CN109607755B

CN109607755B - Method for efficiently generating electricity and denitrifying by microbial fuel cell under high salt condition

Info

Publication number: CN109607755B
Application number: CN201910121472.5A
Authority: CN
Inventors: 张苓花; 曾繁锦; 刘伟凤; 朱益民; 王特
Original assignee: Dalian Maritime University
Current assignee: Dalian Maritime University
Priority date: 2019-02-19
Filing date: 2019-02-19
Publication date: 2022-04-29
Anticipated expiration: 2039-02-19
Also published as: CN109607755A

Abstract

The invention discloses a method for efficiently generating electricity and denitrifying by a microbial fuel cell with a high-salt nitrogen-containing wastewater matrix, belonging to the technical field of biological energy. The invention sets an immobilized cell phase in a traditional two-pole single-chamber Microbial Fuel Cell (MFC) to construct a three-phase single-chamber MFC. Wherein the immobilized cells are ectoine secretory type halomonas with synchronous nitrification, denitrification and denitrification functions. Therefore, the salt tolerance assisting function and the synchronous nitrification and denitrification nitrogen removal function of the halomonas are integrated into the MFC, the salt tolerance of the MFC electrode microorganisms is improved, and the SND nitrogen removal efficiency under high salt is enhanced. The invention solves the problems that the high-salinity wastewater substrate can reduce the internal resistance of the MFC, but can inhibit the activity of microorganisms and reduce the power generation and denitrification efficiency. Has important significance for the resource application of the high-salinity wastewater MFC.

Description

Method for efficiently generating electricity and denitrifying by microbial fuel cell under high salt condition

Technical Field

The invention belongs to the technical field of biological energy, and particularly relates to a method for efficiently generating electricity and denitrifying by a microbial fuel cell with a high-salt nitrogen-containing wastewater matrix.

Background

Microbial Fuel Cells (MFCs) are devices and technologies that use microorganisms as catalysts to oxidize organic or inorganic substances to generate electric current [ Bruce E.Logan, Bert Hamelers, Rene Rozenda, et al. Microbial fuel cells: method and Technology. environmental Science & Technology,2006,40(17): 5181-. MFC power generation and wastewater purification coupling technology is a novel Energy-saving and Energy-producing wastewater treatment technology integrating wastewater reclamation, sludge reduction and water quality harmlessness, and relevant researches have been carried out on municipal or domestic wastewater, waste water of excrement of agricultural animals and wastewater of food processing [ Li He, Peng Du, Yizhong Chen, et al. In recent years, the research on the structure and operation of the MFC of the high-salinity wastewater matrix with high electric quantity production shows the application value and the prospect of the technology.

When the MFC runs in a high-salt matrix, the ion migration speed in the MFC is accelerated, the internal resistance of the MFC can be obviously reduced, and the electricity generation of the MFC is facilitated. When the NaCl concentration is increased from 100mM to 403mM, the power density of MFC is increased from 720 to 1330 mW.m^-2[Raphael Rousseau,Xochitl Dominguez-Benetton,Marie-Line Délia,et al.Microbial bioanodes with high salinity tolerance for microbial fuel cells and microbial electrolysis cells.Electrochemistry Communications,2013,33(8):1-4]. When the concentration of NaCl in the matrix is higher than 20g/L, the growth of non-halophilic bacteria and weak halophilic bacteria is inhibited; when the NaCl concentration exceeds 35.5g/L, the respiratory depression of general microbial cells reaches 81% [ Pernetti M, Di Palma L. Experimental Evaluation of Inhibition of respiration in saline Water on activated sludge. environmental Technology,2005,26(6): 695-charge 704]。

Halomonas (Halomonas) is a representative of moderately halophilic bacteria, and belongs to the taxonomic groups of the genera gamma-Proteobacteria (gamma-Proteobacteria), Anacardiales (Oceanospirillales), Halomonadaceae (Halomonadaceae), and Halomonas (Halomonas). Halomonas currently contains more than 30 species, most of which are isolated from the salt environment. Halomonas salina has a wide environmental adaptability due to the production of the osmotically compensating solute ectoine (1,4,5, 6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) [ E.Rosenberg, E.F.Delong, S.Loryet al.the Prokaryotes-Gamma proteobacteria.Germany: Springer-Verlag Berlin and Heidelberg,2014]. The halomonas strains for synthesizing ectoine reported in the previous research are all non-secretory strains in which ectoine only accumulates in cells, and the previous research of the applicant firstly reports a wild type ectoine secretory halomonas which can secrete to the outside of cells under the condition of basically constant environmental osmotic pressure and can secrete in a culture mediumEctoine is accumulated. It was suggested that ectoine-synthesizing strains could be classified as ectoine non-secreting (e.g. H.elongata DSM 2581)^T) And ectoine secreted form (e.g. H.salina DSM 5928)^T)[Ling-hua Zhang,Ya-jun Lang,Shinichi Nagata.Efficient production of ectoine using ectoine-excreting strain.Extremophiles,2009,13(4):717-724]。

Simultaneous Nitrification and Denitrification (SND) denitrification is performed simultaneously by nitrification and denitrification in the same reactor and under the same operating conditions. The SND denitrification technology has the characteristics of high denitrification efficiency, stable pH of a denitrification system, suitability for denitrification treatment of nitrogen-containing wastewater containing organic matters, simple process operation, small occupied area, lower denitrification cost and the like. SND denitrification Technology has significant advantages in the purification treatment of nitrogenous wastewater [ Te Wang, Jian Li, Linghua Zhang, et al, Simultaneous heterogeneous and aerobic differentiation at high concentrations of NaCl and ammonia nitro by Halomonas bacteria, Water Science & Technology,2017,76:386 395 ]. The wastewater of industries such as offshore area polluted seawater, coastal urban industrial cooling seawater and large living seawater, leather processing, marine product cultivation, synthetic ammonia, fertilizer production, landfill leachate, nickel battery production and the like is high-salt nitrogen-containing wastewater. At present, the denitrification efficiency of the high-salt nitrogen-containing wastewater by microbial purification (including SND) is low, and the main reason is that the high salt inhibits the growth and metabolism of microorganisms. Certain Halomonas bacteria are capable of SND denitrification at high salt [ Te Wang, Jian Li, Linghua Zhang, et al, Simultaneous heterogeneous and aerobic differentiation at high concentrations of NaCl and ammonia nitro gen by Halomonas bacteria Water Science & Technology,2017,76:386 395], demonstrating the significant advantage of such Halomonas in the field of microbial denitrification of high salt nitrogen-containing wastewater.

The MFC electrogenesis and wastewater purification coupling technology under high salt needs to solve the problem of inhibition of growth and metabolism of electrogenesis microorganisms on electrodes by high salt. Studies of this problem have been reported so far: A. domesticating salt-tolerant electrode microorganisms [ luoyong, luohuamna, surplus of spawn, and the like, influence of salinity on MFC power generation and a microbial community thereof, China environmental science, 2013,33(5): 832-containing 837 ]; B. halophilic bacteria were used as electrode microorganisms [ P.Arulanzhagan, N.Vasudevan, Biodegradation of polymeric aromatic hydrocarbons by a halolerant bacterial strain Ochrobactrum sp.VA1, Mar.polar. Bull.62(2011) 388-; C. salt-tolerant additive (betaine) is added [ Fangguo, Wuyue, Zhang Ling Fang, etc.. the electricity generation performance of the microbial fuel cell in the high-salt preserved szechuan pickle wastewater treatment, the report of environmental engineering, 2017,11(1):348 and 352 ]. But the activity stability of the domesticated salt-tolerant electrode microorganisms is poor; the halophilic bacteria pure strain (or single type) has no application value as the electrode microorganism (the waste water substrate is generally mixed flora); the added anti-stress additive is expensive, and the operation cost is greatly improved.

Although the high-salinity wastewater substrate can reduce the internal resistance of the MFC, the high salinity can inhibit the activity of microorganisms and reduce the power generation and denitrification efficiency. The existing method for improving the salt tolerance of MFC microorganisms does not have practical value. Therefore, establishing an efficient and convenient way and technology for improving the salt tolerance of the MFC microbial flora is a key for improving the electricity generation and nitrogen removal efficiency of the high-salt wastewater substrate MFC, and has important significance for the resource application of the high-salt wastewater MFC.

Disclosure of Invention

The invention sets an immobilized cell phase in a traditional two-pole single-chamber Microbial Fuel Cell (MFC) to construct a three-phase single-chamber MFC. Wherein the immobilized cells are ectoine secretory type halomonas with synchronous nitrification, denitrification and denitrification functions. Therefore, the salt tolerance assisting function and the synchronous nitrification and denitrification nitrogen removal function of the halomonas are integrated into the MFC, the salt tolerance of the MFC electrode microorganisms is improved, and the SND nitrogen removal efficiency under high salt is enhanced.

The salt tolerance assisting function of the halomonas is realized based on the salt tolerance generation-transmission-acquisition system constructed by the invention.

Salt tolerance generation: the invention utilizes halomonas for synthesizing osmotic pressure compensation solute as a salt tolerance generation source. Among various kinds of osmotic pressure compensation solutes, ectoine has a significant effect as a stability protective agent for biological macromolecules at a small concentration. Many halomonas cells synthesize ectoine under the stress of salt environment, and particularly under the condition that the growth medium contains monosodium glutamate, ectoine can be synthesized at high concentration. Wherein said Halomonas is Halomonas alkaliphila DSM16354, Halomonas salina DSM 5928, Halomonas venusta DSM 4743, Halomonas halodenitifica DSM 735, Halomonas ventosae DSM 15911, Halomonas pacifica DSM 4742 or Halomonas alimentaria DSM 15356. The invention uses such strains as a salt tolerance generating source.

In the technical scheme, the preferable amount of the monosodium glutamate is 10-60 g/L.

In a traditional two-pole single-chamber MFC, immobilized halomonas is used as a one-phase (salt tolerance generation phase) and is constructed into a three-phase (anode phase, cathode phase and immobilized cell phase) single-chamber MFC. The immobilized cell phase is prepared into an immobilized embedding pellet formed by a polyvinyl alcohol (60-140g/L) and sodium alginate (5-15g/L) composite carrier by using a cell immobilization technology to synthesize and secrete the ectoine halomonas.

Salt resistance transmission: the invention uses ectoine secretion type halomonas strain to secrete the synthesized ectoine to the outside of the cell, so that the MFC system contains the ectoine. Namely, ectoine, a salt-tolerant helper substance, is transported from inside the cell to outside the cell. The strain adopted by the invention is ectoine secretion type halomonas, and the ectoine secretion rate reaches more than 80% under better conditions.

In a three-phase single-chamber MFC, the immobilization support is composed of a complex of polyvinyl alcohol, which forms a body in which the immobilization pellets are embedded, and sodium alginate in a phosphate-containing MFC matrix (KH)₂PO₄2.75g/L，K₂HPO₄11.47g/L), thereby increasing the permeability of the immobilized spherulites and facilitating the transfer of ectoine secreted by the strain from the immobilized spherulites to the MFC matrix, thereby effectively constituting a salt-tolerant transfer channel.

Obtaining the salt resistance: the ectoine secreting halomonas strain not only has salt tolerance, but also has salt tolerance assisting function for other microorganisms in a specific system due to the secretion of ectoine. The three-phase single-chamber MFC anode electrogenesis microbial flora obtains salt tolerance by absorbing ectoine secreted by ectoine secreted halomonas into an MFC matrix, thereby improving the electrogenesis amount of the anode electrogenesis microbes under high salt conditions.

SND denitrification of immobilized halomonas: some ectoine secretory type halomonas has SND denitrification performance, so that the three-phase single-chamber MFC constructed by using the ectoine secretory type strain with SND denitrification capability through an immobilized cell method has the functions of salt tolerance generation-transfer-acquisition and can further improve the denitrification efficiency of the MFC. Particularly, the SND denitrification of the strain has the characteristic that the denitrification efficiency in a non-growth stage (growth equilibrium stage) is far higher than that in a growth stage (logarithmic growth stage), and the strain shows that non-growth cells can maintain higher denitrification activity and have longer duration. The characteristic shows an especially important significance in the aspect of SND denitrification of the immobilized cells.

According to the invention, an immobilized cell phase is arranged in a traditional two-pole single-chamber MFC, so that a three-phase single-chamber MFC is constructed. Wherein the immobilized cell is ectoine secretory type halomonas with SND denitrification function. Therefore, the salt tolerance assisting function and the SND denitrification function of the halomonas are integrated into the MFC, the salt tolerance of the MFC electrode microorganisms is improved, and the SND denitrification efficiency under high salt is enhanced.

In addition, the invention proves that ectoine secreted Halomonas salina DSM 5928, Halomonas venusta DSM 4743, Halomonas halodenitirica DSM 735, Halomonas ventosae DSM 15911, Halomonas pacica DSM 4742 or Halomonas alimentaria DSM 15356 simultaneously have higher ectoine secretion rate and SND denitrification rate, so the strain can also be applied to the three-element single-chamber MFC.

The three single-chamber MFCs are applied to high-salt nitrogen-containing wastewater with NaCl concentration being more than or equal to 30g/L and nitrogen element concentration being more than or equal to 50 mg/L.

The invention has the innovative characteristics that:

(1) the invention establishes a salt tolerance generation-transfer-acquisition system under an MFC high-salt matrix system, and provides a technical method for acquiring the salt tolerance of an MFC electrode microorganism based on the system for the first time.

(2) The invention firstly provides the method that the halomonas with salt resistance (ectoine synthesis and secretion) and high-efficiency SND denitrification function under high salt is introduced into the traditional bipolar single-chamber MFC through the immobilized cell technology to form the three-phase single-chamber MFC, so that the electricity production and denitrification capability of the high-salt nitrogen-containing wastewater MFC are improved.

(3) The composite embedding carrier is formed by the polyvinyl alcohol and the sodium alginate, and the permeability of the immobilized spherulite is increased by utilizing the characteristic that the sodium alginate can be disintegrated in the MFC matrix containing phosphate, so that ectoine secreted by the strain can be conveniently transferred from the immobilized spherulite to the MFC matrix, and a salt-tolerant transfer channel is effectively formed.

(4) The invention firstly proposes that immobilized halomonas is utilized to carry out SND denitrification in an MFC high-salt nitrogen-containing matrix system, and the denitrification capability of the MFC is enhanced.

(5) Based on the method, the power generation efficiency and the denitrification efficiency of the high-salt nitrogen-containing wastewater substrate MFC can be obviously improved.

Drawings

FIG. 1. inhibition of microbial fuel cell power production by high salt species;

FIG. 2.Halomonas alkaliphila DSM16354 synthesizes and secretes ectoine;

FIG. 3 Halomonas alkaliphila DSM16354 SND denitrogenation;

FIG. 4 is a construction diagram of a three-phase single-chamber MFC for immobilized halomonas (wherein, 1, an electrochemical workstation; 2, an anode; 3, a cathode; 4, an immobilized cell phase; 5, halomonas; 6, an anode microbial flora; 7, ectoine; 8, secretion; 9, absorption; 10, high-salt nitrogen-containing wastewater);

FIG. 5. three-phase single-chamber MFC power production;

FIG. 6 three-phase single-chamber MFC SND denitrification.

Detailed Description

The invention is further described by the following examples which are intended to be illustrative only and not to be limiting as to the scope of the invention, wherein the experimental materials used in the examples, unless otherwise specified, are commercially available or prepared by conventional methods, wherein:

the strain is as follows: halomonas alkaliphila DSM16354, Halomonas salina DSM 5928, Halomonas venusta DSM 4743, Halomonas halodenitifica DSM 735, Halomonas ventossae DSM 15911, Halomonas pacifica DSM 4742 or Halomonas alimentaria DSM 15356, available from DSMZ, Germany (German Collection of Microorganismis and Cell Cultures).

Activation medium (g/L): peptone 10, yeast powder 5 and NaCl 30. Sterilizing at 121 deg.C for 20min and pH 7.2.

Growth medium (g/L): glucose 20, monosodium glutamate 15, (NH)₄)₂SO₄10, 0.5 of yeast powder and KH₂PO₄3，K₂HPO₄9，MgSO₄0.4，MnSO₄0.01, the NaCl concentration is determined according to the experimental conditions. Sterilizing at 121 deg.C for 20min and pH 7.2.

Denitrogenation medium (g/L): D-Glucose 20, L-monosodium glutamate 10, sodium succinate 10, (NH)₄)₂SO₄15, yeast powder 0.5, K₂HPO₄·3H₂O 9，KH₂PO₄3，MgSO₄·7H₂O 0.4，MnSO₄·H₂O0.01, NaCl 60, pH7.2, 121 ℃,20 min sterilization. 2mL of trace elements (trace elements: EDTA-2Na 63.7, ZnSO)₄2.2，CaCl₂5.5，MnCl₂·4H₂O 5.1，FeSO₄·7H₂O 5，Na₂MO₄·2H₂O 1.1，CuSO₄·5H₂O 1.6，CoCl₂·6H₂O1.6), trace element filter sterilization (0.22 μm pore size, Millipore Express, usa).

Proliferation medium (g/L): glucose 20, (NH)₄)₂SO₄10，KH₂PO₄3，K₂HPO₄9，MgSO₄0.4，MnSO₄0.01, NaCl 30 and trace elements (the composition is the same as above) 2 mL/L. Sterilizing at 121 deg.C for 20min and pH 7.2.

Embedding agent (g/L): 100 parts of polyvinyl alcohol and 10 parts of sodium alginate; curing agent: 4% of boric acid and 3% of GaCl; NaCl solution 30g/L, 121 ℃ sterilization for 20 min.

MFC substrate (g/L): sodium acetate 5, KH₂PO₄2.75，K₂HPO₄11.47，NH₄Cl 1.12，KCl0.13, mineral 12.5 mL/L. Sterilizing at 121 deg.C for 20min and pH 7.2. (minerals: NTA 1.5, MgSO₄·7H₂O 6.15，MnSO₄H₂O 0.5，NaCl 1，FeSO₄·7H₂O 0.1,CaCl₂·2H₂O 0.1，CoCl₂·6H₂O 0.1，ZnCl₂0.13，CuSO₄·5H₂O 0.01，AlK(SO₄)₂·12H₂O 0.01，H₃BO₃0.01，Na₂MoO₄·2H₂O 0.054，NiCl₂·6H₂O 0.024，Na₂WO₄·2H₂O0.025). The NaCl concentration was determined according to the experimental conditions.

A two-pole single-chamber MFC, having an effective volume of 28mL, had a cylindrical inner space of 7X 2 cm. The anode uses carbon fiber brush, the cathode is air cathode, external resistor 1000 omega. The electrogenesis microbial flora is from denitrified activated sludge, and inoculates and acclimates anode electrogenesis microorganisms for six months, so that the MFC anode grows with a mature and stable biological membrane.

Example 1 inhibition of high salt base to microbial Fuel cell Electricity production

Taking 5 bipolar single-chamber MFCs which stably run in a 0g/L NaCl MFC matrix, setting the NaCl concentrations of the MFC matrix to be 0, 15, 30, 45 and 60g/L respectively, and culturing in a 30 ℃ incubator. The voltage was measured every 1h using a DT9205L multimeter. Three parallel experimental samples were set up for each identical experiment. The same applies below.

The inhibition of high salt species on microbial fuel cell power generation is shown in figure 1. Figure 1 shows that as the NaCl concentration in the MFC matrix increases, the voltage of the MFC also gradually decreases. When the NaCl concentration was increased from 0g/L to 15, 30, 45 and 60g/L, the average voltage decreased by 10.1%, 35.6%, 43.1% and 54.5% over 24 hours, respectively. The result shows that the high-basicity substance has a remarkable inhibiting effect on the electricity generation of the anode microbial community of the bipolar single-chamber MFC.

Example 2 Synthesis and secretion of ectoine by H.alkalililia DSM16354

And (4) an Ectoine concentration determination method. Extracellular Ectoine concentration assay: ectoine-induced synthetic medium 14000 Xg was centrifuged, and the supernatant was diluted 10-fold with distilled water and used for HPLC assay (ectoine secreted from cells). Intracellular ectoine concentration determination: the cells were centrifuged as described above, and the precipitated cells were collected, washed with NaCl-Kpi buffer (100mM, pH7.2, NaCl concentration the same as the medium concentration), extracted with an equal volume of 80% ethanol (v/v) to the centrifuged precipitate, resuspended, and allowed to stand at room temperature overnight. The suspension was centrifuged again and the supernatant was taken for HPLC analysis (as ectoine in cells). The total concentration of ectoine is the sum of the extracellular and intracellular concentration of ectoine. The ectoine concentration was measured by HPLC measurement. The column was TSK-GEL reversed phase column (TOSOH corporation, Japan). And an ultraviolet detector for detecting the wavelength of 210 nm.

Alkaliphila DSM16354 ectoine synthesis and secretion concentrations are shown in FIG. 2. Ectoine synthesis was induced in growth medium at 30, 60, 90, 120g/L NaCl at 120rpm for 36h, and total ectoine concentration, ectoine secretion concentration and cell growth (dry cell weight per liter of fermentation broth, CDW, g/L) were determined, and the results showed that the strain was able to synthesize ectoine at a concentration of NaCl that was the greatest at 60g/L NaCl (1263.8 mg/L). The strain is an ectoine secreting strain, namely the strain can secrete ectoine to the outside of cells under the condition of constant extracellular osmotic pressure and accumulate the ectoine in a culture medium. The ectoine secretion rate (percentage of ectoine concentration to total ectoine concentration) increased with decreasing NaCl concentration, and at 30g/L NaCl concentration, the ectoine secretion rate was highest (82.0%).

Example 3 H.alkalililina DSM16354 SND Denitrification

Total inorganic nitrogen (TN) including ammoniacal nitrogen

Nitrite nitrogen

Nitrate nitrogen

The denitrification rate is defined as the percentage of reduced TN in the denitrification system to the initial TN. Denitrogenation rate (TN)₀－CN－TN_t)/(TN₀－CN)×100％。Wherein NT₀For initial denitrification, TN, CN is total cell nitrogen_tIs TN at a certain time in the denitrification process. Assay by the Nassner reagent method

And (4) concentration. Diazo-azo assay

Determination of concentration by zinc-cadmium reduction method

And (4) concentration. Cell total nitrogen (CN) concentration was determined by Kjeldahl method for CN. And (5) taking CDW with different masses to determine CN, and fitting the relation between the CDW and the CN. CN was calculated by measuring CDW in the experiment.

5mL of LB (60g/L NaCl) medium, 30 ℃ and 120rpm for 24 hours, the strain was activated. The denitrification culture medium is 30mL/300mL, the inoculation amount is 1%, the temperature is 30 ℃, the rpm is 120, and the SND denitrification is 144 h. The results are shown in FIG. 3. Alkaliphila DSM16354 can denitrify by SND, the initial total nitrogen concentration is 4000mg/L, 144h, the denitrification rate is reduced to 90.9mg/L, and the denitrification rate reaches 96.7%. The denitrification rate is 9 percent in the cell growth stage (0-48h), and 87.7 percent in the cell non-growth stage (48-144 h). The denitrification efficiency of the later stage is far higher than that of the former stage, and the characteristic is particularly suitable for denitrification of immobilized cells.

Example 4 construction of three-phase Single-Chamber MFC for immobilized Halomonas

Immobilized halomonas phase: the H.alkalililia DSM16354 strain was activated, inoculated into growth medium at 1% inoculum size, and cultured at 30 ℃ at 120rpm for 24 hours. 30mL of the bacterial solution was centrifuged at 7500 Xg at 4 ℃ for 20 min. The supernatant was discarded, and the cells were collected and resuspended in 5mL of 30g/L NaCl sterile water. 25mL of embedding agent (100 g/L of polyvinyl alcohol and 10g/L of sodium alginate) is sterilized at 121 ℃ for 20min at high temperature, and after being cooled to 45-50 ℃, 5mL of resuspended bacterial liquid is uniformly mixed with the embedding agent. The embedding agent is injected into the stirred curing agent by a syringe to prepare the immobilized spherulites. Standing and curing for 5h at normal temperature. Washed by 30g/L NaCl sterile water, put into the MFC matrix and stirred for 12 hours to remove sodium alginate softening immobilized spherulites. Washing with 30g/L NaCl sterile water, culturing in proliferation medium at 30 deg.C and 120rpm for 48 hr to obtain immobilized H.alkaliphia DSM16354 pellet.

Three-phase single-chamber MFC: immobilized h.alkaliphila DSM16354 pellets 5g were placed in a metal mesh, placed close to the cathode, to construct a three-phase single-chamber MFC, the structure of which is shown in fig. 4.

Example 5 three-phase Single-Chamber MFC Power Generation

The three-phase single-chamber MFC in example 4 was subjected to coupling operation of power generation and denitrification with a 1000 Ω load, and a bipolar single-chamber MFC (without immobilized cells) was set as a control, the substrate of MFC had a NaCl concentration of 30g/L, the cells were incubated at 30 ℃ in an incubator, and the voltage was measured every 1h using a DT9205L multimeter.

The results of the power generation of the three-phase single-chamber MFC and the two-pole single-chamber MFC are shown in fig. 5. When the NaCl concentration of the bipolar single-chamber MFC is changed from 0g/L to 30g/L, the voltage is rapidly reduced from 369mV to 38mV, and the average voltage in a stationary phase (3-72h) is 76.1 mV. And 1h after the NaCl concentration of the three-phase single-chamber MFC is changed from 0g/L to 30g/L, the voltage of the three-phase single-chamber MFC is reduced to 60mV, but then the voltage rapidly rises, and the average voltage in a stable period (3-72h) reaches 232.4 mV. In the 30g/L NaCl MFC matrix, the three-phase single-compartment MFC point voltage is 3.1 times that of the two-pole single-compartment MFC. The results show that the salt tolerance of the anode electrogenesis microbial flora of the three-phase single-chamber MFC system formed by salt tolerance generation-transmission-acquisition is obviously enhanced, so the electrogenesis amount is greatly improved.

Example 6 three-phase Single-Chamber MFC SND Denitrification

The three-phase single-chamber MFC in example 4 was used for coupling with a 1000 Ω load for power generation and denitrification, and a bipolar single-chamber MFC (without immobilized cells) was used as a control. The NaCl concentration of the MFC substrate was 30g/L,

the concentration is 293mg/L, the culture is carried out in a 30 ℃ incubator, samples are taken every 12 hours to determine ammonia nitrogen, and 48 hours is a running period. The N concentration was measured and calculated as in example 3.

SND denitrification results for three-phase single-chamber MFCs and two-pole single-chamber MFCs are shown in FIG. 6. When the reactor is operated for 48 hours, the denitrification rate of the bipolar single-chamber MFC is 50.7Percent, while the denitrogenation rate of the three-phase single-chamber MFC is 70.6 percent, and the denitrogenation rate is improved by 39.3 percent. The denitrification rate of the bipolar single-chamber MFC is 3.14 mg.L^-1·h^-1While the denitrification rate of the three-phase single-chamber MFC was 4.94 mg.L^-1·h^-1The denitrification rate is improved by 57.3 percent. Experimental results show that the three-phase single-chamber MFC obviously improves the denitrification efficiency of high-salt nitrogen-containing wastewater due to the fact that the SND denitrification function is enhanced by the immobilized halomonas phase.

Example 7 ectoine secretion and SND Denitrification of Halomonas

Three single-compartment MFCs were constructed according to the method of example 4, with the difference that the Halomonas species used were Halomonas salina DSM 5928, Halomonas venusta DSM 4743, Halomonas halodenittificans DSM 735, Halomonas ventossae DSM 15911, Halomonas pacifica DSM 4742 or Halomonas alimentaria DSM 15356, respectively. Ectoine synthesis and secretion of the above halomonas were measured under the conditions of example 2, and the secretion rate was calculated. The total inorganic nitrogen concentration for SND denitrification of Halomonas described above was determined according to the method and conditions of example 3, and the denitrification rate was calculated.

The halomonas described above had the same properties as the h.alkaliphia DSM16354 strain, and its ectoine secretion rate and SND denitrification rate are shown in table 1.

TABLE 1 Halomonas secretes ectoine and SND denitrogenation

Claims

1. A microbial fuel cell comprises an electrochemical workstation, an anode phase and a cathode phase, and is characterized in that an immobilized embedding pellet is arranged between the anode phase and the cathode phase of the microbial fuel cell, the immobilized embedding pellet is placed in a metal net and is placed close to the cathode phase, and the immobilized embedding pellet contains ectoine secretion type halomonas with synchronous nitrification and denitrification functions;

the ectoine-secreting Halomonas having simultaneous nitrification and denitrification is Halomonas alkaliphila DSM16354, Halomonas salina DSM 5928, Halomonas venusta DSM 4743, Halomonas halodenitifica DSM 735, Halomonas ventosae DSM 15911, Halomonas pacifica DSM 4742 or Halomonas alimentaria DSM 15356.

2. The use of the microbial fuel cell of claim 1 in high salt nitrogen-containing wastewater treatment.

3. The application of the high-salt nitrogen-containing wastewater as claimed in claim 2, wherein the high-salt nitrogen-containing wastewater is wastewater with a NaCl concentration of more than or equal to 30g/L and a nitrogen element concentration of more than or equal to 50 mg/L.