An anode solution of a microbial fuel cell and a Shewanella-based microbial fuel cell

Abstract

The present invention discloses an anode solution of a microbial fuel cell and a microbial fuel cell based on Shewanella, wherein the anode solution comprises an electron donor, a basal medium, a buffer solution and bacterial cells, and the bacterial cells are a mixed flora of Shewanella putrefaciens and Shewanella xiamenensis with a quantity ratio of 1:1; the microbial fuel cell adopts the above anode solution, so it has a relatively high output voltage and electric power and has a broad application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial fuel cells, and particularly relates to an anode solution of a microbial fuel cell and a microbial fuel cell based on Shewanella bacteria. Background Art

[0002] Microbial fuel cells (MFCs) have been rapidly developed and widely applied in recent years in research on environmental pollution treatment and energy conversion. This technology can directly convert the chemical energy of organic pollutants into electrical energy through the action of microorganisms. MFCs have been applied to the degradation research of various difficult-to-treat environmental pollutants and shown good application prospects, including various industrial and domestic wastewaters, landfill leachates, aromatic compounds, and trichloroethylene, etc.

[0003] A general microbial fuel cell includes an anode chamber, a cathode chamber, an anode electrode, a cathode electrode, a proton-permeable membrane, and an external circuit. Microorganisms are inoculated in the anode chamber, and a culture solution of the microorganisms and an electron donor are also installed. A cathode reaction solution is installed in the cathode chamber. Before startup or during operation, the dissolved oxygen in the anode chamber culture solution needs to be removed by methods such as blowing nitrogen to maintain the device operating under anaerobic conditions. However, the current microbial fuel cells have the problem of low output voltage and cannot be put into practical use in industrial applications. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects or problems in the background art, and provide an anode solution of a microbial fuel cell and a microbial fuel cell based on Shewanella bacteria. This microbial fuel cell has a relatively high output voltage and electric power, and has a relatively broad application prospect.

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

[0006] An anode solution of a microbial fuel cell, comprising an electron donor, a basal medium, a buffer solution, and bacterial cells; the bacterial cells are a mixed bacterial population of Shewanella putrefaciens and Shewanella xiamenensis with a quantity ratio of 1:1.

[0007] Further, both the Shewanella putrefaciens and Shewanella xiamenensis are obtained in the following manner: Activation: In a laminar flow hood, use sterilized toothpicks to inoculate the single colonies separated by the streak plate method on the petri dish into test tubes containing 10 mL of sterilized liquid medium respectively, and place them in a constant temperature shaker. Incubate at 37 °C and 150 rpm for 24 hours; Cultivation: Take 5 mL of the activated Shewanella bacteria respectively and add them into 300 mL conical flasks containing 200 mL of sterilized liquid medium, and place them in a constant temperature shaker. Incubate at 37 °C and 150 rpm for 24 hours; Extraction: Take 200 mL of the cultivated Shewanella bacteria and put them into a 500 mL centrifuge tube, centrifuge at 8000 rpm for 5 minutes in a high-speed centrifuge, and discard the supernatant; Then add sterile water, mix them evenly, and then put them into a high-speed centrifuge and centrifuge at 8000 rpm for 5 minutes. Repeat three times, discard the supernatant, and only keep the bacterial cells.

[0008] Further, the electron donor is one of sodium formate, sodium acetate, sodium lactate or glucose.

[0009] Further, the basal medium comprises the following components: 10.5 g / L dipotassium hydrogen phosphate, 4.5 g / L potassium dihydrogen phosphate, 1 g / L ammonium sulfate, 0.5 g / L sodium citrate dihydrate.

[0010] Further, the buffer solution comprises the following components: 0.5 g / L ammonium chloride, 0.6 g / L potassium dihydrogen phosphate, 0.1 g / L potassium chloride, 0.1 g / L calcium chloride dihydrate, 0.1 g / L magnesium chloride tetrahydrate.

[0011] Further, the concentration of the electron donor in the anolyte is 10 mmol / L; the volume ratio of the basal medium in the anolyte is 80%; the volume ratio of the buffer solution in the anolyte is 1%.

[0012] In addition, the present invention also provides a microbial fuel cell based on Shewanella bacteria, which comprises an anodic chamber, a cathodic chamber, an anode electrode, a cathode electrode, a proton-permeable membrane and an external circuit; the anodic chamber is filled with an anolyte of a microbial fuel cell as described in any one of the above.

[0013] Further, the cathodic chamber is filled with a catholyte, and the catholyte is a 0.2 g / L potassium permanganate solution.

[0014] Further, both the anode electrode and the cathode electrode are rod-shaped carbon felts.

[0015] Further, the model of the proton exchange membrane is DuPont N-117 of the United States.

[0016] As described above for the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0017] Compared with a microbial fuel cell with a single bacterial community, the microbial fuel cell with a mixed bacterial community has a higher output voltage and a longer voltage stabilization time, and has more application prospects in the industry; the present invention selects Shewanella putrefaciens and Shewanella xiamenensis as the mixed bacterial community. During the electricity generation process of the microbial fuel cell, Shewanella putrefaciens is in a dominant position in terms of electricity generation ability. However, at this time, Shewanella xiamenensis will not compete with Shewanella putrefaciens, but will instead play a certain auxiliary role in Shewanella putrefaciens, thereby making the output voltage of the fuel cell higher than that of a single bacterial community and the duration longer. At the same time, the adaptability of this mixed bacterial community to the environment is also stronger than that of a single bacterial community, which is more conducive to the mixed bacterial community playing a role under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic diagram of the time change of the voltage generated by the embodiment and the comparative example of the microbial fuel cell based on Shewanella provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are the preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] In the claims, the description, and the above drawings of the present invention, terms such as "comprising", "having", and their variants are intended to mean "including but not limited to".

[0022] Embodiment 1

[0023] Embodiment 1 of the present invention provides a microbial fuel cell based on Shewanella. The fuel cell includes an anode chamber, a cathode chamber, an anode electrode, a cathode electrode, a proton-permeable membrane, and an external circuit; and the anode chamber is filled with an anode solution of a microbial fuel cell provided by the present invention.

[0024] The anodic solution of the microbial fuel cell includes an electron donor, a basal medium, a buffer solution, and bacteria; the bacteria are a mixed flora of Shewanella putrefaciens and Shewanella xiamenensis.

[0025] Among them, both the above-mentioned Shewanella putrefaciens and Shewanella xiamenensis are obtained in the following manner:

[0026] Activation: In a laminar flow hood, use sterilized toothpicks to inoculate the single colonies separated by the streak plate method on the plate into test tubes containing 10 mL of sterilized liquid medium respectively, place them in a constant temperature shaker, and culture them for 24 hours at 37°C and 150 rpm.

[0027] Cultivation: Take 5 mL of each activated Shewanella and add them to 300 mL conical flasks containing 200 mL of sterilized liquid medium respectively, place them in a constant temperature shaker, and culture them for 24 hours at 37°C and 150 rpm.

[0028] Extraction: Take 200 ml of the cultivated Shewanella and put it into a 500 ml centrifuge tube, centrifuge it at 8000 rpm for 5 minutes in a high-speed centrifuge, and discard the supernatant; then add sterile water, mix it evenly, and then put it into a high-speed centrifuge and centrifuge at 8000 rpm for 5 minutes, repeat three times, discard the supernatant, and only keep the bacteria.

[0029] The above-mentioned electron donor is one of sodium formate, sodium acetate, sodium lactate, or glucose.

[0030] The above-mentioned basal medium includes the following components: 10.5 g / L dipotassium hydrogen phosphate, 4.5 g / L potassium dihydrogen phosphate, 1 g / L ammonium sulfate, 0.5 g / L sodium citrate dihydrate.

[0031] The above-mentioned buffer solution includes the following components: 0.5 g / L ammonium chloride, 0.6 g / L potassium dihydrogen phosphate, 0.1 g / L potassium chloride, 0.1 g / L calcium chloride dihydrate, 0.1 g / L magnesium chloride tetrahydrate.

[0032] Among them, the concentration of the above-mentioned electron donor in the anodic solution of this embodiment is 5 mmol / L; the volume ratio of the above-mentioned basal medium in the anodic solution of this embodiment is 60%; the volume ratio of the above-mentioned buffer solution in the anodic solution of this embodiment is 1%.

[0033] For example, taking 1 L of anodic solution as an example, the amount of the electron donor added to the anodic solution is 5 mmol, the basal medium is 600 mL, the buffer solution is 10 mL, and the rest is the above-mentioned mixed flora. The quantity ratio of Shewanella putrefaciens and Shewanella xiamenensis in the mixed flora is 1:1.

[0034] In addition, the cathode chamber described above is filled with a cathode solution, which is a potassium permanganate solution with a concentration of 0.2 g / . In this embodiment, the pH of the cathode solution is adjusted to around 3.0.

[0035] Both the anode electrode and the cathode electrode described above are long strip-shaped rod-like carbon felts.

[0036] The above-mentioned proton exchange membrane model is DuPont N-117 of the United States.

[0037] Embodiment 2

[0038] Embodiment 1 of the present invention provides a microbial fuel cell based on Shewanella, which includes an anode chamber, a cathode chamber, an anode electrode, a cathode electrode, a proton-permeable membrane, and an external circuit; the anode chamber is filled with a microbial fuel cell anode solution provided by the present invention.

[0039] The microbial fuel cell anode solution includes an electron donor, a basal medium, a buffer solution, and bacterial cells; the bacterial cells are a mixed flora of Shewanella putrefaciens and Shewanella xiamenensis.

[0040] Among them, both the above-mentioned Shewanella putrefaciens and Shewanella xiamenensis are obtained by the following method:

[0041] Activation: In a laminar flow hood, use a sterilized toothpick to inoculate the single colonies separated by the streak plate method on the plate into test tubes containing 10 ml of sterilized liquid medium respectively, and place them in a constant temperature shaker. Cultivate at 37°C and 150 rpm for 24 hours;

[0042] Cultivation: Take 5 ml of each of the activated Shewanella and add them to 300 ml conical flasks containing 200 ml of sterilized liquid medium respectively, and place them in a constant temperature shaker. Cultivate at 37°C and 150 rpm for 24 hours;

[0043] Extraction: Take 200 ml of the cultivated Shewanella and put it into a 500 ml centrifuge tube. Centrifuge at 8000 rpm for 5 minutes in a high-speed centrifuge, and discard the supernatant; then add sterile water, mix it evenly, and then put it into a high-speed centrifuge and centrifuge at 8000 rpm for 5 minutes. Repeat three times, discard the supernatant, and only keep the bacterial cells.

[0044] The above-mentioned electron donor is one of sodium formate, sodium acetate, sodium lactate, or glucose.

[0045] The above-mentioned basal medium includes the following components: 10.5 g / L dipotassium hydrogen phosphate, 4.5 g / L potassium dihydrogen phosphate, 1 g / L ammonium sulfate, 0.5 g / L sodium citrate dihydrate.

[0046] The above buffer solution comprises the following components: 0.5 g / L ammonium chloride, 0.6 g / L potassium dihydrogen phosphate, 0.1 g / L potassium chloride, 0.1 g / L calcium chloride dihydrate, and 0.1 g / L magnesium chloride tetrahydrate.

[0047] Among them, the concentration of the above electron donor in the anode solution of this embodiment is 8 mmol / L; the volume ratio of the above basic medium in the anode solution of this embodiment is 70%; the volume ratio of the above buffer solution in the anode solution of this embodiment is 1.5%.

[0048] For example, taking 500 mL of anode solution as an example, the amount of the electron donor added to the anode solution is 8 mmol, the basic medium is 700 mL, the buffer solution is 15 mL, and the rest is the above-mentioned mixed bacterial community. The quantity ratio of Shewanella putrefaciens and Shewanella xiamenensis in the mixed bacterial community is 1:1.

[0049] In addition, the cathode chamber is filled with a cathode solution, which is a potassium permanganate solution of 0.2 g / . In this embodiment, the pH of the cathode solution is adjusted to about 3.0.

[0050] The above anode electrode and cathode electrode are both long strip-shaped rod-like carbon felts.

[0051] The model of the above proton exchange membrane is DuPont N-117 of the United States.

[0052] Example Three

[0053] Embodiment 1 of the present invention provides a microbial fuel cell based on Shewanella bacteria. The fuel cell comprises an anode chamber, a cathode chamber, an anode electrode, a cathode electrode, a proton-permeable membrane, and an external circuit; the anode chamber is filled with an anode solution of a microbial fuel cell provided by the present invention.

[0054] The anode solution of the microbial fuel cell comprises an electron donor, a basic medium, a buffer solution, and bacterial cells; the bacterial cells are a mixed bacterial community of Shewanella putrefaciens and Shewanella xiamenensis.

[0055] Among them, the above Shewanella putrefaciens and Shewanella xiamenensis are both obtained by the following method:

[0056] Activation: In a laminar flow hood, use a sterilized toothpick to inoculate the single colonies separated by the streak plate method on the plate into a sterilized test tube containing 10 mL of liquid medium respectively, and place it in a constant temperature shaker. Culture at 37 °C and 150 rpm for 24 hours;

[0057] Cultivation: Take 5 ml of each activated Shewanella bacteria and add them to 300-ml conical flasks containing 200 ml of sterilized liquid medium respectively. Place them in a constant temperature shaker and cultivate for 24 hours at 37°C and 150 revolutions per minute.

[0058] Extraction: Take 200 ml of the cultivated Shewanella bacteria and put them into a 500-ml centrifuge tube. Centrifuge at 8000 revolutions per minute in a high-speed centrifuge for 5 minutes, and discard the supernatant; then add sterile water, mix well, and centrifuge at 8000 revolutions per minute for 5 minutes again. Repeat three times, discard the supernatant, and only retain the bacterial cells.

[0059] The above electron donor is one of sodium formate, sodium acetate, sodium lactate or glucose.

[0060] The above basic medium includes the following components: 10.5 g / L dipotassium hydrogen phosphate, 4.5 g / L potassium dihydrogen phosphate, 1 g / L ammonium sulfate, 0.5 g / L sodium citrate dihydrate.

[0061] The above buffer solution includes the following components: 0.5 g / L ammonium chloride, 0.6 g / L potassium dihydrogen phosphate, 0.1 g / L potassium chloride, 0.1 g / L calcium chloride dihydrate, 0.1 g / L magnesium chloride tetrahydrate.

[0062] Among them, the concentration of the above electron donor in the anode solution of this embodiment is 10 mmol / L; the volume ratio of the above basic medium in the anode solution of this embodiment is 80%; the volume ratio of the above buffer solution in the anode solution of this embodiment is 2%.

[0063] For example, taking 500 mL of anode solution as an example, the amount of electron donor added to this anode solution is 10 mmol, the basic medium is 800 mL, the buffer solution is 20 mL, and the rest is the above mixed bacterial population. The quantity ratio of Shewanella putrefaciens and Shewanella xiamenensis in the mixed bacterial population is 1:1.

[0064] In addition, the above cathode chamber is filled with a cathode solution, which is a potassium permanganate solution of 0.2 g / . In this embodiment, the pH of this cathode solution is adjusted to about 3.0.

[0065] The above anode electrode and cathode electrode are both long strip-shaped rod-shaped carbon felts.

[0066] The model of the above proton exchange membrane is DuPont N-117 of the United States.

[0067] To illustrate the power generation ability of the Shewanella-based microbial fuel cell provided by the present invention, the power generation abilities of the above Examples 1, 2, and 3 are tested. The test method is as follows: Use a data collector to detect the load voltage, and calculate the current and power from the load resistance.

[0068] The test results are shown in the following table:

[0069] Maximum Voltage (V) <![CDATA[Maximum electric power (mW / m 2 )]]> Example 1 2.331 840 Example 2 2.421 844 Example 3 2.362 842

[0070] In addition, to illustrate the superiority of the microbial fuel cell based on Shewanella provided by the present invention in power generation capacity, the following comparative examples are also provided in the specification of the present invention:

[0071] Comparative Example 1

[0072] Comparative Example 1 is based on Example 1, and the difference is that the bacterial cells used are Shewanella putrefaciens with a total amount equal to the mixed bacterial population in Example 1.

[0073] Comparative Example 2

[0074] Comparative Example 2 is based on Example 1, and the difference is that the bacterial cells used are Shewanella xiamenensis with a total amount equal to the mixed bacterial population in Example 1.

[0075] Refer to Figure 1 , the discharge capacities of the above Example 1, Comparative Example 1 and Comparative Example 2 were tested, where the curve of Example 1 is Figure 1 the 1 curve in Figure 1 the curve of Comparative Example 1 is Figure 1 the 3 curve in

[0076] From Figure 1 it can be seen that the best power generation capacity is Example 1 with a mixed bacterial population of Shewanella xiamenensis and Shewanella putrefaciens as the anode solution, whose maximum voltage reached 2.331V, and the maximum electric power Pmax was 840mW / m 2 , and the duration of the voltage stabilizing above 2.0V was also the longest; in Comparative Example 1, the power generation capacity of Shewanella putrefaciens was weaker, and the duration of the voltage above 2.0V was very short; in Comparative Example 2, the power generation capacity of Shewanella xiamenensis was the worst, and the highest voltage did not exceed 1.8V.

[0077] A microbial fuel cell anode solution provided by the present invention and a microbial fuel cell based on Shewanella have a higher output voltage and a longer voltage stability time compared to a microbial fuel cell with a single bacterial community, and thus have more application prospects in the industry. The present invention selects Shewanella putrefaciens and Shewanella xiamenensis as the mixed bacterial community. During the power generation process of the microbial fuel cell, Shewanella putrefaciens has an advantage in power generation ability. However, at this time, Shewanella xiamenensis will not compete with Shewanella putrefaciens, but will instead play a certain auxiliary role in Shewanella putrefaciens, thereby making the output voltage of the fuel cell higher and the duration longer than that of a single bacterial community. At the same time, the adaptability of this mixed bacterial community to the environment is also stronger than that of a single bacterial community, which is more conducive to the mixed bacterial community playing a role under different working conditions.

[0078] The above description of the specification and embodiments is used to explain the protection scope of the present invention, but does not constitute a limitation on the protection scope of the present invention. Through the inspiration of the present invention or the above embodiments, those of ordinary skill in the art, combined with common general knowledge, ordinary technical knowledge in the art, and / or prior art, can obtain modifications, equivalent substitutions, or other improvements to the embodiments of the present invention or some of its technical features through logical analysis, reasoning, or limited experiments, and all of them should be included within the protection scope of the present invention.

Claims

1. A microbial fuel cell anode solution, comprising an electron donor, a basal medium, a buffer solution, and bacterial cells; characterized in that: The bacterial cells are a mixed bacterial population of Shewanella putrefaciens and Shewanella xiamenensis with a quantity ratio of 1:1; Both the Shewanella putrefaciens and Shewanella xiamenensis are obtained by the following method: Activation: In a clean bench, use sterilized toothpicks to inoculate the single colonies separated by the streak plate method on the plate into test tubes containing 10 mL of sterilized liquid medium respectively, place them in a constant temperature shaker, and culture for 24 hours under the conditions of 37 °C and 150 rpm; Cultivation: Take 5 mL of the activated Shewanella bacteria respectively and add them into 300 mL conical flasks containing 200 mL of sterilized liquid medium, place them in a constant temperature shaker, and culture for 24 hours under the conditions of 37 °C and 150 rpm; Extraction: Take 200 mL of the cultivated Shewanella bacteria in a 500 mL centrifuge tube, centrifuge at 8000 rpm for 5 minutes in a high-speed centrifuge, and discard the supernatant; then add sterile water, mix it evenly, and then place it in a high-speed centrifuge and centrifuge at 8000 rpm for 5 minutes, repeat three times, discard the supernatant, and only retain the bacterial cells.

2. The anodic solution of a microbial fuel cell according to claim 1, characterized in that, The electron donor is one of sodium formate, sodium acetate, sodium lactate, or glucose.

3. The anodic solution of a microbial fuel cell according to claim 1, characterized in that, The basal medium comprises the following components: 10.5 g / L dipotassium hydrogen phosphate, 4.5 g / L potassium dihydrogen phosphate, 1 g / L ammonium sulfate, 0.5 g / L sodium citrate dihydrate.

4. The anolyte of a microbial fuel cell according to claim 1, wherein The buffer solution comprises the following components: 0.5 g / L ammonium chloride, 0.6 g / L potassium dihydrogen phosphate, 0.1 g / L potassium chloride, 0.1 g / L calcium chloride dihydrate, 0.1 g / L magnesium chloride tetrahydrate.

5. A microbial fuel cell anode solution according to claim 1, characterized in that, The concentration of the electron donor in the anode solution is 5 - 10 mmol / L; the volume ratio of the basal medium in the anode solution is 60% - 80%; the volume ratio of the buffer solution in the anode solution is 1% - 2%.

6. A microbial fuel cell based on Shewanella, characterized in that, It includes an anode chamber, a cathode chamber, an anode electrode, a cathode electrode, a proton-permeable membrane, and an external circuit; The anode chamber is filled with a microbial fuel cell anode solution as described in any one of claims 1 - 5.

7. The microbial fuel cell based on Shewanella as claimed in claim 6, characterized in that, The cathode chamber is filled with a cathode solution, and the cathode solution is a 0.2 g / L potassium permanganate solution.

8. The microbial fuel cell based on Shewanella as claimed in claim 6, characterized in that, Both the anode electrode and the cathode electrode are rod-shaped carbon felts.

9. The microbial fuel cell based on Shewanella as claimed in claim 6, characterized in that, The proton exchange membrane model is DuPont N-117 of the United States.

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