Acetate-producing strain and method for producing acetate using syngas and application thereof

Abstract

This invention belongs to the field of bioengineering and carbon one-carbon resource utilization technology, specifically relating to a bacterial strain that produces acetic acid and acetate through syngas fermentation, as well as its applications and methods. The strain is *Clostridium yongdarii* (…). Clostridium ljungdahlii SL40, deposited at the Guangdong Provincial Microbial Culture Collection Center (GDMCC No. 67679) on January 15, 2026, represents a strain that achieves highly efficient H2 / CO2 conversion in syngas, with a maximum CO2 utilization rate of 1.8 g / L / h. The anaerobic fermentation process produces zero pollutants, enabling resource utilization and carbon reduction of industrial waste gas, and providing a new technological pathway for carbon resource conversion.

Description

Technical Field

[0001] This invention belongs to the field of bioengineering and carbon resource utilization technology, specifically relating to a strain of bacteria that produces acetic acid and acetate by fermentation of syngas, and its application and method. Background Technology

[0002] Syngas mainly consists of H2, CO2, and CO, and has the advantages of low cost and large production volume. Converting syngas into high-value-added chemicals through biological processes is an important technological pathway to achieve efficient utilization of carbon resources and carbon emission reduction.

[0003] In recent years, microbial biotechnology processes have gained increasing attention as a green route for acetic acid production. Compared with traditional chemical synthesis and fossil fuel-based methods, microbial biotechnology processes are promising solutions due to their inherent robustness, adaptability, and lower energy intensity. Acetic acid-producing bacteria are becoming increasingly important because they possess the autotrophic ability to utilize CO2 as their sole carbon source, and in particular, these bacteria can absorb a combination of H2, CO2, and CO (i.e., syngas) released from various industrial processes.

[0004] Anaerobic acetogenic bacteria are a class of autotrophic microorganisms capable of converting one-carbon (C1) compounds (such as CO2, CO, formate, or methanol) into value-added chemicals using the Wood-Ljungdahl (WLP) pathway. Common examples include *Clostridium jungdahl* (…). Clostridium ljungdahlii ), self-producing alcohol-producing Clostridium ( Clostridium autoethanogenum ), Clostridium carbonmonoxide ( Clostridium carboxidivorans Clostridium lagus ( Clostridium ragsdalei Clostridium perfringens ( ), Clostridium difficile Clostridium coskatii These microorganisms convert one-carbon gas into the central metabolite acetyl-CoA via the WLP pathway, and then guide it into the production of biomass and acetate. The whole genomes of these strains have been sequenced, and related molecular genetic manipulation tools are becoming increasingly sophisticated. These tools can transform exogenous DNA into host cells and stably replicate it, enabling manipulation of gene expression and genome editing, thereby controlling product production.

[0005] However, existing syngas fermentation strains for acetic acid production suffer from problems such as poor syngas tolerance, low acetic acid conversion efficiency, and limited adaptability of natural strains to syngas, resulting in acetic acid yields and production efficiency that fail to meet industrial demands. Furthermore, the separation and purification steps of syngas fermentation products in existing processes are complex and energy-intensive, further limiting the industrial application of this technology. Therefore, screening and domesticating specialized strains with high tolerance and high yield, and optimizing the fermentation process, are crucial for promoting the industrialization of syngas bioconversion to acetic acid technology. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a strain of bacteria that produces acetic acid and acetate through syngas fermentation, along with its applications and methods.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A strain of Clostridium yunnanense that produces acetic acid and acetate through syngas fermentation; the strain is Clostridium yunnanense (Clostridium yunnanense). Clostridium ljungdahlii SL40, deposited at Guangdong Provincial Center for Microbial Culture Collection, accession number GDMCC No: 67679, deposited on January 15, 2026, at the address of Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0008] An application of a strain of bacteria that produces acetic acid and acetate by syngas fermentation, wherein the strain is used in the production of acetic acid or acetate by syngas fermentation.

[0009] The synthesis gas is a mixture of H2 and CO2, wherein the volume ratio of H2 to CO2 is preferably 9:1 to 5:5.

[0010] A method for producing acetic acid and acetate using syngas involves introducing syngas into a culture system containing the strain and fermenting it under anaerobic conditions. The fermentation temperature is controlled at 30-60℃, the pH is controlled at 4.5-6.5, and the mixture is shaken for 108 hours. The fermentation broth is then separated to obtain a clear liquid containing acetic acid and acetate, which is then purified to obtain acetic acid or acetate products.

[0011] The syngas is a mixture of H2 and CO2, wherein the volume ratio of H2 to CO2 is preferably 9:1 to 5:5; the syngas is introduced into the culture system containing the strain at a flow rate of 1 to 20 L / min.

[0012] The culture system containing the strain involves inoculating the strain into a culture medium at an inoculation rate of 8-15% (v / v). The culture medium is PETC medium, with the following added per liter of water: ammonium chloride 1.0 g, potassium dihydrogen phosphate 0.1 g, potassium chloride 0.1 g, magnesium sulfate heptahydrate 0.2 g, sodium chloride 0.8 g, calcium chloride dihydrate 0.02 g, sodium tungstate dihydrate 0.000025 g, sodium bicarbonate 1.0 g, cysteine ​​hydrochloride monohydrate 1.0 g, yeast extract 1.0 g, cysteine ​​0.5 g, resazurin 0.0005 g, nitrilotriacetic acid 0.02 g, manganese chloride monohydrate 0.013 g, ferrous sulfate heptahydrate 0.004 g, cobalt chloride heptahydrate 0.002 g, zinc sulfate heptahydrate 0.002 g, sodium molybdate dihydrate 0.002 g, and nickel chloride hexahydrate 0.00002 g. g, Sodium selenite pentahydrate 0.001 g, Biotin 0.02 mg, Folic acid 0.02 mg, Pyridoxine hydrochloride 0.1 mg, Thiamine hydrochloride dihydrate 0.25 mg, Riboflavin 0.05 mg, Niacin 0.05 mg, D-calcium pantothenate 0.05 mg, Vitamin B 12 0.001 mg, para-aminobenzoic acid 0.05 mg, thioctic acid 0.05 mg.

[0013] Furthermore, syngas is introduced into a culture system containing the strain for anaerobic fermentation. The fermentation temperature is controlled at 35-39℃, the pH is controlled at 5.6-6.1, and the culture is shaken for 160 hours. Then, the fermentation broth is separated to obtain a clear liquid containing acetic acid and acetate. The acetic acid or acetate product is then purified. The syngas flow rate is 3-10 L / min.

[0014] The acetate is ammonium acetate or other acetates.

[0015] Furthermore, *Clostridium yongdarii* SL40 was fermented in a culture medium under anaerobic conditions. The selected control temperature was 35–39°C, preferably 37°C; the selected control pH was 5.6–6.1, preferably 5.8; the selected alkali for adjusting the pH was potassium hydroxide or ammonia, preferably ammonia; the selected H2 to CO2 volume ratio of the syngas was preferably 7:3–6:4, preferably 6:4; during the fermentation process, a 50 μm ceramic membrane retention device was used to retain and concentrate the cells, and the concentrated liquid was refluxed back to the fermenter to maintain a high cell concentration; as the biomass increased, the stirring speed and gas flow rate were gradually increased to ensure sufficient carbon source supply; the acetic acid concentration and cell growth status were monitored in real time to ensure stable fermentation.

[0016] The product, acetic acid or acetate, is determined by the pH-controlled base. If it is a base, it is ammonia water, and the product is ammonium acetate. If it is a base, it is potassium hydroxide, and the product is potassium acetate.

[0017] The selected fermenter is equipped with a membrane retention device containing a 50 μm ceramic membrane. After fermentation, the membrane retention device is used for concentration and separation. The concentrated liquid is returned to the fermenter, and the clear liquid flows to the crude acetate solution storage tank and concentration and purification system. When fermentation is complete or reaches a stable state, crude acetic acid and acetate fermentation broth (the clear liquid obtained above) is obtained. The crude fermentation broth contains the target product acetate ions (CH3COO). - ) and ammonium ions (NH4) + ), as well as the cells, residual substrates, trace fermentation byproducts (such as ethanol, organic acids) and culture medium components.

[0018] This invention has the following significant advantages and positive effects: This invention provides a strain capable of efficiently producing acetic acid and acetate through syngas fermentation, overcoming the problems of poor syngas tolerance and low acetic acid yield in existing strains. This enables low-cost, efficient, and sustainable bioconversion of syngas to produce acetic acid and acetate. Specifically: 1. Green and efficient process: The fermentation process is anaerobic, with low energy consumption and no pollutant emissions; the application of membrane retention technology enables the recycling of microbial cells, reduces material loss, and lowers equipment investment and operating costs; intermediate products can be directly used in downstream production, simplifying the process flow.

[0019] 2. Low raw material cost: Using widely available syngas as raw material, it eliminates dependence on traditional resources such as grain and oil, reducing raw material costs by more than 30%, while realizing the resource utilization of industrial waste gas and reducing carbon emissions.

[0020] 3. Strong adaptability to raw materials: It has good adaptability to fluctuations in syngas composition and is suitable for syngas feedstocks from various sources.

[0021] 4. Specialized tolerant strains: Acetic acid production strains that have undergone adaptive evolution have stronger syngas tolerance and acetic acid conversion efficiency, ensuring high and stable production under high dilution conditions.

[0022] 5. Broad application prospects: The product, acetic acid, can be used as a chemical raw material or a substrate for downstream biosynthesis, which is in line with the concept of circular economy and has significant economic, environmental and social benefits. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the growth curve of the original strain of Clostridium yongdar provided in an embodiment of the present invention.

[0024] Figure 2This is a schematic diagram illustrating the growth of the original Clostridium yongdar and Clostridium yongdar SL40 strain during the adaptive evolution process provided in this embodiment of the invention.

[0025] Figure 3 This is a schematic diagram showing the acetic acid content of the original strain of Clostridium yongdar and the Clostridium yongdar SL40 strain during the adaptive evolution process provided in this embodiment of the invention.

[0026] Figure 4 This is a schematic diagram showing the gas pressure changes in shake flasks of the original Clostridium yongdar and Clostridium yongdar SL40 strains during the adaptive evolution process provided in this embodiment of the invention.

[0027] Figure 5 This is a schematic diagram of the process for obtaining acetate by syngas fermentation, provided as an embodiment of the present invention.

[0028] Figure 6 The diagram shows the yield of acetate produced by batch fermentation of Clostridium yongdarii using syngas in a 10L tank, as provided in an embodiment of the present invention.

[0029] Figure 7 The diagram shows the yield of acetate produced by continuous fermentation of Clostridium yongdarii using syngas in a 150L tank, as provided in an embodiment of the present invention. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0031] In the following embodiments, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0032] Example 1: Adaptive evolution of Clostridium yunnanense in H2 / CO2 1. Growth curve of the original strain of Clostridium yongdarii Bacterial strain: Clostridium yunnanense DSM 13528 (purchased from the German Microbiology and Cell Collection Center (DSMZ, Leibniz-Institut DSMZ) in June 2020) was used as the original starting strain; Culture medium: 50 mL PETC medium, initial pH 5.9, H2:CO2 = 6:4 (v / v) gas was introduced into the anaerobic bottle until the pressure reached 0.12 MPa; Culture conditions: cultured at 37℃ in a shaker at 200 rpm; Inoculum size: 11% (v / v).

[0033] Results: Growth curves of Clostridium yongdarii were obtained after the sample culture was completed (see...). Figure 1It can be divided into four stages: the lag period is about 0-12 hours, during which microorganisms adapt to the environment, and OD... 600 Growth is slow; the logarithmic growth phase lasts approximately 12-78 hours, during which microbial metabolism is vigorous and proliferation is rapid, resulting in high OD. 600 It exhibits rapid logarithmic growth; a stationary phase occurs around 78-90 hours, during which cell growth and death rates tend to balance, and OD... 600 Basically stable; after 90 hours, it enters the decline phase, due to nutrient depletion and accumulation of metabolic products, the rate of microbial death exceeds the rate of growth, OD... 600 Gradually decreasing.

[0034] 2. Adaptive evolution of Clostridium yongdar in H2 / CO2 (1) The original strain of Clostridium yongdar, which was frozen and preserved in an ultra-low temperature freezer at -80℃, was thawed at 4℃, and then the bacterial culture was inoculated into PETC gas medium for activation and cultured until OD. 600 It is 0.3-0.4.

[0035] (2) The activated bacterial strain was inoculated into an anaerobic bottle containing 50 mL of PETC gas medium at an inoculation rate of 11% (v / v). The culture was carried out at 37°C and 200 rpm in a shaker. The OD was measured every 24 hours. 600 And acetic acid production.

[0036] (3) Adaptive evolution of activated Clostridium yongdarii under a mixed gas environment of H2:CO2=6:4 (v / v): under the condition of 200 rpm of shaking at 37℃ and the pressure of H2:CO2=6:4 (v / v) mixed gas being introduced to 0.14MPa, continuous subculture was carried out in 50mL PETC gas medium every 24h, and the inoculum amount for each subculture was 11% (v / v).

[0037] (4) After 40 generations of continuous subculturing, Clostridium yongdarii strains resistant to H2 / CO2 mixed gas environment were obtained. Clostridium ljungdahlii SL40. The obtained strain is Clostridium yongdarii (SL40). Clostridium ljungdahlii SL40 was deposited at the Guangdong Provincial Center for Microbial Culture Collection on January 15, 2026, with accession number GDMCC No: 67679.

[0038] 3. Comparison of the preserved strain of Clostridium yongdar with the original strain The preserved strain of Clostridium yongdarii and the original strain were cultured separately in a shaker at 37℃ and 200 rpm, and the OD was measured every 24 hours. 600 Pressure inside the shake flask and acetate production.

[0039] Figure 2 The results showed that Clostridium yongdarii ( Clostridium ljungdahlii The growth curve of SL40 shows a shorter lag phase, a faster logarithmic growth rate, and a higher final biomass, with its maximum OD... 600 (0.514) The maximum OD of the original Clostridium yongdar strain 600 (0.285) Increased by approximately 80%.

[0040] Figure 3 A comparison of acetic acid concentrations showed that Clostridium yongdarii ( Clostridium ljungdahlii The final acetic acid concentration of SL40 reached 2.29 g / L, which is about 183% higher than the final acetic acid concentration of the original Clostridium yongdar strain (0.81 g / L).

[0041] Figure 4 The results of the gas pressure change in the shake flask indicated that Clostridium yongdarii ( Clostridium ljungdahlii SL40 exhibited a faster gas consumption rate during cultivation, and the final system pressure dropped to a negative value (below atmospheric pressure), while the original Clostridium yongdar strain maintained a positive pressure level (above atmospheric pressure). This reflects its rapid utilization efficiency of H2 and CO2 substrates, and its stronger absorption and transformation capabilities for H2 and CO2 substrates.

[0042] 4. Whole genome resequencing of Clostridium yongdarii preserved strain Collect the above-mentioned Clostridium yongdarii ( Clostridium ljungdahlii Fresh bacterial pellets of strain SL40 and the starting strain were flash-frozen in liquid nitrogen and stored at -80°C. The samples were then sent to Shanghai Ouyi Biotechnology Co., Ltd. for library construction and high-throughput sequencing. The sequencing platform used was the DNBSEQ high-throughput sequencing platform. Qualified DNA samples were first randomly fragmented into 350 bp-500 bp fragments using Covaris. Library construction was performed using the TruSeq DNA LT Sample Prep kit. The DNA fragments underwent end repair, polyA tailing, sequencing adapter addition, purification, and PCR amplification to complete the final library construction.

[0043] By performing whole-genome resequencing on Clostridium yongdarii SL40 and comparing it with the genome sequence of the original starting strain (DSM 13528), mutation sites of multiple genes were identified. Some of the mutation sites are shown below.

[0044] (1) ① The initial gene sequence encoding the dnaK protein of Clostridium yongdar is shown in SEQ ID NO:1 in the sequence listing.

[0045] ②The initial amino acid sequence of the dnaK protein encoded by Clostridium yongdar is shown in SEQ ID NO:2 in the sequence listing.

[0046] ③The 1741st base in the initial gene sequence encoding the dnaK protein of SL40 was mutated from G to T. The gene sequence after the mutation is shown in SEQ ID NO:3 in the sequence listing.

[0047] ④The 581st amino acid in the initial amino acid sequence of the SL40 encoding dnaK protein was mutated from alanine to serine. The amino acid sequence after the mutation is shown in SEQ ID NO:4 in the sequence listing.

[0048] (2) ① The initial gene sequence encoding the protein containing the AAA domain of Clostridium yongdar is shown in SEQ ID NO:5 in the sequence listing.

[0049] ②The initial amino acid sequence of the protein encoding the AAA domain of Clostridium yongdar is shown in SEQ ID NO:6 in the sequence listing.

[0050] ③The 1532nd base of the initial gene sequence encoding the AAA domain protein of SL40 was mutated from G to C. The gene sequence after the mutation is shown in SEQ ID NO:7 in the sequence listing.

[0051] ④The 511th amino acid in the initial amino acid sequence of the protein encoding the AAA domain of SL40 was mutated from glycine to alanine. The amino acid sequence after the mutation is shown in SEQ ID NO:8 in the sequence listing.

[0052] (3) ① The initial gene sequence of the biotin-dependent carboxyltransferase protein encoded by Clostridium yongdar is shown in SEQ ID NO:9 in the sequence listing.

[0053] ②The initial amino acid sequence of the biotin-dependent carboxyltransferase protein encoded by Clostridium yongdar is shown in SEQ ID NO:10 in the sequence listing.

[0054] ③The 386th base in the initial gene sequence of SL40, which encodes the biotin-dependent carboxyltransferase protein, was mutated from T to G. The gene sequence after the mutation is shown in SEQ ID NO:11 in the sequence listing.

[0055] ④The 129th amino acid in the initial amino acid sequence of the biotin-dependent carboxyltransferase protein encoded by SL40 is mutated from isoleucine to serine. The amino acid sequence after the mutation is shown in SEQ ID NO:12 in the sequence listing.

[0056] (4) ① The initial gene sequence encoding the aroA protein of Clostridium yunnanense is shown in SEQ ID NO:13 in the sequence listing. ②The initial amino acid sequence of the aroA protein encoded by Clostridium yongdar is shown in SEQ ID NO:14 in the sequence listing.

[0057] ③The 67th base in the initial gene sequence encoding the aroA protein of SL40 was mutated from G to A. The gene sequence after the mutation is shown in SEQ ID NO:15 in the sequence listing.

[0058] ④The 23rd amino acid in the initial amino acid sequence of the aroA protein encoding SL40 was mutated from valine to isoleucine. The amino acid sequence after the mutation is shown in SEQ ID NO:16 in the sequence listing.

[0059] (5) ① The initial gene sequence encoding the 4Fe-4S binding protein of Clostridium yongdar is shown in SEQ ID NO:17 in the sequence listing.

[0060] ②The initial amino acid sequence encoding the 4Fe-4S binding protein of Clostridium yongdar is shown in SEQ ID NO:18 in the sequence listing.

[0061] ③The 324th base in the initial gene sequence encoding the 4Fe-4S binding protein of SL40 was mutated from G to T. The gene sequence after the mutation is shown in SEQ ID NO:19 in the sequence listing.

[0062] ④The 108th amino acid in the initial amino acid sequence encoding the 4Fe-4S binding protein of SL40 was mutated from glutamic acid to aspartic acid. The amino acid sequence after the mutation is shown in SEQ ID NO:20 in the sequence listing.

[0063] (6) ① The initial gene sequence encoding the cooS protein of Clostridium yongdar is shown in SEQ ID NO:21 in the sequence listing.

[0064] ②The initial amino acid sequence of the cooS protein encoded by Clostridium yongdar is shown in SEQ ID NO:22 in the sequence listing.

[0065] ③The 293rd base in the initial gene sequence encoding the cooS protein of SL40 was mutated from G to A. The gene sequence after the mutation is shown in SEQ ID NO:23 in the sequence listing.

[0066] ④The 98th amino acid in the initial amino acid sequence of the cooS protein encoding SL40 was mutated from arginine to lysine. The amino acid sequence after the mutation is shown in SEQ ID NO:24 in the sequence listing.

[0067] (7) ① The initial gene sequence of the transmembrane protein EcfT, which encodes the energy coupling factor transporter of Clostridium yongdar, is shown in SEQ ID NO:25 in the sequence listing.

[0068] ②The initial amino acid sequence of EcfT, the energy coupling factor transporter transmembrane protein of Clostridium yongdarii, is shown in SEQ ID NO:26 in the sequence listing.

[0069] ③The 483rd base in the initial gene sequence of EcfT, the energy coupling factor transporter transmembrane protein encoded by SL40, was mutated from T to G. The gene sequence after the mutation is shown in SEQ ID NO:27 in the sequence listing.

[0070] ④The 161st amino acid in the initial amino acid sequence of EcfT, the energy coupling factor transporter protein encoded by SL40, was mutated from isoleucine to methionine. The amino acid sequence after the mutation is shown in SEQ ID NO:28 in the sequence listing.

[0071] Example 2: Operation of the process for obtaining acetic acid (salt) by syngas fermentation Process flow ( Figure 5 As shown below, one side of the anaerobic fermenter is connected to an ammonia tank and a syngas storage tank via pipelines, while the other side is connected to a membrane filtration device via pipelines. The membrane filtration device is connected to the crude acetate solution storage tank via pipelines, and a concentration and purification system is connected through these pipelines. In each piece of equipment: Syngas storage tanks are primarily used for syngas storage, gas ratio adjustment, and gas supply. If the upstream gas source is pre-mixed syngas, it can be directly stored and supplied in the syngas tank. If the upstream gas source is CO2, H2, or other proportions of syngas supplied independently, H2 and CO2 can be introduced into the syngas tank separately, and the ratio can be adjusted before storage and supply. The syngas has an H2:CO2 ratio of 6:4-7:3 (v / v) and a gas pressure of 0.5 MPa.

[0072] The anaerobic fermenter is a reactor for the fermentation of acetic acid (salt) from syngas. Syngas from the syngas tank is introduced at a flow rate controlled at 1000 mL / min. *Clostridium yunnanense* is inoculated at a rate of 10%. The culture medium is PETC. The temperature is controlled at 37℃. The stirring speed is controlled at 500 rpm. During fermentation, the pH is adjusted using ammonia and maintained at 5.8.

[0073] The membrane retention device separates the bacterial broth from the anaerobic fermenter into a concentrated broth and a clear broth through its intercepting effect. A portion of the concentrated broth is returned to the fermenter, while the remainder enters the cell recovery device. The clear broth enters the crude acetate solution storage tank and the concentration and purification system. The membrane retention device is a ceramic membrane with a pore size of 50 μm.

[0074] The obtained fermentation broth is further purified to obtain a pure product. Specifically, the clarified liquid from the anaerobic fermenter obtained after the above separation is first passed through an electrodialysis device to increase the acetate concentration, and then passed through a multi-effect continuous evaporation crystallization device to produce the acetate product. The concentrated bacterial broth from the anaerobic fermenter obtained above is centrifuged and spray-dried to produce a microbial protein product.

[0075] Example 3: Batch fermentation of syngas to produce crude acetic acid (salt) in a 10 L system Microbial strain: Clostridium yongdarii SL40; Reactor: 10 L anaerobic stirred tank; Culture medium PETC: Ammonium chloride 1.0 g / L, potassium dihydrogen phosphate 0.1 g / L, potassium chloride 0.1 g / L, magnesium sulfate heptahydrate 0.2 g / L, sodium chloride 0.8 g / L, calcium chloride dihydrate 0.02 g / L, sodium tungstate dihydrate 0.000025 g / L, sodium bicarbonate 1.0 g / L, cysteine ​​hydrochloride monohydrate 1.0 g / L, yeast extract 1.0 g / L, cysteine ​​0.5 g / L, resazurin 0.0005 g / L, nitrilotriacetic acid 0.02 g / L, manganese chloride monohydrate 0.013 g / L, ferrous sulfate heptahydrate 0.004 g / L, cobalt chloride heptahydrate 0.002 g / L, zinc sulfate heptahydrate 0.002 g / L, sodium molybdate dihydrate 0.002 g / L. The following are the main components of the fermentation process: nickel chloride hexahydrate 0.00002 g / L, sodium selenite pentahydrate 0.001 g / L, biotin 0.02 mg / L, folic acid 0.02 mg / L, pyridoxine hydrochloride 0.1 mg / L, thiamine hydrochloride dihydrate 0.25 mg / L, riboflavin 0.05 mg / L, niacin 0.05 mg / L, D-calcium pantothenate 0.05 mg / L, vitamin B12 0.001 mg / L, para-aminobenzoic acid 0.05 mg / L, and lipoic acid 0.05 mg / L. Fermentation conditions: temperature 37℃, pH controlled at approximately 5.8 (adjusted with potassium hydroxide), stirring speed 500 rpm, synthesis gas (H2:CO2 = 6:4, v / v) introduced at a flow rate of 1000 mL / min.

[0076] Fermentation Process: The culture medium was sterilized in an anaerobic fermenter. After sterilization, nitrogen was purged for 30 minutes to achieve an anaerobic state. Syngas was then introduced for 30 minutes to displace the nitrogen, followed by inoculation at an 11% (v / v) inoculum. During fermentation, the stirring speed and gas flow rate were gradually increased as the biomass increased. Figure 6 It can be seen that by culturing in a 10 L tank, a bacterial fermentation broth containing a high concentration of acetate (potassium acetate) can be obtained, with the acetate (potassium acetate) concentration reaching 81.4 g / L.

[0077] Example 4: Continuous fermentation of syngas to produce crude acetic acid (salt) in a 150 L system Microbial strain: *Clostridium yongdarii*; Reactor: 150 L anaerobic stirred tank; Culture medium PETC: Ammonium chloride 1.0 g / L, potassium dihydrogen phosphate 0.1 g / L, potassium chloride 0.1 g / L, magnesium sulfate heptahydrate 0.2 g / L, yeast extract 0.5 g / L, resazurin 0.0002 g / L, cysteine ​​hydrochloride 1.5 g / L, cysteine ​​0.1 g / L, ferrous sulfate heptahydrate 0.004 g / L, sodium chloride 0.8 g / L, manganese sulfate 0.0011 g / L, cobalt chloride hexahydrate 0.0002 g / L, zinc sulfate heptahydrate 0.0002 g / L, nickel chloride hexahydrate 0.00002 g / L, anhydrous calcium chloride 0.002 g / L, nitric acid 0.002 g / L, sodium tungstate dihydrate 0.000025 g / L, sodium molybdate dihydrate 0.0002 g / L. The following ingredients were added: g / L, biotin 0.01 mg / L, folic acid 0.002 mg / L, pyridoxine hydrochloride 0.01 mg / L, thiamine 0.025 mg / L, riboflavin 0.005 mg / L, niacin 0.005 mg / L, calcium pantothenate 0.04 mg / L, cyanocobalamin 0.005 mg / L, p-aminobenzoic acid 0.005 mg / L, and lipoic acid 0.005 mg / L. Fermentation conditions: temperature 37℃, pH controlled at approximately 5.8 (adjusted with ammonia), stirring speed 300 rpm, synthesis gas (H2:CO2 = 6:4, v / v) introduced, flow rate controlled at 8000 mL / min.

[0078] Fermentation Process: The above-mentioned culture medium is sterilized in an anaerobic fermenter. After sterilization, nitrogen is purged for 30 minutes to achieve an anaerobic state. Syngas is then introduced for 30 minutes to displace the nitrogen, followed by inoculation at an 11% inoculum size. During fermentation, the stirring speed, gas flow rate, and dilution rate are gradually increased as the biomass increases. Figure 7 It can be seen that the continuous fermentation time in the 150 L fermenter exceeds 500 h. During the 438-546 h stage, the ammonium acetate can reach about 50 g / L, with the highest value of ammonium acetate at 546 h being 55.54 g / L. The ammonium acetate production rate is 1.15 g / L / h, the ethanol is 2.25 g / L, the CO2 utilization rate exceeds 1 g / L / h, and the highest CO2 utilization rate is 1.8 g / L / h.

Claims

1. A bacterial strain that produces acetic acid and acetate through syngas fermentation, characterized in that: The strain was Clostridium yongdarii ( Clostridium ljungdahlii SL40, deposited at Guangdong Provincial Center for Microbial Culture Collection, accession number GDMCCNo: 67679, deposited on January 15, 2026.

2. An application of the syngas fermentation strain for producing acetic acid and acetate as described in claim 1, characterized in that: Application of the strain in the production of acetic acid or acetate by syngas fermentation.

3. The application of the syngas fermentation strain for producing acetic acid and acetate according to claim 2, characterized in that: The synthesis gas is a mixture of H2 and CO2, wherein the volume ratio of H2 to CO2 is 9:1 to 5:

5.

4. A method for producing acetic acid and acetates using syngas, characterized in that: Synthetic gas is introduced into a culture system containing the strain described in claim 1 for anaerobic fermentation. The fermentation temperature is controlled at 30-60℃ and the pH is controlled at 4.5-6.

5. The mixture is stirred and cultured for 5-7 days. The fermentation broth is then separated to obtain a clear liquid containing acetic acid and acetate. The acetic acid or acetate product is then purified.

5. The method for producing acetic acid and acetates using syngas according to claim 4, characterized in that: The syngas is a mixture of H2 and CO2, wherein the volume ratio of H2 to CO2 is 9:1 to 5:5; the flow rate of the syngas introduced into the culture system of the strain is 1 to 20 L / min.

6. The method for producing acetic acid and acetates using syngas according to claim 4, characterized in that: The culture system for the strain involves inoculating the strain into a culture medium at an inoculation rate of 8-15% v / v. The culture medium is PETC medium, with the following added per liter of water: ammonium chloride 1.0 g, potassium dihydrogen phosphate 0.1 g, potassium chloride 0.1 g, magnesium sulfate heptahydrate 0.2 g, sodium chloride 0.8 g, calcium chloride dihydrate 0.02 g, sodium tungstate dihydrate 0.000025 g, sodium bicarbonate 1.0 g, cysteine ​​hydrochloride monohydrate 1.0 g, yeast extract 1.0 g, cysteine ​​0.5 g, resazurin 0.0005 g, nitrilotriacetic acid 0.02 g, manganese chloride monohydrate 0.013 g, ferrous sulfate heptahydrate 0.004 g, cobalt chloride heptahydrate 0.002 g, zinc sulfate heptahydrate 0.002 g, sodium molybdate dihydrate 0.002 g, and nickel chloride hexahydrate 0.00002 g. g, Sodium selenite pentahydrate 0.001 g, Biotin 0.02 mg, Folic acid 0.02 mg, Pyridoxine hydrochloride 0.1 mg, Thiamine hydrochloride dihydrate 0.25 mg, Riboflavin 0.05 mg, Niacin 0.05 mg, D-Calcium pantothenate 0.05 mg, Vitamin B12 0.001 mg, Para-aminobenzoic acid 0.05 mg, Lipoic acid 0.05 mg.

7. The method for producing acetic acid and acetates using syngas according to claim 6, characterized in that: Synthetic gas was introduced into the culture system of the strain for anaerobic fermentation. The fermentation temperature was controlled at 35-39℃ and the pH was controlled at 5.6-6.

1. The culture was stirred for 5-7 days, and then the fermentation broth was separated to obtain a clear liquid containing acetic acid and acetate. The acetic acid or acetate product was purified. The synthetic gas flow rate was 3-10 L / min.

8. The method for producing acetic acid and acetates using syngas according to claim 7, characterized in that: The acetate is ammonium acetate or other acetates.

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