Method for producing saccharomyces cerevisiae protein through electrochemical biological coupling

Abstract

The invention discloses a method for producing saccharomyces cerevisiae protein through electrochemical biological coupling, which comprises the following steps: reducing carbon dioxide through an electrochemical module to generate formic acid, and producing the saccharomyces cerevisiae protein through a biological module by using the generated formic acid as a carbon source and a substrate, wherein the electrochemical module comprises a gas chamber, an extraction chamber filled with solid electrolyte, an anode chamber, a cathode arranged between the gas chamber and the extraction chamber, and an anode arranged between the anode chamber and the extraction chamber; the biological module is divided into two chambers by a diaphragm, one chamber is an acetogenic bacteria chamber for converting formic acid into acetic acid, and the other chamber is a yeast chamber for producing yeast protein by using acetic acid. According to the method, formic acid is produced by reducing carbon dioxide through electro-catalysis, acetic acid is produced by taking formic acid as a substrate, and the production of the saccharomyces cerevisiae protein is realized by further utilizing cascade reaction of acetic acid synthesis thalli, so that the method is expected to be applied to green biological manufacturing.

Description

Technical Field

[0001] The invention belongs to the technical fields of electrochemistry, carbon dioxide utilization, bioengineering and modern agriculture, and specifically relates to a method for producing brewer's yeast protein by electrochemical biological coupling. Background Art

[0002] Saccharomyces cerevisiae has long been widely used in the food industry, ensuring its safety, nutritional value and public acceptance. In addition, Saccharomyces cerevisiae can also be a source of high-value products (such as the essential vitamin folic acid). The production of yeast protein mostly relies on traditional fermentation processes, usually using organic carbon sources such as sugars as a nutrient source. However, with the global emphasis on sustainable development and the need for efficient use of resources, it has become particularly important to find new and sustainable sources of carbon sources. Carbon dioxide, as a widely existing greenhouse gas, will have a profound impact on environmental protection and resource utilization if it can be effectively utilized and converted into valuable chemicals or food ingredients. However, natural yeast cannot directly autotrophically fix carbon dioxide.

[0003] Electrochemical-biocoupling technology is a technology that connects electrochemical modules and biological modules in series to generate small-molecule organic matter through electrocatalytic carbon dioxide reduction. In it, carbon dioxide is first converted into small-molecule organic matter through the electrochemical carbon dioxide reduction reaction (CO2RR) driven by renewable energy, and then these small-molecule organic matter can be used to cultivate food-producing organisms including fungi, yeast, algae and even crops. Previous studies have proposed a conversion pathway for intermediate carbon compounds involving "electrochemical hydrogen production, bacterial acetic acid production, and yeast protein production"; but the production of acetic acid in this method requires hydrogen as an electron donor, which brings challenges in safety and mass transfer. Another envisioned pathway is "electrochemical acetic acid production, followed by protein production by yeast." However, this method ignores the fact that high selectivity and partial current density of carbon dioxide to C1 compounds can only be achieved through CO2RR, and even with the use of a series of electrochemical carbon dioxide reduction reactions (CORR), controlling the selectivity of acetic acid remains a challenge.

[0004] In addition, an important challenge for the practical application of electrochemical biocoupling technology is the formic acid concentration in the extract of the electrochemical module and the operational stability. For example, the extract containing formic acid is usually diluted when it flows into the biological module, so a higher formic acid concentration is required in the extract. In addition, in the prior art, the electrochemical module is usually only stable for a few to ten hours, and it cannot be well matched with the biological module using microbial catalysts. Therefore, there are still many technical obstacles to how to use electrochemical biocoupling technology to effectively convert the intermediate product (formic acid) produced by CO2 reduction into brewer's yeast protein. Summary of the invention

[0005] The invention proposes an innovative electrochemical bio-coupling method for producing saccharomyces cerevisiae protein, which can achieve efficient conversion from carbon dioxide to saccharomyces cerevisiae protein.

[0006] To achieve the above object, the present invention adopts the following technical solution: A method for producing brewer's yeast protein by electrochemical biological coupling, which includes first reducing carbon dioxide to generate formic acid through an electrochemical module, and then using the generated formic acid as a carbon source and substrate to produce brewer's yeast protein through a biological module.

[0007] The electrochemical module includes a gas chamber for introducing carbon dioxide, an extraction chamber filled with a solid electrolyte, an anode chamber for oxidation reaction, a cathode arranged between the gas chamber and the extraction chamber for catalyzing carbon dioxide reduction, and an anode arranged between the anode chamber and the extraction chamber for catalyzing oxygen evolution reaction.

[0008] Furthermore, the solid electrolyte filled in the extraction chamber is an ion exchange resin.

[0009] Furthermore, an extraction liquid can be introduced into the extraction chamber to extract formic acid generated by the reduction of carbon dioxide. The concentration of formic acid in the extraction liquid can be adjusted by controlling the current density, voltage or flow rate of the extraction liquid. The current density can be 10-300 mA / cm 2 The voltage can be 3-15 V, the extraction liquid flow rate can be 0.01-1 mL / min, and the concentration of the obtained formic acid solution is 0-100 g L -1 .

[0010] Furthermore, the extract can be pure water, a solution containing alkali metal cations or a biological culture medium.

[0011] Furthermore, an anolyte is introduced into the anode chamber.

[0012] Furthermore, the cathode surface and the side facing the extraction chamber are covered with anion exchange membrane, filter paper and other materials as a diaphragm to regulate the local microenvironment and improve the catalytic performance.

[0013] Furthermore, the surface of the anode, the side facing the extraction chamber, is covered with a cation exchange membrane to prevent anions in the anode chamber from entering the extraction chamber.

[0014] The biological module has a two-chamber structure, one of which is an acetogenic bacteria chamber for culturing acetogenic bacteria to convert formic acid into acetic acid, and the other is a yeast chamber for culturing saccharomyces cerevisiae to convert acetic acid to produce yeast protein (i.e., acetic acid is the product of the acetogenic bacteria chamber and also the substrate of the yeast chamber).

[0015] Furthermore, the biological module is divided into two chambers by a separation material such as filter paper or anion membrane that can block microorganisms but cannot block the migration of acetic acid.

[0016] Furthermore, the acetogenic bacteria chamber and the yeast chamber may not have an organic carbon source, that is, the formic acid extracted by the electrochemical module may be used as the sole carbon source. Alternatively, a certain concentration of an organic carbon source may be added to the two chambers to enhance the effect of producing brewer's yeast protein. For example, adding fructose to the acetogenic bacteria chamber at the same time may increase the growth rate of acetogenic bacteria, thereby increasing the rate of converting formic acid into acetic acid.

[0017] Furthermore, the formic acid extracted from the electrochemical module can be continuously pumped into the acetic acid-producing bacteria chamber of the biological module to achieve simultaneous production and use of formic acid. Alternatively, the extract containing formic acid of a certain concentration and volume can be collected and then fed into the acetic acid-producing bacteria chamber of the biological module in batches.

[0018] The significant advantages of the present invention are: (1) In the present invention, an electrochemical module is used to catalyze the reduction of carbon dioxide to produce formic acid, and an extraction liquid is introduced into an extraction chamber filled with a solid electrolyte to extract the formic acid. During the process, the concentration of formic acid in the extraction liquid and the operating stability can be increased by regulating parameters such as the flow rate of the extraction liquid and the current density, thereby providing a stable carbon source for the subsequent biological transformation process.

[0019] (2) The biomodule used in the present invention adopts a two-chamber structure, and the two chambers are separated by a partition material that can block microorganisms but cannot block the migration of acetic acid, ensuring the effective transfer of substrates and the independent progress of biological processes, and preventing the mixing of acetic acid-producing bacteria into brewer's yeast. In addition, the biomodule is also flexible, and it can be selected whether to add an organic carbon source to enhance the effect of brewer's yeast protein production as needed.

[0020] (3) During operation, after formic acid is extracted from the electrochemical module, the extract can be continuously pumped into the acetic acid-producing bacteria chamber of the biological module to achieve simultaneous production and use of formic acid. Alternatively, the extract can be collected and put into use in batches to meet different production needs.

[0021] In summary, the present invention produces brewer's yeast protein through innovative electrochemical biocoupling technology, which provides a new method for high-value utilization of carbon dioxide driven by sustainable energy, and also provides an important reference for generating edible protein through modern agricultural innovative technology under the background of big food concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a schematic structural diagram of an electrochemical biological coupling device for producing brewer's yeast protein in a specific embodiment of the present invention, wherein: 1-gas chamber; 2-cathode; 3-diaphragm; 4-extraction chamber; 5-cation exchange membrane; 6-anode; 7-anode chamber; 8-acetogenic bacteria chamber; 9-separation material; 10-yeast chamber.

[0023] Figure 2 This is a diagram showing how the concentration of formic acid in the extract is controlled by adjusting the flow rate of the extract in a specific embodiment of the present invention.

[0024] Figure 3 This is a diagram showing the long-term stable operation effect of the electrochemical module producing formic acid in a specific embodiment of the present invention.

[0025] Figure 4 This is a diagram showing the conversion of organic acids and bacterial production in an acetogenic bacteria chamber when formic acid is used as a substrate of a biological module in a specific embodiment of the present invention.

[0026] Figure 5 This is a diagram showing the conversion of organic acids and bacterial production in a yeast chamber when formic acid is used as a substrate of a biological module in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0028] The present invention proposes an electrochemical biological coupling technology for efficiently producing saccharomyces cerevisiae protein, which is to first reduce carbon dioxide to formic acid through an electrochemical module, and then use the generated formic acid as a carbon source and substrate to produce saccharomyces cerevisiae protein through a biological module. The technology integrates electrochemical and biological modules, and can realize the direct conversion from carbon dioxide to saccharomyces cerevisiae protein. In the electrochemical module, carbon dioxide is catalytically reduced to generate formic acid, and is enriched in an extraction chamber filled with solid electrolytes and extracted by an extract. By adjusting parameters such as current density, voltage and extraction liquid flow rate, the formic acid concentration in the extract is accurately controlled to meet the carbon source requirements of subsequent biological transformation. The biological module adopts a dual-chamber structure design: one chamber is responsible for the conversion of formic acid to acetic acid, and the other chamber is responsible for the biosynthesis of acetic acid to saccharomyces cerevisiae protein. The two chambers are isolated by a partition material that is impermeable to microorganisms but can migrate acetic acid, which not only ensures the effective transfer of substrates, but also maintains the independence of the biological process, and effectively prevents the contamination of yeast protein by acetogenic bacteria.

[0029] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0030] Example 1 In this embodiment, combined with Figure 1, the structure of the electrochemical bio-coupling device for producing saccharomyces cerevisiae protein in a specific embodiment of the present invention is described, which includes: 1. Electrochemical carbon dioxide reduction device: The main components of the device include a gas chamber 1 for introducing CO2 gas, a cathode 2 for catalyzing the reduction of CO2 to generate formic acid, a diaphragm 3 covering the cathode surface for adjusting the catalytic interface microenvironment and preventing impurities in the extract from inhibiting the catalytic activity, an extraction chamber 4 filled with a solid electrolyte, a cation exchange membrane 5 covering the anode surface for preventing inorganic acid anions in the anode chamber from migrating to the extraction chamber, an anode 6 for catalyzing the oxidation reaction, and an anode chamber 7 for introducing an anode liquid.

[0031] Under the condition of power on, the carbon dioxide introduced into the gas chamber 1 is catalytically reduced by the catalyst in the cathode 2 to generate negatively charged formate ions, which are then gathered in the extraction chamber 4 filled with solid electrolytes, and further combined with the positively charged hydrogen ions generated by the anode 6 to form formic acid molecules. At this time, the extraction liquid is introduced into the extraction chamber 4, and the generated formic acid can be extracted by the extraction liquid. By adjusting parameters such as current density, voltage and extraction liquid flow rate, the formic acid concentration in the extraction liquid can be accurately controlled to meet the carbon source demand for subsequent biological conversion.

[0032] In this embodiment, the preferred diaphragm is filter paper (Whatman No. 1), the preferred solid electrolyte is a strongly acidic cation exchange resin (particle size of 30-1200 μM), the preferred cathode is a sandwich-shaped gas diffusion electrode composed of a catalytic layer sprayed with a nano-bismuth catalyst (particle size of 50 nM) on hydrophobic carbon paper, a cation layer and a protective layer (the preparation method thereof is described in patent CN 119243201A), the preferred anode is platinum-plated titanium felt (0.25 thickness, 0.5 μm platinum layer), and the preferred anolyte is 0.5 M H2SO4 solution.

[0033] 2. Bioconversion device; The main components of the device include an acetogenic bacteria chamber 8 for culturing acetogenic bacteria to convert formic acid into acetic acid, a partition material 9 for preventing microorganisms from penetrating but allowing acetic acid to migrate, and a yeast chamber 10 for culturing brewer's yeast to convert acetic acid into yeast protein.

[0034] The formic acid delivered from the electrochemical module is bioconverted into acetic acid in the acetogenic bacteria chamber 8 and then delivered to the yeast chamber 10 for further fermentation to produce brewer's yeast protein.

[0035] In this embodiment, the preferred acetogenic bacteria are Acetobacteriumwoodii (DSM1030), the preferred separation material is an anion membrane, and the preferred Saccharomyces cerevisiae is Saccharomyces cerevisiae (BNCC341572).

[0036] Example 2 In this embodiment, combined with Figure 2 , a specific embodiment of the present invention is described in which the change of formic acid concentration in the extract is controlled by adjusting the flow rate of the extract.

[0037] In this example, filter paper (Whatman No. 1) was used as the separator, the extraction chamber was filled with 0.67 g of hydrogen-type strongly acidic cation exchange resin (IRC120H), and the anode was platinum-coated titanium felt. The anolyte was 100 mL of 0.5 M H2SO4 solution. The anolyte circulated at a flow rate of 2 ml min -1 The cathode is a gas diffusion electrode in a sandwich configuration, which is composed of a catalytic layer and a cationic layer and a protective layer, and a nano-bismuth catalyst (particle size of 50 nM) sprayed on hydrophobic carbon paper with an airbrush. The electrochemical module is operated at a constant current of 400 mA by a battery test system. Considering the area of ​​the cathode is 4 cm 2 , so the current density is constant at 100 mA·cm -2 Pure CO2 gas was introduced into the gas chamber at a rate of 50 mL min -1 , run at room temperature. Deionized water was used as the extraction solution, and the flow rate of the extraction solution was adjusted to 0.05, 0.1, 0.18, 0.26, 0.5, 0.75, and 1 mL·min -1 The electrochemical module was operated for 1 h at each flow rate to ensure stable operation. The effluent from the extract was collected and the change in formic acid concentration in the extract was determined by liquid chromatography.

[0038] Depend on Figure 2 It can be seen that the formic acid concentration decreases with the increase of the extraction liquid flow rate. The formic acid concentration is -1 The maximum value reached 53.5 g L -1 , at a flow rate of 1 mL min -1 The lowest value reached 3.4 g·L -1 . It can be found that by controlling the flow rate of the extract, the formic acid concentration in the extract can be easily adjusted. In this way, the formic acid extracted from the electrochemical module can be continuously pumped into the acetic acid-producing bacteria chamber of the biological module to achieve the simultaneous production and use of formic acid; or after collecting a certain concentration and volume of formic acid-containing extracts, they can be put into the acetic acid-producing bacteria chamber of the biological module in batches. In other words, according to the parameters such as the concentration, activity, and volume of the microorganisms in the biological module, the collected extract can be mixed with a certain volume of biological culture medium, or compounds can be directly added to the extract to prepare the culture medium.

[0039] Example 3 In this embodiment, combined with Figure 3, in a specific embodiment of the present invention, the long-term stable operation effect of the electrochemical module to produce formic acid is described.

[0040] In this example, filter paper (Whatman No. 1) was used as the separator, the extraction chamber was filled with 0.67 g of hydrogen-type strongly acidic cation exchange resin (IRC120H), the anode was platinum-coated titanium felt, and the cathode was a sandwich gas diffusion electrode composed of a catalytic layer and a cation layer and a protective layer sprayed with a nano-bismuth catalyst (particle size of 50 nM) on a hydrophobic carbon paper. The flow rate of the unidirectional flow of the extract (deionized water) was 0.05 mL min -1 The anolyte was 100 mL of 0.5 MH2SO4 solution and the flow rate was 2 mL min -1 , CO2 was introduced into the gas chamber at a flow rate of 50 mL min -1 The instrument was operated at a constant current of 480 mA, and the extract was collected and the formic acid was determined.

[0041] Depend on Figure 3 The results show that the electrochemical module has long-term stability in producing formic acid. The concentration of formic acid in the extract remains at 40 g L within 60 hours. -1 Above, about 1M level.

[0042] Example 4 In this embodiment, combined with Figure 4 and Figure 5 , in a specific embodiment of the present invention, when formic acid is used as the substrate of the biological module, the organic acid conversion and bacterial production in the acetogenic bacteria chamber and the yeast chamber are described.

[0043] In this embodiment, the acetogenic bacteria chamber and the yeast chamber are separated by an anionic membrane, and the liquid volume of the two chambers is 100 mL. A. woodii The medium formula is: 1.00 g NH4Cl; 0.33 g KH4PO4; 0.45 g K2HPO4; 0.10 g MgSO4×7H2O; 20.00 mL modified Wolin's mineral solution; 2.00 g yeast extract; 0.50 mL Soudium resazurin (0.1% w / v); 10.00 g NaHCO3; 1.00 mL Wolin's vitamin solution (10×); 0.50 g L-Cysteine ​​HCl×H2O; 0.50 g Na2S×9H2O; 1000.00 mL deionized water. The strain used in the yeast room is S. cerevisiaeThe culture medium formula is: 1.000 g (NH4)2SO4; 1.000 g KH2PO4; 1.000 g MgSO4×7H2O; 0.100 g NaCl; 0.033 g CaCl2×2H2O; 5.000 mg Fe(II)SO4×7H2O; 1.600 mg ZnSO4×7H2O; 1.120 mg Mn(II)SO4×H2O; 0.280 mg Na2MoO4; 0.180 mg Co(II)Cl2; 0.180 mg Cu(II)Cl2×2H2O; 20.000 mg myo-inositol; 4.400 mg thiamine; 1.200 mg pyridoxine; 1.000 mg D-pantothenicacid hemicalcium salt; 0.030 mg biotin; 1000 mL deionized water. The culture temperature was 30 ℃.

[0044] Depend on Figure 4 , 5 The results showed that during the 96 h of culture, the formic acid concentration in the acetic acid-producing bacteria chamber increased from the initial 18.5 g·L -1 Down to 3.9 g·L -1 At the same time, the acetic acid concentration accumulates from 0 to 3.0 g L -1 In addition, the OD value of acetic acid-producing bacteria increased from 0.06 at the time of inoculation to 0.12. The formic acid concentration in the yeast chamber was between 1.8 and 2.2 g·L -1 This indicates that formic acid can diffuse from the acetogenic bacteria chamber to the yeast chamber; the acetic acid concentration accumulates from 0 to 0.3 g L -1 In addition, the OD value of yeast increased from 0.08 when it was just inoculated to 0.3. After the reaction was completed, the yeast cells in the yeast room were collected by centrifugation to obtain yeast protein raw materials.

[0045] In summary, culturing acetogenic bacteria in the acetogenic bacteria chamber can convert formic acid into acetic acid; culturing Saccharomyces cerevisiae in the yeast chamber can convert acetic acid into yeast protein. That is, formic acid is the initial carbon source of the entire biological module; acetic acid is the product of the acetogenic bacteria chamber and the substrate of the yeast chamber.

[0046] Although the present invention has been described in detail, modifications within the spirit and scope of the present invention will be apparent to those skilled in the art, and the above description is intended only as an example and is not intended to limit the present invention.

Claims

1. A method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling, characterized in that: Carbon dioxide is first reduced to formic acid through an electrochemical module, and then the generated formic acid is used as a carbon source and substrate to produce brewer's yeast protein through a biological module.

2. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 1, characterized in that: The electrochemical module includes a gas chamber for introducing carbon dioxide, an extraction chamber filled with a solid electrolyte, an anode chamber for oxidation reaction, a cathode arranged between the gas chamber and the extraction chamber, and an anode arranged between the anode chamber and the extraction chamber.

3. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 2, characterized in that: The solid electrolyte filled in the extraction chamber is ion exchange resin.

4. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 2, characterized in that: An extraction liquid is introduced into the extraction chamber to extract formic acid generated by the reduction of carbon dioxide.

5. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 2, characterized in that: The cathode surface, the side facing the extraction chamber, is covered with a diaphragm.

6. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 2, characterized in that: The anode surface, the side facing the extraction chamber, is covered with a cation exchange membrane.

7. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 1, characterized in that: The biological module has a two-chamber structure, one of which is an acetogenic bacteria chamber for culturing acetogenic bacteria to convert formic acid into acetic acid, and the other is a yeast chamber for culturing saccharomyces cerevisiae to convert acetic acid to produce yeast protein.

8. The method for producing Saccharomyces cerevisiae protein by electrochemical biocoupling according to claim 7, characterized in that: The biological module is divided into two chambers by a partition material that can block microorganisms but cannot block the migration of acetic acid.

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