Construction method and application of a Clostridium butyricum / CdS hybrid system

Abstract

The present invention discloses a method for constructing a Clostridium butyricum / CdS hybrid system and its application, which mainly comprises the following steps: (1) culturing microorganisms: culturing Clostridium butyricum at 37°C using a TGY culture medium to obtain a fresh Clostridium butyricum bacterial liquid; (2) constructing a Clostridium butyricum / CdS composite system: adding L-cysteine ​​hydrochloride and CdS to the bacterial liquid; 2+ Metal ions in situ form nanoparticles CdS and self-assemble on the surface of Clostridium butyricum cells; under light irradiation, the concentration of NADH in the Clostridium butyricum / CdS system is detected to evaluate the photocatalytic performance of the system. Starting from the current energy shortage problem, the present invention utilizes the renewable solar energy in nature to construct a photosynthetic biological hybrid system that combines the advantages of semiconductor light-harvesting ability and microbial metabolic catalytic ability, and can be applied to microorganisms to efficiently produce high value-added products such as butyric acid, H2, ethanol, 1,3-propylene glycol, etc.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysts, and in particular to a construction method and application of a Clostridium butyricum / CdS hybrid system. Background Art

[0002] Fossil fuels represented by oil, coal and natural gas are the main forms of energy in the world today. However, with the advancement of global industrialization, the huge demand for energy in various production sectors and people's daily lives has caused a rapid consumption of fossil fuels. In addition, the widespread use of fossil fuels has caused excessive emissions of carbon dioxide, which has led to continued global climate change, extreme weather and glacier melting. Therefore, based on the non-renewable and environmentally consuming characteristics of traditional fossil fuels, the development of renewable green energy to achieve orderly replacement of fossil fuels has become an inevitable trend for future development. Solar energy is the most abundant renewable energy on earth, but current industrial microorganisms cannot directly utilize solar energy.

[0003] Photocatalytic materials can mimic natural biological light-absorbing pigments, such as carotenoids and chlorophyll. Photocatalytic materials have a wider absorption of the solar spectrum, segmented complementary absorption of the solar spectrum, and easier charge separation, so they have higher light harvesting efficiency. CdS, as one of the most promising visible light-driven hydrogen production photocatalysts, has attracted widespread attention due to its narrow band gap (Eg≈2.4eV), suitable band edge position, and efficient photoexciton generation. In particular, one-dimensional CdS nanostructures have shown great application potential in photocatalytic hydrogen production due to their excellent performance in internal carrier separation. Clostridium butyricum is a strictly anaerobic, Gram-positive bacterium. Clostridium butyricum has a rich substrate spectrum and can utilize a large number of sugars, including complex mixtures such as molasses, potato starch, whey, most disaccharides, and glycerol. It can produce not only butyric acid, but also bulk chemicals such as acetic acid, H2, ethanol, and 1,3-propylene glycol. Because of its high stability and operability, it has been used as the main microorganism for the production of high value-added products. At present, the ability of Clostridium butyricum to synthesize chemicals has been studied by metabolic engineering and fermentation process optimization, but the limitations such as easy mutation and cumbersome operation have greatly restricted the industrialization process of Clostridium butyricum. The present invention proposes a method for constructing a Clostridium butyricum / CdS hybrid system, which is expected to utilize the light-harvesting advantage of CdS to efficiently enhance the productivity of Clostridium butyricum. Summary of the invention

[0004] The purpose of the present invention is to provide a method for constructing a Clostridium butyricum / CdS hybrid system and its application. By means of modern biotechnology, a Clostridium butyricum / CdS composite system is constructed by in-situ synthesis of photocatalyst CdS by Clostridium butyricum and self-assembly on the surface of Clostridium butyricum, which can improve the regeneration of intracellular NADH of Clostridium butyricum under a certain light intensity and further promote the metabolic flux of intracellular products; the constructed Clostridium butyricum / CdS composite system converts abundant and cheap solar energy into industrial products through microbial cell factories, which will be an effective way to solve the dual crises of energy shortage and environmental deterioration.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for constructing a Clostridium butyricum / CdS hybrid system comprises the following steps:

[0007] (1) Cultivation of microorganisms: inoculate Clostridium butyricum into 10-20 mL of TGY liquid medium and culture at 37° C. for 12-18 h, add the bacterial solution to fresh TGY medium at a ratio of 5-8% (v / v) and continue culturing for 10-16 h, take 50-80 mL of the bacterial solution and centrifuge at 4° C., 4000 rpm for 10 min, and remove the supernatant;

[0008] (2) Construction of Clostridium butyricum / CdS hybrid system: 0.1-0.4 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium, Clostridium butyricum was transferred to the mineralization medium, and cultured at 37°C for 32-40 h. It was observed that the color of the bacterial liquid changed from the color of the medium to bright yellow;

[0009] (3) Detection of photocatalytic performance of Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 24-48 h. 2 The culture medium system is continuously irradiated with visible light, and samples are taken at regular intervals to detect the intracellular NADH concentration in the system.

[0010] The formula of the TGY liquid culture medium in step (1) is: 10-30 g / L peptone, 10-20 g / L glucose, 10-20 g / L yeast powder, and 0.5-1.0 g / L cysteine ​​hydrochloride.

[0011] Preferably, in step (1), high-purity nitrogen (N2, 99.999%) is introduced into the TGY liquid culture medium for 15-20 minutes for deoxygenation and then sealed with a rubber stopper.

[0012] Preferably, the mineralization medium prepared in step (2) needs to be prepared and used immediately, and the storage time cannot exceed 10-12 hours. The pH of the mineralization medium is adjusted to about 6.5-7.0 by adding 1-2 mol / L HCl or 1-2 mol / L NaOH.

[0013] Preferably, the wavelength range of the visible light used in step (3) is 400-650 nm.

[0014] Preferably, in step (3), the intracellular NADH concentration and the butyrate production are detected using an NADH detection kit and high performance liquid chromatography, respectively.

[0015] The construction method constructs a Clostridium butyricum / CdS hybrid system.

[0016] The Clostridium butyricum / CdS hybrid system is used in the production of butyric acid, H2, ethanol and 1,3-propylene glycol.

[0017] Application of the Clostridium butyricum / CdS hybrid system in the preparation of butyric acid: The Clostridium butyricum / CdS hybrid system was transferred to 100-200 mL of TGY medium for batch fermentation for 64-72 h, using 1000-3000 W / m 2 The culture medium system is continuously irradiated with visible light, and samples are taken at regular intervals to detect the butyric acid concentration in the system.

[0018] Application of Clostridium butyricum / CdS hybrid system in the preparation of H2: The Clostridium butyricum / CdS hybrid system was transferred to 100-200 mL of TGY medium for batch fermentation for 64-72 h, using 1000-3000 W / m 2 The culture medium system is continuously irradiated with visible light, and samples are taken at regular intervals to detect the H2 concentration in the system.

[0019] Application of the Clostridium butyricum / CdS hybrid system in the preparation of ethanol: The Clostridium butyricum / CdS hybrid system was transferred to 100-200 mL of TGY medium for batch fermentation for 64-72 h, using 1000-3000 W / m 2 The culture medium system is continuously irradiated with visible light, and samples are taken at regular intervals to detect the ethanol concentration in the system.

[0020] Application of the Clostridium butyricum / CdS hybrid system in the preparation of 1,3-propylene glycol. The Clostridium butyricum / CdS hybrid system was transferred to 100-200 mL of TGY medium for batch fermentation for 64-72 h, using 1000-3000 W / m 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the concentration of 1,3-propanediol in the system.

[0021] The Clostridium butyricum / CdS hybrid system uses nanoparticle CdS driven by solar energy to increase the regeneration intensity of the intracellular reducing power NADH of Clostridium butyricum, thereby achieving efficient synthesis of its high value-added products.

[0022] Beneficial effects: The present invention proposes a strategy of combining Clostridium butyricum with the inorganic photocatalytic material CdS to construct a Clostridium butyricum / CdS hybrid system, using renewable energy to enhance the productivity of Clostridium butyricum, and applying it to the green production of high value-added products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 .SEM images of Clostridium butyricum / CdS hybrid system, (A): scale bar is 2nm, (B): scale bar is 4nm;

[0024] Figure 2 .NADH levels of Clostridium butyricum / CdS hybrid systems constructed in different implementation cases. DETAILED DESCRIPTION

[0025] The present invention will be further described below by way of specific examples.

[0026] Example 1

[0027] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205, purchased from China General Microbiological Culture Collection Center) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0028] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.1 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.1 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1 As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0029] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0030] Example 2

[0031] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0032] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.1 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.1 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1 As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0033] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0034] Example 3

[0035] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0036] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.2 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.2 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1 As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0037] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0038] Example 4

[0039] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0040] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.2 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.2 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1 As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0041] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0042] Example 5

[0043] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0044] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.3 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.3 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0045] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0046] Example 6

[0047] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0048] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.4 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.4 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1 As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0049] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0050] Example 7

[0051] (1) Cultivation of microorganisms: Clostridium butyricum (CGMCC1.5205) was inoculated into 20 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride), and high-purity nitrogen (N2, 99.999%) was introduced for 15-20 min for deoxygenation and then sealed with a rubber stopper) and cultured at 37°C for 12 h. The bacterial solution was added to fresh TGY liquid medium at a ratio of 5% (v / v) and cultured for 10 h. 50 mL of the bacterial solution was centrifuged at 4°C, 4000 rpm for 10 min, and the supernatant was removed to obtain Clostridium butyricum cells.

[0052] (2) Construction of the Clostridium butyricum / CdS hybrid system: 0.3 g / L Cd(NO3)2·4H2O was added to 50 mL of TGY liquid medium to prepare a mineralization medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride, 0.3 g / L Cd(NO3)2·4H2O). The Clostridium butyricum cells were transferred to the mineralization medium at a 100% inoculation rate and cultured at 37°C for 32 h. It was observed that the color of the bacterial solution changed from the color of the culture medium to bright yellow, indicating that the Clostridium butyricum / CdS hybrid system had been constructed. Figure 1 As shown, it can be observed that the optical nanoparticles CdS are uniformly coated on the surface of Clostridium butyricum bacteria, forming a Clostridium butyricum / CdS hybrid system with a relatively stable structure.

[0053] Detection of the photocatalytic performance of the Clostridium butyricum / CdS hybrid system: The collected Clostridium butyricum / CdS hybrid system was transferred to a new 50 mL TGY liquid culture medium and cultured for 48 h. 2 The culture medium system was continuously irradiated with visible light, and samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0054] Control group

[0055] (1) The Clostridium butyricum cells were transferred into 50 mL of TGY liquid medium (30 g / L peptone, 20 g / L glucose, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride) and cultured at 37°C for 32 h.

[0056] (2) The Clostridium butyricum was transferred to a new 50 mL TGY liquid medium and cultured for 48 h. Samples were taken at regular intervals to detect the intracellular NADH concentration in the system. The results were as follows: Figure 2 shown.

[0057] The results show that the NADH level in the cells of Clostridium butyricum / CdS prepared by in situ synthesis of Cd(NO3)2·4H2O at a concentration of 0.1 g / L is relatively high, mainly due to the visible light excitation. CdS generates more photoelectrons that pass through the cell membrane and enter To the cell The regeneration of NADH in the cell is beneficial to the further synthesis of high value-added products. As the concentration of Cd(NO3)2·4H2O increases, the level of NADH in the cell shows a downward trend. It is speculated that high concentration of Cd(NO3)2·4H2O is toxic to Clostridium butyricum, inhibiting its cell growth and affecting the level of NADH in the cell. In addition, we found that at 2000W / m 2 The NADH level in the cells of Clostridium butyricum / CdS under visible light of 100 nm was significantly higher than that under other intensities, indicating that light intensity is a key factor affecting the level of NADH in cells. Therefore, the level of NADH in the cells of Example 2 was the highest.

[0058] Example 8 Preparation of butyric acid by Clostridium butyricum / CdS hybrid system under photocatalysis

[0059] The C. butyricum / CdS hybrid system prepared in steps 1 and 2 was subjected to batch fermentation for 72 h in a medium (30 g / L peptone, 10 g / L yeast powder, 0.5 g / L cysteine ​​hydrochloride) with 60 g / L glucose as the initial carbon source. 2 The culture medium system was continuously irradiated with visible light, and the ability of the Clostridium butyricum / CdS hybrid system to produce butyrate under visible light was evaluated using butyrate as the determination index. The results are shown in Table 1.

[0060] Table 1. Detection of butyric acid production in the Clostridium butyricum / CdS hybrid system

[0061]

[0062] The results show that compared with the butyrate production of 13.42 g / L obtained in the control group The butyrate production in Example 2 increased by 16.36%, and both the butyrate benefit and the butyrate yield reached a higher level. It is speculated that the higher intracellular NADH concentration promoted the synthesis of the product butyrate.

[0063] In summary, the Clostridium butyricum / CdS hybrid system proposed in the present invention can significantly increase the reducing power within the cells of Clostridium butyricum, and promote the efficient synthesis of high value-added products using Clostridium butyricum as the production strain driven by solar energy. Compared with the previous redirection of carbon pathways based on synthetic biology technology, this system can realize the green production of chemicals such as butyric acid, and alleviate the environmental pressure caused by the current continuous consumption of fossil fuels.

Claims

1. A method for constructing a Clostridium butyricum / CdS hybrid system, characterized in that: The steps include: (1) Cultivation of microorganisms: inoculate Clostridium butyricum into 10-20 mL of TGY medium and culture it statically for 12-18 h. Add the bacterial solution into fresh TGY medium at a volume ratio of 5-8% and continue culturing for 10-16 h. Centrifuge and remove the supernatant. (2) Construction of Clostridium butyricum / CdS hybrid system: 0.1-0.2 g / L Cd(NO3)2·4H2O was added to TGY liquid culture medium to prepare a mineralized culture medium. The Clostridium butyricum cells were transferred to the mineralized culture medium and cultured statically for 32-40 h. It was observed that the color of the bacterial liquid changed from the color of the culture medium to bright yellow. The Clostridium butyricum / CdS hybrid system was constructed.

2. The method for constructing a Clostridium butyricum / CdS hybrid system according to claim 1, characterized in that: The formula of TGY medium in step (1) is: 10-30 g / L peptone, 10-20 g / L glucose, 10-20 g / L yeast powder, and 0.5-1.0 g / L cysteine ​​hydrochloride.

3. The method for constructing a Clostridium butyricum / CdS hybrid system according to claim 1, characterized in that: The formula of the mineralization medium in step (2) is: 10-30 g / L peptone, 10-20 g / L glucose, 10-20 g / L yeast powder, 0.5-1.0 g / L cysteine ​​hydrochloride, 0.1-0.2 g / L Cd(NO3)2·4H2O, pH to 6.5-7.

0.

4. The method for constructing a Clostridium butyricum / CdS hybrid system according to claim 3, characterized in that: The concentration of Cd(NO3)2·4H2O in the mineralization medium is 0.1 g / L.

5. A Clostridium butyricum / CdS hybrid system is constructed by the construction method according to any one of claims 1 to 4.

6. Use of the Clostridium butyricum / CdS hybrid system according to claim 5 in the production of butyric acid, H2, ethanol and 1,3-propylene glycol.

7. The use according to claim 6, characterized in that: The C. butyricum / CdS hybrid system was inoculated into the fermentation medium and heated to 1000-2000 W / m 2 The culture medium system is continuously irradiated with visible light to increase the regeneration intensity of the reducing power NADH in the cells of Clostridium butyricum, thereby achieving efficient and green conversion of agricultural waste biomass and producing corresponding products.

8. The use according to claim 7, characterized in that: The visible light wavelength range is 400-650nm.

9. The use according to claim 7, characterized in that: The visible light is 2000 W / m 2 .

10. The use according to claim 7, characterized in that: The fermentation medium comprises 10-30 g / L peptone, 10-20 g / L glucose, 10-20 g / L yeast powder, and 0.5-1.0 g / L cysteine ​​hydrochloride.

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