CN114369630A - Method for preparing biodiesel from rhodosporidium toruloides - Google Patents

Abstract

The invention discloses a method for preparing biodiesel by rhodosporidium toruloides, which comprises the steps of putting the rhodosporidium toruloides, methanol and an acidic ionic liquid catalyst into a closed reaction kettle, heating the reaction kettle in an inert atmosphere, damaging the cell wall of the yeast by the acidic ionic liquid, and overflowing oil in the reaction kettle H⁺And the fatty acid methyl ester (biodiesel) is generated by ester exchange reaction with methanol under the catalysis. Compared with the traditional process, the invention prepares the biodiesel by matching the thermochemical method with the acidic ionic liquid catalyst, the reaction condition is mild, the catalyst plays a role in catalyzing wall breaking and ester exchange, and two processes of wall breaking and ester exchange are realized in one step; after the reaction is finished, the biodiesel and the yeast cell wallThe separation is simple, and the yeast cell wall can be used as feed and other purposes after being recovered; the used acidic ionic liquid catalyst can be recycled, is safe and pollution-free, and is an environment-friendly and efficient method for preparing biodiesel by using rhodosporidium toruloides.

Description

Method for preparing biodiesel from rhodosporidium toruloides

Technical Field

The invention relates to the technical field of preparation of biodiesel, in particular to a method for preparing biodiesel by rhodosporidium toruloides.

Background

With the development of society, the demand of human beings for fossil fuels is increasing, so that the problems of energy shortage and environmental pollution are increasing, and the problem can be effectively alleviated by using renewable energy. Wherein, the biomass is the only renewable carbon source on the earth, and the total amount of the biomass growing on the earth per year is about 1400-1800 billion tons, which is equivalent to 10 times of the total energy consumption in the world at present. The development and utilization of biomass energy have important significance for the sustainable development of human beings. Biodiesel is a fatty acid monoalkyl ester, most typically fatty acid methyl ester, which has the advantages of no toxicity, low sulfur content, biodegradability and the like, and is widely concerned by researchers in various countries around the world. The existing biodiesel usually uses agricultural and forestry wastes, illegal cooking oil, aged grains and the like as raw materials, although the wastes are effectively utilized, the problems that the yield and the quality of the biodiesel at the later stage are influenced because the raw materials are unstable in source and poor in consistency are caused, and the exploration of the raw materials with stable source and good consistency is urgent. In recent years, oleaginous microorganisms have been gaining importance to scholars. The oleaginous microorganism generally refers to microorganism with oil content of more than 20%, and comprises algae, bacteria, mold and yeast. Since the microorganisms consume CO during the cultivation₂Can slow down greenhouse effect, and has wide prospect when being used as a novel raw material for preparing biodiesel. Among oleaginous microorganisms, Rhodosporidium toruloides has received much attention because it accumulates up to 70% of oil on a dry weight basis in vivo.

The existing technology for preparing biodiesel by rhodosporidium toruloides needs two steps, namely extracting oil after cell wall breaking, and then carrying out ester exchange reaction by using methanol or ethanol to obtain fatty acid methyl ester or ethyl ester, namely the biodiesel. The existing wall breaking technology has the defects of expensive equipment, complex process and the like. For example, Hemin et al, in CN106947693B, disclose an ultrasonic cell wall breaking device which is noisy, difficult to dissipate heat, and susceptible active substances are easily deactivated; hongfeng et al disclose a method for extracting oil by breaking wall in CN103911288B, the method uses too high air pressure, not only the energy consumption is high, but also there is potential safety hazard; liu Wei Feng et al disclose a method for breaking the cell wall of beer yeast by using enzyme in CN101717733B, but the method has long reaction time, a complete test at least needs 36 hours to complete, and the reaction conditions are severe, so that the method is difficult to realize in large-scale production. For the ester exchange reaction after the oil extraction, strong acid (such as sulfuric acid and hydrochloric acid) or strong base (such as sodium hydroxide and potassium hydroxide) is required to be used as a catalyst, so that equipment is easily corroded, the generated waste liquid pollutes the environment, and the used homogeneous catalyst can not be reused. In the case of Rhodosporidium toruloides, the cell wall is thick and solid, and the main structure of the cell wall is glucomannan. The polymer structure formed by connecting glucose and mannose in beta (1, 3) and beta (1, 4) is extremely tough, and the wall breaking of the polymer structure is usually realized by a complex process by using the prior art, so that the requirement of industrial large-scale production is difficult to meet.

Therefore, a novel method for preparing biodiesel by using rhodosporidium toruloides needs to be developed, and the method is required to be simple in process, energy-saving, environment-friendly and low in cost.

Disclosure of Invention

Aiming at the defects of difficult wall breaking of rhodosporidium toruloides, complex ester exchange reaction process, pollution of a catalyst and the like in the prior art, the invention discloses a method for preparing biodiesel by rhodosporidium toruloides. The method for preparing the biodiesel by using the rhodosporidium toruloides as the raw material through one step has the advantages of mild reaction conditions, simple process flow, easy separation of the biodiesel from yeast cell walls after reaction, capability of using the cell walls for other purposes such as feed and the like, and high-efficiency utilization of the yeast. Meanwhile, the ionic liquid catalyst used in the method has high catalytic efficiency and can be recycled, the problems that the catalyst pollutes the environment and cannot be recycled in the traditional process are solved, and sustainable development is realized.

The invention provides a method for preparing biodiesel by rhodosporidium toruloides, which comprises the steps of putting rhodosporidium toruloides, methanol and an acidic ionic liquid catalyst into a closed reaction kettle in an inert atmosphere, heating the reaction kettle in the inert atmosphere, and ionizing H in the methanol by the acidic ionic liquid⁺Breaking C-O in yeast cell wall to break cell wall, mixing with methanol in H⁺Carrying out ester exchange reaction under the catalysis, filtering out residues, and extracting a liquid phase by using n-hexane to obtain fatty acid methyl ester, namely biodiesel; the heating reaction temperature is 80-120 ℃.

Further, the inert atmosphere is CO₂、N₂And Ar atmosphere.

Further, the mass ratio of the rhodosporidium toruloides to the methanol is 0.01-1: 1.

Further, the mass ratio of the acidic ionic liquid to the rhodosporidium toruloides is 0.3-1.1: 1.

Further, the oil content in the rhodosporidium toruloides is 50% -70%.

Further, the acidic ionic liquid is one of 1-butyl-3-methylimidazole hydrogen sulfate, di (1-butyl-3-methylimidazole) hydrogen phosphate and 1-butyl-3-methylimidazole dihydrogen phosphate.

Further, the dosage ratio of the liquid phase to n-hexane is 1:1 extraction 3 times.

The method for preparing the biodiesel by using the rhodosporidium toruloides concretely comprises the following steps:

(1) drying the rhodosporidium toruloides at 95 ℃ for 12h, and screening the rhodosporidium toruloides by using a 100-150-mesh sieve for later use;

(2) adding the reaction material and the catalyst into a reaction kettle in proportion, sealing the reaction kettle, and using CO₂、N₂And Ar, removing air in the reaction kettle, and heating;

(3) when the reaction temperature reaches 80-120 ℃, the retention time of the materials in the reaction kettle is less than or equal to 120 min;

(4) after the reaction is finished, naturally cooling to room temperature, filtering out residues, adding n-hexane into the liquid phase to extract the biodiesel, and taking an organic layer to remove the n-hexane to obtain the biodiesel;

(5) and (3) carrying out rotary evaporation on the residual liquid to remove methanol, washing for 3 times by using ethyl acetate to remove glycerol, and then recovering the catalyst.

Further, the reaction materials are rhodosporidium toruloides and methanol, the catalyst is acidic ionic liquid, and a rotary evaporator is adopted to remove n-hexane.

Further, the mass ratio of the rhodosporidium toruloides to the methanol is 0.01-1: 1; the mass ratio of the acidic ionic liquid to the rhodosporidium toruloides is 0.3-1.1: 1.

Has the advantages that:

compared with the prior art, the method for preparing the biodiesel by using the rhodosporidium toruloides has the following advantages that:

1. according to the method, rhodosporidium toruloides is prepared into the biodiesel by a thermochemical method in one step, so that the step of breaking the cell wall of yeast is omitted, methanol is used as a reactant and a solvent, the reaction conditions are mild, and the problem of difficult cell wall breaking caused by over-thick yeast cell wall is solved;

2. the acidic ionic liquid catalyst selected by the invention has catalytic effects on cell wall breaking and ester exchange reactions, the catalytic effect of the acidic ionic liquid catalyst is equivalent to that of the traditional homogeneous catalyst, and meanwhile, the catalyst can be recycled, so that the cost is reduced, and the acidic ionic liquid catalyst is safe and environment-friendly;

3. in the method, two processes of wall breaking and ester exchange are realized in one reaction, and the product obtained after the reaction is a mixture (i.e. biodiesel) taking methyl oleate, methyl palmitate and methyl stearate as main components, so that the process is simplified, and the problems of difficult wall breaking of yeast, environmental pollution caused by subsequent ester exchange reaction and the like in the prior art are solved;

4. in the method, the yeast cell wall can be completely reserved and can be continuously used as feed or other purposes, and compared with the prior acid-heat method for completely destroying the cell wall, the method realizes the high-efficiency comprehensive utilization of the rhodosporidium toruloides;

5. the method has simple process and strong operability, can be widely used for preparing the biodiesel by taking the rhodosporidium toruloides as the raw material, improves the production efficiency and reduces the commercial application cost of the rhodosporidium toruloides;

drawings

FIG. 1 is a GC-MS spectrum of a Rhodosporidium toruloides preparation biodiesel according to example 1 of the present invention;

FIG. 2 shows the contents of the components of biodiesel prepared by Rhodosporidium toruloides according to example 1 of the present invention;

FIG. 3 shows the effect of different catalysts on biodiesel production in examples 1, 2 and 3 according to the invention;

FIG. 4 is a graph comparing the consumption and emissions of biodiesel and 0# diesel on an engine in example 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

A method for preparing biodiesel by rhodosporidium toruloides comprises the following steps:

(1) drying the rhodosporidium toruloides at 95 ℃ for 12h, and screening the rhodosporidium toruloides by using a 100-150-mesh sieve for later use;

(2) adding the reaction material and the catalyst into a reaction kettle in proportion, sealing the reaction kettle, and using CO₂、N₂And Ar, removing air in the reaction kettle, and heating;

(3) when the reaction temperature reaches 80-120 ℃, the retention time of the materials in the reaction kettle is less than or equal to 120 min;

(4) after the reaction is finished, naturally cooling to room temperature, filtering out residues, adding n-hexane into the liquid phase to extract the biodiesel, and taking an organic layer to remove the n-hexane to obtain the biodiesel;

(5) and (3) carrying out rotary evaporation on the residual liquid to remove methanol, washing for 3 times by using ethyl acetate to remove glycerol, and then recovering the catalyst.

The principle of the above inventive concept of the present invention is: the main component of the cell wall of the rhodosporidium toruloides is glucomannan which is polymerized by glucose and mannose in beta (1, 3) and beta (1, 4). The structure makes the cell wall thick, and the prior wall breaking technology has no obvious effect on the cell wall, thereby leading to difficult wall breaking. The invention uses thermochemical method, using acidic ionic liquids as catalyst, H ionized in methanol⁺The C-O bond is broken, breaking the C-O bond, and thus breaking the cell wall. On the basis, the oil in the cells overflows and then is in H⁺The catalyst and methanol are subjected to ester exchange reaction, so that wall breaking and ester exchange are realized in one-step reaction, and the fatty acid methyl ester, namely the biodiesel is obtained. After the reaction is finished, the ionic liquid catalyst can be recycled, so that the cost is reduced, the environment is not polluted, and the problems of equipment corrosion and environmental pollution caused by the conventional homogeneous catalyst are solved.

The invention carries out wall breaking and ester exchange reaction in one step, simplifies the process flow, improves the production efficiency and solves the problem of difficult wall breaking of the rhodosporidium toruloides cell wall; the used solvent is cheap and pollution-free, and the problem that the conventional biodiesel production process is easy to generate wastewater in the ester exchange reaction is solved; the reaction condition is mild, safe and energy-saving; the used catalyst can be recycled, and the method is environment-friendly and pollution-free. The invention relates to a novel environment-friendly method for preparing biodiesel by utilizing rhodosporidium toruloides.

In order to illustrate the process of the invention in more detail, reference is made to the following specific examples.

Example 1

The embodiment provides a method for preparing biodiesel by rhodosporidium toruloides, which specifically comprises the following steps:

(1): drying rhodosporidium toruloides, screening by using a 120-mesh sieve, and weighing 5g for later use;

(2): weighing 40g of methanol and 5g of 1-butyl-3-methylimidazole hydrogen sulfate;

(3): putting the yeast in the step (1), the methanol in the step (2) and the 1-butyl-3-methylimidazole bisulfate into a reaction kettle, slightly shaking to uniformly mix reactants, and covering a reaction kettle cover to seal the reaction kettle;

(5): introducing enough N into the reaction kettle₂Discharging air in the reaction kettle;

(6): heating the reaction kettle at the reaction temperature of 100 ℃;

(7): after the reaction temperature is reached, keeping the temperature for 60min, namely, the reaction time is 60 min;

(8): after the reaction is finished, naturally cooling to room temperature;

(9): opening the cover of the reaction kettle, filtering out residues by using filter paper, and keeping a liquid phase;

(10): adding n-hexane into the liquid phase in the step (9);

(11): sucking the upper liquid in the step (10) out and transferring the upper liquid into a pear-shaped bottle, and removing n-hexane by using a rotary evaporator to obtain the biodiesel;

(12): transferring the lower layer liquid obtained in the step (10) into a pear-shaped bottle, and removing methanol by using a rotary evaporator;

(13): and (3) washing the liquid obtained in the step (12) with ethyl acetate for 3 times, and recovering the 1-butyl-3-methylimidazole bisulfate for next use.

Example 2:

the embodiment provides a method for preparing biodiesel by rhodosporidium toruloides, which specifically comprises the following steps:

(1): drying rhodosporidium toruloides, screening by using a 120-mesh sieve, and weighing 5g for later use;

(2): weighing 40g of methanol and 5g of bis (1-butyl-3-methylimidazole) hydrogen phosphate;

(3): putting the yeast in the step (1), the methanol in the step (2) and the di (1-butyl-3 methylimidazole) hydrogen phosphate salt into a reaction kettle, slightly shaking to uniformly mix reactants, and covering a reaction kettle cover to seal the reaction kettle;

(5): introducing enough N into the reaction kettle₂Discharging air in the reaction kettle;

(6): heating the reaction kettle at the reaction temperature of 100 ℃;

(7): after the reaction temperature is reached, keeping the temperature for 60min, namely, the reaction time is 60 min;

(8): after the reaction is finished, naturally cooling to room temperature;

(9): opening the cover of the reaction kettle, filtering out residues by using filter paper, and keeping a liquid phase;

(10): adding n-hexane into the liquid phase in the step (9);

(11): sucking the upper liquid in the step (10) out and transferring the upper liquid into a pear-shaped bottle, and removing n-hexane by using a rotary evaporator to obtain the biodiesel;

(12): transferring the lower layer liquid obtained in the step (10) into a pear-shaped bottle, and removing methanol by using a rotary evaporator;

(13): and (3) washing the liquid obtained in the step (12) with ethyl acetate for 3 times, and recovering the bis (1-butyl-3 methylimidazole) hydrogen phosphate for next use.

Example 3

The embodiment provides a method for preparing biodiesel by rhodosporidium toruloides, which specifically comprises the following steps:

(1): drying rhodosporidium toruloides, screening by using a 120-mesh sieve, and weighing 5g for later use;

(2): weighing 40g of methanol and 5g of 1-butyl-3-methylimidazole dihydrogen phosphate;

(3): putting the yeast in the step (1), the methanol in the step (2) and the 1-butyl-3-methylimidazole dihydrogen phosphate into a reaction kettle, slightly shaking to uniformly mix reactants, and covering a reaction kettle cover to seal the reaction kettle;

(5): introducing enough N into the reaction kettle₂Discharging air in the reaction kettle;

(6): heating the reaction kettle at the reaction temperature of 100 ℃;

(7): after the reaction temperature is reached, keeping the temperature for 60min, namely, the reaction time is 60 min;

(8): after the reaction is finished, naturally cooling to room temperature;

(9): opening the cover of the reaction kettle, filtering out residues by using filter paper, and keeping a liquid phase;

(10): adding n-hexane into the liquid phase in the step (9);

(11): sucking the upper liquid in the step (10) out and transferring the upper liquid into a pear-shaped bottle, and removing n-hexane by using a rotary evaporator to obtain the biodiesel;

(12): transferring the lower layer liquid obtained in the step (10) into a pear-shaped bottle, and removing methanol by using a rotary evaporator;

(13): and (3) washing the liquid obtained in the step (12) with ethyl acetate for 3 times, and recovering the 1-butyl-3-methylimidazole dihydrogen phosphate for next use.

It can be seen by comparing example 1, example 2 and example 3 above that the yield of biodiesel is greatly improved by using acidic ionic liquid catalyst compared to the use of no catalyst. When the 1-butyl-3-methylimidazole dihydrogen phosphate catalyst is used, the yield of the biodiesel is 37 times that of the biodiesel without the catalyst, and the effect is equivalent to that of using sulfuric acid as the catalyst. Qualitative and quantitative detection of the product by gas phase-mass spectrometry shows that the main components of the product are methyl oleate, methyl palmitate and methyl stearate, namely the biodiesel.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (9)

1. A method for preparing biodiesel by rhodosporidium toruloides is characterized by comprising the following steps: putting rhodosporidium toruloides, methanol and an acidic ionic liquid catalyst into a closed reaction kettle in an inert atmosphere, heating the reaction kettle in the inert atmosphere, and ionizing the acidic ionic liquid in the methanolH of (A) to (B)⁺Breaking C-O in yeast cell wall to break cell wall, mixing with methanol in H⁺Carrying out ester exchange reaction under the catalysis, filtering out residues, and extracting a liquid phase by using n-hexane to obtain fatty acid methyl ester, namely biodiesel; the heating reaction temperature is 80-120 ℃.

2. The method for preparing biodiesel according to claim 1, wherein the method comprises the following steps: the inert atmosphere is CO₂、N₂And Ar atmosphere.

3. The method for preparing biodiesel according to claim 1, wherein the method comprises the following steps: the mass ratio of the rhodosporidium toruloides to the methanol is 0.01-1: 1.

4. The method for preparing biodiesel according to claim 1, wherein the method comprises the following steps: the mass ratio of the acidic ionic liquid to the rhodosporidium toruloides is 0.3-1.1: 1.

5. The method for preparing biodiesel according to claim 1, wherein the method comprises the following steps: the acidic ionic liquid is one of 1-butyl-3-methylimidazole hydrogen sulfate, di (1-butyl-3-methylimidazole) hydrogen phosphate and 1-butyl-3-methylimidazole dihydrogen phosphate.

6. The method for preparing biodiesel according to claim 1, wherein the method comprises the following steps: the content of grease in the rhodosporidium toruloides is 50-70%.

7. The method for preparing biodiesel according to claim 1, wherein the method comprises the following steps: the dosage ratio of the liquid phase to n-hexane is 1:1 extraction 3 times.

8. The method for preparing biodiesel according to claim 1, which comprises the following steps:

(1) drying the rhodosporidium toruloides at 95 ℃ for 12h, and screening the rhodosporidium toruloides by using a 100-150-mesh sieve for later use;

(2) adding the reaction material and the catalyst into a reaction kettle in proportion, sealing the reaction kettle, and using CO₂、N₂And Ar, removing air in the reaction kettle, and heating;

(3) when the reaction temperature reaches 80-120 ℃, the retention time of the materials in the reaction kettle is less than or equal to 120 min;

(4) after the reaction is finished, naturally cooling to room temperature, filtering out residues, adding n-hexane into the liquid phase to extract the biodiesel, and taking an organic layer to remove the n-hexane to obtain the biodiesel;

(5) and (3) carrying out rotary evaporation on the residual liquid to remove methanol, washing for 3 times by using ethyl acetate to remove glycerol, and then recovering the catalyst.

9. The method for preparing biodiesel according to claim 8, wherein the method comprises the following steps: the reaction materials are rhodosporidium toruloides and methanol, the catalyst is acidic ionic liquid, and a rotary evaporator is adopted to remove n-hexane.

Images