Chemical catalyst–microbial carbon sequestration system for improving utilization efficiency of h 2 and use thereof

Abstract

The present invention belongs to the field of biochemical engineering, and relates to a chemical catalyst–microbial carbon sequestration system for improving the utilization efficiency of H2 and the use thereof. By culturing a chemical catalyst having H2 activation performance and acetogens in a culture medium containing H2 and CO2, the utilization efficiency of H2 and CO2 can be significantly improved, and the concentrations of ethanol and acetic acid are significantly increased, thereby reducing the acid-alcohol ratio; moreover, the biomass is also significantly improved. The provided hydrogenase-mimicking chemical catalyst and acetogens carbon sequestration system significantly improves the utilization efficiency of H2 and the carbon sequestration efficiency, increases the content of ethanol and thus increases the added value of the product, and is of great significance to the industrial implementation of biological fixation of CO2 using H2 as an energy source.

Description

A chemical catalyst-microbial carbon fixation system for improving H2 utilization efficiency and its application

[0001] This application claims priority to a Chinese patent application filed with the Patent Office of China on January 24, 2024, with application number 202410099504.7 and invention name “A chemical catalyst-microbial carbon fixation system for improving H2 utilization efficiency and its application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to a chemical catalyst-microbial carbon fixation system for improving H2 utilization efficiency and its application, belonging to the field of biochemical engineering. Background Art

[0003] Biological carbon sequestration is a crucial functional foundation for maintaining biosphere stability and development. Against the backdrop of the current environmental crisis and increasing energy shortages, its technological and engineering significance is increasingly attracting attention and recognition. Using carbon-fixing microorganisms as a platform, the catalytic fixation of CO2 into various energy sources and chemicals, combined with green synthesis, effectively combines carbon sequestration and emission reduction, with significant implications for alleviating resource crises, mitigating environmental pollution, and promoting sustainable social development.

[0004] Acetogens are obligate anaerobic chemoautotrophic microorganisms that synthesize acetyl-CoA and its derivatives, such as acetate and ethanol, through the linear Wood-Ljungdahl pathway (also known as the reductive acetyl-CoA pathway), achieving terminal electron acceptance and energy conservation, enabling autotrophic growth. Unlike CO2 fixation through cyclic reactions like the Calvin cycle, the Wood-Ljungdahl pathway is less dependent on or susceptible to interference from central metabolism, offering unique advantages for achieving the high throughput required for industrial applications.

[0005] All naturally occurring acetogenic bacteria are CO2-fixing, anaerobic, autotrophic, and non-methanotrophic. Since CO2 can only serve as a carbon source, its fixation requires additional energy. Acetogenic bacteria use the energy released by the oxidation of H2 or CO to generate reducing power for CO2 fixation and ATP synthesis.

[0006] Acetogenic bacteria, using CO as an energy source, fix CO₂ to produce ethanol, a process already commercially viable (Nat Biotech 2022, 40:335). However, when using CO as an energy source to produce ethanol, two-thirds of the carbon is excreted as CO₂, resulting in poor carbon economy. Therefore, adding H₂ provides energy to refix the CO₂ produced by CO oxidation, promoting carbon recovery.

[0007] Acetogenic bacteria use H2 as an energy donor, and fixing CO2 is a future development trend. However, there are currently great shortcomings, mainly manifested in low gas utilization and energy conversion efficiency, long carbon fixation and circulation cycles, low product output and yield, and only producing acetic acid but not ethanol, resulting in low product added value. These have greatly limited the efficient bioconversion and utilization of CO2.

[0008] When acetogenic bacteria use H2 as an energy donor, hydrogenase plays a key role; hydrogenase captures H2 and catalyzes the oxidation of H2 Through electron disproportionation reactions, reduced ferredoxin and NAD(P)H coenzymes are produced for the conversion and utilization of CO2. Due to the extremely low solubility of H2 in the liquid phase, it is difficult for hydrogenase in the cell to capture H2, affecting the continuous and efficient supply of coenzymes and limiting the efficiency of CO2 biofixation.

[0009] Through artificial design and modification, artificial functional material elements are integrated into biological metabolic activities, supplementing or even replacing some biological elements, constructing microorganism-artificial material chimeras, and realizing the functional chimera of "biology-material". It is expected to play a role in major areas such as efficient conversion and utilization of energy and artificial carbon fixation.

[0010] For example, a report has constructed a chimeric system of the non-photoautotrophic microorganism Moore's bacterium thermoacetica and the semiconductor material cadmium sulfide. In this chimeric system, cadmium sulfide nanoparticles on the cell surface capture solar energy to generate extracellular electrons, which the microbial cells use to generate reducing power outside or inside the cell, fixing CO2 through the Wood-Jungdahl pathway, and ultimately achieving light-driven acetic acid synthesis (Proc Natl Acad Sci USA. 2016, 113(42):11750-11755).

[0011] Another example is the use of polyphenols to interact with the cell wall to assemble indium phosphide particles onto the surface of Saccharomyces cerevisiae cells, creating a chimera of the yeast and the semiconductor material indium phosphide. The yeast cells use the surface nanoparticles to capture photogenerated electrons and use them to regenerate the redox cofactor NADPH, promoting the efficient synthesis of the metabolite shikimic acid (Science 2018, 362, 813-816).

[0012] For example, East China Normal University reported an in vivo non-metallic inorganic semiconductor-microorganism hybrid system. The semiconductor material C3N4·QDs has good biocompatibility and suitable size. It enters the Escherichia coli cell through bacterial endocytosis to form an in vivo inorganic semiconductor-microorganism hybrid system. In the Escherichia coli cell, the unique π-π electron conjugation forms the C3N4·QDs / NAD + The photocatalysis is directly carried out in the bacteria to achieve efficient hydrogen production.

[0013] Hydrogenase-like catalysts are heterogeneous catalysts designed to mimic the function of hydrogenases and capable of hydrogen activation. They consist of a support and an active center. The support is typically composed of carbon nanotubes, silica, graphene, graphene oxide, carbon dots, or ferrosoferric oxide. The active center is typically a metal nanoparticle such as iron, cobalt, nickel, palladium, or platinum. The support enhances the stability of the hydrogenase-like catalyst, accelerates electron transfer, and serves to immobilize the metal active center. Hydrogenase-like catalysts can achieve efficient hydrogen activation at room temperature and pressure.

[0014] The hydrogenase-like catalyst is applied to the gas fermentation system of acetic acid-producing bacteria. It efficiently activates hydrogen extracellularly. The extracellular electrons generated can be transferred to the cell by electron carriers or acceptors such as riboflavin, metal ions, and respiratory enzymes to generate reducing power, which is expected to achieve efficient utilization of H2 and efficient fixation of CO2.

[0015] No research or application of a hybrid system of a hydrogenase-like catalyst and acetogenic bacteria has been found in the patents and literature disclosed in the prior art.

[0016] Summary of the Invention

[0017] In order to solve the problem of low H2 utilization and CO2 fixation efficiency of acetogenic bacteria, the present invention provides a chemical catalyst-microbial carbon fixation system and its application for improving H2 utilization efficiency. In this application, the efficient hydrogen activation ability of the hydrogenase-like catalyst is combined with acetogenic bacteria to construct a hybrid system of hydrogenase-like catalyst-acetogenic bacteria, which can achieve efficient H2 utilization and efficient CO2 fixation.

[0018] According to one aspect of the present application, a carbon fixation system for efficient utilization of H2 is provided, wherein the carbon fixation system comprises a composition, wherein the composition comprises a hydrogenase-like catalyst and acetogenic bacteria; further, the hydrogenase-like catalyst is a heterogeneous catalyst having hydrogen activation ability designed to mimic the function of hydrogenase; further, the hydrogenase-like catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silicon dioxide, graphene, graphene oxide, carbon dots or ferrosoferric oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the hydrogenase-like catalyst The catalyst is selected from one or more of a platinum-ferrocetate imitating hydrogenase catalyst, a cobalt-carbon nanotube imitating hydrogenase catalyst, a nickel-carbon nanotube imitating hydrogenase catalyst, an iron-carbon nanotube imitating hydrogenase catalyst, an iron-silicon dioxide imitating hydrogenase catalyst, a nickel-silicon dioxide imitating hydrogenase catalyst and a cobalt-silicon dioxide imitating hydrogenase catalyst; further, the acetogenic bacteria is a bacterium that fixes CO2 through the Wood-Jungdahl pathway and grows autotrophically; further, the acetogenic bacteria is selected from one or more of Clostridium jungdahl, Clostridium autoethanogenum, Clostridium ragsallii and Clostridium carboxydophorum; further, the acetogenic bacteria is selected from one or more of Clostridium jungdahl DSM 13528 and Clostridium ethanologenum DSM 10061 or Clostridium carboxydophorum P7 DSM15243T.

[0019] According to another aspect of the present application, a composition is provided, comprising a hydrogenase-like catalyst and acetogenic bacteria; further, the hydrogenase-like catalyst is a heterogeneous catalyst designed to mimic the function of hydrogenase and having hydrogen activation ability; further, the hydrogenase-like catalyst comprises a carrier and an active center; further, the carrier is selected from carbon nanotubes, One or more of silicon dioxide, graphene, graphene oxide, carbon dots or ferrous oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the hydrogenase-like catalyst is selected from one or more of platinum-ferrous oxide hydrogenase-like catalyst, cobalt-carbon nanotube hydrogenase-like catalyst, nickel-carbon nanotube hydrogenase-like catalyst, iron-carbon nanotube hydrogenase-like catalyst, iron-silica hydrogenase-like catalyst, nickel-silica hydrogenase-like catalyst and cobalt-silica hydrogenase-like catalyst; further, the acetogenic bacteria is a bacterium that fixes CO2 through the Wood-Jungdahl pathway and grows autotrophically; further, the acetogenic bacteria is selected from one or more of Clostridium jondahl, Clostridium autoethanogenum, Clostridium ragsallii and Clostridium monoxide-eating; further, the acetogenic bacteria is selected from one or more of Clostridium jondahl DSM 13528 and Clostridium ethanologenum DSM 10061 or Clostridium monoxide-eating P7 DSM15243T.

[0020] According to another aspect of the present application, one of the following uses of a hydrogenase-like catalyst is provided,

[0021] 1) Used to promote the efficiency of microbial H2 utilization:

[0022] 2) Use for promoting microbial carbon fixation;

[0023] 3) Use for promoting microbial fixation of CO2;

[0024] 4) Use for promoting or increasing the biomass or cell mass of microorganisms;

[0025] 5) Use for promoting the yield or production efficiency of metabolites produced by microorganisms;

[0026] 6) Use for promoting the yield or production efficiency of ethanol, butanol, hexanol, acetic acid, butyric acid, caproic acid, lactic acid, 2,3-butanediol, acetone, isopropanol, or 3-hydroxybutyric acid produced by microorganisms;

[0027] The composition comprises a hydrogenase-like catalyst and acetogenic bacteria; further, the hydrogenase-like catalyst is a heterogeneous catalyst designed to mimic the function of hydrogenase and has hydrogen activation ability; further, the hydrogenase-like catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silicon dioxide, graphene, graphene oxide, carbon dots or ferroferric oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the hydrogenase-like catalyst is selected from platinum-ferroferric oxide hydrogenase-like catalyst, cobalt- One or more of a carbon nanotube-like hydrogenase catalyst, a nickel-carbon nanotube-like hydrogenase catalyst, an iron-carbon nanotube-like hydrogenase catalyst, an iron-silica-like hydrogenase catalyst, a nickel-silica-like hydrogenase catalyst and a cobalt-silica-like hydrogenase catalyst; further, the acetogenic bacteria is a bacterium that fixes CO2 through the Wood-Jungdahl pathway and grows autotrophically; further, the acetogenic bacteria is selected from one or more of Clostridium jungdahl, Clostridium autoethanogenum, Clostridium rassenbergii and Clostridium carboxydophorum; further, the acetogenic bacteria is selected from one or more of Clostridium jungdahl DSM 13528 and Clostridium ethanologenum DSM 10061 or Clostridium carboxydophorum P7 DSM15243T; further, the metabolites are primary metabolites or secondary metabolites of microorganisms; further, the metabolites include one or more of acetic acid, ethanol, butyric acid, butanol, hexanoic acid and hexanol.

[0028] According to another aspect of the present application, a method for producing metabolites by microorganisms is provided, comprising the steps of utilizing the above-mentioned carbon fixation system or the above-mentioned composition; further, the metabolites are primary metabolites or secondary metabolites of the microorganisms; further, the metabolites include one or more of acetic acid, ethanol, butyric acid, butanol, hexanoic acid, and hexanol.

[0029] According to another aspect of the present application, a method for improving the efficiency of H2 utilization by microorganisms is provided, comprising the step of adding a hydrogenase-like catalyst during the production or fermentation process of the microorganism, for example, before fermentation culture inoculation or at a certain stage after inoculation; the hydrogenase-like catalyst is a heterogeneous catalyst with hydrogen activation ability designed to mimic the function of hydrogenase; further, the hydrogenase-like catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silicon dioxide, graphene, graphene oxide, carbon dots or ferrosoferric oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, The hydrogenase-like catalyst is selected from one or more of a platinum-ferric oxide hydrogenase-like catalyst, a cobalt-carbon nanotube hydrogenase-like catalyst, a nickel-carbon nanotube hydrogenase-like catalyst, an iron-carbon nanotube hydrogenase-like catalyst, an iron-silicon dioxide hydrogenase-like catalyst, a nickel-silicon dioxide hydrogenase-like catalyst and a cobalt-silicon dioxide hydrogenase-like catalyst; further, the acetogenic bacteria is a bacterium that fixes CO2 through the Wood-Ljungdahl pathway and grows autotrophically; further, the acetogenic bacteria is selected from one or more of Clostridium Ljungdahl, Clostridium autoethanogenum, Clostridium ragbe and Clostridium carboxydotrophicum; further, the acetogenic bacteria is selected from Clostridium Ljungdahl DSM 13528 and one or more of ethanol-producing Clostridium DSM 10061 or edible carbon monoxide Clostridium P7DSM15243T; further, the production or fermentation process uses H2 and C1 gases as the main gas sources; further, the gas source composition is H2, CO2, or H2, CO2 and CO, or H2, CO; further, the H2 ratio is 10% to 90%.

[0030] According to another aspect of the present application, a method for promoting carbon fixation in microorganisms is provided, comprising the step of adding a hydrogenase-like catalyst during the production or fermentation process of the microorganism, for example, before fermentation culture inoculation or at a certain stage after inoculation; the hydrogenase-like catalyst is a heterogeneous catalyst with hydrogen activation ability designed to mimic the function of hydrogenase; further, the hydrogenase-like catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silicon dioxide, graphene, graphene oxide, carbon dots or ferrosoferric oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the The hydrogenase-like catalyst is selected from one or more of a platinum-ferric oxide hydrogenase-like catalyst, a cobalt-carbon nanotube hydrogenase-like catalyst, a nickel-carbon nanotube hydrogenase-like catalyst, an iron-carbon nanotube hydrogenase-like catalyst, an iron-silicon dioxide hydrogenase-like catalyst, a nickel-silicon dioxide hydrogenase-like catalyst and a cobalt-silicon dioxide hydrogenase-like catalyst; further, the acetogenic bacteria is a bacterium that fixes CO2 through the Wood-Jungdahl pathway and grows autotrophically; further, the acetogenic bacteria is selected from one or more of Clostridium jungdahl, Clostridium autoethanogenum, Clostridium ragbeckii and Clostridium carboxydophorum; further, the acetogenic bacteria is selected from Clostridium jungdahlii DSM. 13528 and one or more of ethanologenic Clostridium DSM 10061 or edible carbon monoxide Clostridium P7 DSM15243T; further, the production or fermentation process uses H2 and C1 gases as the main gas sources; further, the gas source composition is H2, CO2, or H2, CO2 and CO, or H2, CO; further, the H2 ratio is 10% to 90%.

[0031] According to another aspect of the present application, a method for promoting or improving the carbon fixation efficiency of microorganisms is provided, comprising the step of adding a hydrogenase-like catalyst during the production or fermentation process of the microorganism, for example, before fermentation culture inoculation or at a certain stage after inoculation; the hydrogenase-like catalyst is a heterogeneous catalyst with hydrogen activation ability designed to mimic the function of hydrogenase; further, the hydrogenase-like catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silicon dioxide, graphene, graphene oxide, carbon dots or ferrosoferric oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further , the hydrogenase-like catalyst is selected from one or more of a platinum-ferric oxide hydrogenase-like catalyst, a cobalt-carbon nanotube hydrogenase-like catalyst, a nickel-carbon nanotube hydrogenase-like catalyst, an iron-carbon nanotube hydrogenase-like catalyst, an iron-silicon dioxide hydrogenase-like catalyst, a nickel-silicon dioxide hydrogenase-like catalyst and a cobalt-silicon dioxide hydrogenase-like catalyst; further, the acetogenic bacteria is a bacterium that fixes CO2 through the Wood-Jungdahl pathway and grows autotrophically; further, the acetogenic bacteria is selected from one or more of Clostridium jungdahl, Clostridium autoethanogenum, Clostridium ragsallii and Clostridium carboxydophorum; further, the acetogenic bacteria is selected from Clostridium jungdahlii DSM 13528 and one or more of ethanol-producing Clostridium DSM 10061 or edible carbon monoxide Clostridium P7DSM15243T; further, the production or fermentation process uses H2 and C1 gases as the main gas sources; further, the gas source composition is H2, CO2, or composed of H2, CO2 and CO, or further composed of H2, CO; further, the H2 ratio is 10% to 90%.

[0032] According to another aspect of the present application, a method for producing ethanol by microorganisms is provided, comprising the step of utilizing the above-mentioned carbon fixation system or the above-mentioned composition; further, comprising a process of fermenting in an environment containing H2 and C1 gases; further, the gas source composition is H2, CO2, or H2, CO2 and CO, or H2, CO; further, the H2 ratio is 10% to 90%; further, comprising the steps of strain activation, adaptation subculture and fermentation culture stages, and adding the hydrogenase-like catalyst during the fermentation culture stage.

[0033] According to another aspect of the present application, a method for producing acetic acid by microorganisms is provided, comprising the steps of the above-mentioned carbon fixation system or the above-mentioned composition; further, comprising a process of fermentation in an environment containing H2 and Cl gases; further, the gas source composition is H2, CO2, or H2, CO2 and CO, or H2, CO; further, the H2 ratio is 10% to 90%; further, comprising the steps of strain activation, adaptation subculture and fermentation culture stages, and adding the hydrogenase-like catalyst during the fermentation culture stage.

[0034] Optionally, H2 and Cl gases are used as the main gas sources during the adaptation and subculture stage, and the H2 content is 20% to 80%, for example, 20%, 30%, 40%, 50%, 60%, 70%, or 80%. The Cl gas may be CO or CO2, and the gas source may be H2 and CO2, or the gas source may be H2, CO, and CO2, or the gas source may be H2 and CO.

[0035] Optionally, H2 and Cl gases are used as the main gas sources during the fermentation culture stage, and the H2 content is 20% to 80%, for example, 20%, 30%, 40%, 50%, 60%, 70%, or 80%. The Cl gas may be CO or CO2, and the gas source may be H2 and CO2, or the gas source may be H2, CO, and CO2, or the gas source may be H2 and CO.

[0036] It should be noted that the present invention improves the efficiency of CO2 fixation in the environment and increases the yield of the target product by improving the utilization efficiency of H2. The proportion of CO2 in the C1 gas raw material is different, and the target product is different, and the requirements for the proportion of H2 are also different. Therefore, it can be understood by those skilled in the art that, depending on the different proportions of CO and CO2 in the C1 gas raw material and the difference in the target product, the H2 proportion ranges from 10% to 90%, for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%, and this solution may be applicable. The C1 gas can be CO or CO2, and the gas source can be H2 and CO2, or the gas source can be H2, CO and CO2, or the gas source can be H2 and CO.

[0037] Optionally, the hydrogenase-like catalyst is added to the culture system, and the content of the hydrogenase catalyst is greater than 0.05 g / L, and further the content can be greater than 0.1 g / L, greater than 0.2 g / L, and the range can be 0.1 g / L, 0.15 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L or 0.5 g / L.

[0038] It should be noted that the above-mentioned carbon fixation products are directly or indirectly synthesized by acetic acid-producing bacteria through the Wood-Jungdahl pathway. It can be understood by those skilled in the art that the carbon fixation system provided in this application can be used to transform the strains during the microbial carbon fixation process and then use gas fermentation to synthesize other products in addition to natural products such as acetic acid and ethanol. Therefore, the carbon fixation products referred to in this application are not limited to the above-mentioned products.

[0039] Those skilled in the art will appreciate that some acetogenic bacteria can utilize CO2 for autotrophic growth and product synthesis. During this process, some CO2 is converted into CO2 and discharged. The present invention improves the efficiency of CO2 fixation in the environment by improving the efficiency of H2 utilization. Therefore, those skilled in the art will understand that the present invention is also applicable to H2 and CO fermentation processes.

[0040] It should be noted that the amount of hydrogenase-like catalyst required to achieve the best effect may vary depending on the activity of the catalyst, the fermentation method and the technology. The scope of protection of this solution should not be limited by the catalyst content in the system.

[0041] The beneficial effects of this application include but are not limited to:

[0042] 1. According to the carbon fixation system for efficient utilization of H2 of the present application, the utilization efficiency of H2 and CO2 gases is significantly improved, the concentration of acid and alcohol in the product is significantly increased, the acid-alcohol ratio is reduced, and the biomass of acetic acid-producing bacteria is also significantly increased.

[0043] 2. According to the carbon fixation system of the present application that efficiently utilizes H2, compared with using only acetic acid-producing bacteria, in one embodiment, the biomass is increased by 1 times, the acetic acid yield is increased by 60%, and the ethanol concentration is increased by as much as 20 times, reaching 45g / L, which is a significant technological advancement compared to the existing technical solutions.

[0044] 3. According to the carbon fixation system of the present application that efficiently utilizes H2, the utilization efficiency of H2 and CO2 is significantly improved, the ethanol content is increased, and thus the added value of the product is increased. It is of great significance to the industrial implementation of CO2 biological fixation using H2 as an energy source, and has broad application scenarios and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0046] FIG1 shows the in vitro model experimental results of the reduction of p-nitrophenol by seven hydrogenase-like catalysts involved in this application;

[0047] Figure 2 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Co@NCNT-Clostridium Jungdalar hybrid system constructed by adding different amounts of Co@NCNT catalyst at the 50 ml shake flask fermentation scale involved in Example 1 of the present application (circle: Clostridium Jungdalar; square: Co@NCNT-Clostridium Jungdalar hybrid system containing 2.5 mg of catalyst; equilateral triangle: Co@NCNT-Clostridium Jungdalar hybrid system containing 5 mg of catalyst; inverted triangle: Co@NCNT-Clostridium Jungdalar hybrid system containing 10 mg of catalyst; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0048] FIG3 shows the growth and metabolite characteristics of the fermentation of gas feedstocks containing different ratios of H2 using the Co@NCNT-Clostridium jondahl hybrid system at a 50 ml shake flask fermentation scale according to Example 2 of the present application (circles: CO2:H2=4:6; triangles: CO2:H2=3:7; squares: CO2:H2=1:3);

[0049] FIG4 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Yungdal in the Pt@Fe3O4-Clostridium Yungdal hybrid system at the 50 ml shake flask fermentation scale involved in Example 3 of the present application (circles: Clostridium Yungdal; squares: Pt@Fe3O4-Clostridium Yungdal hybrid system; A is the growth status of Clostridium Yungdal cells; B is the acetic acid content; C is the ethanol content);

[0050] FIG5 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Fe@NCNT-Clostridium Jungdalar hybrid system at a 50 ml shake flask fermentation scale according to Example 4 of the present application (solid circles: Clostridium Jungdalar; hollow circles: Fe@NCNT-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0051] FIG6 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Ni@NCNT-Clostridium Jungdalar hybrid system at the 50 ml shake flask fermentation scale involved in Example 5 of the present application (circles: Clostridium Jungdalar; inverted triangles: Ni@NCNT-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0052] FIG7 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Ni@SiO2-Clostridium Jungdalar hybrid system at the 50 ml shake flask fermentation scale involved in Example 6 of the present application (solid circles: Clostridium Jungdalar; half hollow circles: Ni@SiO2-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0053] FIG8 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Co@SiO2-Clostridium Jungdalar hybrid system at the 50 ml shake flask fermentation scale involved in Example 7 of the present application (solid circles: Clostridium Jungdalar; open squares: Co@SiO2-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0054] FIG9 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Fe@SiO2-Clostridium Jungdalar hybrid system at the 50 ml shake flask fermentation scale involved in Example 8 of the present application (circles: Clostridium Jungdalar; diamonds: Fe@SiO2-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0055] FIG10 shows the results of the Co@NCNT-Clostridium autoethanogenum hybrid system compared with the fermentation growth and metabolite characteristics of Clostridium autoethanogenum at the 50 ml shake flask fermentation scale involved in Example 9 of the present application (hexagons: Clostridium autoethanogenum; triangles: Co@NCNT-Clostridium autoethanogenum hybrid system; A is the growth status of Clostridium autoethanogenum cells; B is the acetic acid content; C is the ethanol content);

[0056] FIG11 shows the results of comparing the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the Co@NCNT-Clostridium Jungdalar hybrid system at a 50 L fermentor scale according to Example 10 of the present application (circles: Clostridium Jungdalar; triangles: Co@NCNT-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0057] FIG12 is a comparison of the fermentation growth and metabolite characteristics of Clostridium Jungdalar in the optimized Co@NCNT-Clostridium Jungdalar hybrid system at the 50 L fermentor scale according to Example 11 of the present application (circles: Clostridium Jungdalar; inverted triangles: Co@NCNT-Clostridium Jungdalar hybrid system; A is the growth status of Clostridium Jungdalar cells; B is the acetic acid content; C is the ethanol content);

[0058] Figure 13 is the results of comparing the fermentation growth and metabolite characteristics of Clostridium monoxide-eating bacteria in the Co@NCNT-Clostridium monoxide-eating hybrid system at the 50 ml shake flask fermentation scale involved in Example 12 of the present application (solid figures: Clostridium monoxide-eating bacteria; hollow figures: Co@NCNT-Clostridium monoxide-eating bacteria hybrid system; the circles in Figure A represent the growth status of Clostridium monoxide-eating bacteria, the circles in Figure B represent the acetic acid concentration; the triangles in Figure B represent the butyric acid concentration; the diamonds represent the hexanoic acid concentration; the circles in Figure C represent the ethanol concentration; the triangles in Figure C represent the butanol concentration; the diamonds in Figure C represent the hexanol concentration). DETAILED DESCRIPTION

[0059] The present application is described in detail below with reference to examples, but the present application is not limited to these examples. Unless otherwise specified, the raw materials and catalyst preparation raw materials in the examples of the present application are purchased through commercial channels.

[0060] The present application scheme is described in detail below with reference to specific embodiments.

[0061] The strains used in this application were Clostridium jondahlii DSM 13528, Clostridium ethanologenum DSM 10061 and Clostridium carboxydodecene P7 DSM 15243T (purchased from the German Collection of Microorganisms and Cell Cultures).

[0062] All preserved strains need to be activated before fermentation: the corresponding strains are inoculated at a 10% inoculum rate into 50 mL of PETC gas culture medium (containing 20% ​​to 90% CO, the rest being synthesis gas of CO2 and H2, at a pressure of 0.15 to 0.2 MPa) and incubated at a constant temperature of 37°C for 48 hours for activation.

[0063] The liquid PETC medium used for fermentation contains: macroelements (ammonium chloride 0.5 g / L, potassium chloride 0.2 g / L, magnesium sulfate heptahydrate 0.4 g / L, sodium chloride 1 g / L, potassium dihydrogen phosphate 0.2 g / L, sodium tungstate 0.005 g / L), trace metal elements (manganese chloride tetrahydrate 0.015 g / L, manganese sulfate monohydrate 0.015 g / L, ferrous sulfate 0.04 g / L, cobalt chloride hexahydrate 0.004 g / L, zinc sulfate heptahydrate 0.0 04g / L, nickel chloride hexahydrate 0.0004g / L, sodium molybdate 0.004g / L, sodium selenate 0.002g / L), magnesium chloride 0.4g / L, calcium chloride monohydrate 0.02g / L, calcium chloride 0.2g / L, nitrilotriacetic acid 0.002g / L, resazurin 0.001g / L, yeast powder 1g / L, L-cysteine ​​0.25g / L, 0.1% vitamin mixture (biotin 2mg / L, folic acid 2mg / L, vitamin B6 10mg / L, thiamine 5mg / L, riboflavin 5mg / L, calcium pantothenate 5mg / L, lipoic acid 5mg / L, p-aminobenzoic acid 5mg / L, cyanocobalamin 5mg / L, niacin 5mg / L).

[0064] Cell biomass was determined by measuring the absorbance at 600 nm (OD 600nm ) evaluation. Due to the magnetic properties of the catalyst support or the catalytic center metal, after sampling, the catalyst is removed by magnetic adsorption and the OD of the culture medium is measured. 600nm value.

[0065] Product analysis was performed using high-performance liquid chromatography (HPLC). The instrument used was an Agilent HPLC 1260 (differential refractive index). Chromatographic conditions included: an Aminex HPX-87H column; a mobile phase of 5 mM sulfuric acid; a flow rate of 0.5 mL / min; an injection volume of 10 μL; a column temperature of 55°C; and a differential refractive index detector. Sample preparation involved centrifugation of the fermentation broth at 12,000 rpm for 5 minutes at 4°C. The supernatant was diluted appropriately and filtered through a 0.22 μm microporous filter before analysis by HPLC.

[0066] The hydrogenase-like catalysts used in this application, such as Pt@Fe3O4, Co@NCNT, Ni@NCNT, Fe@NCNT, Fe@SiO2, Ni@SiO2, Co@SiO2, etc., can be prepared by methods known in the prior art or purchased through commercial channels, for example, they can be prepared by reference to the literature (Physicochemical and Engineering Aspects, 2004, 245(1-3), 15-19; Journal of Energy Chemistry, 2021, 52, 12-19; ​​ACS Sustainable Chemistry & Engineering, 2018, 6(10), 13287-13295.). At the same time, the present invention provides the following optional but not exclusive preparation methods:

[0067] Preparation of platinum-ferroferric oxide hydrogenase-like catalyst Pt@Fe3O4:

[0068] 1) Preparation of Fe3O4 Nanoparticles: 2.35 g of FeCl3·6H2O and 0.86 g of FeCl2·4H2O were weighed and placed in a 250 mL Schlenk flask. 100 mL of deionized water was added to dissolve the mixture. 13% aqueous ammonia was slowly added dropwise with stirring until the pH of the reaction solution reached 10. The reaction system transformed from a solution to a suspension, and its color changed from orange-red to reddish-brown and finally to inky black. The black powder was collected by centrifugation, washed with deionized water until the supernatant maintained its pH, and freeze-dried to obtain Fe3O4 nanoparticles.

[0069] 2) Preparation of aminated Fe3O4 nanoparticles (Fe3O4-NH2): 0.3 g of Fe3O4 nanoparticles were ultrasonically dispersed in 250 mL of deionized water, heated to 60°C, and 0.2 mL of APTES was added with stirring. Stirring was continued for 30 min, and 0.5 mL of ammonia was added dropwise. The reaction was continued for 1 h. The solid was collected by centrifugation, rinsed with deionized water and then with flowing CO2 gas, and dried in vacuo to obtain a black magnetic powder.

[0070] 3) Under nitrogen protection, 0.2 g of Fe3O4-NH2 nanoparticles were dispersed in a freshly prepared sodium borohydride solution. 1 mL of H2PtCl6 solution (10 mg / mL) was added dropwise with stirring. The mixture was stirred for 6 h, and the black powder was collected by centrifugation. The powder was washed with deionized water and ethanol, and dried in vacuo to obtain Pt@Fe3O4 nanoparticles.

[0071] Preparation of Cobalt-Carbon Nanotube Hydrogenase-like Catalyst Co@NCNT:

[0072] 1) Weigh 0.4 g of melamine, 0.4 g of citric acid monohydrate, and 0.3 g of Co(NO₃)₂·6H₂O into a 500 mL round-bottom flask. Add 200 mL of deionized water and react at 85°C overnight to obtain a pink powder.

[0073] 2) 1 g of the pink powder was spread evenly on a quartz boat, placed in a tube furnace, and calcined at 700°C for 1 h under a nitrogen atmosphere. The temperature was then raised to 800°C and calcined for 0.5 h to obtain Co@NCNT material.

[0074] Preparation of nickel-carbon nanotube hydrogenase-like catalyst Ni@NCNT:

[0075] 1) Weigh 0.4 g of melamine, 0.4 g of citric acid monohydrate, and 0.27 g of Ni(NO₃)₂·6H₂O into a 500 mL round-bottom flask. Add 200 mL of deionized water and react at 85°C overnight to obtain a light green powder.

[0076] 2) 1 g of light green powder was spread evenly on a quartz boat, placed in a tube furnace, and calcined at 700°C for 1 h under a nitrogen atmosphere. The temperature was then raised to 800°C and calcined for 0.5 h to obtain Ni@NCNT material.

[0077] Preparation of Fe-carbon nanotube hydrogenase-like catalyst Fe@NCNT:

[0078] 1) Weigh 0.4 g of melamine, 0.4 g of citric acid monohydrate, and 0.42 g of Fe(NO₃)₃·9H₂O into a 500 mL round-bottom flask. Add 200 mL of deionized water and react at 85°C overnight to obtain a yellow powder.

[0079] 2) 1 g of the yellow powder was spread evenly on a quartz boat, placed in a tube furnace, and calcined at 700°C for 1 h under a nitrogen atmosphere. The temperature was then raised to 800°C and calcined for 0.5 h to obtain Ni@NCNT material.

[0080] Preparation of iron-silica hydrogenase-like catalyst Fe@SiO2:

[0081] 1) Weigh 0.28 g of Fe(NO3)3·9H2O and dissolve it in 3.5 mL of deionized water. Add 3 g of SiO2 and disperse it by ultrasonication for 1 h. Stir at room temperature for 8 h. Remove the water by rotary evaporation and dry at 80°C overnight.

[0082] 2) In a tube furnace, in static air, the temperature was raised to 450°C at a heating rate of 1.5°C / min and calcined for 1 h to obtain Fe@SiO2 material.

[0083] Preparation of nickel-silica hydrogenase-like catalyst Ni@SiO2:

[0084] 1) Weigh 0.18 g of Ni(NO3)2·6H2O and dissolve it in 3.5 mL of deionized water. Add 3 g of SiO2 and disperse it by ultrasonication for 1 h. Stir at room temperature for 8 h. Remove the water by rotary evaporation and dry at 80°C overnight.

[0085] 2) In a tube furnace, in static air, the temperature was raised to 450°C at a heating rate of 1.5°C / min and calcined for 1 h to obtain Ni@SiO2 material.

[0086] Preparation of Cobalt-Silica Hydrogenase-like Catalyst Co@SiO2:

[0087] 1) Weigh 0.2 g of Co(NO3)2·6H2O and dissolve it in 3.5 mL of deionized water. Add 3 g of SiO2 and disperse it by ultrasonication for 1 h. Stir at room temperature for 8 h. Remove the water by rotary evaporation and dry at 80°C overnight.

[0088] 2) In a tube furnace, in static air, the temperature was raised to 450°C at a heating rate of 1.5°C / min and calcined for 1 h to obtain Co@SiO2 material.

[0089] The in vitro hydrogen activation performance of the catalyst was tested by an in vitro model experiment of reducing p-nitrophenol. The specific method is as follows:

[0090] 1) At room temperature, add 10 mg of catalyst powder to a Schlenk tube, add 9 mL of pure water, and ultrasonically disperse. Add 1 mL of 10 mmol / L p-nitrophenol solution, and introduce hydrogen replacement gas three times under hydrogen protection. Sampling is performed regularly.

[0091] 2) Scan the absorbance between 250 and 550 nm using a UV-visible spectrophotometer until the curve no longer changes. The scan results are shown in Figure 1. p-Nitrophenol has a characteristic absorption peak at 400 nm. After the nitro group is reduced to an amine group, the absorption peak at 400 nm gradually disappears over time. The results in Figure 1 show that the prepared Pt@Fe3O4, Co@NCNT, Ni@NCNT, Fe@NCNT, Ni@SiO2, Co@SiO2, and Fe@SiO2 materials only take 3 minutes, 15 minutes, 11 minutes, 20 minutes, 14 minutes, 17 minutes, and 20 minutes, respectively, to completely catalyze the p-nitrophenol solution, demonstrating that the prepared catalyst materials can efficiently activate hydrogen.

[0092] Comparative Example 1: Gas fermentation experiment of Clostridium jondahlii DSM 13528 on a 50 ml scale

[0093] The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2+H2, ratio of 4:6, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the culture was subcultured in PETC gas medium (CO2+H2, ratio of 4:6, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source. The acclimated bacterial liquid was then transferred to 50mL PETC gas medium (CO2+H2, ratio of 4:6) at a 10% inoculum volume and cultured in shake flasks at 37℃.

[0094] Example 1 Comparative Experiment on Catalyst Addition Amount of Co@NCNT-Clostridium jundal Hybrid System

[0095] 1) The activated Clostridium jundal DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 4:6, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 4:6, pressure of 0.1-0.2MPa) for more than 2 generations to make the strain completely adapt to growing with CO2 as the carbon source.

[0096] 2) Weigh 2.5 mg, 5 mg, and 10 mg of Co@NCNT catalyst, respectively, resuspend them in 500 μL of PETC medium, and add them to anaerobic bottles containing 50 ml of PETC medium. Then, each anaerobic bottle is filled with CO2+H2 gas (ratio of 4:6, pressure of 0.2 MPa).

[0097] 3) The bacterial solution acclimated in step 1) was transferred to 50 mL of the above-mentioned PETC gas culture medium containing different doses of hydrogenase-like catalyst at a 10% inoculum volume, and fermented in a shake flask at 37°C.

[0098] The results are shown in Figure 2. Compared with the fermentation of Clostridium jundal, the hybrid system with the addition of catalyst fermented CO2 + H2, and the cell biomass, acetic acid concentration, and ethanol concentration were all improved. At the 50ml scale, the addition of 5mg (0.1g / L) of catalyst had the best effect, with the biomass and acetic acid concentrations increased by about 100%, and the ethanol concentration increased by nearly 3 times to 0.65g / L. In addition, the addition of 0.2g / L catalyst slowed the growth of primary cells in the fermentation, but in the later stages of fermentation, the fermentation effect was comparable to that of 0.1g / L catalyst, indicating that at higher cell concentrations, the addition of higher doses of catalyst is expected to have better fermentation effects.

[0099] Example 2 Comparative fermentation experiment of Co@NCNT-Clostridium jundal hybrid system under different CO2 and H2 ratios

[0100] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2+H2, ratio of 4:6 to 1:3, pressure of 0.1 to 0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 4:6~1:3, pressure of 0.1~0.2MPa) for more than 2 generations to make the strain completely adapt to growth with CO2 as carbon source.

[0101] 2) Weigh 5 mg of Co@NCNT catalyst and resuspend each in 500 μl of PETC medium. Add each to an anaerobic bottle containing 50 ml of PETC medium. Each anaerobic bottle is then filled with CO2+H2 gas (CO2:H2 ratios of 4:6, 3:7, and 1:3, respectively, and the pressure is 0.2 MPa).

[0102] 3) The bacterial solution acclimated under the corresponding gas ratio in step 1) was transferred at a 10% inoculum volume into 50 mL of PETC gas culture medium with different CO2 and H2 ratios, and fermented in a shake flask at 37°C.

[0103] The results are shown in Figure 3. At a 50 ml scale, under the three gas ratios, compared with Comparative Example 1, the biomass and acetic acid concentrations were both increased by about 100%, and the ethanol concentrations were increased by 3 times, 5 times, and 7 times, respectively. The highest ethanol yield and the shortest growth delay period were achieved when the CO2:H2 ratio was 1:3, and the ethanol concentration reached 1.1 g / L. The subsequent shake flask fermentation experiment was conducted using a gas source with a CO2:H2 ratio of 1:3.

[0104] Comparative Example 2: 50 ml scale gas fermentation experiment of Clostridium jondahlii DSM 13528 (CO2:H2=1:3)

[0105] The activated Clostridium jundal DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the culture was subcultured in PETC gas medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source. The acclimated bacterial liquid was then transferred to 50mL PETC gas medium (CO2+H2, ratio of 1:3, pressure of 0.2MPa) at a 10% inoculum volume and cultured in shake flasks at 37℃.

[0106] Example 3 Pt@Fe3O4-Clostridium jundal 50ml scale gas fermentation experiment

[0107] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0108] 2) Take 5 mg of Pt@Fe3O4 catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio of 1:3, pressure of 0.2 MPa).

[0109] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Pt@Fe3O4 catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37°C. Samples were taken every 24 hours to monitor biomass and product.

[0110] The results are shown in Figure 4. Compared with Comparative Example 2, the Pt@Fe3O4-Clostridium jundal hybrid system fermented CO2+H2, and the cell biomass and acetic acid concentrations increased by more than 100%, and the ethanol concentration increased by 2.3 times, reaching 0.75 g / L.

[0111] Example 4: Fe@NCNT-Clostridium jundal 50 ml scale gas fermentation experiment

[0112] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0113] 2) Take 5 mg of Fe@NCNT catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio of 1:3, pressure of 0.2 MPa).

[0114] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Fe@NCNT catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37° C. Sampling was performed every 24 hours to monitor the biomass and product.

[0115] The results are shown in Figure 5. Compared with Comparative Example 2, the Fe@NCNT-Clostridium jundal hybrid system fermented CO2+H2, and the cell biomass increased by about 50%, the acetic acid concentration increased by 1 times, and the ethanol concentration increased by about 2 times to 0.6 g / L.

[0116] Example 5 Ni@NCNT-Clostridium jundal 50ml scale gas fermentation experiment

[0117] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0118] 2) Take 5 mg of Ni@NCNT catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio of 1:3, pressure of 0.2 MPa).

[0119] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Ni@NCNT catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37° C. Sampling was performed every 24 hours to monitor the biomass and product.

[0120] The results are shown in Figure 6. Compared with Comparative Example 2, the cell biomass of the Ni@NCNT-Clostridium jundal hybrid system fermented CO2+H2, increased by 60%, the acetic acid concentration increased by about 100%, and the ethanol concentration increased by 2.5 times to 0.78 g / L.

[0121] Example 6 Ni@SiO2-Clostridium jundal 50ml scale gas fermentation experiment

[0122] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0123] 2) Take 5 mg of Ni@SiO2 catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio is 1:3, pressure is 0.2 MPa).

[0124] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Ni@SiO2 catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37°C. Samples were taken every 24 hours to monitor biomass and product.

[0125] The results are shown in Figure 7. Compared with Comparative Example 2, the cell biomass of the Ni@SiO2-Clostridium jundal hybrid system fermented CO2+H2, increased by about 1 times, the acetic acid concentration increased by 1.2 times, and the ethanol concentration increased by 2 times to 0.67 g / L.

[0126] Example 7 Co@SiO2-Clostridium jundal 50ml scale gas fermentation experiment

[0127] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0128] 2) Take 5 mg of Co@SiO2 catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio is 1:3, pressure is 0.2 MPa).

[0129] 3) The acclimated bacterial liquid was inoculated into the above-mentioned PETC gas culture medium containing Co@SiO2 catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37°C. Samples were taken every 24 hours to monitor biomass and product.

[0130] As shown in FIG8 , compared with Comparative Example 2, the cell biomass of the Co@SiO2-Clostridium jundal hybrid system fermenting CO2+H2 increased by 50%, the acetic acid concentration increased by 1.3 times, and the ethanol concentration increased by 1.5 times to 0.56 g / L.

[0131] Example 8 Fe@SiO2-Clostridium jundal 50ml scale gas fermentation experiment

[0132] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0133] 2) Take 5 mg of Fe@SiO2 catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio is 1:3, pressure is 0.2 MPa).

[0134] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Fe@SiO2 catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37°C. Samples were taken every 24 hours to monitor biomass and product.

[0135] The results are shown in FIG9 . Compared with comparative example 2 , the Fe@SiO2 - Clostridium jundal hybrid system fermented CO2 + H2 , and the cell biomass and acetic acid concentration increased by 1 times , and the ethanol concentration increased by 1.5 times to 0.5 g / L .

[0136] Comparative Example 3: Fermentation experiment of autoethanogen Clostridium DSM 10061 in 50 ml shake flask

[0137] The activated Clostridium autoethanogenum DSM 10061 bacterial suspension was transferred to 50 mL of PETC gas medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and adaptively cultured to an OD600nm value of approximately 0.2. The strain was then subcultured in PETC gas medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) for two or more generations to fully adapt the strain to growth using CO2 as a carbon source. The acclimated bacterial suspension was then transferred to 50 mL of PETC gas medium (CO2 + H2, ratio of 1:3, pressure of 0.2 MPa) at a 10% inoculum volume and cultured in shake flasks at 37°C.

[0138] Example 9 Co@NCNT-Clostridium autoethanogenum 50ml scale gas fermentation experiment

[0139] 1) The activated autoethanogenous Clostridium DSM 10061 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0140] 2) Take 5 mg of Co@NCNT catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with CO2+H2 gas (CO2:H2 ratio is 1:3, pressure is 0.2 MPa).

[0141] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Co@NCNT catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37° C. Sampling was performed every 24 hours to monitor biomass and product.

[0142] The results are shown in Figure 10. Compared with Comparative Example 3, the cell biomass of the Co@NCNT-autoethanogenic Clostridium hybrid system in the fermentation of CO2+H2 increased by more than 1 times, the acetic acid concentration increased by more than 50%, and the ethanol concentration increased by more than 1 times to 0.8 g / L.

[0143] Comparative Example 4: 50L scale gas fermentation experiment of Clostridium Yongdal

[0144] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nmThe value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0145] 2) Using a 5-L fermentor as a seed tank, transfer the acclimated bacterial liquid to a 4-L PETC gas medium (CO₂ + H₂, ratio 1:3, pressure 0.1 MPa) at a 10% inoculum volume. After incubation at 37°C for 48 h, use it as the seed liquid for larger-scale fermentation.

[0146] 3) A 50-L fermentor was used, 40 L of PETC gas culture medium was added, the fermentation temperature was 37°C, the fermentation pH was maintained at approximately 5.6, CO2 and H2 were used as the primary gas source in a ratio of 1:3, the pressure was controlled at approximately 0.1 MPa, and the fermentation was continued for 192 h. Samples were taken every 12 h to monitor changes in biomass and product yields.

[0147] Example 10 Co@NCNT-Clostridium jundal 50 L scale gas fermentation experiment

[0148] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0149] 2) Using a 5-L fermentor as a seed tank, transfer the acclimated bacterial liquid to a 4-L PETC medium (gas supply: CO₂ + H₂, ratio: 1:3, pressure: 0.1 MPa) at a 10% inoculum volume. After incubation at 37°C for 48 h, use the culture medium as a seed for larger-scale fermentation.

[0150] 3) Select a 50L fermenter, add 40L of PETC gas culture medium and 4g of Co@NCNT catalyst. Inoculate the seed solution into the 50L fermenter (gas supply: CO2 + H2, ratio 1:3), ferment at 37°C, maintain pH around 5.6, and control pressure at around 0.1 MPa. Ferment for 192 hours, supplementing nitrogen, sulfur, and Fe as needed. 2+ , samples were taken every 12 h to monitor changes in biomass and product yield.

[0151] The results are shown in Figure 11. Compared with Comparative Example 4, the cell biomass and acetic acid concentrations of the 50 L scale CO2 + H2 fermentation of the Co@NCNT-Clostridium jundal hybrid system increased by about 50%, the acetic acid concentration reached 30 g / L, and the ethanol concentration reached 25 g / L, an increase of one order of magnitude.

[0152] Example 11 Optimization experiment of Co@NCNT-Clostridium jundal 50 L scale gas fermentation

[0153] Based on the CO2+H2 reaction equations for the synthesis of acetic acid and ethanol, two CO2 molecules and four H2 molecules produce one acetic acid molecule, with a CO2:H2 ratio of 1:2; two CO2 molecules and six H2 molecules produce one ethanol molecule, with a CO2:H2 ratio of 1:3. Furthermore, given that H2 is much lower than CO2, limiting mass transfer, the H2 ratio was further increased to 80% during the fermentation process. Furthermore, to ensure that the intracellular metabolism of Clostridium jundalus rapidly responds to the extracellular electrons provided by the catalyst-activated H2, a catalyst was added during the culture stage. Furthermore, to achieve higher cell densities, catalyst was added to the 50L fermenter.

[0154] The operation in this embodiment is as follows:

[0155] 1) The activated Clostridium jungdalariensis DSM 13528 bacterial solution was transferred to 50 mL of PETC gas culture medium (CO2 + H2, ratio of 1:3, pressure of 0.1-0.2 MPa) at a 10% inoculum volume and cultured to OD 600nm The value was about 0.2, and then the strain was subcultured in PETC gas culture medium (CO2+H2, ratio of 1:3, pressure of 0.1-0.2MPa) for more than 2 generations to allow the strain to completely adapt to growth with CO2 as the carbon source.

[0156] 2) Using a 5-L fermenter as a seed tank, 4 L of PETC medium and 0.4 g of Co@NCNT catalyst were added (gas supply: CO2 + H2, ratio: 1:3, pressure: 0.1 MPa). The acclimated bacterial liquid was transferred to a 5-L fermenter at a 10% inoculum size and cultured at 37°C for 48 h. The culture was then used as a seed solution for larger-scale fermentation.

[0157] 3) Select a 50L fermenter, add 40L of PETC gas culture medium and 4g of Co@NCNT catalyst. Inoculate the seed solution into the 50L fermenter (gas supply is CO2+H2, ratio is 1:4), fermentation temperature is 37°C, fermentation pH is maintained at around 5.6, pressure is controlled at around 0.1Mpa, and nitrogen, sulfur and Fe are supplemented as needed during the fermentation process. 2+ , take samples every 12 hours to monitor the changes in biomass and product yield. 600nmWhen the pH reached about 2, 4 g of Co@NCNT catalyst was added and the fermentation was continued for 216 h.

[0158] The results are shown in Figure 12. Compared with Comparative Example 4, the optimized Co@NCNT-Clostridium jundal hybrid system fermented CO2+H2 on a 50 L scale, and the cell biomass increased by 100%, the acetic acid concentration increased by 60% to 36 g / L, and the ethanol concentration reached 45 g / L, a 20-fold increase.

[0159] Comparative Example 5: Gas fermentation experiment of 50 ml scale of Clostridium monoxide-eating

[0160] The activated carbon monoxide-eating Clostridium P7 DSM15243T bacterial solution was transferred to 50 mL of PETC gas culture medium (20% to 90% CO, the rest being CO2 and H2 synthesis gas, pressure 0.15 to 0.2 MPa) at a 10% inoculum volume and cultured to an OD of 600nm The acclimated bacterial liquid was transferred to 50 mL of PETC gas medium (synthesis gas of 40% CO, 40% H2, 10% CO2 and N2 as the main gas source, with a pressure of 0.2 MPa) at a 10% inoculum volume and cultured in shake flasks at 37°C.

[0161] Example 12 Co@NCNT-Carbon monoxide-eating Clostridium 50ml scale gas fermentation experiment

[0162] 1) The activated Clostridium monoxide-eating bacteria P7 DSM15243T was transferred to 50 mL of PETC gas culture medium (20% to 90% CO, the rest being CO2 and H2 synthesis gas, pressure 0.15 to 0.2 MPa) at a 10% inoculum volume and cultured to an OD of 600nm The acclimated strain was then subcultured in PETC gas medium for at least two generations to fully adapt to growth on syngas as a carbon source. The acclimated bacterial broth was then transferred to 50 mL of PETC gas medium (syngas consisting of 40% CO, 40% H₂, 10% CO₂, and N₂ as the primary gas source) containing the Co@NCNT catalyst at a 10% inoculum rate and cultured in shake flasks at 37°C.

[0163] 2) Take 5 mg of Co@NCNT catalyst, resuspend it in 500 μl of PETC medium, and add it to an anaerobic bottle containing 50 ml of PETC medium. Then, the anaerobic bottle is filled with synthesis gas (40% CO, 40% H2, 10% CO2 and N2, with a pressure of 0.2 MPa).

[0164] 3) The acclimated bacterial liquid was inoculated into the PETC gas culture medium containing the Co@NCNT catalyst at a rate of 10%, and the culture was cultured and fermented at a constant temperature of 37° C. Sampling was performed every 24 hours to monitor biomass and product.

[0165] The results are shown in Figure 13. Compared with Comparative Example 5, the Co@NCNT-Carbon monoxide-eating Clostridium hybrid system fermented CO+CO2+H2, and the biomass and acetic acid concentrations increased by 20%, the butyric acid and hexanoic acid concentrations increased by nearly one-fold, the ethanol and butanol concentrations increased by about 70%, and the hexanol concentration increased by 2 times.

[0166] The fermentation results of the above examples and comparative examples are summarized in Table 1 below.

[0167] Table 1 Fermentation effect of each embodiment compared with the comparative example

[0168] According to conventional speculation by those skilled in the art, in view of the growth and metabolite characteristics displayed by the Co@NCNT-autoethanologenic clostridium hybrid system under 50ml scale fermentation conditions, the Co@NCNT-autoethanologenic clostridium hybrid system should also have higher biomass and product concentrations under larger-scale fermentation conditions. Similarly, in view of the growth and metabolite characteristics displayed by the Co@NCNT-carbohydrate clostridium hybrid system under 50ml scale fermentation conditions, the Co@NCNT-carbohydrate clostridium hybrid system should also have higher biomass and product concentrations such as acetic acid, ethanol, butyric acid, butanol and hexanol under larger-scale fermentation conditions. In view of the above-mentioned remarkable technical effects obtained in the present application, the technical scheme of the present application is suitable for application in large-scale industrial production, and has broad application scenarios and economic value, for the industrial implementation of CO2 gas biological fixation with H2 as an energy source is of great significance.

[0169] The foregoing is merely an embodiment of the present application, and the scope of protection of the present application is not limited by these embodiments, but is determined by the claims of the present application. For those skilled in the art, various modifications and variations can be made to the present application. Any modifications, equivalent substitutions, improvements, etc. made within the technical ideas and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A carbon fixation system for efficiently utilizing H2, wherein, The carbon fixation system includes a composition, and the composition includes a hydrogenase-mimicking catalyst and acetogenic bacteria; further, the hydrogenase-mimicking catalyst is a heterogeneous catalyst with hydrogen activation ability designed by mimicking the function of hydrogenase; further, the hydrogenase-mimicking catalyst includes a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silica, graphene, graphene oxide, carbon dots, or magnetite; further, the active center is selected from one or more of iron, cobalt, nickel, palladium, and platinum; further, the hydrogenase-mimicking catalyst is selected from one or more of platinum-magnetite hydrogenase-mimicking catalyst, cobalt-carbon nanotube hydrogenase-mimicking catalyst, nickel-carbon nanotube hydrogenase-mimicking catalyst, iron-carbon nanotube hydrogenase-mimicking catalyst, iron-silica hydrogenase-mimicking catalyst, nickel-silica hydrogenase-mimicking catalyst, and cobalt-silica hydrogenase-mimicking catalyst; further, the acetogenic bacteria are bacteria that fix CO2 through the Wood-Ljungdahl pathway and grow autotrophically; further, the acetogenic bacteria are selected from one or more of Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei, and Clostridium carboxidivorans; further, the acetogenic bacteria are selected from one or more of Clostridium ljungdahlii DSM 13528, Clostridium autoethanogenum DSM 10061, or Clostridium carboxidivorans P7 DSM15243T.

2. A composition, wherein, including a hydrogenase-mimicking catalyst and acetogenic bacteria; further, the hydrogenase-mimicking catalyst is a heterogeneous catalyst with hydrogen activation ability designed by mimicking the function of hydrogenase; further, the hydrogenase-mimicking catalyst includes a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silica, graphene, graphene oxide, carbon dots, or magnetite; further, the active center is selected from one or more of iron, cobalt, nickel, palladium, and platinum; further, the hydrogenase-mimicking catalyst is selected from one or more of platinum-magnetite hydrogenase-mimicking catalyst, cobalt-carbon nanotube hydrogenase-mimicking catalyst, nickel-carbon nanotube hydrogenase-mimicking catalyst, iron-carbon nanotube hydrogenase-mimicking catalyst, iron-silica hydrogenase-mimicking catalyst, nickel-silica hydrogenase-mimicking catalyst, and cobalt-silica hydrogenase-mimicking catalyst; further, the acetogenic bacteria are bacteria that fix CO2 through the Wood-Ljungdahl pathway and grow autotrophically; further, the acetogenic bacteria are selected from one or more of Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei, and Clostridium carboxidivorans; further, the acetogenic bacteria are selected from one or more of Clostridium ljungdahlii DSM 13528, Clostridium autoethanogenum DSM 10061, or Clostridium carboxidivorans P7 DSM15243T.

3. One of the following uses of the hydrogenase-mimicking catalyst 1) The use for promoting the efficiency of microorganisms in utilizing H2: 2) The use for promoting carbon fixation by microorganisms; 3) The use for promoting the fixation of CO2 by microorganisms; 4) The use for promoting or increasing the biomass or cell mass of microorganisms; 5) Use for promoting the yield or production efficiency of microbial metabolites; 6) Use for promoting the yield or production efficiency of ethanol, butanol, hexanol, acetic acid, butyric acid, hexanoic acid, lactic acid, 2,3-butanediol, acetone, isopropanol, or 3-hydroxybutyric acid produced by microorganisms; The composition includes a hydrogenase-mimicking catalyst and acetogenic bacteria; further, the hydrogenase-mimicking catalyst is a heterogeneous catalyst with hydrogen activation ability designed by mimicking the function of hydrogenase; further, the hydrogenase-mimicking catalyst includes a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silica, graphene, graphene oxide, carbon dots, or iron oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium, and platinum; further, the hydrogenase-mimicking catalyst is selected from one or more of platinum-iron oxide hydrogenase-mimicking catalyst, cobalt-carbon nanotube hydrogenase-mimicking catalyst, nickel-carbon nanotube hydrogenase-mimicking catalyst, iron-carbon nanotube hydrogenase-mimicking catalyst, iron-silica hydrogenase-mimicking catalyst, nickel-silica hydrogenase-mimicking catalyst, and cobalt-silica hydrogenase-mimicking catalyst; further, The acetogenic bacteria are bacteria that fix CO2 through the Wood-Ljungdahl pathway and grow autotrophically; further, the acetogenic bacteria are selected from one or more of Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei, and Clostridium carboxidivorans; further, the acetogenic bacteria are selected from one or more of Clostridium ljungdahlii DSM 13528, Clostridium autoethanogenum DSM 10061, or Clostridium carboxidivorans P7 DSM15243T; further, the metabolite is a primary metabolite or a secondary metabolite of the microorganism; further, the metabolite includes one or more of acetic acid, ethanol, butyric acid, butanol, hexanoic acid, and hexanol.

4. A method for a microorganism to produce a metabolite, wherein, It includes the step of using the carbon fixation system described in claim 1 or the composition described in claim 2; further, the metabolite is a primary metabolite or a secondary metabolite of the microorganism; further, the metabolite includes one or more of acetic acid, ethanol, butyric acid, butanol, hexanoic acid, and hexanol.

5. A method for improving the efficiency of H2 utilization by microorganisms, wherein, A step of adding a hydrogenase-mimicking catalyst during the production or fermentation process of the microorganism, for example, before inoculation of fermentation culture or at a certain stage after inoculation; the hydrogenase-mimicking catalyst is a heterogeneous catalyst with hydrogen activation ability designed by mimicking the function of hydrogenase; further, the hydrogenase-mimicking catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silica, graphene, graphene oxide, carbon dots or magnetite; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the hydrogenase-mimicking catalyst is selected from one or more of platinum-magnetite hydrogenase-mimicking catalyst, cobalt-carbon nanotube hydrogenase-mimicking catalyst, nickel-carbon nanotube hydrogenase-mimicking catalyst, iron-carbon nanotube hydrogenase-mimicking catalyst, iron-silica hydrogenase-mimicking catalyst, nickel-silica hydrogenase-mimicking catalyst and cobalt-silica hydrogenase-mimicking catalyst; further, the acetic acid-producing bacteria are bacteria that fix CO2 through the Wood-Ljungdahl pathway and carry out autotrophic growth; further, the acetic acid-producing bacteria are selected from one or more of Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei and Clostridium carboxidivorans; further, the acetic acid-producing bacteria are selected from one or more of Clostridium ljungdahlii DSM 13528, Clostridium autoethanogenum DSM 10061 or Clostridium carboxidivorans P7 DSM15243T; further, the production or fermentation process uses H2 and C1 gases as the main gas sources; further, the gas source composition is H2, CO2 or is composed of H2, CO2 and CO or is composed of H2, CO; further, the proportion of H2 is 10% to 90%.

6. A method for promoting microbial carbon fixation, wherein, Including the step of adding a hydrogenase mimic catalyst during the production or fermentation process of the microorganism, for example, before inoculation of fermentation culture or at a certain stage after inoculation; the hydrogenase mimic catalyst is a heterogeneous catalyst with hydrogen activation ability designed by mimicking the function of hydrogenase; further, the hydrogenase mimic catalyst includes a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silica, graphene, graphene oxide, carbon dots or magnetite; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the hydrogenase mimic catalyst is selected from one or more of platinum-magnetite hydrogenase mimic catalyst, cobalt-carbon nanotube hydrogenase mimic catalyst, nickel-carbon nanotube hydrogenase mimic catalyst, iron-carbon nanotube hydrogenase mimic catalyst, iron-silica hydrogenase mimic catalyst, nickel-silica hydrogenase mimic catalyst and cobalt-silica hydrogenase mimic catalyst; further, the acetic acid-producing bacteria are bacteria that fix CO2 through the Wood-Ljungdahl pathway and carry out autotrophic growth; further, the acetic acid-producing bacteria are selected from one or more of Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei and Clostridium carboxidivorans; further, the acetic acid-producing bacteria are selected from one or more of Clostridium ljungdahlii DSM 13528, Clostridium autoethanogenum DSM 10061 or Clostridium carboxidivorans P7 DSM15243T; further, the production or fermentation process uses H2 and C1 gases as the main gas sources; further, the gas source composition is H2, CO2 or the composition is H2, CO2 and CO or the composition is H2, CO; further, the proportion of H2 is 10% to 90%.

7. A method for promoting or enhancing the carbon fixation efficiency of microorganisms, wherein, A step of adding a hydrogenase-mimicking catalyst during the production or fermentation process of the microorganism, for example, before inoculation of fermentation culture or at a certain stage after inoculation; the hydrogenase-mimicking catalyst is a heterogeneous catalyst with hydrogen activation ability designed by mimicking the function of hydrogenase; further, the hydrogenase-mimicking catalyst comprises a carrier and an active center; further, the carrier is selected from one or more of carbon nanotubes, silica, graphene, graphene oxide, carbon dots or iron oxide; further, the active center is selected from one or more of iron, cobalt, nickel, palladium and platinum; further, the hydrogenase-mimicking catalyst is selected from one or more of platinum-iron oxide hydrogenase-mimicking catalyst, cobalt-carbon nanotube hydrogenase-mimicking catalyst, nickel-carbon nanotube hydrogenase-mimicking catalyst, iron-carbon nanotube hydrogenase-mimicking catalyst, iron-silica hydrogenase-mimicking catalyst, nickel-silica hydrogenase-mimicking catalyst and cobalt-silica hydrogenase-mimicking catalyst; further, the acetic acid-producing bacteria are bacteria that fix CO2 through the Wood-Ljungdahl pathway and carry out autotrophic growth; further, the acetic acid-producing bacteria are selected from one or more of Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium ragsdalei and Clostridium carboxidivorans; further, the acetic acid-producing bacteria are selected from one or more of Clostridium ljungdahlii DSM 13528, Clostridium autoethanogenum DSM 10061 or Clostridium carboxidivorans P7 DSM15243T; further, the production or fermentation process uses H2 and C1 gases as the main gas sources; further, the gas source composition is H2, CO2 or the composition is H2, CO2 and CO or the composition is further H2, CO; further, the proportion of H2 is 10% to 90%.

8. A method for producing ethanol by a microorganism, wherein, A step of using the carbon fixation system according to claim 1 or the composition according to claim 2; further, it includes a process of fermentation in an environment containing H2 and C1 gases; further, the gas source composition is H2, CO2 or the composition is H2, CO2 and CO or the composition is further H2, CO; further, the proportion of H2 is 10% to 90%; further, it includes the stages of strain activation, adaptive subculture and fermentation culture, and a step of adding the hydrogenase-mimicking catalyst in the fermentation culture stage.

9. A method for producing acetic acid by microorganisms, wherein, A step of using the carbon fixation system according to claim 1 or the composition according to claim 2; further, it includes a process of fermentation in an environment containing H2 and C1 gases; further, the gas source composition is H2, CO2 or the composition is H2, CO2 and CO or the composition is further H2, CO; further, the proportion of H2 is 10% to 90%; further, it includes the stages of strain activation, adaptive subculture and fermentation culture, and a step of adding the hydrogenase-mimicking catalyst in the fermentation culture stage.

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