Microbial electrochemical system based on aerobic extracellular electron transfer and application thereof

Abstract

The invention discloses a microbial electrochemical system based on aerobic extracellular electron transfer and application thereof, and belongs to the field of microbial electrochemistry, the microbial electrochemical system based on aerobic extracellular electron transfer comprises a reaction tank, the reaction tank is inoculated with flora, the flora contains shewanella genus, the dissolved oxygen concentration of the reaction tank is maintained to be greater than or equal to 1mg / L, and the dissolved oxygen concentration of the reaction tank is maintained to be greater than or equal to 1mg / L; and carrying out extracellular electron transfer on the shewanella genus. The shewanella genus is inoculated in a reaction tank and combined with the condition that the dissolved oxygen concentration is kept to be larger than or equal to 1 mg / L, the phenomenon that extracellular electron transfer can be conducted under the condition that the dissolved oxygen concentration is kept to be larger than or equal to 1 mg / L through the shewanella genus is utilized, and the shewanella genus has wide application prospects in the fields of biosensors, clean energy production and biomedicine and can also be applied to sewage treatment. And efficient electric energy recovery and COD removal are realized in sewage treatment.

Description

Technical Field

[0001] The present invention belongs to the field of microbial electrochemistry, and particularly relates to a microbial electrochemical system based on aerobic extracellular electron transfer and its application. Background Art

[0002] Extracellular electron transfer is a microbial process in which microorganisms oxidize and decompose organic matter into electrons, and the electrons are transferred to extracellular receptors through transmembrane transport proteins. Microorganisms with the ability of extracellular electron transfer are called electroactive microorganisms. This characteristic of electroactive microorganisms enables them to convert toxic pollutants such as heavy metals and antibiotics extracellularly, reducing the impact of toxic pollutants on microbial metabolism. Therefore, various microbial electrochemical technologies (such as microbial electrochemical systems) developed based on the extracellular electron transfer process have a significant strengthening effect on the microbial transformation of toxic and refractory pollutants compared with traditional sewage biological treatment processes. In addition, extracellular electron transfer can also achieve the resource treatment of pollutants, the bioelectrosynthesis of high-value products, etc. Because the redox potential of oxygen is higher than that of electrodes or minerals, it has always been believed that under aerobic conditions, microorganisms will use oxygen as an intracellular electron acceptor and do not use the extracellular electron transfer process to transfer electrons extracellularly. Extracellular electron transfer is an anaerobic process. However, the main function of sewage treatment plants is to remove pollutants.

[0003] A microbial fuel cell for degrading glucose wastewater to generate electricity with a publication number of CN105845959A includes an anode chamber and a cathode chamber. The anode chamber is filled with wastewater and a culture solution as an electrolyte. The wastewater contains xylose and / or glucose, and the culture solution contains riboflavin. The anode chamber is inoculated with Shewanella oneidensis MR-1. Like traditional microbial electrochemical systems, since it is carried out under anaerobic conditions, the COD removal efficiency is very slow. Therefore, it is very difficult to efficiently treat sewage while recovering energy, which greatly hinders the practical application of microbial electrochemical systems. At the same time, because microbial electrochemical systems do not need to rely on a power source during operation, they have attracted much attention in the sensor field. However, most of the environments where people live are surrounded by oxygen, and anaerobic microbial electrochemical systems are very sensitive to changes in dissolved oxygen, seriously hindering the application of anaerobic microbial electrochemical systems in the sensor field. Summary of the Invention

[0004] The purpose of the present invention is to provide a microbial electrochemical system based on aerobic extracellular electron transfer and its application to overcome at least one of the above defects in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The microbial electrochemical system based on aerobic extracellular electron transfer provided by the present invention includes a reaction tank, the reaction tank is inoculated with a bacterial community, the bacterial community contains Shewanella, and the reaction tank maintains a dissolved oxygen concentration ≥ 1 mg / L to enable Shewanella to perform extracellular electron transfer.

[0007] Preferably, the dissolved oxygen concentration in the reaction tank is maintained ≥ 4 mg / L.

[0008] Preferably, the reaction tank includes an anodic chamber and a cathodic chamber, the bacterial community is inoculated in the anodic chamber, and the anodic chamber maintains a dissolved oxygen concentration ≥ 1 mg / L.

[0009] Preferably, the Shewanella includes Shewanella oneidensis MR-1.

[0010] Preferably, the potential of the reaction tank is 0.1 - 0.25 V.

[0011] Preferably, the Shewanella inoculated into the reaction tank is obtained by centrifugally washing the Shewanella cultured overnight in LB medium with PBS buffer.

[0012] Preferably, the reaction tank has an air inlet and an air outlet. The air inlet is provided with a sterile filter with a pore size of 0.20 - 0.24 μm, the air outlet is provided with a breathable sealing film, the air inlet flow rate of the reaction tank is 35 - 45 ml / min, the reaction tank is provided with a stirrer, and the rotation speed of the stirrer is 90 - 110 rpm.

[0013] Preferably, the microbial electrochemical system based on aerobic extracellular electron transfer is a microbial electrolytic cell based on aerobic extracellular electron transfer, and further includes an anode, a cathode, a power supply, and an electrolyte. The electrolyte is filled in the reaction tank, the anode and the cathode are both arranged in the reaction tank and extend out of the reaction tank to be electrically connected to the positive and negative electrodes of the power supply respectively.

[0014] Preferably, it further includes a cation exchange membrane. The reaction tank includes an anodic chamber and a cathodic chamber. The electrolytes in both the anodic chamber and the cathodic chamber include DL-lactic acid and a first culture medium. The anode is arranged in the anodic chamber and extends out of the anodic chamber to be electrically connected to the positive electrode of the power supply, the cathode is arranged in the cathodic chamber and extends out of the cathodic chamber to be electrically connected to the negative electrode of the power supply. The anodic chamber and the cathodic chamber are separated by a cation exchange membrane, and the anode and the cathode are equipped with carbon felt electrodes or carbon paper electrodes.

[0015] Preferably, it further includes a reference electrode. The reference electrode is arranged in the anodic chamber and extends out of the anodic chamber. The power supply is an electrochemical workstation. The anode is electrically connected to the positive electrode interface of the electrochemical workstation, the cathode is electrically connected to the cathode interface of the electrochemical workstation, and the reference electrode is electrically connected to the reference electrode interface of the electrochemical workstation.

[0016] Preferably, the microbial electrochemical system based on aerobic extracellular electron transfer is a microbial fuel cell based on aerobic extracellular electron transfer, and further includes an anode, a cathode, and a resistor. An electrolyte is contained in the reaction cell. The anode and the cathode are both disposed in the reaction cell and respectively extend out of the reaction cell and are electrically connected to the resistor.

[0017] Preferably, it further includes a cation exchange membrane. The reaction cell includes an anode chamber and a cathode chamber. Electrolytes are contained in both the anode chamber and the cathode chamber. The electrolyte in the anode chamber includes DL-lactic acid and a first culture medium. The electrolyte in the cathode chamber includes the first culture medium. The anode is disposed in the anode chamber and extends out of the anode chamber. The cathode is disposed in the cathode chamber and extends out of the cathode chamber. One end of the anode extending out of the anode chamber is electrically connected to one end of the cathode extending out of the cathode chamber through a resistor. The anode chamber and the cathode chamber are separated by a cation exchange membrane. The anode and the cathode are equipped with carbon felt electrodes or carbon paper electrodes.

[0018] Preferably, the concentration of DL-lactic acid is 15-25 mM.

[0019] The present invention also provides an application of the above-mentioned microbial electrochemical system based on aerobic extracellular electron transfer in sewage treatment, biosensors, biomedicine, or clean energy production.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. Under the condition of inoculating Shewanella in the reaction cell and maintaining the dissolved oxygen concentration ≥ 1 mg / L, by using the phenomenon that Shewanella can perform extracellular electron transfer under the condition of maintaining the dissolved oxygen concentration ≥ 1 mg / L, it has broad application prospects in the fields of biosensors, clean energy production, and biomedicine. At the same time, it can also be applied to sewage treatment to achieve efficient recovery of electric energy and removal of COD in sewage treatment.

[0022] 2. And it solves the influence of oxygen on the microbial electrochemical system.

[0023] 3. The air inlet is provided with a sterile filter, and the air outlet is covered with a layer of breathable sealing film to prevent external bacteria from entering the anode chamber.

[0024] 4. A stirrer is arranged in the anode chamber to evenly disperse air through the stirrer to ensure the dissolved oxygen content. Description of the Drawings

[0025] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention.

[0026] Figure 2 is a schematic structural diagram of Embodiment 3 of the present invention.

[0027] Figure 3It is a graph showing the change in current density of the microbial electrochemical system under anaerobic conditions in Example 1 of the present invention and the traditional production method.

[0028] Figure 4 It is a graph showing the change in dissolved oxygen content in the anode chamber during the operation of Example 1 of the present invention.

[0029] Figure 5 It is a graph showing the change in current density of the microbial electrochemical system under anaerobic conditions in Example 2 of the present invention and the traditional production method.

[0030] Figure 6 It is a scanning electron microscope image of the carbon paper electrode in Example 2 of the present invention.

[0031] Figure 7 It is a graph showing the change in COD removal of the microbial electrochemical system under anaerobic conditions in Example 1 of the present invention and the traditional production method.

[0032] Figure 8 It is a graph showing the change in voltage generated during the operation of Example 3 of the present invention.

[0033] Figure 9 It is a graph showing the maximum current generated by inoculating different strains of Shewanella into Example 1 of the present invention.

[0034] Figure 10 It is a graph showing the current change generated by inoculating the activated sludge from a sewage treatment plant into Example 1, Example 2, and Example 3 of the present invention.

[0035] Figure 11 It is a schematic structural diagram of Example 4 of the present invention.

[0036] The reference numerals in the drawings are: 1 - anode chamber, 2 - cathode chamber, 3 - electrolyte, 4 - power supply, 5 - air inlet, 6 - air outlet, 7 - sterile filter, 8 - breathable sealing film, 9 - stirrer, 10 - anode, 11 - cathode, 12 - cation exchange membrane, 13 - resistor, 14 - reference electrode, 100 - reaction cell. Detailed Embodiments

[0037] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0038] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used for differential description and should not be construed as indicating or implying relative importance.

[0039] Example 1:

[0040] As Figure 1 shown, the microbial electrochemical system based on aerobic extracellular electron transfer provided in this embodiment is specifically a microbial electrolytic cell based on aerobic extracellular electron transfer. It includes a reaction cell 100, an anode 10, a cathode 11, a reference electrode 14, a cation exchange membrane 12, an electrolyte 3, and a power supply 4. The reaction cell 100 of this embodiment includes an anode chamber 1 and a cathode chamber 2. The power supply 4 is a CHI 1030c electrochemical workstation (Shanghai, Chenhua), and the reference electrode 14 is Ag / AgCl.

[0041] Both the anode 10 and the reference electrode 14 are arranged in the anode chamber 1, and their tops extend out of the anode chamber 1 and are respectively electrically connected to the anode interface and the reference electrode interface of the electrochemical workstation. The cathode 11 is arranged in the cathode chamber 2, and its top extends out of the cathode chamber 2 and is connected to the cathode interface of the electrochemical workstation. The anode chamber 1 and the cathode chamber 2 are separated by a cation exchange membrane 12. The anode 10 is equipped with a 4 cm 2 carbon felt electrode, and the cathode 11 is equipped with a 9 cm 2 carbon felt electrode. It operates at a constant temperature of 30 °C, and a potential of 0.2 V is applied using a CHI 1030c electrochemical workstation, and the current change is recorded.

[0042] The anode chamber 1 has an air inlet 5 and an air outlet 6. The air inlet 5 is provided with a sterile filter 7 with a pore size of 0.22 μm, and the air outlet 6 is covered with a layer of breathable sealing film 8 to prevent external bacteria from entering the anode chamber 1. An air pump and a flow meter are used to control the inlet air flow rate into the anode chamber 1 to 40 ml / min, so that the dissolved oxygen concentration in the anode chamber 1 is always ≥1 mg / L. In this embodiment, the dissolved oxygen concentration in the anode chamber 1 is maintained at ≥4 mg / L. The anode chamber 1 is provided with a stirrer 9, and the rotation speed of the stirrer 9 is 100 rpm. The air is evenly dispersed through the stirrer 9 to ensure the dissolved oxygen content.

[0043] Both the anode chamber 1 and the cathode chamber 2 are filled with an electrolyte solution 3, which includes 20 mM DL-lactic acid and 120 ml of a first culture medium. DL-lactic acid serves as an electron donor, and the first culture medium serves as an electrolyte. Shewanella oneidensis MR-1 cultured overnight in LB medium was centrifuged (5000 g, 5 min) and washed three times with 50 mM PBS buffer to obtain a culture solution, and then 1.2 ml of the washed culture solution was inoculated into the anode chamber 1. Shewanella oneidensis MR-1 performs extracellular electron transfer under the condition that the dissolved oxygen concentration ≥ 1 mg / L, especially when the dissolved oxygen concentration ≥ 4 mg / L. In this example, Shewanella oneidensis MR-1 is used. Of course, in other examples, any single strain or a mixture of multiple strains in the genus Shewanella can also be used, or a mixed culture of the genus Shewanella and other genera can be used.

[0044] Among them, each liter of the first culture medium includes 0.31 g of NH4Cl, 10.32 g of Na2HPO4, 3.32 g of NaH2PO4, 0.13 g of KCl, 0.1 g of CaCl2, 0.1 g of MgSO4·7H2O, 10 ml of minerals. Each liter of minerals includes 1.5 g of NTA, 0.1 g of MnCl2·4H2O, 0.3 g of FeSO4·7H2O, 0.17 g of CoCl2·6H2O, 0.1 g of ZnCl2, 0.04 g of CuSO4·5H2O, 0.005 g of AlK(SO4)2·12H2O, 0.005 g of H3BO3, 0.09 g of Na2MoO4, 0.12 g of NiCl2, and 0.02 g of NaWO4·2H2O; the pH is adjusted to 7.00. After high-temperature sterilization, 0.02 ml of acid-hydrolyzed casein and 1 ml of vitamins are added. Each liter of vitamins includes 0.005 g of aminobenzoic acid, 0.001 g of biotin, 0.01 g of nicotinic acid, 0.0025 g of calcium pantothenate, 0.025 g of pyridoxamine dihydrochloride, 0.005 g of ifosfamide, and 0.005 g of cobalamin.

[0045] LB medium includes 10 g / L peptone; 10 g / L sodium chloride; 5 g / L yeast extract; pH 7.00.

[0046] This example also provides an application of the above-mentioned microbial electrochemical system based on aerobic extracellular electron transfer in sewage treatment.

[0047] Example two:

[0048] The difference between this example and Example 1 is that the anode 10 is equipped with a carbon paper electrode with a thickness of 0.1 mm.

[0049] Power generation experiments were conducted on the microbial electrochemical systems based on aerobic extracellular electron transfer in Example 1 and Example 2. The microbial electrochemical systems based on aerobic extracellular electron transfer were operated at a constant temperature of 30 °C. A potential of 0.2 V was applied using a CHI 1030c, and the current changes were recorded.

[0050] Example 3:

[0051] As Figure 2 shown, the microbial electrochemical system based on aerobic extracellular electron transfer provided in this embodiment is specifically a microbial fuel cell based on aerobic extracellular electron transfer. It includes a reaction cell 100, an anode 10, a cathode 11, a cation exchange membrane 12, an electrolyte 3, and a resistor 13. The reaction cell 100 of this embodiment includes an anode chamber 1 and a cathode chamber 2.

[0052] The anode 10 is disposed in the anode chamber 1, and its top extends out of the anode chamber 1. The cathode 11 is disposed in the cathode chamber 2, and its top extends out of the cathode chamber 2. One end of the anode 10 extending out of the anode chamber 1 is electrically connected to one end of the cathode 11 extending out of the cathode chamber 2 through a 1000-ohm resistor 13. The anode chamber 1 and the cathode chamber 2 are separated by a cation exchange membrane 12. The anode 10 is equipped with a 4-cm 2 carbon felt electrode, and the cathode 11 is equipped with a 9-cm 2 carbon felt electrode.

[0053] The anode chamber 1 has an air inlet 5 and an air outlet 6. The air inlet 5 is provided with a sterile filter 7 with a pore size of 0.22 μm. The air outlet 6 is covered with a layer of breathable sealing film 8 to prevent external bacteria from entering the anode chamber 1. An air pump and a flow meter are used to control the inlet air flow rate into the anode chamber 1 to 40 ml / min, so that the dissolved oxygen concentration in the anode chamber 1 is always ≥ 4 mg / L. The potential of the anode chamber 1 only needs to be 0.20 V. The anode chamber 1 is provided with a stirrer 9, and the rotation speed of the stirrer 9 is 100 rpm. The air is evenly dispersed through the stirrer 9 to ensure the dissolved oxygen content.

[0054] The anode chamber 1 is filled with an electrolyte solution 3 (anolyte). The electrolyte solution 3 in the anode chamber 1 includes 20 mM DL-lactic acid and 120 ml of a first culture medium. The cathode chamber 2 is filled with an electrolyte solution 3 (catholyte). The electrolyte solution 3 in the cathode chamber 2 includes 120 ml of a 50 mM potassium ferricyanide solution. DL-lactic acid serves as an electron donor, and the first culture medium serves as an electrolyte. Shewanella oneidensis MR-1 cultured overnight in LB medium was centrifuged (5000 g, 5 min) and washed three times with 50 mM PBS buffer to obtain a culture solution. Then, 1.2 ml of the washed culture solution was inoculated into the anode chamber 1. Shewanella oneidensis MR-1 performs extracellular electron transfer under the condition that the dissolved oxygen concentration ≥ 1 mg / L, especially when the dissolved oxygen concentration ≥ 4 mg / L. The voltage change of the microbial electrochemical system based on aerobic extracellular electron transfer in this example was recorded by MACCOR. After the voltage of the microbial electrochemical system based on aerobic extracellular electron transfer decreased by 80%, new anolyte and catholyte were replaced under sterile conditions, and this was repeated twice.

[0055] As Figure 3 shown, it is a graph of the change in current density generated by the microbial electrochemical system based on aerobic extracellular electron transfer in Example 1 and the microbial electrochemical system under traditional anaerobic conditions. It can be seen that the current density in Example 1 is 5 times that under traditional anaerobic conditions. And as Figure 4 shown, the dissolved oxygen concentration in the anode chamber 1 was always maintained ≥ 4 mg / L during the operation.

[0056] As Figure 5 shown, it is a graph of the change in current density generated by the microbial electrochemical system based on aerobic extracellular electron transfer in Example 2 and the microbial electrochemical system under traditional anaerobic conditions. It can be seen that the current density generated in Example 2 is 3 times that under traditional anaerobic conditions. As Figure 6 shown, it was observed by scanning electron microscopy that the microorganisms on the carbon paper electrode all exist in a monolayer form, and it is difficult for the monolayer microorganisms to form an anaerobic region. This result further confirms that Shewanella oneidensis MR-1 can perform extracellular electron transfer under the condition that the dissolved oxygen concentration ≥ 1 mg / L.

[0057] As Figure 7 shown, it is a graph of the change in COD removal within 40 hours of the microbial electrochemical system based on aerobic extracellular electron transfer in Example 1 and the microbial electrochemical system under traditional anaerobic conditions. It can be seen that the COD removal rate of the microbial electrochemical system based on aerobic extracellular electron transfer in Example 1 within 40 hours is 83%, while the COD removal rate of the microbial electrochemical system under traditional anaerobic conditions is only 13%.

[0058] As Figure 8As shown, it is a voltage change diagram generated during the operation of the microbial electrochemical system based on aerobic extracellular electron transfer in Example 3. It can be seen that the microbial electrochemical system based on aerobic extracellular electron transfer in Example 3 can generate a stable voltage during three operation cycles.

[0059] As Figure 9 shown, different strains of Shewanella were separately inoculated into the microbial electrochemical system based on aerobic extracellular electron transfer in Example 1, and significant currents could be generated.

[0060] As Figure 10 shown, the activated sludge from a sewage treatment plant was inoculated into Example 1, Example 2, and Example 3, and significant currents could be generated.

[0061] Compared with the traditional anaerobic microbial electrochemical system, in this application, under the condition of inoculating Shewanella in the anode chamber 1 and with a dissolved oxygen concentration ≥ 1 mg / L, taking advantage of the phenomenon that Shewanella can perform extracellular electron transfer while maintaining a dissolved oxygen concentration ≥ 1 mg / L, it has broad application prospects in the fields of biosensors, clean energy production, and biomedicine. At the same time, it can also be applied to sewage treatment, achieving efficient recovery of electric energy and removal of COD in sewage treatment, and solving the influence of oxygen on the microbial electrochemical system.

[0062] Example 4:

[0063] The difference between this example and Example 1 is that:

[0064] As Figure 11 shown, the reaction tank 100 does not have a cation exchange membrane 12 and does not distinguish between the anode and cathode chambers. The air inlet 5, air outlet 6, stirrer 9, anode 10, cathode 11, and reference electrode 14 are all arranged in the reaction tank 100.

[0065] The above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A microbial electrochemical system based on aerobic extracellular electron transfer, characterized in that: It includes a reaction tank; The reaction tank is inoculated with a bacterial community, the bacterial community contains Shewanella, and the reaction tank maintains a dissolved oxygen concentration ≥ 1 mg / L to enable Shewanella to perform extracellular electron transfer.

2. The microbial electrochemical system based on aerobic extracellular electron transfer according to claim 1, characterized in that: The dissolved oxygen concentration in the reaction tank is maintained ≥ 4 mg / L.

3. The microbial electrochemical system based on aerobic extracellular electron transfer according to claim 1, characterized in that: The reaction tank includes an anode chamber and a cathode chamber; The bacterial community is inoculated in the anode chamber, and the anode chamber maintains a dissolved oxygen concentration ≥ 1 mg / L.

4. The microbial electrochemical system based on aerobic extracellular electron transfer according to claim 1, characterized in that: The Shewanella includes Shewanella oneidensis MR-1; The potential of the reaction tank is 0.1 - 0.25 V; The Shewanella inoculated into the reaction tank is obtained by centrifuging and washing the Shewanella cultured overnight in LB medium with PBS buffer; The reaction tank has an air inlet and an air outlet; The air inlet is provided with a sterile filter with a pore size of 0.20 - 0.24 μm; The air outlet is provided with a breathable sealing film; The air inlet flow rate of the reaction tank is 35 - 45 ml / min; The reaction tank is provided with a stirrer, and the rotation speed of the stirrer is 90 - 110 rpm.

5. The microbial electrochemical system based on aerobic extracellular electron transfer according to any one of claims 1 - 4, characterized in that: The microbial electrochemical system based on aerobic extracellular electron transfer is a microbial electrolytic cell based on aerobic extracellular electron transfer; It further includes an anode, a cathode, a power source, and an electrolyte; The reaction tank is filled with an electrolyte; The anode and the cathode are both arranged in the reaction tank and extend out of the reaction tank to be electrically connected to the positive and negative electrodes of the power source respectively.

6. The microbial electrochemical system based on aerobic extracellular electron transfer according to claim 5, characterized in that: It further includes a cation exchange membrane; The reaction tank includes an anode chamber and a cathode chamber. Both the anode chamber and the cathode chamber are filled with an electrolyte. The electrolytes in the anode chamber and the cathode chamber both include DL-lactic acid and a first culture medium; The anode is arranged in the anode chamber and extends out of the anode chamber to be electrically connected to the positive electrode of the power source; The cathode is arranged in the cathode chamber and extends out of the cathode chamber to be electrically connected to the negative electrode of the power source; The anode chamber and the cathode chamber are separated by a cation exchange membrane; The anode and the cathode are equipped with carbon felt electrodes or carbon paper electrodes.

7. The microbial electrochemical system based on aerobic extracellular electron transfer according to claim 6, characterized in that: It further includes a reference electrode, and the reference electrode is arranged in the anode chamber and extends out of the anode chamber; The power source is an electrochemical workstation; The anode is electrically connected to the positive electrode interface of the electrochemical workstation; The cathode is electrically connected to the cathode interface of the electrochemical workstation; The reference electrode is electrically connected to the reference electrode interface of the electrochemical workstation.

8. The microbial electrochemical system based on aerobic extracellular electron transfer according to any one of claims 1 - 4, characterized in that: The microbial electrochemical system based on aerobic extracellular electron transfer is a microbial fuel cell based on aerobic extracellular electron transfer; It further includes an anode, a cathode, and a resistor; The reaction tank is filled with an electrolyte; The anode and the cathode are both disposed in the reaction tank and respectively extend out of the reaction tank and are electrically connected to the resistor.

9. The microbial electrochemical system based on aerobic extracellular electron transfer according to claim 8, wherein: It further includes a cation exchange membrane; The reaction tank includes an anode chamber and a cathode chamber. The anode chamber and the cathode chamber are both filled with an electrolyte. The electrolyte in the anode chamber includes DL-lactic acid and a first culture medium, and the electrolyte in the cathode chamber includes the first culture medium; The anode is disposed in the anode chamber and extends out of the anode chamber; The cathode is disposed in the cathode chamber and extends out of the cathode chamber; One end of the anode extending out of the anode chamber is electrically connected to one end of the cathode extending out of the cathode chamber through a resistor; The anode chamber and the cathode chamber are separated by a cation exchange membrane; The anode and the cathode are equipped with carbon felt electrodes or carbon paper electrodes.

10. Application of the microbial electrochemical system based on aerobic extracellular electron transfer according to any one of claims 1-9 in sewage treatment, biosensors, biomedicine, or clean energy production.

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