Method for promoting acid production and alcohol production through fermentation of clostridium perdali C1 gas by using biogenic carbon-based redox regulation and control medium

Abstract

The invention discloses a method for promoting acid production and alcohol production through fermentation of clostridium perdali C1 gas by using a biological source carbon-based redox regulation and control medium. The preparation method comprises the following steps: obtaining biochar by adopting a high-temperature pyrolysis method, grinding and sieving to obtain a biogenic carbon-based redox regulation medium, adding the biogenic carbon-based redox regulation medium into a fermentation culture medium, inoculating clostridium perdali into a fermentation device filled with the fermentation culture medium, controlling the volume ratio of H2 to CO2 in the fermentation device to be (1.5: 1)-(2.5: 1), and carrying out anaerobic fermentation for 20-30 days to obtain the biogenic carbon-based redox regulation medium. According to the invention, a biological source carbon-based redox regulation medium is introduced into a clostridium perdali gas fermentation system, and the medium not only can enrich CO2 gas, but also can improve the mass transfer efficiency of a gaseous substrate; the method has the advantages that the method is simple and convenient to operate, extra reducing power is provided for a fermentation system, electron transfer is mediated, the CO2 utilization rate of the strain and the fermentation product generation rate are remarkably increased, secondary resource utilization of solid waste biomass is achieved, C1 gas is effectively converted into high-value chemicals, and a green, economical and sustainable development road is provided for conversion of CO2.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial gas fermentation, and particularly relates to a method for promoting acid and alcohol production in the C1 gas fermentation of Clostridium ljungdahlii by using a biogenic carbon-based redox regulation medium. Background Art

[0002] With the increasingly severe global climate change and energy crisis, the development of clean and renewable energy has become a major issue faced by the world today. As a new biological energy conversion pathway, gas fermentation technology can convert industrial waste gases containing carbon dioxide (CO2) and carbon monoxide (CO) into valuable chemicals such as ethanol and acetic acid, creating economic benefits while achieving carbon emission reduction, and thus has attracted much attention. In this technical field, Clostridium ljungdahlii has become a research hotspot due to its unique metabolic pathway and high carbon fixation ability. Clostridium ljungdahlii can convert CO or CO2 into chemicals such as acetic acid and ethanol through the Wood-Ljungdahl pathway, and this pathway only requires the consumption of 1 mol of ATP and 8 mol of reducing equivalents [H] for every 2 mol of CO2 reduced, demonstrating its great potential in the resource utilization of C1 gases.

[0003] However, the gas fermentation process of Clostridium ljungdahlii still faces many challenges. Firstly, the low solubility and low mass transfer efficiency of C1 gases (such as CO and CO2) limit the utilization of substrates by microorganisms, resulting in low fermentation efficiency. Secondly, the problem of redox imbalance during the fermentation process is particularly prominent. During the gas fermentation process of Clostridium ljungdahlii, the reducing power [H] mainly depends on the supply of hydrogen gas (H2), and the insufficient supply and low solubility of H2 will lead to limited reducing power, thereby affecting the stability of the metabolic pathway and the product yield. Although traditional regulation methods (such as adding chemical reducing agents) can partially alleviate these problems, they have limitations such as high cost, environmental unfriendliness, and complex operation, and are difficult to meet the requirements of industrial applications.

[0004] In recent years, as a new type of biogenic carbon-based material, biochar has shown broad application prospects in the fields of environmental remediation, energy storage, and biocatalysis due to its porous structure, high specific surface area, and rich surface functional groups. In addition, the raw materials for the preparation of biochar are widely sourced (such as agricultural waste, forestry residues, etc.), and have advantages such as low cost and environmental friendliness.

[0005] However, so far, there have been no reports on the application of this biogenic carbon-based material, biochar, in promoting acid and alcohol production in the C1 gas fermentation of Clostridium ljungdahlii. Summary of the Invention

[0006] In order to solve problems such as low mass transfer efficiency and redox imbalance in the gas fermentation process, the object of the present invention is to provide a method for promoting acid and alcohol production by Clostridium ljungdahlii C1 gas fermentation using a biogenic carbon-based redox regulation medium. The present invention introduces the biogenic carbon-based redox regulation medium into the gas fermentation system. On the one hand, this medium can enrich CO2 gas and improve the mass transfer efficiency of gaseous substrates; on the other hand, it provides additional reducing power for the fermentation system and mediates electron transfer, thus significantly improving the CO2 utilization rate of the strain and the fermentation product formation rate.

[0007] To achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a method for promoting acid and alcohol production by Clostridium ljungdahlii C1 gas fermentation using a biogenic carbon-based redox regulation medium, comprising the following steps:

[0009] S1: Treat the biomass material by high-temperature pyrolysis to obtain biochar, grind it, and pass through a 150-200 mesh sieve to prepare the biogenic carbon-based redox regulation medium;

[0010] S2: Add the biogenic carbon-based redox regulation medium obtained in S1 to the Clostridium ljungdahlii fermentation medium and mix evenly;

[0011] S3: Inoculate the activated Clostridium ljungdahlii into a sealed fermentation device containing the fermentation medium obtained in S2, control the volume ratio of H2 and CO2 in the gas in the fermentation device to be 1.5:1 - 2.5:1, and anaerobically ferment for 20 - 30 days to obtain the product.

[0012] Based on the above technical solution, further, the biomass material described in S1 includes corn straw, barley straw, and wheat straw.

[0013] Based on the above technical solution, further, the specific process of the high-temperature pyrolysis method in S1 is as follows: Crush the dry biomass material, pass through a 20-mesh sieve, and then place it in a high-purity nitrogen atmosphere and pyrolyze it at 400 - 800 °C for 1 - 4 h.

[0014] Based on the above technical solution, further, the nitrogen flux during the pyrolysis process is maintained at 0.1 - 0.3 L / min, and the heating rate is 5 - 15 °C / min.

[0015] Based on the above technical solution, further, the formula of the fermentation medium for Clostridium ljungdahlii in S2 includes 0.7 - 0.9 g / L sodium chloride, 0.05 - 0.15 g / L potassium chloride, 0.05 - 0.12 g / L magnesium chloride heptahydrate, 0.8 - 1.2 g / L yeast extract, 0.015 - 0.025 g / L calcium chloride dihydrate, 0.4 - 0.6 g / L dipotassium hydrogen phosphate, 8 - 12 mL / L trace element solution, 8 - 12 mL / L vitamin solution, 1.0 - 2.0 mg / L resazurin, 0.4 - 0.6 g / L L-cysteine hydrochloride, 8 - 15 g / L sodium carbonate;

[0016] The composition of the trace element solution is: 1.0 - 2.0 g / L nitrilotriacetic acid, 2.5 - 3.5 g / L magnesium sulfate heptahydrate, 0.4 - 0.6 g / L manganese sulfate monohydrate, 0.5 - 1.5 g / L sodium chloride, 0.05 - 0.15 g / L ferrous sulfate heptahydrate, 0.10 - 0.20 g / L cobalt sulfate heptahydrate, 0.05 - 0.15 g / L calcium chloride dihydrate, 0.15 - 0.20 g / L zinc sulfate heptahydrate, 0.005 - 0.02 g / L copper sulfate pentahydrate, 0.01 - 0.03 g / L potassium alum dodecahydrate, 0.005 - 0.02 g / L boric acid, 0.005 - 0.02 g / L sodium molybdate dihydrate, 0.02 - 0.05 g / L nickel chloride hexahydrate, pH adjusted to 6.5 - 7.0;

[0017] The composition of the vitamin solution is: 1.0 - 3.0 mg / L biotin, 1.0 - 3.0 mg / L folic acid, 5 - 15 mg / L pyridoxine phosphate, 2 - 8 mg / L thiamine hydrochloride, 2 - 8 mg / L riboflavin, 2 - 8 mg / L nicotinic acid, 2 - 8 mg / L D-calcium pantothenate, 0.05 - 0.15 mg / L vitamin B 12 , 2 - 8 mg / L p-aminobenzoic acid, 2 - 8 mg / L lipoic acid, pH adjusted to 6.5 - 7.0.

[0018] Based on the above technical solution, further, the concentration of the biogenic carbon-based redox regulation medium in the fermentation medium in S2 is 5 - 30 g / L.

[0019] Based on the above technical solution, further, the Clostridium ljungdahlii in S3 is Clostridium ljungdahlii DSMZ 13528.

[0020] Based on the above technical solution, further, the inoculation volume percentage of the Clostridium ljungdahlii in S3 is 5 - 15%.

[0021] Based on the above technical solution, further, before inoculating Clostridium ljungdahlii in S3, the gas in the sealed fermentation device containing the gas fermentation medium is replaced with hydrogen, and autoclaved at 121 °C for 20 minutes. After sterilization, the pH of the medium is adjusted to 6.5 - 6.8, and CO2 gas is added to make the volume ratio of H2 and CO2 in the fermentation device 1.5:1 - 2.5:1, and the gas pressure is 0.15 - 0.20 MPa.

[0022] Based on the above technical solution, further, during the fermentation process in S3, the volume ratio of H2 and CO2 in the fermentation device is maintained at 1.5:1 - 2.5:1, and the gas pressure is 0.15 - 0.20 MPa.

[0023] Based on the above technical solution, further, the formula of the activation medium for Clostridium ljungdahlii in S3 includes: 4.0 - 6.0 g / L fructose, 1.5 - 2.5 g / L yeast extract, 3.0 - 5.0 g / L tryptone, 1.5 - 2.5 g / L ammonium sulfate, 0.4 - 0.6 g / L potassium dihydrogen phosphate, 0.4 - 0.6 g / L dipotassium hydrogen phosphate, 0.05 - 0.12 g / L magnesium chloride heptahydrate, 8 - 12 mL / L trace element solution, 8 - 12 mL / L vitamin solution, 1.0 - 2.0 mg / L resazurin, 0.8 - 1.2 g / L L-cysteine hydrochloride;

[0024] The composition of the trace element solution is: 1.0 - 2.0 g / L nitrilotriacetic acid, 2.5 - 3.5 g / L magnesium sulfate heptahydrate, 0.4 - 0.6 g / L manganese sulfate monohydrate, 0.5 - 1.5 g / L sodium chloride, 0.05 - 0.15 g / L ferrous sulfate heptahydrate, 0.10 - 0.20 g / L cobalt sulfate heptahydrate, 0.05 - 0.15 g / L calcium chloride dihydrate, 0.15 - 0.20 g / L zinc sulfate heptahydrate, 0.005 - 0.02 g / L copper sulfate pentahydrate, 0.01 - 0.03 g / L potassium alum dodecahydrate, 0.005 - 0.02 g / L boric acid, 0.005 - 0.02 g / L sodium molybdate dihydrate, 0.02 - 0.05 g / L nickel chloride hexahydrate, and the pH is adjusted to 6.5 - 7.0;

[0025] The composition of the vitamin solution is: 1.0 - 3.0 mg / L biotin, 1.0 - 3.0 mg / L folic acid, 5 - 15 mg / L pyridoxine phosphate, 2 - 8 mg / L thiamine hydrochloride, 2 - 8 mg / L riboflavin, 2 - 8 mg / L nicotinic acid, 2 - 8 mg / L D-calcium pantothenate, 0.05 - 0.15 mg / L vitamin B 12 , 2 - 8 mg / L p-aminobenzoic acid, 2 - 8 mg / L lipoic acid, and the pH is adjusted to 6.5 - 7.0.

[0026] Based on the above technical solution, further, the fermentation conditions in S3 are pH 6.0 - 8.0, 32 - 38 °C, and 100 - 200 rpm.

[0027] The beneficial effects of the present invention compared with the prior art are as follows:

[0028] 1. By introducing a biogenic carbon-based redox regulation medium into the gas fermentation system, the present invention significantly enhances the mass transfer efficiency during the gas fermentation process. This medium has a developed pore structure and a high specific surface area, which can effectively enrich CO2 gas and increase its local concentration in the fermentation system. At the same time, its porous structure can also immobilize Clostridium ljungdahlii cells, enhancing the contact between the cells and CO2, thereby solving the problem of insufficient substrate utilization caused by low CO2 solubility and poor mass transfer efficiency in traditional gas fermentation.

[0029] 2. The surface of the biogenic carbon-based redox regulation medium of the present invention is rich in various active functional groups (such as phenolic hydroxyl groups, quinone groups, etc.). These functional groups can provide additional reducing power for the fermentation system, alleviating the problem of redox imbalance caused by insufficient reducing power in the traditional fermentation process. In addition, the graphitized structure of this medium has good electrical conductivity, which can mediate electron transfer and improve the electron transfer efficiency in the metabolic pathway of Clostridium ljungdahlii. The above characteristics work together to significantly improve the utilization rate of CO2 by the strain and the production rate of fermentation products such as ethanol and acetic acid.

[0030] 3. The biogenic carbon-based redox regulation medium of the present invention is prepared from renewable biomass (such as wheat straw). It not only has a wide source and low cost, but also has a green and environmentally friendly preparation process. Compared with traditional chemical reducing agents or expensive electron transfer media, the present invention reduces the production cost and the negative impact on the environment while having significant economic and ecological benefits. Description of the Drawings

[0031] In order to more clearly illustrate the embodiments of the present invention, the drawings related to the embodiments will be briefly introduced below.

[0032] Figure 1 It is a result diagram of the electron gain and loss ability of the biogenic carbon-based redox regulation medium at different pyrolysis temperatures;

[0033] Figure 2 It is a result diagram of the concentrations of ethanol and acetic acid products and the CO2 utilization rate obtained from the gas fermentation of Clostridium ljungdahlii under the conditions of adding BRM400, BRM600, and BRM800;

[0034] Figure 3 It is a result diagram of the concentrations of ethanol and acetic acid products and the CO2 utilization rate obtained from the gas fermentation without adding the biogenic carbon-based redox regulation medium and when the biogenic carbon-based redox regulation medium is not in contact with the strain. Detailed implementation manners

[0035] The present invention will be described in detail below in conjunction with embodiments. However, the implementation manners of the present invention are not limited thereto. Obviously, the embodiments described below are only partial embodiments of the present invention. For those skilled in the art, without creative efforts, obtaining other similar embodiments will fall within the protection scope of the present invention.

[0036] In the embodiment, the Clostridium ljungdahlii is Clostridium ljungdahlii DSMZ13528, which can carry out autotrophic growth through the Wood-Ljungdahl pathway (WLP), where H2 is used as an electron donor, CO2 is used as an electron acceptor, acetic acid is used as the main end product, and a small amount of acetyl-CoA is assimilated into biomass; Clostridium ljungdahlii can also utilize syngas, a gas mixture containing H2, CO2 and CO, as an autotrophic nutrient substrate for the WLP pathway.

[0037] Example 1

[0038] This embodiment provides a preparation method of a biogenic carbon-based redox regulation medium, and the specific process is as follows:

[0039] S1: Use wheat straw as the raw material for preparing the biogenic carbon-based redox regulation medium;

[0040] S2: Dry the wheat straw described in S1 at 80 °C and grind it to 20 mesh;

[0041] S3: Place the ground wheat straw described in S2 in a small high-temperature sintering furnace, and carry out high-temperature pyrolysis in a nitrogen atmosphere with a flux of 0.15 L / min. The pyrolysis temperatures are 400 °C, 600 °C, and 800 °C, the heating rate is 10 °C / min, and the holding time is 2 h;

[0042] S4: Grind the pyrolyzed wheat straw in S3, pass it through a 200-mesh sieve, and obtain the biogenic carbon-based redox regulation medium, which is dried and stored. The samples prepared at pyrolysis temperatures of 400 °C, 600 °C, and 800 °C are respectively denoted as BRM400, BRM600, and BRM800.

[0043] The detection method for the electron gain and loss ability of the biogenic carbon-based redox regulation medium refers to Chinese invention patent CN109239166A.

[0044] Figure 1 For the electron gain and loss ability of the biogenic carbon-based redox regulation medium at different pyrolysis temperatures.

[0045] Example 2

[0046] This example uses the biogenic carbon-based redox regulation medium (denoted as BRM400) prepared under the pyrolysis temperature of 400 °C in Example 1 to enhance the gas fermentation of Clostridium ljungdahlii. The specific process is as follows:

[0047] S1: The Clostridium ljungdahlii strain cryopreserved at -80 °C was inoculated into the seed medium at an inoculation amount of 2% (v / v) and cultured in a static incubator at 37 °C for 24 h, with two consecutive transfers. The composition of the seed medium was: 5.0 g / L fructose, 2.0 g / L yeast extract, 4.0 g / L tryptone, 2.0 g / L ammonium sulfate, 0.5 g / L potassium dihydrogen phosphate, 0.5 g / L dipotassium hydrogen phosphate, 0.1 g / L magnesium chloride heptahydrate, 10 mL / L trace element solution, 10 mL / L vitamin solution, 1.5 mg / L resazurin, 1.0 g / L L-cysteine hydrochloride. The medium was continuously purged with nitrogen for 20 minutes to remove oxygen and autoclaved at 121 °C for 20 minutes. The composition of the trace element solution was: 1.5 g / L nitrilotriacetic acid, 3 g / L magnesium sulfate heptahydrate, 0.5 g / L manganese sulfate monohydrate, 1.0 g / L sodium chloride, 0.10 g / L ferrous sulfate heptahydrate, 0.17 g / L cobalt sulfate heptahydrate, 0.10 g / L calcium chloride dihydrate, 0.17 g / L zinc sulfate heptahydrate, 0.01 g / L copper sulfate pentahydrate, 0.02 g / L potassium alum dodecahydrate, 0.01 g / L boric acid, 0.01 g / L sodium molybdate dihydrate, 0.03 g / L nickel chloride hexahydrate, and the pH was adjusted to 6.5. The composition of the vitamin solution was: 2.0 mg / L biotin, 2.0 mg / L folic acid, 10 mg / L pyridoxine phosphate, 5 mg / L thiamine hydrochloride, 5 mg / L riboflavin, 5 mg / L nicotinic acid, 5 mg / L D-calcium pantothenate, 0.1 mg / L vitamin B 12 , 5 mg / L p-aminobenzoic acid, 5 mg / L lipoic acid, and the pH was adjusted to 6.5;

[0048] S2: The Clostridium ljungdahlii seed culture grew to an optical density (OD 600 ) of 0.4 - 0.6 to ensure that it was in the exponential growth phase. The Clostridium ljungdahlii seed culture was added to the fermentation medium (contained in an anaerobic serum bottle) at an inoculation amount of 10% (v / v). The composition of the fermentation medium was as follows: 0.8 g / L sodium chloride, 0.1 g / L potassium chloride, 0.1 g / L magnesium chloride heptahydrate, 1.0 g / L yeast extract, 0.02 g / L calcium chloride dihydrate, 0.5 g / L dipotassium hydrogen phosphate, 10 mL / L trace element solution, 10 mL / L vitamin solution, 1.5 mg / L resazurin, 0.5 g / L L-cysteine hydrochloride, 10 g / L sodium carbonate, 10 g / L BRM400. The compositions of the trace element and vitamin solutions were the same as those in S1, and the pH of the medium was adjusted to 6.5 - 6.8. The gas composition in the anaerobic serum bottle was H2:CO2 = 2:1, and the gas pressure was 0.20 MPa;

[0049] S3: Place the fermentation medium inoculated with the inoculum solution in step S2 under anaerobic fermentation at 37 °C and 160 rpm for 25 days. During the fermentation process, supplement gas according to the ratio of H2:CO2 = 2:1. Take samples every 2 days, and store the samples frozen at -20 °C.

[0050] Comparative Example 1

[0051] In this comparative example, the C1 gas fermentation of Clostridium ljungdahlii was carried out without adding a biogenic carbon-based redox regulation medium (denoted as NC).

[0052] The experimental method was the same as that in Example 2, except that BRM400 was not added to the fermentation medium.

[0053] Comparative Example 2

[0054] In this comparative example, the C1 gas fermentation of Clostridium ljungdahlii was carried out under the condition that the biogenic carbon-based redox regulation medium was separated from Clostridium ljungdahlii by a dialysis bag (denoted as BRM400 not in contact).

[0055] The experimental method was the same as that in Example 2, except that BRM400 was wrapped with a dialysis bag, and BRM400 could not be in direct contact with Clostridium ljungdahlii, and only water molecules could pass through the dialysis bag.

[0056] Example 3

[0057] In this example, the biogenic carbon-based redox regulation medium prepared at a pyrolysis temperature of 600 °C in Example 1 (denoted as BRM600) was used to enhance the C1 gas fermentation of Clostridium ljungdahlii.

[0058] The experimental method was the same as that in Example 2, except that BRM600 was added to the fermentation medium.

[0059] Example 4

[0060] In this example, the biogenic carbon-based redox regulation medium prepared at a pyrolysis temperature of 800 °C in Example 1 (denoted as BRM800) was used to enhance the C1 gas fermentation of Clostridium ljungdahlii.

[0061] The experimental method was the same as that in Example 2, except that BRM800 was added to the fermentation medium.

[0062] Example 5

[0063] The measurement methods of the fermentation product concentrations in Comparative Examples 1-2 and Examples 2-4 are as follows:

[0064] Take out the sample from the -20 °C condition to thaw, centrifuge at 8000 rpm for 2 min, take the supernatant, and filter through a 0.22 μm filter membrane to remove impurities.

[0065] The concentrations of acetic acid and ethanol were detected by gas chromatography under the following conditions: an Agilent gas chromatograph (Agilent8860GC System, USA) was used, the injection volume was 0.5 μL, the injection port temperature was 250 °C, the chromatographic column was a DB-FFAP capillary chromatographic column (30 m × 0.32 mm × 0.5 μm), the detector temperature was 250 °C, the flow rate of the carrier gas (nitrogen) was 30 mL / min, the air flow rate was 400 mL / min, the hydrogen flow rate was 30 mL / min, and the split ratio was 50:1. The temperature programming of the column oven was as follows: starting at 60 °C, then increasing to 180 °C at a rate of 10 °C / min (12 min), and holding for 1 min.

[0066] Figure 2 They are the concentrations of ethanol and acetic acid products and the CO2 utilization rate obtained by fermentation under the conditions of the above Examples 2-4.

[0067] When BRM400 was added, 0.68 ± 0.06 g / L of ethanol and 4.85 ± 0.18 g / L of acetic acid were produced by gas fermentation, and the CO2 utilization rate was 72.8%;

[0068] When BRM600 was added, 0.51 ± 0.01 g / L of ethanol and 4.80 ± 0.03 g / L of acetic acid were produced by gas fermentation, and the CO2 utilization rate was 70.1%;

[0069] When BRM800 was added, 0.39 ± 0.03 g / L of ethanol and 4.44 ± 0.14 g / L of acetic acid were produced by gas fermentation, and the CO2 utilization rate was 70.3%.

[0070] Figure 3 They are the concentrations of ethanol and acetic acid products and the CO2 utilization rate obtained by fermentation under the conditions of the above Comparative Examples 1-2.

[0071] When the biogenic carbon-based redox regulation medium was not added, 0.32 ± 0.03 g / L of ethanol and 1.66 ± 0.04 g / L of acetic acid were produced by gas fermentation, and the CO2 utilization rate was 30.7%;

[0072] When BRM400 was fermented without contact with the strain, 0.09 ± 0.02 g / L of ethanol and 3.00 ± 0.08 g / L of acetic acid were produced, and the CO2 utilization rate was 47.9%;

[0073] From Figure 2 and Figure 3It can be seen that adding biogenic carbon-based redox regulation mediators can significantly increase the ethanol and acetic acid yields and CO2 utilization rate in the gas fermentation of Clostridium ljungdahlii. Among them, the fermentation effect of BRM400 is the best. Compared with the NC group, the ethanol yield increases by 113%, the acetic acid yield increases by 192%, and the CO2 utilization rate increases by 42.1%. By comparing the fermentation data of the BRM400 group and the BRM400 non-contact group, it can be seen that the biogenic carbon-based redox regulation mediator promotes electron transfer by acting as an electron donor or an electron mediator through the active functional groups on the surface, thereby enhancing the metabolic activity of Clostridium ljungdahlii.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for promoting acid and alcohol production by Clostridium ljungdahlii C1 gas fermentation using a biogenic carbon-based redox regulation medium, characterized in that, It includes the following steps: S1: Treat biomass materials by high-temperature pyrolysis to obtain biochar, grind it, and pass through a 150-200 mesh sieve to prepare a bio-based carbon-based redox regulation medium; S2: Add the bio-based carbon-based redox regulation medium obtained in S1 to the Clostridium ljungdahlii fermentation medium and mix evenly; S3: Inoculate the activated Clostridium ljungdahlii into a sealed fermentation device containing the fermentation medium obtained in S2, control the volume ratio of H2 and CO2 in the fermentation device to be 1.5:1 - 2.5:1, and perform anaerobic fermentation for 20 - 30 days to obtain the product.

2. The method according to claim 1, characterized in that, The biomass materials described in S1 include corn straw, barley straw, and wheat straw; the specific process of the high-temperature pyrolysis method is: crush the dry biomass materials, pass through a 20 mesh sieve, and then pyrolyze them in a high-purity nitrogen atmosphere at 400 - 800 °C for 1 - 4 h.

3. The method according to claim 2, characterized in that During the pyrolysis process, the nitrogen flux is maintained at 0.1 - 0.3 L / min, and the heating rate is 5 - 15 °C / min.

4. The method according to claim 1, characterized in that, The formula of the Clostridium ljungdahlii fermentation medium described in S2 includes 0.7 - 0.9 g / L sodium chloride, 0.05 - 0.15 g / L potassium chloride, 0.05 - 0.12 g / L magnesium chloride heptahydrate, 0.8 - 1.2 g / L yeast extract, 0.015 - 0.025 g / L calcium chloride dihydrate, 0.4 - 0.6 g / L dipotassium hydrogen phosphate, 8 - 12 mL / L trace element solution, 8 - 12 mL / L vitamin solution, 1.0 - 2.0 mg / L resazurin, 0.4 - 0.6 g / L L-cysteine hydrochloride, 8 - 15 g / L sodium carbonate; The composition of the trace element solution is: 1.0 - 2.0 g / L nitrilotriacetic acid, 2.5 - 3.5 g / L magnesium sulfate heptahydrate, 0.4 - 0.6 g / L manganese sulfate monohydrate, 0.5 - 1.5 g / L sodium chloride, 0.05 - 0.15 g / L ferrous sulfate heptahydrate, 0.10 - 0.20 g / L cobalt sulfate heptahydrate, 0.05 - 0.15 g / L calcium chloride dihydrate, 0.15 - 0.20 g / L zinc sulfate heptahydrate, 0.005 - 0.02 g / L copper sulfate pentahydrate, 0.01 - 0.03 g / L potassium alum dodecahydrate, 0.005 - 0.02 g / L boric acid, 0.005 - 0.02 g / L sodium molybdate dihydrate, 0.02 - 0.05 g / L nickel chloride hexahydrate, and the pH is adjusted to 6.5 - 7.0; The composition of the vitamin solution is as follows: 1.0 - 3.0 mg / L biotin, 1.0 - 3.0 mg / L folic acid, 5 - 15 mg / L pyridoxine phosphate, 2 - 8 mg / L thiamine hydrochloride, 2 - 8 mg / L riboflavin, 2 - 8 mg / L nicotinic acid, 2 - 8 mg / L D-calcium pantothenate, 0.05 - 0.15 mg / L vitamin B 12 , 2 - 8 mg / L p-aminobenzoic acid, 2 - 8 mg / L lipoic acid, and the pH is adjusted to 6.5 - 7.

0.

5. The method according to claim 1, wherein The concentration of the bio-based carbon-based redox regulation medium described in S2 in the fermentation medium is 5 - 30 g / L.

6. The method according to claim 1, wherein The Clostridium ljungdahlii described in S3 is Clostridium ljungdahlii DSMZ 13528; the inoculation volume percentage of the Clostridium ljungdahlii is 5 - 15%.

7. The method according to claim 1, characterized in that Before inoculating Clostridium ljungdahlii in S3, replace the gas in the sealed fermentation device containing the fermentation medium with hydrogen, sterilize at 121 °C under high pressure for 20 minutes, adjust the pH of the medium to 6.5 - 6.8 after sterilization, and supplement CO2 gas to make the volume ratio of H2 and CO2 in the fermentation device 1.5:1 - 2.5:1, and the gas pressure 0.15 - 0.20 MPa.

8. The method according to claim 1, characterized in that, During the fermentation process in S3, maintain the volume ratio of H2 and CO2 in the fermentation device at 1.5:1 - 2.5:1, and the gas pressure at 0.15 - 0.20 MPa.

9. The method according to claim 1, wherein The formula of the activation medium for Clostridium ljungdahlii described in S3 includes: 4.0 - 6.0 g / L fructose, 1.5 - 2.5 g / L yeast extract, 3.0 - 5.0 g / L tryptone, 1.5 - 2.5 g / L ammonium sulfate, 0.4 - 0.6 g / L potassium dihydrogen phosphate, 0.4 - 0.6 g / L dipotassium hydrogen phosphate, 0.05 - 0.12 g / L magnesium chloride heptahydrate, 8 - 12 mL / L trace element solution, 8 - 12 mL / L vitamin solution, 1.0 - 2.0 mg / L resazurin, 0.8 - 1.2 g / L L-cysteine hydrochloride; The composition of the trace element solution is: 1.0 - 2.0 g / L nitrilotriacetic acid, 2.5 - 3.5 g / L magnesium sulfate heptahydrate, 0.4 - 0.6 g / L manganese sulfate monohydrate, 0.5 - 1.5 g / L sodium chloride, 0.05 - 0.15 g / L ferrous sulfate heptahydrate, 0.10 - 0.20 g / L cobalt sulfate heptahydrate, 0.05 - 0.15 g / L calcium chloride dihydrate, 0.15 - 0.20 g / L zinc sulfate heptahydrate, 0.005 - 0.02 g / L copper sulfate pentahydrate, 0.01 - 0.03 g / L potassium alum dodecahydrate, 0.005 - 0.02 g / L boric acid, 0.005 - 0.02 g / L sodium molybdate dihydrate, 0.02 - 0.05 g / L nickel chloride hexahydrate, and adjust the pH to 6.5 - 7.0; The composition of the vitamin solution is as follows: 1.0 - 3.0 mg / L biotin, 1.0 - 3.0 mg / L folic acid, 5 - 15 mg / L pyridoxine phosphate, 2 - 8 mg / L thiamine hydrochloride, 2 - 8 mg / L riboflavin, 2 - 8 mg / L nicotinic acid, 2 - 8 mg / L D-calcium pantothenate, 0.05 - 0.15 mg / L vitamin B 12 , 2 - 8 mg / L p-aminobenzoic acid, 2 - 8 mg / L lipoic acid, and the pH is adjusted to 6.5 - 7.

0.

10. The method according to claim 1, wherein The fermentation conditions described in S3 are pH 6.0 - 8.0, 32 - 38 °C, 100 - 200 rpm.

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