)). Although the aldehyde dehydrogenase functionality of these enzymes is similar to the bifunctional dehydrogenase from Chloroflexus aurantiacus, there is little sequence similarity. Both malonyl-CoA reductase enzyme candidates have high sequence similarity to aspartate semialdehyde dehydrogenase, an enzyme catalyzing the reduction and concurrent 15 dephosphorylation of aspartyl-4-phosphate to aspartate semialdehyde. Additional gene candidates can be found by sequence homology to proteins in other organisms including Sulfolobus solfataricus and Sulfolobus acidocaldarius. Yet another candidate for CoA-acylating aldehyde dehydrogenase is the ald gene from Clostridium beijerinckii (Toth et al., Appl. Environ.Microbiol. 65:4973-4980 (1999)). This enzyme has been reported to reduce acetyl 20 CoA and butyryl-CoA to their corresponding aldehydes. This gene is very similar to eutE that encodes acetaldehyde dehydrogenase of Salmonella typhimurium and E. coli (Toth et al., Appl. Environ. Microbiol. 65:4973-4980 (1999)). Gene Accession No. GI No. Organism Msed_0709 YP_001190808.1 146303492 Metallosphaera sedula mcr NP_378167.1 15922498 Sulfolobus tokodaii asd-2 NP_343563.1 15898958 Sulfolobus solfataricus Saci_2370 YP_256941.1 70608071 Sulfolobus acidocaldarius 237 Ald AAT66436 49473535 Clostridium beijerinckii eutE AAA80209 687645 Salmonella typhimurium eutE P77445 2498347 Escherichia coli 1.2.1.c Oxidoreductase (2-oxo acid to acyl-CoA, decarboxylation). Step AA in Figure 62 depicts the conversion of 5-hydroxy-2-oxopentanoic acid to 4 hydroxybutyryl-CoA. Candidate enzymes for this transformation include 1) branched-chain 2 5 keto-acid dehydrogenase, 2) alpha-ketoglutarate dehydrogenase, and 3) the pyruvate dehydrogenase multienzyme complex (PDHC). These enzymes are multi-enzyme complexes that catalyze a series of partial reactions which result in acylating oxidative decarboxylation of 2-keto-acids. Each of the 2-keto-acid dehydrogenase complexes occupies key positions in intermediary metabolism, and enzyme activity is typically tightly regulated (Fries et al. 10 Biochemistry 42:6996-7002 (2003)). The enzymes share a complex but common structure composed of multiple copies of three catalytic components: alpha-ketoacid decarboxylase (El), dihydrolipoamide acyltransferase (E2) and dihydrolipoamide dehydrogenase (E3). The E3 component is shared among all 2-keto-acid dehydrogenase complexes in an organism, while the El and E2 components are encoded by different genes. The enzyme components are present in 15 numerous copies in the complex and utilize multiple cofactors to catalyze a directed sequence of reactions via substrate channeling. The overall size of these dehydrogenase complexes is very large, with molecular masses between 4 and 10 million Da (that is, larger than a ribosome). Activity of enzymes in the 2-keto-acid dehydrogenase family is normally low or limited under anaerobic conditions in E. coli. Increased production of NADH (or NADPH) could lead to a 20 redox-imbalance, and NADH itself serves as an inhibitor to enzyme function. Engineering efforts have increased the anaerobic activity of the E. coli pyruvate dehydrogenase complex (Kim et al. Appl.Environ.Microbiol. 73:1766-1771 (2007); Kim et al. J.Bacteriol. 190:3851 3858 ) 2008); Zhou et al. Biotechnol.Lett. 30:335-342 (2008)). For example, the inhibitory effect of NADH can be overcome by engineering an H322Y mutation in the E3 component 25 (Kim et al. J.Bacteriol. 190:3851-3858 (2008)). Structural studies of individual components and how they work together in complex provide insight into the catalytic mechanisms and architecture of enzymes in this family (Aevarsson et al. Nat.Struct.Biol. 6:785-792 (1999); Zhou et al. Proc.Natl.Acad. Sci. U.S.A. 98:14802-14807 (2001)). The substrate specificity of the 238 dehydrogenase complexes varies in different organisms, but generally branched-chain keto-acid dehydrogenases have the broadest substrate range. Alpha-ketoglutarate dehydrogenase (AKGD) converts alpha-ketoglutarate to succinyl-CoA and is the primary site of control of metabolic flux through the TCA cycle (Hansford, R. G. 5 Curr. Top.Bioenerg. 10:217-278 (1980)). Encoded by genes sucA, sucB and lpd in E. coli, AKGD gene expression is downregulated under anaerobic conditions and during growth on glucose (Park et al. Mol.Microbiol. 15:473-482 (1995)). Although the substrate range of AKGD is narrow, structural studies of the catalytic core of the E2 component pinpoint specific residues responsible for substrate specificity (Knapp et al. J.Mol.Biol. 280:655-668 (1998)). The Bacillus 10 subtilis AKGD, encoded by odhAB (El and E2) and pdhD (E3, shared domain), is regulated at the transcriptional level and is dependent on the carbon source and growth phase of the organism (Resnekov et al. Mol.Gen.Genet. 234:285-296 (1992)). In yeast, the LPD1 gene encoding the E3 component is regulated at the transcriptional level by glucose (Roy and Dawes J.Gen.Microbiol. 133:925-933 (1987)). The El component, encoded by KGD1, is also regulated 15 by glucose and activated by the products of HAP2 and HAP3 (Repetto and Tzagoloff Mol. Cell Biol. 9:2695-2705 (1989)). The AKGD enzyme complex, inhibited by products NADH and succinyl-CoA, is well-studied in mammalian systems, as impaired function of has been linked to several neurological diseases (Tretter and dam-Vizi Philos. Trans.R.Soc.Lond B Biol.Sci. 360:2335-2345 (2005)). Gene Accession No. GI No. Organism sucA NP_415254.1 16128701 Escherichia coli str. K12 substr. MG1655 sucB NP_415255.1 16128702 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1 16128109 Escherichia coli str. K12 substr. MG1655 odhA P23129.2 51704265 Bacillus subtilis odhB P16263.1 129041 Bacillus subtilis pdhD P21880.1 118672 Bacillus subtilis KGD1 NP_012141.1 6322066 Saccharomyces cerevisiae KGD2 NP_010432.1 6320352 Saccharomyces cerevisiae LPD1 NP_116635.1 14318501 Saccharomyces cerevisiae 20 Branched-chain 2-keto-acid dehydrogenase complex (BCKAD), also known as 2-oxoisovalerate dehydrogenase, participates in branched-chain amino acid degradation pathways, converting 2 keto acids derivatives of valine, leucine and isoleucine to their acyl-CoA derivatives and CO 2

.

239 The complex has been studied in many organisms including Bacillus subtilis (Wang et al. Eur.J.Biochem. 213:1091-1099 (1993)), Rattus norvegicus (Namba et al. J.Biol. Chem. 244:4437-4447 (1969)) and Pseudomonas putida (Sokatch J.Bacteriol. 148:647-652 (1981)). In Bacillus subtilis the enzyme is encoded by genes pdhD (E3 component), bfmBB (E2 5 component), bfmBAA and bfmBAB (El component) (Wang et al. Eur.J.Biochem. 213:1091-1099 (1993)). In mammals, the complex is regulated by phosphorylation by specific phosphatases and protein kinases. The complex has been studied in rat hepatocites (Chicco et al. J.Biol. Chem. 269:19427-19434 (1994)) and is encoded by genes Bckdha (El alpha), Bckdhb (El beta), Dbt (E2), and Dld (E3). The El and E3 components of the Pseudomonas putida BCKAD complex 10 have been crystallized (Aevarsson et al. Nat.Struct.Biol. 6:785-792 (1999); Mattevi Science 255:1544-1550 (1992)) and the enzyme complex has been studied (Sokatch et al. J.Bacteriol. 148:647-652 (1981)). Transcription of the P. putida BCKAD genes is activated by the gene product of bkdR (Hester et al. Eur.J.Biochem 233:828-836 (1995)). In some organisms including Rattus norvegicus (Paxton et al. Biochem.J. 234:295-303 (1986)) and Saccharomyces 15 cerevisiae (Sinclair et al. Biochem.Mol.Biol.Int. 31:911-922 (1993)), this complex has been shown to have a broad substrate range that includes linear oxo-acids such as 2-oxobutanoate and alpha-ketoglutarate, in addition to the branched-chain amino acid precursors. The active site of the bovine BCKAD was engineered to favor alternate substrate acetyl-CoA (Meng and Chuang, Biochemistry 33:12879-12885 (1994)). Gene Accession No. GI No. Organism bfnBB NP_390283.1 16079459 Bacillus subtilis bfnBAA NP_390285.1 16079461 Bacillus subtilis bfnBAB NP_390284.1 16079460 Bacillus subtilis pdhD P21880.1 118672 Bacillus subtilis lpdV P09063.1 118677 Pseudomonas putida bkdB P09062.1 129044 Pseudomonas putida bkdAl NP_746515.1 26991090 Pseudomonas putida bkdA2 NP_746516.1 26991091 Pseudomonas putida Bckdha NP_036914.1 77736548 Rattus norvegicus Bckdhb NP_062140.1 158749538 Rattus norvegicus Dbt NP_445764.1 158749632 Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus 20 The pyruvate dehydrogenase complex, catalyzing the conversion of pyruvate to acetyl-CoA, has also been extensively studied. In the E. coli enzyme, specific residues in the El component are responsible for substrate specificity (Bisswanger, H. J Biol Chem. 256:815-822 (1981); Bremer, 240 J. Eur.J Biochem. 8:535-540 (1969); Gong et al. J Biol Chem. 275:13645-13653 (2000)). As mentioned previously, enzyme engineering efforts have improved the E. coli PDH enzyme activity under anaerobic conditions (Kim et al. Appl.Environ.Microbiol. 73:1766-1771 (2007); Kim J.Bacteriol. 190:3851-3858 (2008); Zhou et al. Biotechnol.Lett. 30:335-342 (2008)). In 5 contrast to the E. coli PDH, the B. subtilis complex is active and required for growth under anaerobic conditions (Nakano J.Bacteriol. 179:6749-6755 (1997)). The Klebsiella pneumoniae PDH, characterized during growth on glycerol, is also active under anaerobic conditions (Menzel et al. J.Biotechnol. 56:135-142 (1997)). Crystal structures of the enzyme complex from bovine kidney (Zhou et al. Proc.Natl.Acad.Sci. U.S.A. 98:14802-14807 (2001)) and the E2 10 catalytic domain from Azotobacter vinelandii are available (Mattevi et al. Science 255:1544 1550 (1992)). Some mammalian PDH enzymes complexes can react on alternate substrates such as 2-oxobutanoate, although comparative kinetics of Rattus norvegicus PDH and BCKAD indicate that BCKAD has higher activity on 2-oxobutanoate as a substrate (Paxton et al. Biochem.J. 234:295-303 (1986)). Gene Accession No. GI No. Organism aceE NP_414656.1 16128107 Escherichia coli str. K12 substr. MG1655 aceF NP_414657.1 16128108 Escherichia coli str. K12 substr. MG1655 lpd NP_414658.1 16128109 Escherichia coli str. K12 substr. MG1655 pdhA P21881.1 3123238 Bacillus subtilis pdhB P21882.1 129068 Bacillus subtilis pdhC P21883.2 129054 Bacillus subtilis pdhD P21880.1 118672 Bacillus subtilis aceE YP_001333808.1 152968699 Klebsiella pneumonia MGH78578 aceF YP_001333809.1 152968700 Klebsiella pneumonia MGH78578 /pdA YP_001333810.1 152968701 Klebsiella pneumonia MGH78578 Pdhal NP_001004072.2 124430510 Rattus norvegicus Pdha2 NP_446446.1 16758900 Rattus norvegicus Dlat NP_112287.1 78365255 Rattus norvegicus Dld NP_955417.1 40786469 Rattus norvegicus 15 As an alternative to the large multienzyme 2-keto-acid dehydrogenase complexes described above, some anaerobic organisms utilize enzymes in the 2-ketoacid oxidoreductase family (OFOR) to catalyze acylating oxidative decarboxylation of 2-keto-acids. Unlike the 241 dehydrogenase complexes, these enzymes contain iron-sulfur clusters, utilize different cofactors, and use ferredoxin or flavodixin as electron acceptors in lieu of NAD(P)H. While most enzymes in this family are specific to pyruvate as a substrate (POR) some 2-keto-acid:ferredoxin oxidoreductases have been shown to accept a broad range of 2-ketoacids as substrates including 5 alpha-ketoglutarate and 2-oxobutanoate (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2002); Zhang et al. J.Biochem. 120:587-599 (1996)). One such enzyme is the OFOR from the thermoacidophilic archaeon Sulfolobus tokodaii 7, which contains an alpha and beta subunit encoded by gene ST2300 (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2002); Zhang et al. J.Biochem. 120:587-599 (1996)). A plasmid-based expression system has been developed 10 for efficiently expressing this protein in E. coli ( Fukuda et al. Eur.J.Biochem. 268:5639 5646 (2001)) and residues involved in substrate specificity were determined (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2002)). Two OFORs from Aeropyrum pernix str. K1 have also been recently cloned into E. coli, characterized, and found to react with a broad range of 2-oxoacids (Nishizawa et al. FEBS Lett. 579:2319-2322 (2005)). The gene sequences 15 of these OFOR candidates are available, although they do not have GenBank identifiers assigned to date. There is bioinformatic evidence that similar enzymes are present in all archaea, some anaerobic bacteria and amitochondrial eukarya (Fukuda and Wakagi Biochim.Biophys.Acta 1597:74-80 (2005)). This class of enzyme is also interesting from an energetic standpoint, as reduced ferredoxin could be used to generate NADH by ferredoxin-NAD reductase 20 (Petitdemange et al. Biochim.Biophys.Acta 421:334-337 (1976)). Also, since most of the enzymes are designed to operate under anaerobic conditions, less enzyme engineering may be required relative to enzymes in the 2-keto-acid dehydrogenase complex family for activity in an anaerobic environment. Gene Accession No. GI No. Organism ST2300 NP_378302.1 15922633 Sulfolobus tokodaii 7 25 1.2.1.d Oxidoreductase (phosphonate reductase). The conversion of 4-hydroxybutyryl-phosphate to 4-hydroxybutanal can be catalyzed by an oxidoreductase in the EC class 1.2.1. Aspartate semialdehyde dehydrogenase (ASD, EC 1.2.1.11) catalyzes the NADPH-dependent reduction of 4-aspartyl phosphate to aspartate-4 semialdehyde. ASD participates in amino acid biosynthesis and recently has been studied as an 30 antimicrobial target (Hadfield et al., Biochemistry 40:14475-14483 (2001). The E. coli ASD structure has been solved (Hadfield et al.,. J. Mol. Biol. 289:991-1002 (1999)) and the enzyme has been shown to accept the alternate substrate beta-3-methylaspartyl phosphate (Shames et al., 242 J. Biol. Chem. 259:15331-15339 (1984)). The Haemophilus influenzae enzyme has been the subject of enzyme engineering studies to alter substrate binding affinities at the active site (Blanco et al., Acta Crystallogr. D. Biol. Crystallogr. 60:1388-1395 (2004); Blanco et al., Acta Crystallogr. D. Biol. Crystallogr. 60:1808-1815 (2004)). Other ASD candidates are found in 5 Mycobacterium tuberculosis (Shafiani et al., J. Apple. Microbiol. 98:832-838 (2005), Methanococcusjannaschii (Faehnle et al.,. J. Mol. Biol. 353:1055-1068 (2005)), and the infectious microorganisms Vibrio cholera and Heliobacter pylori (Moore et al., Protein Expr. Purif 25:189-194 (2002)). A related enzyme candidate is acetylglutamylphosphate reductase (EC 1.2.1.38), an enzyme that naturally reduces acetylglutamylphosphate to acetylglutamate-5 10 semialdehyde, found in S. cerevisiae (Pauwels et al., Eur. J. Biochem. 270:1014-1024 (2003), B. subtilis (O'Reilly and Devine, Microbiology 140 ( Pt 5):1023-1025 (1994)). and other organisms. Gene Accession No. GI No. Organism asd NP_417891.1 16131307 Escherichia coli asd YP 248335.1 68249223 Haemophilus influenzae asd AAB49996 1899206 Mycobacterium tuberculosis VC2036 NP 231670 15642038 Vibrio cholera asd YP 002301787.1 210135348 Heliobacterpylori ARG5,6 NP 010992.1 6320913 Saccharomyces cerevisiae argC NP 389001.1 16078184 Bacillus subtilis Other exemplary enzymes in this class include glyceraldehyde 3-phosphate dehydrogenase 15 which converts glyceraldehyde-3-phosphate into D-glycerate 1,3-bisphosphate (for example, E. coli gapA (Branlant and Branlant,. Eur. J. Biochem. 150:61-66 (1985)), N-acetyl-gamma glutamyl-phosphate reductase which converts N-acetyl-L-glutamate-5-semialdehyde into N acetyl-L-glutamyl-5-phosphate (for example, E. coli argC (Parsot et al., Gene 68:275-283 (1988)), and glutamate-5-semialdehyde dehydrogenase, which converts L-glutamate-5 20 semialdehyde into L-glutamyl-5 -phospate (for example, E. coli proA (Smith et al., J. Bacteriol. 157:545-551 (1984)). Genes encoding glutamate-5-semialdehyde dehydrogenase enzymes from Salmonella typhimurium (Mahan and Csonka, J. Bacteriol. 156:1249-1262 (1983)) and Campylobacterjejuni (Louie and Chan, Mol. Gen. Genet. 240:29-35 (1993)) were cloned and expressed in E. coli. Gene Accession No. GI No. Organism gapA POA9B2.2 71159358 Escherichia coli argC NP 418393.1 16131796 Escherichia coli proA NP 414778.1 16128229 Escherichia coli 243 proA NP_459319.1 16763704 Salmonella typhimurium proA P53000.2 9087222 Campylobacterjejuni 1.2.1.e Acid reductase. Several steps in Figures 58, 62 and 63 depict the conversion of unactivated acids to aldehydes by an acid reductase. These include the conversion of 4-hydroxybutyrate, succinate, alpha 5 ketoglutarate, and 4-aminobutyrate to 4-hydroxybutanal, succinate semialdehyde, 2,5 dioxopentanoate, and 4-aminobutanal, respectively. One notable carboxylic acid reductase can be found in Nocardia iowensis which catalyzes the magnesium, ATP and NADPH-dependent reduction of carboxylic acids to their corresponding aldehydes (Venkitasubramanian et al., J. Biol. Chem. 282:478-485 (2007)). This enzyme is encoded by the car gene and was cloned and 10 functionally expressed in E. coli (Venkitasubramanian et al., J. Biol. Chem. 282:478-485 (2007)). Expression of the npt gene product improved activity of the enzyme via post transcriptional modification. The npt gene encodes a specific phosphopantetheine transferase (PPTase) that converts the inactive apo-enzyme to the active holo-enzyme. The natural substrate of this enzyme is vanillic acid, and the enzyme exhibits broad acceptance of aromatic and 15 aliphatic substrates (Venkitasubramanian et al., in Biocatalysis in the Pharmaceutical and Biotechnology Industires, ed. R.N. Patel, Chapter 15, pp. 425-440, CRC Press LLC, Boca Raton, FL. (2006)). Gene Accession No. GI No. Organism Nocardia iowensis (sp. NRRL car AAR91681.1 40796035 5646) Nocardia iowensis (sp. NRRL npt AB183656.1 114848891 5646) Additional car and npt genes can be identified based on sequence homology. Gene Accession No. GI No. Organism fadD9 YP_978699.1 121638475 Mycobacterium bovis BCG BCG_2812c YP_978898.1 121638674 Mycobacterium bovis BCG nfa20150 YP_118225.1 54023983 Nocardiafarcinica IFM 10152 nfa40540 YP_120266.1 54026024 Nocardiafarcinica IFM 10152 Streptomyces griseus subsp. SGR_6790 YP_001828302.1 182440583 griseus NBRC 13350 Streptomyces griseus subsp. SGR 665 YP_001822177.1 182434458 griseus NBRC 13350 20 244 An additional enzyme candidate found in Streptomyces griseus is encoded by the griC and griD genes. This enzyme is believed to convert 3-amino-4-hydroxybenzoic acid to 3-amino-4 hydroxybenzaldehyde as deletion of either griC or griD led to accumulation of extracellular 3 acetylamino-4-hydroxybenzoic acid, a shunt product of 3-amino-4-hydroxybenzoic acid 5 metabolism (Suzuki, et al., J. Antibiot. 60(6):380-387 (2007)). Co-expression of griC and griD with SGR_665, an enzyme similar in sequence to the Nocardia iowensis npt, can be beneficial. Gene Accession No. GI No. Organism Streptomyces griseus griC 182438036 YP_001825755.1 subsp. griseus NBRC 13350 Streptomyces griseus griD 182438037 YP_001825756.1 subsp. griseus NBRC 13350 Mycobacterium smegmatis MSMEG_2956 YP_887275.1 YP_887275.1 MC2 155 MSMEG_5739 YP_889972.1 118469671 Mycobactun smegmatis MSMEG_2648 YP_886985.1 118471293 Mycobacterium smegmatis SMC2 155 Mycobacterium avium MAP1040c NP_959974.1 41407138 subsp. paratuberculosis K 10 Mycobacterium avium MAP2899c NP_961833.1 41408997 subsp. paratuberculosis K 10 MMAR_2117 YP_001850422.1 183982131 Mycobacterium marinum M MMAR_2936 YP 001851230.1 183982939 Mycobacterium marinum M MMAR_1916 YP_001850220.1 183981929 Mycobacterium marinum M Tsukamurella TpauDRAFT_33060 ZP_04027864.1 227980601 paurometabola DSM 20162 Tsukamurella TpauDRAFT_20920 ZP_04026660.1 227979396 paurometabola DSM 20162 CPCC7001_1320 ZP 05045132.1 254431429 Cyanobium PCC7001 DDBDRAFT_0187729 XP_636931.1 66806417 Dictyostelium discoideum _______________ AX4 An enzyme with similar characteristics, alpha-aminoadipate reductase (AAR, EC 1.2.1.3 1), 10 participates in lysine biosynthesis pathways in some fungal species. This enzyme naturally reduces alpha-aminoadipate to alpha-aminoadipate semialdehyde. The carboxyl group is first 245 activated through the ATP-dependent formation of an adenylate that is then reduced by NAD(P)H to yield the aldehyde and AMP. Like CAR, this enzyme utilizes magnesium and requires activation by a PPTase. Enzyme candidates for AAR and its corresponding PPTase are found in Saccharomyces cerevisiae (Morris et al., Gene 98:141-145 (1991)), Candida albicans 5 (Guo et al., Mol. Genet. Genomics 269:271-279 (2003)), and Schizosaccharomyces pombe (Ford et al., Curr. Genet. 28:131-137 (1995)). The AAR from S. pombe exhibited significant activity when expressed in E. coli (Guo et al., Yeast 21:1279-1288 (2004)). The AAR from Penicillium chrysogenum accepts S-carboxymethyl-L-cysteine as an alternate substrate, but did not react with adipate, L-glutamate or diaminopimelate (Hijarrubia et al., J. Biol. Chem. 278:8250-8256 10 (2003)). The gene encoding the P. chrysogenum PPTase has not been identified to date. Gene Accession No. GI No. Organism LYS2 AAA34747.1 171867 Saccharomyces cerevisiae LYS5 P50113.1 1708896 Saccharomyces cerevisiae LYS2 AAC02241.1 2853226 Candida albicans LYS5 AA026020.1 28136195 Candida albicans LysIp P40976.3 13124791 Schizosaccharomyces pombe Lys7p Q10474.1 1723561 Schizosaccharomyces pombe Lys2 CAA74300.1 3282044 Penicillium chrysogenum 1.4.1.a Oxidoreductase (aminating). Glutamate dehydrogenase (Step J, Figures 62 and 63), 4-aminobutyrate dehydrogenase (Step M, Figures 62 and 63), putrescine dehydrogenase (Step D, Figure 63), 5-amino-2-oxopentanoate 15 dehydrogenase (Step P, Figure 63), and ornithine dehydrogenase (Step S, Figure 63) can be catalyzed by aminating oxidoreductases. Enzymes in this EC class catalyze the oxidative deamination of alpha-amino acids with NAD+ or NADP+ as acceptor, and the reactions are typically reversible. Exemplary oxidoreductases operating on amino acids include glutamate dehydrogenase (deaminating), encoded by gdhA, leucine dehydrogenase (deaminating), encoded 20 by ldh, and aspartate dehydrogenase (deaminating), encoded by nadX. The gdhA gene product from Escherichia coli (Korber et al., J. Mol. Biol. 234:1270-1273 (1993); McPherson and Wootton, Nucleic Acids Res. 11:5257-5266 (1983)), gdh from Thermotoga maritima (Kort et al., Extremophiles 1:52-60 (1997); Lebbink, et al. J. Mol. Biol. 280:287-296 (1998); Lebbink et al. J. Mol. Biol. 289:357-369 (1999)), and gdhA1 from Halobacterium salinarum (Ingoldsby et al., 25 Gene 349:237-244 (2005)) catalyze the reversible interconversion of glutamate to 2-oxoglutarate and ammonia, while favoring NADP(H), NAD(H), or both, respectively. The ldh gene of Bacillus cereus encodes the LeuDH protein that has a wide of range of substrates including 246 leucine, isoleucine, valine, and 2-aminobutanoate (Ansorge and Kula, Biotechnol. Bioeng. 68:557-562 (2000); Stoyan et al. J. Biotechnol. 54:77-80 (1997)). The nadX gene from Thermotoga maritime encoding for the aspartate dehydrogenase is involved in the biosynthesis of NAD (Yang et al., J. Biol. Chem. 278:8804-8808 (2003)). 5 Gene Accession No. GI No. Organism gdhA P00370 118547 Escherichia coli gdh P96110.4 6226595 Thermotoga maritima gdhA1 NP 279651.1 15789827 Halobacterium salinarum ldh P0A393 61222614 Bacillus cereus nadX NP 229443.1 15644391 Thermotoga maritima Additional glutamate dehydrogenase gene candidates are found in Bacillus subtilis (Khan et al., Biosci. Biotechnol. Biochem. 69:1861-1870 (2005)), Nicotiana tabacum (Purnell et al., Planta 222:167-180 (2005)), Oryza sativa (Abiko et al., Plant Cell Physiol. 46:1724-1734 (2005)), 10 Haloferax mediterranei (Diaz et al., Extremophiles 10: 105-115 (2006)) and Halobactreium salinarum (Hayden et al., FEMS Microbiol. Lett 211:37-41 (2002)). The Nicotiana tabacum enzyme is composed of alpha and beta subunits encoded by gdh1 and gdh2 (Purnell et al., Planta 222:167-180 (2005)). Overexpression of the NADH-dependent glutamate dehydrogenase was found to improve ethanol production in engineered strains of S. cerevisiae 15 (Roca et al., Appl. Environ. Microbiol. 69:4732-4736 (2003)). Gene Accession No. GI No. Organism rocG NP 391659.1 16080831 Bacillus subtilis gdh1 AAR11534.1 38146335 Nicotiana tabacum gdh2 AAR11535.1 38146337 Nicotiana tabacum GDH Q852M0 75243660 Oryza sativa GDH Q977U6 74499858 Haloferax mediterranei GDH P29051 118549 Halobactreium salinarum GDH2 NP 010066.1 6319986 Saccharomyces cerevisiae An exemplary enzyme for catalyzing the conversion of aldehydes to their corresponding primary amines is lysine 6-dehydrogenase (EC 1.4.1.18), encoded by the lysDH genes. The lysine 6 dehydrogenase (deaminating), encoded by lysDH gene, catalyze the oxidative deamination of 20 the E-amino group of L-lysine to form 2-aminoadipate-6-semialdehyde, which in turn nonenzymatically cyclizes to form Al-piperideine-6-carboxylate (Misono and Nagasaki, J. Bacteriol. 150:398-401 (1982)). The lysDH gene from Geobacillus stearothermophilus encodes a thermophilic NAD-dependent lysine 6-dehydrogenase (Heydari et al., Appl. Environ. Microbiol 70:937-942 (2004)). The lysDH gene from Aeropyrum pernix K1 is identified 247 through homology from genome projects. Additional enzymes can be found in Agrobacterium tumefaciens (Hashimoto et al., J. Biochem. 106:76-80 (1989); Misono and Nagasaki, J. Bacteriol. 150:398-401 (1982)) and Achromobacter denitrificans (Ruldeekulthamrong et al., BMB. Rep. 41:790-795 (2008)). Gene Accession No. GI No. Organism lysDH BAB39707 13429872 Geobacillus stearothermophilus lysDH NP 147035.1 14602185 Aeropyrum pernix K1 lysDH NP_353966 15888285 Agrobacterium tumefaciens lysDH AAZ94428 74026644 Achromobacter denitrificans 5 An enzyme that converts 3-oxoacids to 3-amino acids is 3,5-diaminohexanoate dehydrogenase (EC 1.4.1.11), an enzyme found in organisms that ferment lysine. The gene encoding this enzyme, kdd, was recently identified in Fusobacterium nucleatum (Kreimeyer et al., J. Biol. Chem. 282:7191-7197 (2007)). The enzyme has been purified and characterized in other 10 organisms (Baker et al., J. Biol. Chem. 247:7724-7734 (1972); Baker and and van der Drift, Biochemistry 13:292-299 (1974)), but the genes associated with these enzymes are not known. Candidates in Myxococcus xanthus, Porphyromonas gingivalis W83 and other sequenced organisms can be inferred by sequence homology. Gene Accession No. GI No. Organism kdd AAL93966.1 19713113 Fusobacterium nucleatum mxan_4391 ABF87267.1 108462082 Myxococcus xanthus pg_1069 AAQ66183.1 34397119 Porphyromonas gingivalis 15 2.3.1.a Acyltransferase (transferring phosphate group to CoA). Step P of Figure 62 depicts the transformation of 4-hydroxybutyryl-CoA to 4-hydroxybutyryl Pi. Exemplary phosphate transferring acyltransferases include phosphotransacetylase, encoded by pta, and phosphotransbutyrylase, encoded by ptb. The pta gene from E. coli encodes an enzyme that can convert acetyl-CoA into acetyl-phosphate, and vice versa (Suzuki, Biochim. 20 Biophys. Acta 191:559-569 (1969)). This enzyme can also utilize propionyl-CoA instead of acetyl-CoA forming propionate in the process (Hesslinger et al., Mol. Microbiol. 27:477-492 (1998)). Similarly, the ptb gene from C. acetobutylicum encodes an enzyme that can convert butyryl-CoA into butyryl-phosphate (Walter et al., Gene 134:107-111 (1993)); Huang et al., J Mol. Microbiol. Biotechno.l 2:33-38 (2000). Additional ptb genes can be found in butyrate 25 producing bacterium L2-50 (Louis et al., J.Bacteriol. 186:2099-2106 (2004)) and Bacillus megaterium (Vazquez et al., Curr. Microbiol. 42:345-349 (2001)).

248 Gene Accession No. GI No. Organism pta NP 416800.1 16130232 Escherichia coli ptb NP 349676 15896327 Clostridium acetobutylicum ptb AAR19757.1 38425288 butyrate-producing bacterium L2-50 ptb CAC07932.1 10046659 Bacillus megaterium 2.6.1. Aminotransferase. Aminotransferases reversibly convert an aldehyde or ketone to an amino group. Common amino donor/acceptor combinations include glutamate/alpha-ketoglutarate, alanine/pyruvate, 5 and aspartate/oxaloacetate. Several enzymes have been shown to convert aldehydes to primary amines, and vice versa, such as 4-aminobutyrate, putrescine, and 5-amino-2-oxopentanoate. These enzymes are particularly well suited to carry out the following transformations: Step N in Figures 62 and 63, Steps E and Q in Figure 63. Lysine-6-aminotransferase (EC 2.6.1.36) is one exemplary enzyme capable of forming a primary amine. This enzyme function, converting 10 lysine to alpha-aminoadipate semialdehyde, has been demonstrated in yeast and bacteria. Candidates from Candida utilis (Hammer and Bode, J. Basic Microbiol. 32:21-27 (1992)), Flavobacterium lutescens (Fujii et al., J. Biochem. 128:391-397 (2000)) and Streptomyces clavuligenus (Romero et al., J. Ind. Microbiol. Biotechnol. 18:241-246 (1997)) have been characterized. A recombinant lysine-6-aminotransferase from S. clavuligenus was functionally 15 expressed in E. coli (Tobin et al., J. Bacteriol. 173:6223-6229 (1991)). The F. lutescens enzyme is specific to alpha-ketoglutarate as the amino acceptor (Soda and Misono, Biochemistry 7:4110 4119 (1968)). Other enzymes which convert aldehydes to terminal amines include the dat gene product in Acinetobacter baumanii encoding 2,4-diaminobutanoate:2-ketoglutarate 4 transaminase (Ikai and Yamamoto, J. Bacteriol. 179:5118-5125 (1997)). In addition to its 20 natural substrate, 2,4-diaminobutyrate, DAT transaminates the terminal amines of lysine, 4 aminobutyrate and ornithine. Gene Accession No. GI No. Organism lat BAB13756.1 10336502 Flavobacterium lutescens lat AAA26777.1 153343 Streptomyces clavuligenus dat P56744.1 6685373 Acinetobacter baumanii The conversion of an aldehyde to a terminal amine can also be catalyzed by gamma aminobutyrate transaminase (GABA transaminase or 4-aminobutyrate transaminase). This 25 enzyme naturally interconverts succinic semialdehyde and glutamate to 4-aminobutyrate and alpha-ketoglutarate and is known to have a broad substrate range (Liu et al., Biochemistry 43:10896-10905 2004); Schulz et al., Appl. Environ. Microbiol. 56:1-6 (1990)). The two GABA 249 transaminases in E. coli are encoded by gabT (Bartsch et al., J. Bacteriol. 172:7035-7042 (1990)) and puuE (Kurihara et al., J. Biol. Chem. 280:4602-4608. (2005)). GABA transaminases in Mus musculus, Pseudomonasfluorescens, and Sus scrofa have been shown to react with a range of alternate substrates including 6-aminocaproic acid (Cooper, Methods 5 Enzymol. 113:80-82 (1985); Scott and Jakoby, J. Biol. Chem. 234:932-936 (1959)). Gene Accession No. GI No. Organism gabT NP 417148.1 16130576 Escherichia coli puuE NP 415818.1 16129263 Escherichia coli abat NP 766549.2 37202121 Mus musculus gabT YP 257332.1 70733692 Pseudomonasfluorescens abat NP 999428.1 47523600 Sus scrofa Additional enzyme candidates for interconverting aldehydes and primary amines are putrescine transminases or other diamine aminotransferases. The E. coli putrescine aminotransferase is encoded by the ygjG gene, and the purified enzyme also was able to transaminate cadaverine and 10 spermidine (Samsonova et al., BMC Microbiol. 3:2 (2003)). In addition, activity of this enzyme on 1,7-diaminoheptane and with amino acceptors other than 2-oxoglutarate (for example, pyruvate, 2-oxobutanoate) has been reported (Kim, J. Biol. Chem. 239:783-786 (1964); Samsonova et al., BMC Microbiol. 3:2 (2003)). A putrescine aminotransferase with higher activity with pyruvate as the amino acceptor than alpha-ketoglutarate is the spuC gene of 15 Pseudomonas aeruginosa (Lu et al., J. Bacteriol. 184:3765-3773 (2002)). Gene Accession No. GI No. Organism ygjG NP_417544 145698310 Escherichia coli spuC AAG03688 9946143 Pseudomonas aeruginosa Enzymes that transaminate 3-oxoacids include GABA aminotransferase (described above), beta alanine/alpha-ketoglutarate aminotransferase and 3-amino-2-methylpropionate aminotransferase. Beta-alanine/alpha-ketoglutarate aminotransferase (WO08027742) reacts with beta-alanine to 20 form malonic semialdehyde, a 3-oxoacid. The gene product of SkPYD4 in Saccharomyces kluyveri was shown to preferentially use beta-alanine as the amino group donor (Andersen and Hansen, Gene 124:105-109 (1993)). SkUGA1 encodes a homologue of Saccharomyces cerevisiae GABA aminotransferase, UGA1 (Ramos et al., Eur. J. Biochem. 149:401-404 (1985)), whereas SkPYD4 encodes an enzyme involved in both beta-alanine and GABA 25 transamination (Andersen and Hansen, Gene 124:105-109 (1993)). 3-Amino-2 methylpropionate transaminase catalyzes the transformation from methylmalonate semialdehyde to 3-amino-2-methylpropionate. The enzyme has been characterized in Rattus norvegicus and 250 Sus scrofa and is encoded by Abat (Kakimoto et al., Biochim. Biophys. Acta 156:374-380 (1968); Tamaki et al., Methods Enzymol. 324:376-389 (2000)). Gene Accession No. GI No. Organism SkyPYD4 ABF58893.1 98626772 Lachancea kluyveri SkUGA] ABF58894.1 98626792 Lachancea kluyveri UGA1 NP 011533.1 6321456 Saccharomyces cerevisiae Abat P50554.3 122065191 Rattus norvegicus Abat P80147.2 120968 Sus scrofa Several aminotransferases transaminate the amino groups of amino acids to form 2-oxoacids. 5 Aspartate aminotransferase is an enzyme that naturally transfers an oxo group from oxaloacetate to glutamate, forming alpha-ketoglutarate and aspartate. Aspartate is similar in structure to OHED and 2-AHD. Aspartate aminotransferase activity is catalyzed by, for example, the gene products of aspC from Escherichia coli (Yagi et al., FEBS Lett. 100:81-84 (1979); Yagi et al., Methods Enzymol. 113:83-89 (1985)), AAT2 from Saccharomyces cerevisiae (Yagi et al., J. 10 Biochem. 92:35-43 (1982)) and ASP5 from Arabidopsis thaliana (de la Torre et al., Plant J. 46:414-425 (2006); Kwok and Hanson. J. Exp. Bot. 55:595-604 (2004); Wilkie and Warren, Protein Expr. Purif 12:381-389 (1998)). The enzyme from Rattus norvegicus has been shown to transaminate alternate substrates such as 2-aminohexanedioic acid and 2,4-diaminobutyric acid (Recasens et al., Biochemistry 19:4583-4589 (1980)). Aminotransferases that work on 15 other amino-acid substrates can also be able to catalyze this transformation. Valine aminotransferase catalyzes the conversion of valine and pyruvate to 2-ketoisovalerate and alanine. The E. coli gene, avtA, encodes one such enzyme (Whalen and Berg, J. Bacteriol. 150:739-746 (1982)). This gene product also catalyzes the transamination of a-ketobutyrate to generate a-aminobutyrate, although the amine donor in this reaction has not been identified 20 (Whalen and Berg, J. Bacteriol. 158:571-574 1984)). The gene product of the E. coli serC catalyzes two reactions, phosphoserine aminotransferase and phosphohydroxythreonine aminotransferase (Lam and Winkler, J. Bacteriol. 172:6518-6528 (1990)), and activity on non phosphorylated substrates could not be detected (Drewke et al., FEBS Lett. 390:179-182 (1996)). Gene Accession No. GI No. Organism aspC NP 415448.1 16128895 Escherichia coli A AT2 P23542.3 1703040 Saccharomyces cerevisiae ASP5 P46248.2 20532373 Arabidopsis thaliana Got2 P00507 112987 Rattus norvegicus avtA YP 026231.1 49176374 Escherichia coli serC NP_415427.1 16128874 Escherichia coli 251 Another enzyme candidate is alpha-aminoadipate aminotransferase (EC 2.6.1.39), an enzyme that participates in lysine biosynthesis and degradation in some organisms. This enzyme interconverts 2-aminoadipate and 2-oxoadipate, using alpha-ketoglutarate as the amino acceptor. Gene candidates are found in Homo sapiens (Okuno et al., Enzyme Protein 47:136-148 (1993)) 5 and Thermus thermophilus (Miyazaki et al., Microbiology 150:2327-2334 (2004)). The Thermus thermophilus enzyme, encoded by lysN, is active with several alternate substrates including oxaloacetate, 2-oxoisocaproate, 2-oxoisovalerate, and 2-oxo-3-methylvalerate. Gene Accession No. GI No. Organism lysN BAC76939.1 31096548 Thermus thermophilus AadAT-II Q8N5ZO.2 46395904 Homo sapiens 2.7.2.a Phosphotransferase (carboxy acceptor). 10 Phosphotransferase enzymes in the EC class 2.7.2 transform carboxylic acids to phosphonic acids with concurrent hydrolysis of one ATP. Step 0 of Figure 62 involves the conversion of 4 hydroxybutyrate to 4-hydroxybutyryl-phosphate by such an enzyme. Butyrate kinase (EC 2.7.2.7) carries out the reversible conversion of butyryl-phosphate to butyrate during acidogenesis in C. acetobutylicum (Cary et al., Appl. Environ. Microbiol. 56:1576-1583 (1990)). 15 This enzyme is encoded by either of the two buk gene products (Huang et al., J. Mol. Microbiol. Biotechnol. 2:33-38 (2000)). Other butyrate kinase enzymes are found in C. butyricum and C. tetanomorphum (Twarog and Wolfe, J. Bacteriol. 86:112-117 (1963)). Related enzyme isobutyrate kinase from Thermotoga maritima has also been expressed in E. coli and crystallized (Diao et al., Acta Crystallogr. D. Biol. Crystallogr. 59:1100-1102 (2003); Diao and Hasson, J. 20 Bacteriol. 191:2521-2529 (2009)). Aspartokinase catalyzes the ATP-dependent phosphorylation of aspartate and participates in the synthesis of several amino acids. The aspartokinase III enzyme in E. coli, encoded by lysC, has a broad substrate range, and the catalytic residues involved in substrate specificity have been elucidated (Keng and Viola, Arch. Biochem. Biophys. 335:73-81 (1996)). Two additional kinases in E. coli are also good candidates: acetate kinase 25 and gamma-glutamyl kinase. The E. coli acetate kinase, encoded by ackA (Skarstedt and Silverstein, J. Biol. Chem. 251:6775-6783 (1976)), phosphorylates propionate in addition to acetate (Hesslinger et al., Mol. Microbiol. 27:477-492 (1998)). The E. coli gamma-glutamyl kinase, encoded by proB (Smith et al., J. Bacteriol. 157:545-551 (1984)), phosphorylates the gamma carbonic acid group of glutamate.

252 Gene Accession No. GI No. Organism buki NP 349675 15896326 Clostridium acetobutylicum buk2 Q97111 20137415 Clostridium acetobutylicum buk2 Q9X278.1 6685256 Thermotoga maritima lysC NP 418448.1 16131850 Escherichia coli ackA NP 416799.1 16130231 Escherichia coli proB NP 414777.1 16128228 Escherichia coli Acetylglutamate kinase phosphorylates acetylated glutamate during arginine biosynthesis. This enzyme is not known to accept alternate substrates; however, several residues of the E. coli 5 enzyme involved in substrate binding and phosphorylation have been elucidated by site-directed mutagenesis (Marco-Marin et al., J. Mol. Biol. 334:459-476 (2003); Ramon-Maiques et al., Structure 10:329-342 (2002)). The enzyme is encoded by argB in Bacillus subtilis and E. coli (Parsot et al., Gene 68:275-283 (1988)), and ARG5,6 in S. cerevisiae (Pauwels et al., Eur. J. Biochem. 270:1014-1024 (2003)). The ARG5,6 gene of S. cerevisiae encodes a polyprotein 10 precursor that is matured in the mitochondrial matrix to become acetylglutamate kinase and acetylglutamylphosphate reductase. Gene Accession No. GI No. Organism argB NP_418394.3 145698337 Escherichia coli argB NP_389003.1 16078186 Bacillus subtilis ARG5,6 NP_010992.1 6320913 Saccharomyces cerevisiae 2.8.3.a CoA transferase. The gene products of cat], cat2, and cat3 of Clostridium kluyveri have been shown to exhibit 15 succinyl-CoA (Step G, Figures 62 and 63), 4-hydroxybutyryl-CoA (Step T, Figure 62), and butyryl-CoA acetyltransferase activity, respectively (Seedorf et al., Proc. Natl. Acad. Sci. USA 105:2128-2133 (2008); Sohling and Gottschalk, JBacteriol 178:871-880 (1996)). Similar CoA transferase activities are also present in Trichomonas vaginalis (van Grinsven et al., J. Biol. Chem. 283:1411-1418 (2008)) and Trypanosoma brucei (Riviere et al., J. Biol. Chem. 20 279:45337-45346 (2004)). Gene Accession No. GI No. Organism cat] P38946.1 729048 Clostridium kluyveri cat2 P38942.2 1705614 Clostridium kluyveri cat3 EDK35586.1 146349050 Clostridium kluyveri TVAG_395550 XP_001330176 123975034 Trichomonas vaginalis G3 Tb11.02.0290 XP 828352 71754875 Trypanosoma brucei 253 An additionally useful enzyme for this type of transformation is acyl-CoA:acetate-CoA transferase, also known as acetate-CoA transferase (EC 2.8.3.8), which has been shown to transfer the CoA moiety to acetate from a variety of branched and linear acyl-CoA substrates, including isobutyrate (Matthies and Schink, Appl. Environ. Microbiol. 58:1435-1439 (1992)), 5 valerate (Vanderwinkel et al., Biochem. Biophys. Res. Commun. 33:902-908 (1968)) and butanoate (Vanderwinkel, supra (1968)). This enzyme is encoded by atoA (alpha subunit) and atoD (beta subunit) in E. coli sp. K12 (Korolev et al., Acta Crystallogr. D Biol. Crystallogr. 58:2116-2121 (2002); Vanderwinkel, supra (1968)). Similar enzymes exist in Corynebacterium glutamicum ATCC 13032 (Duncan et al., Appl. Environ. Microbiol. 68:5186-5190 (2002)), 10 Clostridium acetobutylicum (Cary et al., Appl. Environ. Microbiol. 56:1576-1583 (1990); Wiesenborn et al., Appl. Environ. Microbiol. 55:323-329 (1989)), and Clostridium saccharoperbutylacetonicum (Kosaka et al., Biosci. Biotechnol. Biochem. 71:58-68 (2007)). Gene Accession No. GI No. Organism atoA P76459.1 2492994 Escherichia coli K12 atoD P76458.1 2492990 Escherichia coli K12 actA YP_226809.1 62391407 Corynebacterium glutamicum cg0592 YP_224801.1 62389399 Corynebacterium glutamicum ctfA NP_149326.1 15004866 Clostridium acetobutylicum ctfB NP_149327.1 15004867 Clostridium acetobutylicum ctfA AAP42564.1 31075384 Clostridium saccharoperbutylacetonicum ctfB AAP42565.1 31075385 Clostridium saccharoperbutylacetonicum The glutaconate-CoA-transferase (EC 2.8.3.12) enzyme from anaerobic bacterium 15 Acidaminococcusfermentans reacts with diacid glutaconyl-CoA and 3-butenoyl-CoA (Mack and Buckel, FEBS Lett. 405:209-212 (1997)). The genes encoding this enzyme are gctA and gctB. This enzyme has reduced but detectable activity with other CoA derivatives including glutaryl CoA, 2-hydroxyglutaryl-CoA, adipyl-CoA and acrylyl-CoA (Buckel et al., Eur. J. Biochem. 118:315-321 (1981)). The enzyme has been cloned and expressed in E. coli (Mac et al., 20 Eur.J.Biochem. 226:41-51 (1994)). Gene Accession No. GI No. Organism gctA CAA57199.1 559392 Acidaminococcusfermentans gctB CAA57200.1 559393 Acidaminococcusfermentans 254 3.1.2.a CoA hydrolase. Enzymes in the 3.1.2 family hydrolyze acyl-CoA molecules to their corresponding acids. However, such enzymes can be modified to empart CoA-ligase or synthetase functionality if coupled to an energy source such as a proton pump or direct ATP hydrolysis. Several 5 eukaryotic acetyl-CoA hydrolases (EC 3.1.2.1) have broad substrate specificity. For example, the enzyme from Rattus norvegicus brain (Robinson et al., Biochem. Biophys. Res. Common. 71:959-965 (1976)) can react with butyryl-CoA, hexanoyl-CoA and malonyl-CoA. Though its sequence has not been reported, the enzyme from the mitochondrion of the pea leaf also has a broad substrate specificity, with demonstrated activity on acetyl-CoA, propionyl-CoA, butyryl 10 CoA, palmitoyl-CoA, oleoyl-CoA, succinyl-CoA, and crotonyl-CoA (Zeiher and Randall, Plant. Physiol. 94:20-27 (1990)). The acetyl-CoA hydrolase, ACH1, from S. cerevisiae represents another candidate hydrolase (Buu et al., J. Biol. Chem. 278:17203-17209 (2003)). Gene Accession No. GI No. Organism acotl2 NP_570103.1 18543355 Rattus norvegicus ACH] NP_009538 6319456 Saccharomyces cerevisiae Another candidate hydrolase is the human dicarboxylic acid thioesterase, acot8, which exhibits 15 activity on glutaryl-CoA, adipyl-CoA, suberyl-CoA, sebacyl-CoA, and dodecanedioyl-CoA (Westin et al., J. Biol. Chem. 280:38125-38132 (2005)) and the closest E. coli homolog, tesB, which can also hydrolyze a broad range of CoA thioesters (Naggert et al., J. Biol. Chem. 266:11044-11050 (1991)). A similar enzyme has also been characterized in the rat liver (Deana, Biochem. Int. 26:767-773 (1992)). Other potential E. coli thioester hydrolases include the gene 20 products of tesA (Bonner and Bloch, J. Biol. Chem. 247:3123-3133 (1972)), ybgC (Kuznetsova et al., FEMS Microbiol. Rev. 29:263-279 (2005); Zhuang et al., FEBS Lett. 516:161-163 (2002)), paaI (Song et al., J. Biol. Chem. 281:11028-11038 (2006)), and ybdB (Leduc et al., J. Bacteriol. 189:7112-7126 (2007)). Gene Accession No. GI No. Organism acot8 CAA15502 3191970 Homo sapiens tesB NP_414986 16128437 Escherichia coli acot8 NP_570112 51036669 Rattus norvegicus tesA NP_415027 16128478 Escherichia coli ybgC NP_415264 16128711 Escherichia coli paaI NP_415914 16129357 Escherichia coli ybdB NP_415129 16128580 Escherichia coli 255 Yet another candidate hydrolase is the glutaconate CoA-transferase from Acidaminococcus fermentans. This enzyme was transformed by site-directed mutagenesis into an acyl-CoA hydrolase with activity on glutaryl-CoA, acetyl-CoA and 3-butenoyl-CoA (Mack and Buckel, FEBS Lett. 405:209-212 (1997)). This indicates that the enzymes encoding succinyl-CoA:3 5 ketoacid-CoA transferases and acetoacetyl-CoA:acetyl-CoA transferases can also serve as candidates for this reaction step but would likely require certain mutations to change their function. Gene Accession No. GI No. Organism gctA CAA57199.1 559392 Acidaminococcusfermentans gctB CAA57200.1 559393 Acidaminococcusfermentans Additional hydrolase enzymes include 3-hydroxyisobutyryl-CoA hydrolase which has been 10 described to efficiently catalyze the conversion of 3-hydroxyisobutyryl-CoA to 3 hydroxyisobutyrate during valine degradation (Shimomura et al., J. Biol. Chem. 269:14248 14253 (1994)). Genes encoding this enzyme include hibch of Rattus norvegicus (Shimomura et al., supra (1994); Shimomura et al., Methods Enzymol. 324:229-240 (2000)) and Homo sapiens (Shimomura et al., supra (1994). Candidate genes by sequence homology include hibch of 15 Saccharomyces cerevisiae and BC_2292 of Bacillus cereus. Gene Accession No. GI No. Organism hibch Q5XIE6.2 146324906 Rattus norvegicus hibch Q6NVY1.2 146324905 Homo sapiens hibch P28817.2 2506374 Saccharomyces cerevisiae BC 2292 AP09256 29895975 Bacillus cereus 4.1.1.a Carboxy-lyase. Decarboxylation of Alpha-Keto Acids. Alpha-ketoglutarate decarboxylase (Step B, Figures 58, 62 and 63), 5-hydroxy-2-oxopentanoic acid decarboxylase (Step Z, Figure 62), and 5-amino-2 20 oxopentanoate decarboxylase (Step R, Figure 63) all involve the decarboxylation of an alpha ketoacid. The decarboxylation of keto-acids is catalyzed by a variety of enzymes with varied substrate specificities, including pyruvate decarboxylase (EC 4.1.1.1), benzoylformate decarboxylase (EC 4.1.1.7), alpha-ketoglutarate decarboxylase and branched-chain alpha ketoacid decarboxylase. 25 Pyruvate decarboxylase (PDC), also termed keto-acid decarboxylase, is a key enzyme in alcoholic fermentation, catalyzing the decarboxylation of pyruvate to acetaldehyde. The enzyme from Saccharomyces cerevisiae has a broad substrate range for aliphatic 2-keto acids including 256 2-ketobutyrate, 2-ketovalerate, 3-hydroxypyruvate and 2-phenylpyruvate (Davie et al., J. Biol. Chem. 267:16601-16606 (1992)). This enzyme has been extensively studied, engineered for altered activity, and functionally expressed in E. coli (Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001); Li and Jordan, Biochemistry 38:10004-10012 (1999); ter Schure et al., 5 Appl. Environ. Microbiol. 64:1303-1307 (1998)). The PDC from Zymomonas mobilus, encoded by pdc, also has a broad substrate range and has been a subject of directed engineering studies to alter the affinity for different substrates (Siegert et al., Protein Eng. Des. Sel. 18:345-357 (2005)). The crystal structure of this enzyme is available (Killenberg-Jabs et al., Eur. J. Biochem. 268:1698-1704 (2001)). Other well-characterized PDC candidates include the 10 enzymes from Acetobacterpasteurians (Chandra et al., Arch. Microbiol. 176:443-451 (2001)) and Kluyveromyces lactis (Krieger et al., Eur. J. Biochem. 269:3256-3263 (2002)). Gene Accession No. GI No. Organism pdc P06672.1 118391 Zymomonas mobilus pdc1 P06169 30923172 Saccharomyces cerevisiae pdc AM21208 20385191 Acetobacter pasteurians pdcl Q12629 52788279 Kluyveromyces lactis Like PDC, benzoylformate decarboxylase (EC 4.1.1.7) has a broad substrate range and has been the target of enzyme engineering studies. The enzyme from Pseudomonas putida has been 15 extensively studied and crystal structures of this enzyme are available (Hasson et al., Biochemistry 37:9918-9930 (1998); Polovnikova et al., Biochemistry 42:1820-1830 (2003). Site-directed mutagenesis of two residues in the active site of the Pseudomonas putida enzyme altered the affinity (Km) of naturally and non-naturally occurring substrates (Siegert et al., Protein Eng. Des. Sel. 18:345-357 (2005)). The properties of this enzyme have been further 20 modified by directed engineering (Lingen et al., Protein Eng. 15:585-593 (2002); Lingen et al., Chembiochem. 4:721-726 (2003)). The enzyme from Pseudomonas aeruginosa, encoded by md/C, has also been characterized experimentally (Barrowman et al., FEMS Microbiol. Lett. 34:57-60 (1986)). Additional gene candidates from Pseudomonas stutzeri, Pseudomonas fluorescens and other organisms can be inferred by sequence homology or identified using a 25 growth selection system developed in Pseudomonas putida (Henning et al., Appl. Environ. Microbiol. 72:7510-7517 (2006)).

257 Gene Accession No. GI No. Organism mdlC P20906.2 3915757 Pseudomonas putida mdlC Q9HUR2.1 81539678 Pseudomonas aeruginosa dpgB ABN80423.1 126202187 Pseudomonas stutzeri ilvB-1 YP_260581.1 70730840 Pseudomonasfluorescens A third enzyme capable of decarboxylating 2-oxoacids is alpha-ketoglutarate decarboxylase (KGD). The substrate range of this class of enzymes has not been studied to date. The KDC 5 from Mycobacterium tuberculosis (Tian et al., Proc. Natl. Acad. Sci. USA 102:10670-10675 (2005)) has been cloned and functionally expressed. However, it is not an ideal candidate for strain engineering because it is large (-130 kD) and GC-rich. KDC enzyme activity has been detected in several species of rhizobia including Bradyrhizobium japonicum and Mesorhizobium loti (Green et al., J. Bacteriol. 182:2838-2844 (2000). Although the KDC-encoding gene(s) 10 have not been isolated in these organisms, the genome sequences are available, and several genes in each genome are annotated as putative KDCs. A KDC from Euglena gracilis has also been characterized, but the gene associated with this activity has not been identified to date (Shigeoka and Nakano, Arch. Biochem. Biophys. 288:22-28 (1991)). The first twenty amino acids starting from the N-terminus were sequenced (MTYKAPVKDVKFLLDKVFKV; SEQ ID 15 NO:) (Shigeoka and Nakano, Arch. Biochem. Biophys. 288:22-28 (1991)). The gene can be identified by testing candidate genes containing this N-terminal sequence for KDC activity. Gene Accession No. GI No. Organism kgd 050463.4 160395583 Mycobacterium tuberculosis kgd NP_767092.1 27375563 Bradyrhizobiumjaponicum kgd NP_105204.1 13473636 Mesorhizobium loti A fourth candidate enzyme for catalyzing this reaction is branched chain alpha-ketoacid decarboxylase (BCKA). This class of enzyme has been shown to act on a variety of compounds 20 varying in chain length from 3 to 6 carbons (Oku and Kaneda, J. Biol. Chem. 263:18386-18396 (1988); Smit et al., B. A., J. E. Hylckama Vlieg, W. J. Engels, L. Meijer, J. T. Wouters, and G. Smit. Identification, cloning, and characterization of a Lactococcus lactis branched-chain alpha keto acid decarboxylase involved in flavor formation. Apple. Environ. Microbiol. 71:303-311 (2005)). The enzyme in Lactococcus lactis has been characterized on a variety of branched and 25 linear substrates including 2-oxobutanoate, 2-oxohexanoate, 2-oxopentanoate, 3-methyl-2 oxobutanoate, 4-methyl-2-oxobutanoate and isocaproate (Smit et al., Appl. Environ. Microbiol. 71:303-311 (2005)). The enzyme has been structurally characterized (Berg et al., Science 258 318:1782-1786 (2007)). Sequence alignments between the Lactococcus lactis enzyme and the pyruvate decarboxylase of Zymomonas mobilus indicate that the catalytic and substrate recognition residues are nearly identical (Siegert et al., Protein Eng. Des. Sel. 18:345-357 (2005)), so this enzyme would be a promising candidate for directed engineering. 5 Decarboxylation of alpha-ketoglutarate by a BCKA was detected in Bacillus subtilis; however, this activity was low (5%) relative to activity on other branched-chain substrates (Oku and Kaneda. Biosynthesis of branched-chain fatty acids in Bacillus subtilis. A decarboxylase is essential for branched-chain fatty acid synthetase. J. Biol. Chem. 263:18386-18396 (1988)), and the gene encoding this enzyme has not been identified to date. Additional BCKA gene 10 candidates can be identified by homology to the Lactococcus lactis protein sequence. Many of the high-scoring BLASTp hits to this enzyme are annotated as indolepyruvate decarboxylases (EC 4.1.1.74). Indolepyruvate decarboxylase (IPDA) is an enzyme that catalyzes the decarboxylation of indolepyruvate to indoleacetaldehyde in plants and plant bacteria. Gene Accession No. GI No. Organism kdcA AAS49166.1 44921617 Lactococcus lactis 15 Recombinant branched chain alpha-keto acid decarboxylase enzymes derived from the El subunits of the mitochondrial branched-chain keto acid dehydrogenase complex from Homo sapiens and Bos taurus have been cloned and functionally expressed in E. coli (Davie et al., J. Biol. Chem. 267:16601-16606 1992); Wynn et al., J. Biol. Chem. 267:1881-1887 (1992); Wynn et al., J. Biol. Chem. 267:12400-12403 (1992)). In these studies, the authors found that co 20 expression of chaperonins GroEL and GroES enhanced the specific activity of the decarboxylase by 500-fold (Wynn et al., J. Biol. Chem. 267:12400-12403 (1992)). These enzymes are composed of two alpha and two beta subunits. Gene Accession No. GI No. Organism BCKDHB NP_898871.1 34101272 Homo sapiens BCKDHA NP_000700.1 11386135 Homo sapiens BCKDHB P21839 115502434 Bos taurus BCKDHA P11178 129030 Bos taurus 25 Decarboxylation of Alpha-Keto Acids. Several ornithine decarboxylase (Step U, Figure 63) enzymes also exhibit activity on lysine and other similar compounds. Such enzymes are found in Nicotiana glutinosa (Lee and Cho, Biochem. J. 360:657-665 (2001)), Lactobacillus sp. 30a (Guirard and Snell, J. Biol. Chem. 255:5960-5964 (1980)) and Vibrio vulnificus (Lee et al., J.

259 Biol. Chem. 282:27115-27125 (2007)). The enzymes from Lactobacillus sp. 30a (Momany et al., J. Mol. Biol. 252:643-655 (1995)) and V. vulnificus have been crystallized. The V. vulnificus enzyme efficiently catalyzes lysine decarboxylation, and the residues involved in substrate specificity have been elucidated (Lee et al., J. Biol. Chem. 282:27115-27125 (2007)). A similar 5 enzyme has been characterized in Trichomonas vaginalis, but the gene encoding this enzyme is not known (Yarlett et al., Biochem. J. 293 ( Pt 2):487-493 (1993)). Gene Accession No. GI No. Organism AF323910.1:1..1299 AAG45222.1 12007488 Nicotiana glutinosa odcl P43099.2 1169251 Lactobacillus sp. 30a VV2_1235 NP_763142.1 27367615 Vibrio vulnificus Glutamate decarboxylase enzymes (Step L, Figures 62 and 63) are also well-characterized. Exemplary glutamate decarboxylases can be found in E. coli (De Biase et al., Protein Expr. 10 Purif 8:430-438 (1996)), S. cerevisiae (Coleman et al., J. Biol. Chem. 276:244-250 (2001)), and Homo sapiens (Bu et al., Proc. Natl. Acad. Sci. USA 89:2115-2119 (1992); Bu and Tobin, Genomics 21:222-228 (1994)). Gene Accession No. GI No. Organism GAD] NP_000808 58331246 Homo sapiens GAD2 NP_001127838 197276620 Homo sapiens gadA NP_417974 16131389 Escherichia coli gadB NP_416010 16129452 Escherichia coli GAD] NP_013976 6323905 Saccharomyces cerevisiae Lysine decarboxylase (EC 4.1.1,18) catalyzes the decarboxylation of lysine to cadaverine. Two 15 isozymes of this enzyme are encoded in the E. coli genome by genes cadA and ldcC. CadA is involved in acid resistance and is subject to positive regulation by the cadC gene product (Lemonnier and Lane, Microbiology 144 ( Pt 3):751-760 (1998)). CadC accepts hydroxylysine and S-aminoethylcysteine as alternate substrates, and 2-Aminopimelate and 6-ACA act as competitive inhibitors to this enzyme (Sabo et al., Biochemistry 13:662-670 (1974)). Directed 20 evolution or other enzyme engineering methods can be utilized to increase the activity for this enzyme to decarboxylate 2-aminopimelate. The constitutively expressed ldc gene product is less active than CadA (Lemonnier and Lane, Microbiology 144 ( Pt 3):751-760 (1998)). A lysine decarboxylase analogous to CadA was recently identified in Vibrio parahaemolyticus (Tanaka et al., J. Apple. Microbiol. 104:1283-1293 (2008)). The lysine decarboxylase from Selenomonas 25 ruminantium, encoded by ldc, bears sequence similarity to eukaryotic ornithine decarboxylases, and accepts both L-lysine and L-ornithine as substrates (Takatsuka et al., Biosci. Biotechnol.

260 Biochem. 63:1843-1846 (1999)). Active site residues were identified and engineered to alter the substrate specificity of the enzyme (Takatsuka et al., J. Bacteriol. 182:6732-6741 (2000)). Gene Accession No. GI No. Organism cadA AAA23536.1 145458 Escherichia coli ldcC AAC73297.1 1786384 Escherichia coli ldc 050657.1 13124043 Selenomonas ruminantium cadA AB 124819.1 44886078 Vibrio parahaemolyticus 6.2.1.a CoA synthetase. 5 CoA synthetase or ligase reactions are required by Step I of Figures 62 and 63, and Step V of Figure 62. Succinate or 4-hydroxybutyrate are the required substrates. Exemplary genes encoding enzymes likely to carry out these transformations include the sucCD genes of E. coli, which naturally form a succinyl-CoA synthetase complex. This enzyme complex naturally catalyzes the formation of succinyl-CoA from succinate with the concomitant consumption of 10 one ATP, a reaction which is reversible in vivo (Buck et al., Biochem. 24:6245-6252 (1985)). Gene Accession No. GI No. Organism sucC NP_415256.1 16128703 Escherichia coli sucD AAC73823.1 1786949 Escherichia coli Additional exemplary CoA-ligases include the rat dicarboxylate-CoA ligase for which the sequence is yet uncharacterized (Vamecq et al., Biochemical J. 230:683-693 (1985)), either of the two characterized phenylacetate-CoA ligases from P. chrysogenum (Lamas-Maceiras et al., 15 Biochem. J. 395:147-155 (2005); Wang et al., Biochem Biophy Res Commun 360(2):453-458 (2007)), the phenylacetate-CoA ligase from Pseudomonas putida (Martinez-Blanco et al., J. Biol. Chem. 265:7084-7090 (1990)), and the 6-carboxyhexanoate-CoA ligase from Bacilis subtilis (Boweret al., J. Bacteriol. 178(14):4122-4130 (1996)). Additional candidate enzymes are acetoacetyl-CoA synthetases from Mus musculus (Hasegawa et al., Biochim. Biophys. Acta 20 1779:414-419 (2008)) and Homo sapiens (Ohgami et al., Biochem. Pharmacol. 65:989-994 (2003)), which naturally catalyze the ATP-dependant conversion of acetoacetate into acetoacetyl-CoA. 4-Hydroxybutyryl-CoA synthetase activity has been demonstrated in Metallosphaera sedula (Berg et al., Science 318:1782-1786 (2007)). This function has been tentatively assigned to the Msed_1422 gene.

261 Gene Accession No. GI No. Organism phl CAJ15517.1 77019264 Penicillium chrysogenum phlB ABS19624.1 152002983 Penicillium chrysogenum paaF AAC24333.2 22711873 Pseudomonas putida bioW NP_390902.2 50812281 Bacillus subtilis AACS NP_084486.1 21313520 Mus musculus AACS NP_076417.2 31982927 Homo sapiens Msed_1422 YP_001191504 146304188 Metallosphaera sedula ADP-forming acetyl-CoA synthetase (ACD, EC 6.2.1.13) is another candidate enzyme that couples the conversion of acyl-CoA esters to their corresponding acids with the concurrent 5 synthesis of ATP. Several enzymes with broad substrate specificities have been described in the literature. ACD I from Archaeoglobusfulgidus, encoded by AF121 1, was shown to operate on a variety of linear and branched-chain substrates including acetyl-CoA, propionyl-CoA, butyryl CoA, acetate, propionate, butyrate, isobutyryate, isovalerate, succinate, fumarate, phenylacetate, indoleacetate (Musfeldt et al., J. Bacteriol. 184:636-644 (2002)). The enzyme from Haloarcula 10 marismortui (annotated as a succinyl-CoA synthetase) accepts propionate, butyrate, and branched-chain acids (isovalerate and isobutyrate) as substrates, and was shown to operate in the forward and reverse directions (Brasen et al., Arch. Microbiol. 182:277-287 (2004)). The ACD encoded by PAE3250 from hyperthermophilic crenarchaeon Pyrobaculum aerophilum showed the broadest substrate range of all characterized ACDs, reacting with acetyl-CoA, isobutyryl 15 CoA (preferred substrate) and phenylacetyl-CoA (Brasen et al., supra (2004)). The enzymes from A. fulgidus, H. marismortui and P. aerophilum have all been cloned, functionally expressed, and characterized in E. coli (Musfeldt et al., supra;Brasen et al., supra (2004)). Gene Accession No. GI No. Organism AF1211 NP_070039.1 11498810 ArchaeoglobusfulgidusDSM4304 scs YP_135572.1 55377722 Haloarcula marismortui ATCC 43049 PAE3250 NP_560604.1 18313937 Pyrobaculum aerophilum str. IM2 EXAMPLE XXIII 20 Production of BDO Utilizing Carboxylic Acid Reductase This example describes the generation of a microbial organism that produces 1,4-butanediol using carboxylic acid reductase enzymes. Escherichia coli is used as a target organism to engineer the pathway for 1,4-butanediol synthesis described in Figure 58. E. coli provides a good host for generating a non-naturally 262 occurring microorganism capable of producing 1,4-butanediol. E. coli is amenable to genetic manipulation and is known to be capable of producing various products, like ethanol, acetic acid, formic acid, lactic acid, and succinic acid, effectively under various oxygenation conditions. 5 Integration of 4-Hydroxybutyrate Pathway Genes into Chromosome: Construction of ECKh 432. _The carboxylic acid reductase enzymes were expressed in a strain of E. coli designated ECKh-761 which is a descendent of ECKh-432 with additional deletions of the sad and gabD genes encoding succinate semialdehyde dehydrogenase enzymes. This strain contained the components of the BDO pathway, leading to 4HB, integrated into the chromosome of E. coli at 10 the fimD locus as described in Example XXI. Cloning and Expression of Carboxylic Acid Reductase and PPTase. To generate an E. coli strain engineered to produce 1,4-butanediol, nucleic acids encoding a carboxylic acid reductase and phosphopantetheine transferase are expressed in E. coli using well known molecular biology techniques (see, for example, Sambrook, supra, 2001; Ausubel supra, 1999). In particular, car 15 genes from Nocardia iowensis (designated 720), Mycobacterium smegmatis mc(2)155 (designated 890), Mycobacterium avium subspecies paratuberculosis K-10 (designated 891) and Mycobacterium marinum M (designated 892) were cloned into pZS* 13 vectors (Expressys, Ruelzheim, Germany) under control of PA1/lacO promoters. The npt (ABI83656.1) gene (i.e., 721) was cloned into the pKJL33S vector, a derivative of the original mini-F plasmid vector 20 PML31 under control of promoters and ribosomal binding sites similar to those used in pZS* 13. The car gene (GNM_720) was cloned by PCR from Nocardia genomic DNA. Its nucleic acid and protein sequences are shown in Figures 59A and 59B, respectively. A codon-optimized version of the npt gene (GNM_721) was synthesized by GeneArt (Regensburg, Germany). Its nucleic acid and protein sequences are shown in Figures 60A and 60B, respectively. The 25 nucleic acid and protein sequences for the Mycobacterium smegmatis mc(2)155 (designated 890), Mycobacterium avium subspecies paratuberculosis K-10 (designated 891) and Mycobacterium marinum M (designated 892) genes and enzymes can be found in Figures 64, 65, and 66, respectively. The plasmids were transformed into ECKh-761 to express the proteins and enzymes required for 1,4-butanediol production. 30 Demonstration of 1,4-BDO Production using Carboxylic Acid Reductase. Functional expression of the 1,4-butanediol pathway was demonstrated using E. coli whole-cell culture. Single colonies of E. coli ECKh-761 transformed with the pZS*13 and pKJL33S plasmids 263 containing a car gene and GNM_721, respectively, were inoculated into 5 mL of LB medium containing appropriate antibiotics. Similarly, single colonies of E. coli ECKh-761 transformed with car-containing pZS* 13 plasmids and pKJL33S plasmids with no insert were inoculated into additional 5 mL aliquots of LB medium containing appropriate antibiotics. Ten mL micro 5 aerobic cultures were started by inoculating fresh minimal in vivo conversion medium (see below) containing the appropriate antibiotics with 1.5% of the first cultures. Recipe of the minimal in vivo conversion medium (for 1000 mL) is as follows: Final concentration 10 1M MOPS/KOH buffer 100 mM Glucose (40%) 1% 10XM9 salts solution iX MgSO4 (1 M) 1 mM trace minerals (x1000) iX 15 1M NaHCO3 10 mM Microaerobic conditions were established by initially flushing capped anaerobic bottles with nitrogen for 5 minutes, then piercing the septum with an 18G needle following inoculation. The needle was kept in the bottle during growth to allow a small amount of air to enter the bottles. 20 Protein expression was induced with 0.2 mM IPTG when the culture reached mid-log growth phase. This is considered: time = 0 hr. The culture supernatants were analyzed for BDO, 4HB, and other by-products as described above and in W02008115840 (see Table 31). Table 33 shows the production of various products in the strains expressing various carboxylic acid reductases, including production of BDO.

264 Table 33. Production of various products in strains expressing various carboxylic acid reductases. Oh Cm10 CarblOO CarblOO Strain pKLJ33S pZS*13S pZShc13S OD600 OD600 1 761 034rbs55 no insert 0.54 2.13 5 761 721 720 0.48 1.88 7 761 721 890 0.45 1.63 8 761 721 891 0.48 1.65 9 761 721 892 0.45 1.31 12 761 no insert 720 0.50 1.72 14 761 no insert 890 0.51 1.96 15 761 no insert 891 0.19 2.36 16 761 no insert 892 0.05 1.40 48 h 48 h, mM PA Su La 4HB BDO GBL EtOHEnz 1 10.60 0.00 0.20 8.08 2.40 2.97 0.65 5 3.41 0.00 0.02 6.93 8.53 0.24 1.82 7 0.00 0.00 0.00 6.26 12.30 0.47 5.85 8 2.16 0.00 0.00 7.61 9.08 0.46 2.84 9 0.36 0.00 0.00 5.89 7.83 0.15 2.89 12 8.30 0.00 0.13 9.91 1.99 0.14 0.64 14 2.57 0.00 0.01 9.77 3.53 0.14 1.44 15 1.73 0.00 0.00 9.71 2.68 0.10 0.79 16 0.02 0.00 0.00 10.80 1.30 0.07 0.55 48 h, mM/OD PA Su La 4HB BDO GBL EtOHEnz 1 4.98 0.00 0.09 3.80 1.13 1.40 0.31 5 1.81 0.00 0.01 3.69 4.54 0.13 0.97 7 0.00 0.00 0.00 3.84 7.55 0.29 3.59 8 1.31 0.00 0.00 4.61 5.50 0.28 1.72 9 0.27 0.00 0.00 4.50 5.99 0.12 2.21 12 4.83 0.00 0.07 5.76 1.16 0.08 0.37 14 1.31 0.00 0.01 4.99 1.80 0.07 0.74 15 0.73 0.00 0.00 4.11 1.13 0.04 0.33 16 0.01 0.00 0.00 7.71 0.93 0.05 0.39 PA = pyruvate, SA = succinate, LA = lactate, 4HB = 4-hydroxybutyrate, BDO = 1,4-butanediol, 5 GBL = gamma-butyrolactone, Etoh = ethanol, LLOQ = lower limit of quantification These results show that various carboxylic acid reductases can function in a BDO pathway to produce BDO.

265 Throughout this application various publications have been referenced. The disclosures of these publications in their entireties, including GenBank and GI number publications, are hereby incorporated by reference in this application in order to more fully describe the state of the art to which this invention pertains. Although the invention has been described with reference to the 5 examples provided above, it should be understood that various modifications can be made without departing from the spirit of the invention. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises"3 or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated feature but not to preclude the presence or addition of further features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

Claims (55)

1. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 hydroxybutanal pathway comprising exogenous nucleic acids encoding 4-hydroxybutanal pathway enzymes expressed in a sufficient amount to produce 4-hydroxybutanal, said 4 5 hydroxybutanal pathway comprising 4-hydroxybutyrate reductase; succinyl-CoA reductase (aldehyde forming); and 4-hydroxybutyrate dehydrogenase.

2. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, 10 said 4-hydroxybutanal pathway comprising succinyl-CoA reductase (aldehyde forming); 4 hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase.

3. The non-naturally occurring microbial organism of claims 1 or 2, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.

4. A method for producing 4-hydroxybutanal, comprising culturing the non-naturally occurring 15 microbial organism of any of claims 1-3 under conditions and for a sufficient period of time to produce 4-hydroxybutanal.

5. The method of claim 4, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

6. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 20 hydroxybutanal pathway comprising exogenous nucleic acids encoding a 4-hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, said 4 hydroxybutanal pathway comprising 4-hydroxybutyrate reductase; alpha-ketoglutarate decarboxylase; and 4-hydroxybutyrate dehydrogenase.

7. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 25 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, said 4-hydroxybutanal pathway comprising alpha-ketoglutarate decarboxylase; 4 hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase.

8. The non-naturally occurring microbial organism of any of claims 6 or 7, wherein said at least 30 one exogenous nucleic acid is a heterologous nucleic acid. 267

9. A method for producing 4-hydroxybutanal, comprising culturing the non-naturally occurring microbial organism of any of claims 6-8 under conditions and for a sufficient period of time to produce 4-hydroxybutanal.

10. The method of claim 9, wherein said non-naturally occurring microbial organism is in a 5 substantially anaerobic culture medium.

11. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, said 4-hydroxybutanal pathway comprising succinate reductase; 4-hydroxybutyrate 10 dehydrogenase, and 4-hydroxybutyrate reductase.

12. The non-naturally occurring microbial organism of claim 11, wherein said microbial organism comprises three exogenous nucleic acids encoding succinate reductase; 4 hydroxybutyrate dehydrogenase, and 4-hydroxybutyrate reductase.

13. The non-naturally occurring microbial organism of claim 11, wherein said at least one 15 exogenous nucleic acid is a heterologous nucleic acid.

14. A method for producing 4-hydroxybutanal, comprising culturing the non-naturally occurring microbial organism of any of claims 11-13 under conditions and for a sufficient period of time to produce 4-hydroxybutanal.

15. The method of claim 14, wherein said non-naturally occurring microbial organism is in a 20 substantially anaerobic culture medium.

16. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, said 4-hydroxybutanal pathway comprising alpha-ketoglutarate decarboxylase, or glutamate 25 dehydrogenase or glutamate transaminase and glutamate decarboxylase and 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-hydroxybutyrate dehydrogenase; and 4 hydroxybutyrate reductase.

17. The non-naturally occurring microbial organism of claim 16, wherein said microbial organism comprises at least three exogenous nucleic acids encoding alpha-ketoglutarate 30 decarboxylase, or glutamate dehydrogenase or glutamate transaminase and glutamate decarboxylase and 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4 hydroxybutyrate dehydrogenase; and 4-hydroxybutyrate reductase. 268

18. The non-naturally occurring microbial organism of claim 16, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.

19. A method for producing 4-hydroxybutanal, comprising culturing the non-naturally occurring microbial organism of any of claims 16-18 under conditions and for a sufficient period 5 of time to produce 4-hydroxybutanal.

20. The method of claim 19, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

21. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 hydroxybutanal pathway comprising at least one exogenous nucleic acid encoding a 4 10 hydroxybutanal pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutanal, said 4-hydroxybutanal pathway comprising alpha-ketoglutarate reductase; 5-hydroxy-2 oxopentanoate dehydrogenase; and 5-hydroxy-2-oxopentanoate decarboxylase.

22. The non-naturally occurring microbial organism of claim 21, wherein said microbial organism comprises three exogenous nucleic acids encoding alpha-ketoglutarate reductase; 5 15 hydroxy-2-oxopentanoate dehydrogenase; and 5-hydroxy-2-oxopentanoate decarboxylase.

23. The non-naturally occurring microbial organism of claim 21, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.

24. A method for producing 4-hydroxybutanal, comprising culturing the non-naturally occurring microbial organism of any of claims 21-23 under conditions and for a sufficient period 20 of time to produce 4-hydroxybutanal.

25. The method of claim 24, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

26. A non-naturally occurring microbial organism, comprising a microbial organism having a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine 25 pathway enzyme expressed in a sufficient amount to produce putrescine, said putrescine pathway comprising succinate reductase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase.

27. The non-naturally occurring microbial organism of claim 26, wherein said microbial 30 organism comprises four exogenous nucleic acids encoding succinate reductase; 4- 269 aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase.

28. The non-naturally occurring microbial organism of claim 26, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid. 5

29. A method for producing putrescine, comprising culturing the non-naturally occurring microbial organism of any of claims 26-28 under conditions and for a sufficient period of time to produce putrescine.

30. The method of claim 29, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium. 10

31. A non-naturally occurring microbial organism, comprising a microbial organism having a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, said putrescine pathway comprising alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or 4 aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or 15 putrescine transaminase.

32. The non-naturally occurring microbial organism of claim 31, wherein said microbial organism comprises four exogenous nucleic acids encoding alpha-ketoglutarate decarboxylase; 4-aminobutyrate dehydrogenase or 4-aminobutyrate transaminase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase. 20

33. The non-naturally occurring microbial organism of claim 31, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.

34. A method for producing putrescine, comprising culturing the non-naturally occurring microbial organism of any of claims 31-33 under conditions and for a sufficient period of time to produce putrescine. 25

35. The method of claim 34, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

36. A non-naturally occurring microbial organism, comprising a microbial organism having a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, said putrescine 30 pathway comprising glutamate dehydrogenase or glutamate transaminase; glutamate 270 decarboxylase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase.

37. The non-naturally occurring microbial organism of claim 36, wherein said microbial organism comprises four exogenous nucleic acids encoding glutamate dehydrogenase or 5 glutamate transaminase; glutamate decarboxylase; 4-aminobutyrate reductase; and putrescine dehydrogenase or putrescine transaminase.

38. The non-naturally occurring microbial organism of claim 36, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.

39. A method for producing putrescine, comprising culturing the non-naturally occurring 10 microbial organism of any of claims 36-38 under conditions and for a sufficient period of time to produce putrescine.

40. The method of claim 39, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

41. A non-naturally occurring microbial organism, comprising a microbial organism having a 15 putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, said putrescine pathway comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate transaminase; 5-amino-2-oxopentanoate decarboxylase; and putrescine dehydrogenase or putrescine transaminase. 20

42. The non-naturally occurring microbial organism of claim 41, wherein said microbial organism comprises four exogenous nucleic acids encoding alpha-ketoglutarate reductase; 5 amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate transaminase; 5-amino-2 oxopentanoate decarboxylase; and putrescine dehydrogenase or putrescine transaminase.

43. The non-naturally occurring microbial organism of claim 41, wherein said at least one 25 exogenous nucleic acid is a heterologous nucleic acid.

44. A method for producing putrescine, comprising culturing the non-naturally occurring microbial organism of any of claims 41-43 under conditions and for a sufficient period of time to produce putrescine.

45. The method of claim 44, wherein said non-naturally occurring microbial organism is in a 30 substantially anaerobic culture medium. 271

46. A non-naturally occurring microbial organism, comprising a microbial organism having a putrescine pathway comprising at least one exogenous nucleic acid encoding a putrescine pathway enzyme expressed in a sufficient amount to produce putrescine, said putrescine pathway comprising alpha-ketoglutarate reductase; 5-amino-2-oxopentanoate dehydrogenase or 5 5-amino-2-oxopentanoate transaminase; ornithine dehydrogenase or ornithine transaminase; and ornithine decarboxylase.

47. The non-naturally occurring microbial organism of claim 46, wherein said microbial organism comprises four exogenous nucleic acids encoding alpha-ketoglutarate reductase; 5 amino-2-oxopentanoate dehydrogenase or 5-amino-2-oxopentanoate transaminase; ornithine 10 dehydrogenase or ornithine transaminase; and ornithine decarboxylase.

48. The non-naturally occurring microbial organism of claim 46, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid.

49. A method for producing putrescine, comprising culturing the non-naturally occurring microbial organism of any of claims 46-48 under conditions and for a sufficient period of time 15 to produce putrescine.

50. The method of claim 49, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.

51. A non-naturally occurring microbial organism, comprising a microbial organism having a 4 hydroxybutyryl-CoA (4-HBCoA) pathway comprising at least one exogenous nucleic acid 20 encoding a 4-hydroxybutyryl-CoA pathway enzyme expressed in a sufficient amount to produce 4-hydroxybutyryl-CoA, said 4-hydroxybutyryl-CoA pathway comprising alpha-ketoglutarate reductase; 5-hydroxy-2-oxopentanoate dehydrogenase; and 5-hydroxy-2-oxopentanoate dehydrogenase (decarboxylation).

52. The non-naturally occurring microbial organism of claim 51, wherein said microbial 25 organism comprises three exogenous nucleic acids encoding alpha-ketoglutarate reductase; 5 hydroxy-2-oxopentanoate dehydrogenase; and 5-hydroxy-2-oxopentanoate dehydrogenase (decarboxylation).

53. The non-naturally occurring microbial organism of claim 51, wherein said at least one exogenous nucleic acid is a heterologous nucleic acid. 30

54. A method for producing 4-hydroxybutyryl-CoA, comprising culturing the non-naturally occurring microbial organism of any of claims 51-53 under conditions and for a sufficient period of time to produce 4-hydroxybutyryl-CoA. 272

55. The method of claim 54, wherein said non-naturally occurring microbial organism is in a substantially anaerobic culture medium.