Preparation method of biological hybrid electrode constructed by escherichia coli and ZIF-8 and application of biological hybrid electrode as catalyst
The construction of biohybrid electrodes by E. coli and ZIF-8 solves the problem of slow electron transfer in microbial fuel cells, achieves efficient redox reactions and biopower generation capabilities, and improves the overall performance of microbial fuel cells.
Patent Information
- Application Number
- CN202510279763.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-11
- Publication Date
- 2025-08-01
AI Technical Summary
In microbial fuel cells, electron transfer rates from microorganisms to electrodes are slow, affecting the overall performance. The existing cathode materials are insufficient in performance, limiting their practical application.
E. coli and ZIF-8 are used to construct biohybrid electrodes, and the high specific surface area and conductivity of ZIF-8 are used to promote microbial adhesion and electron transfer, form a conductive network, improve electron transfer efficiency, and regulate the diffusion of reactants and products through pore structure.
It significantly improves the redox reaction efficiency and output power of microbial fuel cells, enhances the growth and metabolic capabilities of microorganisms, and improves electron transfer efficiency and overall performance.
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Figure CN120404880A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of biomaterial chemistry, and particularly relates to a preparation method of a biohybrid electrode constructed by Escherichia coli and ZIF-8 and its application as a catalyst. Background Art
[0002] Energy is an important substance for people's survival and development, and it is also an important factor restricting the development of modern economy and society, playing an increasingly important role in economy, science and technology, and social life. The global economy and industry largely rely on the energy provided by fossil fuels. However, the non-renewability and limited reserves of fossil fuels make it impossible to meet the growing global energy demand. In the global trend of transitioning from fossil energy to clean energy, bioenergy has become an important part of clean energy.
[0003] As an emerging bioelectrochemical system, the core mechanism of a microbial fuel cell (MFC) lies in the attachment and growth of electrochemically active microorganisms on the cathode surface and the catalytic effect of active sites in their bodies on the oxygen reduction reaction. Due to its clean, efficient, and sustainable characteristics, this technology has attracted extensive attention in the fields of environment and energy in recent years. However, compared with traditional energy conversion technologies, the extracellular electron transfer (EET) rate from microorganisms to electrodes in MFCs is relatively slow, and this technical bottleneck severely restricts its practical application. Research has shown that the cathode material, as a key carrier for microbial attachment and reproduction, directly affects the overall performance of MFCs and is the key point to improve the output power of microbial fuel cells.
[0004] To solve these problems, researchers tend to load a layer of metal-organic framework material on carbon cloth. The material derived from the metal-organic framework material can retain the pore structure, provide a high specific surface area, introduce heteroatoms of organic ligands, improve biocompatibility, and reduce internal resistance. It is considered an ideal precursor for modifying the cathode material in multiple dimensions. It promotes the electron transfer between microorganisms and the cathode electrode or increases the attachment points of natural cells on the carbon cloth, enhances the progress of the redox reaction, and provides a suitable microenvironment for the growth and natural catalytic process of microorganisms.
[0005] Therefore, by chemically engineering the carbon cloth to research and develop a new type of microbial cathode catalyst that can overcome low electron transfer efficiency, be inexpensive and easily available, and have good stability, it is very likely to provide a feasible strategy to overcome the key challenges faced by current microbial fuel cells. Summary of the Invention
[0006] In view of the deficiencies of the prior art, the present invention provides a method for preparing a biohybrid electrode constructed by Escherichia coli and ZIF-8, and uses it in a microbial fuel cell. The constructed composite material can effectively improve the catalytic ability of oxygen reduction, thereby regulating its electrocatalytic activity and survival and metabolic ability. It can significantly improve the attachment points of microorganisms in the microbial fuel cell, increase the electron transfer efficiency, and endow it with the dual functions of efficient bioelectricity generation and pollutant treatment.
[0007] The first object of the present invention is to provide a method for preparing a biohybrid electrode constructed by Escherichia coli and ZIF-8.
[0008] The second object of the present invention is to provide the application of the above biohybrid electrode as a catalyst.
[0009] In order to achieve the above invention objects, the present invention provides the following technical solutions:
[0010] A method for preparing a biohybrid electrode constructed by Escherichia coli and ZIF-8 includes dissolving the metal-organic framework ZIF8 material in a solution, then adding carbon cloth and drying to obtain the carbon cloth mixed with ZIF8; then adding it to the Escherichia coli bacterial liquid in LB liquid medium for culture, taking the above cultured Escherichia coli bacterial liquid for further expansion culture, then centrifuging, discarding the supernatant, and then adding the LB liquid medium solution again and adding the carbon cloth mixed with ZIF8 and mixing.
[0011] Preferably, the LB liquid medium is a mixture of 1L ultrapure water, 10g peptone, 5g yeast and 10g sodium chloride.
[0012] The present invention also protects the biohybrid electrode prepared by the above method constructed by Escherichia coli and ZIF-8.
[0013] Furthermore, it protects the application of the biohybrid electrode as an electrocatalyst in the preparation of the cathode of a microbial fuel cell.
[0014] Compared with the prior art, the beneficial effects of the present invention are:
[0015] ZIF-8 has a large specific surface area, providing more active sites for microbial attachment and electron transfer, thus enhancing the efficiency of electrode reactions; ZIF-8 has excellent electrical conductivity, which helps to accelerate the electron transfer from microorganisms to the electrode, reduce energy loss, and increase the output power; ZIF-8 exhibits good chemical stability in the complex environment of MFC, ensuring stable performance during long-term operation; ZIF-8 is friendly to microorganisms, can promote the growth and metabolism of microorganisms, and enhance the electron transfer efficiency; the pore structure of ZIF-8 is adjustable, which is beneficial to the diffusion of reactants and products and improves the reaction rate; ZIF-8 has a catalytic effect on certain reactions and can accelerate key steps such as oxygen reduction reaction, thereby improving the overall performance. Description of the Drawings
[0016] Figure 1 Cyclic voltammetry test chart of the biohybrid electrode constructed with the metal-organic framework ZIF8 material prepared in Example 1 of the present invention and Escherichia coli as a microbial catalyst.
[0017] Figure 2 Linear sweep voltammogram of the biohybrid electrode constructed with the metal-organic framework ZIF8 material prepared in Example 1 of the present invention and Escherichia coli as a microbial catalyst. Detailed Embodiments
[0018] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments and comparative examples of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0019] The test methods used in the following embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all reagents and materials that can be obtained from commercial channels unless otherwise specified. The following Escherichia coli are all based on the biosafe Escherichia coli BL21(DE3) as the starting strain.
[0020] Example 1: A preparation method of a metal-organic framework ZIF8 material and Escherichia coli acting together as an efficient microbial catalyst, comprising the following steps:
[0021] First step, prepare metal-organic framework ZIF8 material by solvent method: Dissolve 3.7 g of 2-methylimidazole in 80 mL of methanol, ultrasonically treat for 30 min to form a homogeneous solution in flask A; dissolve 1.67 g of zinc nitrate hexahydrate and 0.07 g of cobalt acetylacetonate (0.073 g) in 40 mL of methanol, ultrasonically treat for 15 min to form a clear solution in flask B; add the mixture in flask B dropwise to flask A, and vigorously stir at room temperature for 12 h; centrifuge the obtained product, then wash it three times with methanol, and finally dry it overnight under vacuum at 60 °C to obtain the metal-organic framework ZIF8 material.
[0022] Second step, prepare metal-organic framework ZIF8 material by thermal reduction method: Place the metal-organic framework ZIF8 material prepared in the previous step in a tubular furnace and continuously calcine for 3 hours, the calcination temperature is 800 °C, the atmosphere is argon, and after calcination, cool it to room temperature to collect the product to obtain the metal-organic framework ZIF8 material.
[0023] An application of a metal-organic framework ZIF8 material and Escherichia coli (all Escherichia coli strains are based on the biosafe Escherichia coli BL21(DE3) as the starting strain) as an efficient microbial catalyst, including the following steps:
[0024] Take 5 mg of the calcined metal-organic framework ZIF8 material, dissolve it in 50 μL of naphthol, drop it onto carbon cloth, and dry it for later use; use a pipette to aspirate 3 ml of LB liquid medium and 30 μL of wild Escherichia coli liquid, pipette and mix well, and place it in a shaker for 10 h; pour 200 ml of LB liquid medium solution into a triangular flask, then take 2 ml of the cultured strain and add it to the triangular flask, and shake it in a shaker for 12 h; after leveling the cultured bacterial liquid, centrifuge it at 5000 rpn for 4 min, then pour out the supernatant; pour in ultrapure water to level it and centrifuge it again, pour out the supernatant; take 50 ml of LB liquid medium solution and the centrifuged bacterial liquid (the precipitate after discarding the supernatant), mix well, add the treated carbon cloth, and shake it for 24 h; form an electrolytic cell and place it in a constant temperature water bath (37 °C), pour M9 buffer solution into it, and saturate it with oxygen or nitrogen for testing.
[0025] The electrolytic cell is prepared as follows: Weigh 11.3 g of the purchased M9 medium powder and dissolve it in 979 ml of pure water, sterilize it by high temperature and high pressure, and then add 20 ml of 20% D-glucose solution (sterile), 2 ml of 1.0 M MgSO4 solution (sterile), and 0.1 ml of 1.0 M CaCl2 solution (sterile) to prepare M9 complete medium as the electrolyte. The counter electrode uses a platinum electrode, the reference electrode uses a silver chloride electrode, and the working electrode is the carbon cloth loaded with Escherichia coli.
[0026] Example 2:
[0027] A preparation method of a metal-organic framework ZIF8 material and Escherichia coli acting as an efficient microbial catalyst in cooperation, comprising the following steps:
[0028] First step, preparing the metal-organic framework ZIF8 material by a solvent method: Dissolve 2 g of 2-methylimidazole in 80 mL of methanol, ultrasonically treat for 30 min to form a uniform solution in flask A; dissolve 2 g of zinc nitrate hexahydrate and 0.05 g of cobalt acetylacetonate in 40 mL of methanol, ultrasonically for 15 min to form a clear solution in flask B; add the mixture in flask B dropwise to flask A, and vigorously stir at room temperature for 16 h; centrifuge the obtained product, then wash it three times with methanol, and finally dry it overnight under vacuum at 60 °C to obtain the metal-organic framework ZIF8 material.
[0029] Second step, preparing the metal-organic framework ZIF8 material by a thermal reduction method: Place the metal-organic framework ZIF8 material prepared in the previous step in a tube furnace and continuously calcine for 4 hours, the calcination temperature is 900 °C, the atmosphere is argon, and after the calcination is completed, cool it to room temperature and collect the product to obtain the metal-organic framework ZIF8 material.
[0030] An application of a metal-organic framework ZIF8 material and Escherichia coli acting as an efficient microbial catalyst in cooperation, comprising the following steps: Take 5 mg of the calcined metal-organic framework ZIF8 material and dissolve it in 50 μL of naphthol, then drop it onto the carbon cloth and dry it for later use; use a pipette to suck 2 ml of LB liquid medium and 30 μL of wild Escherichia coli bacterial liquid, pipette and mix well, and place it in a shaker for 10 h; pour 200 ml of LB liquid medium solution into a triangular flask, and then take 2 ml of the cultured bacterial strain and add it to the triangular flask, and shake it in a shaker for 12 h; after leveling the cultured bacterial liquid, centrifuge it at 5000 rpn for 4 min, and then pour out the supernatant; pour in ultrapure water to level it and centrifuge again, pour out the supernatant; take 50 ml of LB liquid medium solution and the centrifuged bacterial liquid, mix well, add the treated carbon cloth, and shake it for 24 h; form an electrolytic cell and place it in a constant temperature water bath (37 °C), pour M9 buffer solution into it, and pass oxygen or nitrogen to saturate it for testing.
[0031] Example 3:
[0032] A preparation method of a metal-organic framework ZIF8 material and Escherichia coli acting as an efficient microbial catalyst in cooperation, comprising the following steps:
[0033] First step, prepare metal-organic framework ZIF8 material by solvent method: Dissolve 4 g of 2-methylimidazole in 80 mL of methanol, and ultrasonically treat for 30 min to form a homogeneous solution in flask A; dissolve 2 g of zinc nitrate hexahydrate and 0.1 g of cobalt acetylacetonate in 40 mL of methanol, and ultrasonically treat for 15 min to form a clear solution in flask B; add the mixture in flask B dropwise to flask A, and vigorously stir at room temperature for 12 h; centrifuge the obtained product, then wash it three times with methanol, and finally dry it overnight under vacuum at 60 °C to obtain metal-organic framework ZIF8 material.
[0034] Second step, prepare metal-organic framework ZIF8 material by thermal reduction method: Place the metal-organic framework ZIF8 material prepared in the previous step in a tubular furnace and continuously calcine for 5 hours, the calcination temperature is 1000 °C, the atmosphere is argon, and after calcination, cool it to room temperature to collect the product to obtain metal-organic framework ZIF8 material.
[0035] An application of a metal-organic framework ZIF8 material and Escherichia coli as a highly efficient microbial catalyst, including the following steps:
[0036] Take 5 mg of the calcined metal-organic framework ZIF8 material, dissolve it in 50 μL of naphthol, drop it onto the carbon cloth, and dry it for later use; use a pipette to aspirate 2 ml of LB liquid medium and 30 μL of wild Escherichia coli bacterial liquid, pipette and mix well, and place it in a shaker for 16 h; pour 200 ml of LB liquid medium solution into a triangular flask, and then add 2 ml of the cultured bacteria into the triangular flask, and shake it in a shaker for 12 h; after leveling the cultured bacterial liquid, centrifuge it at 5000 rpn for 4 min, and then pour out the supernatant; pour in ultrapure water to level it and centrifuge it again, pour out the supernatant; take 50 ml of LB liquid medium solution and the centrifuged bacterial liquid, mix well, add the treated carbon cloth, and shake it for 27 h; form an electrolytic cell and place it in a constant temperature water bath (37 °C), pour M9 buffer solution into it, and saturate it with oxygen or nitrogen for testing.
[0037] Figure 1 It is the CV diagram. Figure 1CC in it is simply carbon cloth (without any modification and without growing Escherichia coli); WT is wild Escherichia coli growing on carbon cloth (without any modification); WT-CC / Zn-Co is wild Escherichia coli growing on the chemically engineered carbon cloth as the cathode in a microbial fuel cell, and this modified carbon cloth is our final sample. The nano-cage structure of ZIF-8 can adsorb and slowly release nutrients to maintain the metabolic activity of bacteria. The porous structure and high specific surface area of ZIF-8 provide an ideal growth environment for Escherichia coli, enhance microbial attachment, and promote biofilm formation. At the same time, ZIF-8 combines with the carbon cloth to form a conductive network, reducing the interfacial resistance, accelerating the electron transfer from bacteria to the electrode, and improving the electron transfer efficiency. The synergistic effect between the two further enhances the overall performance of the MFC.
[0038] Through Figure 1 It can be seen from the CV diagrams in that among the three test cells, the CV curve of Escherichia coli growing on the chemically engineered carbon cloth shows the largest enclosed area and the largest peak current response. This observation indicates that the modified carbon cloth has the fastest reaction kinetics and the highest capacity. The larger the peak current, the faster the rate of the redox reaction occurring on the electrode surface. This indicates higher catalyst activity, higher reactant concentration, or higher electron transfer efficiency. Therefore, Figure 1 it can be seen that the modified carbon cloth has good performance. Figure 2 The lower the Tafel slope in, the higher the exchange current density and catalytic activity. The larger the peak current, the faster the rate of the redox reaction occurring on the electrode surface. This indicates higher catalyst activity, higher reactant concentration, or higher electron transfer efficiency, so it can also indicate that the modified carbon cloth has high performance.
[0039] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solutions of the present invention, rather than limitations on the specific implementation manners of the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the claims of the present invention shall be included within the protection scope of the claims of the present invention.
Claims
1. A preparation method of a biohybrid electrode constructed by Escherichia coli and ZIF-8, characterized in that, Dissolve the metal-organic framework ZIF8 material in a solution, then add carbon cloth and dry it to obtain the carbon cloth mixed with ZIF8; then add it to the Escherichia coli bacterial solution in LB liquid medium for cultivation. Take the above-cultivated Escherichia coli bacterial solution and continue to expand the cultivation, then centrifuge, discard the supernatant, then add the LB liquid medium solution again, and add the carbon cloth mixed with ZIF8 and mix them.
2. The preparation method according to claim 1, characterized in that, The LB liquid medium is a mixture of 1 L of ultrapure water, 10 g of peptone, 5 g of yeast, and 10 g of sodium chloride.
3. The preparation method according to claim 1, characterized in that, The preparation of the ZIF8 material is as follows: S1. Dissolve 3.7 g of 2-methylimidazole in 80 mL of methanol and ultrasonically treat it for 30 min to form a homogeneous solution in flask A; dissolve 1.67 g of zinc nitrate hexahydrate and 0.07 g of cobalt acetylacetonate in 40 mL of methanol and ultrasonically treat it for 15 min to form a clear solution in flask B; add the mixture in flask B dropwise to flask A and stir at room temperature for 12 h; centrifuge the obtained product, then wash it three times with methanol, and finally dry it overnight at 60 °C under vacuum. S2. Prepare the metal-organic framework ZIF8 material by the thermal reduction method: place the metal-organic framework ZIF8 material prepared in the previous step in a tubular furnace and continuously calcine it for 3 hours at a calcination temperature of 800 °C and an atmosphere of argon. After the calcination is completed, cool it to room temperature and collect the product to obtain the metal-organic framework ZIF8 material.
4. A biohybrid electrode constructed from Escherichia coli and ZIF-8 prepared by the method described in claim 1.
5. Use of the biohybrid electrode described in claim 4 as an electrocatalyst in the preparation of the cathode of a microbial fuel cell.