A method for directly generating electricity from wood cellulose and its application

Abstract

The present invention discloses a method and application for directly utilizing lignocellulose to generate electricity, and relates to the field of microbial fuel cells. The present invention can solve the problem of ineffective utilization of waste biomass, especially the problem that lignocellulose cannot be directly utilized in MFCs. The specific method of the present invention comprises pretreating a lignocellulose raw material to obtain a pretreated substrate; activating Acetovibrio thermocellum to obtain a seed liquid; injecting the seed liquid into a dual-chamber microbial fuel cell using the pretreated substrate as an electron donor, and outputting electrical energy from the electrodes. The present invention achieves the coupling of waste biomass degradation and electricity production, has low production costs, high electricity generation efficiency, avoids secondary environmental pollution, and has high economic value and broad application prospects in the energy conversion of lignocellulose.

Description

Technical Field

[0001] The present invention relates to the field of microbial fuel cells, and in particular to a method and application of directly utilizing lignocellulose to generate electricity. Background Art

[0002] While the rapid consumption of fossil fuels has brought rapid industrial development, it has also resulted in severe environmental pollution and resource shortages. my country's fossil energy reserves are scarce, and the recent rapid industrial development has led to a surge in coal, oil, and natural gas consumption, exacerbating energy and environmental challenges. Finding sustainable, green, and clean energy sources to replace fossil fuels has become a major challenge for my country and the world.

[0003] my country is a major agricultural country with abundant biomass resources. Theoretically, biomass resources are equivalent to approximately 5 billion tons of standard coal, which is about four times the current total energy consumption, and has broad development and application prospects. At present, biomass is still used to generate electricity using traditional combustion methods, which not only seriously pollutes the environment, but also has a low thermal energy utilization rate. With the development of bioelectrochemical technology, research on using microorganisms as carriers to generate electricity using organic matter has received increasing attention. However, cellulose has a complex cell wall structure, which hinders its further utilization by microorganisms. Therefore, the substrates currently used for microbial fuel cells are mainly soluble sugars and small molecular organic matter, and there has been no research on microbial fuel cells that directly use cellulose as an electron donor. Summary of the Invention

[0004] The primary objective of this invention is to overcome the shortcomings and deficiencies of existing technologies by providing a method for directly generating electricity from lignocellulose. This method uses lignocellulose as an electron donor and couples lignocellulose degradation with electricity generation through the construction of a dual-chamber microbial fuel cell. This process utilizes a wide range of substrates, features a simple reactor structure, and generates electricity rapidly, achieving efficient energy utilization while simultaneously generating electricity from waste biomass.

[0005] Another object of the present invention is to provide an application of the above method for directly utilizing lignocellulose to generate electricity in the conversion of waste biomass into energy.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for directly utilizing lignocellulose to generate electricity comprises the following steps:

[0008] (1) Pretreating the lignocellulosic raw material to obtain a pretreated substrate;

[0009] (2) Activating and culturing Vibrio thermocellum to obtain seed liquid;

[0010] (3) The seed solution obtained in step (2) is inoculated into a dual-chamber fuel cell using the pretreated substrate obtained in step (1) as an electron donor, cultured, and outputting electrical energy from the electrodes of the dual-chamber fuel cell.

[0011] The lignocellulosic raw material in step (1) includes waste biomass containing cellulose, hemicellulose and lignin, including one or a combination of the following materials: garden waste, sugarcane bagasse, crop straw, and agricultural and forestry residues.

[0012] The pretreatment steps described in step (1) are preferably as follows: adding a pretreatment solution containing H2O2 and NaOH to react, separating the solid and the liquid, collecting the solid, and washing.

[0013] The composition of the pretreatment solution containing H2O2 and NaOH is preferably as follows: 1-3% (w / v) H2O2, 0.5-1.5% (w / v) NaOH, and the solvent is water; more preferably as follows: 2% (w / v) H2O2, 1% (w / v) NaOH, and the solvent is water.

[0014] The usage amount of the pretreatment solution containing H2O2 and NaOH is preferably 20-30 mL per 1 g of lignocellulose; more preferably 23-27 mL per 1 g of lignocellulose.

[0015] The reaction conditions are preferably: temperature of 30-80° C., reaction at 100-200 rpm for 4-8 h; more preferably: temperature of 55° C., reaction at 150 rpm for 4-8 h.

[0016] The solid-liquid separation method is preferably centrifugation.

[0017] The centrifugal conditions are preferably: a rotation speed of 2500-3500 rpm, and a centrifugal time of 3-7 min; more preferably: a rotation speed of 3000 rpm, and a centrifugal time of 5 min.

[0018] The washing is preferably performed with deionized water until the pH value is 7.0.

[0019] The Acetovibrio thermocellum described in step (2) is preferably Acetovibrio thermocellum DSM1313.

[0020] The activation culture described in step (2) is preferably carried out by inoculating Vibrio thermocellum into a seed culture medium for cultivation.

[0021] The composition of the seed culture medium is preferably as follows: 8-11 g / L microcrystalline cellulose, 1-1.5 g / L ammonium sulfate, 2.5-3 g / L magnesium chloride hexahydrate, 1.4-1.5 g / L potassium dihydrogen phosphate, 5-6 g / L potassium hydrogen phosphate trihydrate, 0.1-0.15 g / L calcium chloride dihydrate, 5-7 g / L sodium β-glycerophosphate pentahydrate, 0.2-0.3 g / L reduced glutathione, 4-5 g / L yeast powder, 0.4-0.6 mL / L 0.1% (w / v) resazurin, 0.5-1.5 g / L ferric chloride hexahydrate and 1-1.5 mL / L 0.1% (w / v) ferrous sulfate heptahydrate, and the solvent is water; more preferably, it is composed of the following components: 10 g / L microcrystalline cellulose, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium dihydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast powder, 0.5 mL / L 0.1% (w / v) resazurin, 1 g / L ferric chloride hexahydrate, and 1.1 mL / L 0.1% (w / v) ferrous sulfate heptahydrate. The solvent was water.

[0022] The pH value of the seed culture medium is preferably 6.8-7.2, more preferably 7.0.

[0023] The culture is preferably performed with shaking under an inert gas.

[0024] The shaking culture conditions are preferably: temperature of 50-60°C, rotation speed of 120-180 rpm, and shaking culture for 12-20 h; more preferably: temperature of 55°C, rotation speed of 150 rpm, and shaking culture for 16 h.

[0025] The dual-chamber fuel cell using the pretreated substrate as an electron donor in step (3) comprises an anode chamber and a cathode chamber separated by a proton exchange membrane.

[0026] The anode chamber and cathode chamber are both filled with inert gas; the function of the inert gas is to maintain an anaerobic environment.

[0027] The inert gas is preferably nitrogen.

[0028] The anode chamber contains an anode liquid, which contains an anode culture medium and thermoacetovibrio; the anode liquid uses a pretreated substrate as an electron donor.

[0029] The cathode chamber contains cathode liquid; the cathode liquid uses potassium ferrocyanide as an electron acceptor.

[0030] The components of the anode culture medium are preferably as follows: 8-11 g / L pretreated substrate, 1-1.5 g / L ammonium sulfate, 2.5-3 g / L magnesium chloride hexahydrate, 1.4-1.5 g / L potassium dihydrogen phosphate, 5-6 g / L potassium hydrogen phosphate trihydrate, 0.1-0.15 g / L calcium chloride dihydrate, 5-7 g / L sodium β-glycerophosphate pentahydrate, 0.2-0.3 g / L reduced glutathione, 4-5 g / L yeast powder, 0.4-0.6 mL / L 0.1% (w / v) resazurin and 1-1.5 mL / L 0.1% (w / v) ferrous sulfate heptahydrate, and the solvent is water; more preferably: 10 g / L pretreated substrate, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium dihydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast powder, 0.5 mL / L 0.1% (w / v) resazurin, and 1.1 mL / L 0.1% (w / v) ferrous sulfate heptahydrate. The solvent is water.

[0031] The pH value of the anode culture medium is preferably 6.8 to 7.2, more preferably 7.0.

[0032] The components of the cathode liquid are preferably as follows: 40-60 mM potassium ferrocyanide and phosphate buffer with a pH value of 6.8-7.2.

[0033] The dual-chamber fuel cell using the pretreated substrate as an electron donor in step (3) further comprises an anode and a cathode; preferably, the anode and cathode are made of conductive carbon paper.

[0034] The size of the carbon paper anode is preferably 15×15×0.2 mm.

[0035] The size of the carbon paper cathode is preferably 15×15×0.2 mm.

[0036] The inoculation described in step (3) is to inoculate the thermocellum acetovibrio seed solution into the anode chamber of the fuel cell.

[0037] The volume ratio of the Acetovibrio thermocellum seed solution to the anode solution is preferably 1:9.

[0038] The culture described in step (3) is preferably a shaking culture under inert gas.

[0039] The shaking culture conditions are preferably: temperature of 50-60°C, rotation speed of 120-180 rpm, and culture for 20-28 h; more preferably: temperature of 55°C, rotation speed of 150 rpm, and culture for 24 h.

[0040] The method of directly utilizing lignocellulose to generate electricity is used in the conversion of waste biomass into energy.

[0041] The present invention has the following beneficial effects compared to the prior art:

[0042] (1) The present invention can utilize a large amount of waste biomass as raw material, which can be used as a substrate after a simple pretreatment process. It has low cost, wide sources and good sustainability.

[0043] (2) The present invention uses Acetovibrio thermocellum as a catalytic carrier to directly couple the degradation of lignocellulose with the power generation process of a microbial fuel cell. While converting chemical energy into electrical energy, it also realizes the energy utilization of waste biomass. This process is pollution-free and alleviates the environmental problems caused by the combustion of waste biomass.

[0044] (3) The thermophilic pure culture microbial fuel cell used in the present invention has a higher electricity conversion efficiency than the mesophilic microbial fuel cell. Compared with the combined use of natural cellulose-degrading bacteria and electrogenic bacteria, the reaction equipment has a simple structure, easy operation, a short process flow, and a higher reaction efficiency.

[0045] (4) The microbial fuel cell of the present invention, which directly uses cellulose as an electron donor, can achieve an output voltage of 318.4 mV after 24 hours of operation. After three cycles of operation, the maximum voltage can reach 369.2 mV and the maximum power density can reach 21.6 mW / m 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 1 are scanning electron microscope images of the lignocellulosic raw material before and after pretreatment; wherein, A is the image before pretreatment, B is the image after combined pretreatment with NaOH and H2O2 (Example 1), and C is the image after pretreatment with NaOH (Comparative Example 1).

[0047] Figure 2 It is a schematic structural diagram of the lignocellulose electricity generation device provided by the present invention.

[0048] Figure 3 1 and 2 are the output voltage curves of the microbial fuel cells provided in Example 2, Example 3, Example 4, Comparative Example 1, and Comparative Example 2.

[0049] Figure 4 These are the polarization curve and power density curve of the microbial fuel cell provided in Example 2.

[0050] Figure 5 These are the polarization curve and power density curve of the microbial fuel cell provided in Example 3.

[0051] Figure 6 These are the polarization curve and power density curve of the microbial fuel cell provided in Example 4.

[0052] Figure 7 These are the polarization curves and power density curves of the microbial fuel cell provided in Comparative Example 1.

[0053] Among them, 1-anode chamber, 2-cathode chamber, 3-proton exchange membrane, 4-resistance load, 5-data collector, 6-carbon paper anode electrode, 7-carbon paper cathode electrode, 8-anode liquid, 9-cathode liquid. DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0055] While studying microbial electricity generation, the present inventors discovered that Acetovibrio Thermocellus DSM 1313 can generate high levels of electricity using sodium carboxymethylcellulose and cellobiose as electron donors, as demonstrated in Examples 3 and 4. However, this comes at a high cost. By pretreating waste biomass, the inventors discovered that Acetovibrio Thermocellus DSM 1313 can generate electricity using pretreated lignocellulose as a substrate, as demonstrated in Example 2.

[0056] Example 1:

[0057] (1) Pretreatment of lignocellulosic raw materials

[0058] 4 parts by mass of garden waste were diluted to 100 parts by volume using a pretreatment solution containing 2% (w / v) hydrogen peroxide and 1% (w / v) sodium hydroxide. The mass was measured in g and the volume was measured in mL. The mixture was shaken at 55°C and 150 rpm for 6 h, centrifuged at 3000 rpm for 5 min, and the solid was collected and washed with deionized water to a pH of 7.0 to obtain the pretreated substrate. The lignocellulosic raw materials before and after pretreatment were observed by scanning electron microscopy. The results are as follows: Figure 1 The surface of the raw material without pretreatment is smooth and dense, while the surface of the substrate after pretreatment is full of grooves and the surface roughness is significantly improved, indicating that the pretreatment can effectively destroy the surface structure of the raw material.

[0059] (2) Preparation of Vibrio thermocellum seed solution

[0060] The seed culture medium was added to a serum bottle, vacuumed, filled with nitrogen, and sterilized; the seed culture medium consisted of the following components: 10 g / L microcrystalline cellulose, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium dihydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast extract, 0.5 mL / L 0.1% (w / v) resazurin, 1 g / L ferric chloride hexahydrate, and 1.1 mL / L 0.1% (w / v) ferrous sulfate heptahydrate, with the balance being water, pH 7.0; Acetovibrio thermocellum ( Acetivibrio thermocellus DSM 1313, German Collection of Microorganisms) was inoculated into the seed culture medium in a serum bottle; the serum bottle inoculated with Acetovibrio thermocellum was placed in a constant temperature shaker at a temperature of 55°C and a rotation speed of 150 rpm and cultured for 16 h to obtain a seed solution of Acetovibrio thermocellum, whose cell concentration reached 0.36 g cell protein / L seed solution.

[0061] Example 2:

[0062] This embodiment provides a Figure 2 The microbial fuel cell shown in the figure comprises an anode chamber (1), a proton exchange membrane (DuPont Nafion-117) (3), and a cathode chamber (2), and the volume of both chambers is 150 mL;

[0063] The anode chamber includes an anode solution (8) and a carbon paper anode electrode (6); wherein the anode solution (8) is composed of 90 mL anode culture medium and 10 mL thermocellar acetovibrio seed solution obtained in Example 1. The anode culture medium is composed of the following components: 10 g / L pretreated substrate obtained in Example 1, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium dihydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast powder, 0.5 mL / L 0.1% (w / v) resazurin and 1.1 mL / L 0.1% (w / v) ferrous sulfate heptahydrate, the solvent is water, and the pH is 7.0. The size of the carbon paper anode electrode (6) is 15×15×0.2 mm.

[0064] The cathode chamber contains 100 mL of cathode liquid (9) and a carbon paper cathode electrode (7). The cathode liquid is a 50 mM potassium ferrocyanide solution (the solute is potassium ferrocyanide; the solvent is a phosphate buffer solution with a pH value of 7.0); the size of the carbon paper cathode is 15×15×0.2 mm.

[0065] The method for constructing the microbial fuel cell comprises:

[0066] The anode culture medium, carbon paper anode electrode (6), proton exchange membrane (DuPont Nafion-117) (3), cathode liquid (9) and carbon paper cathode electrode (7) were placed in a Figure 2 The anode chamber and cathode chamber were respectively filled with nitrogen for 30 minutes and sterilized at 115°C for 20 minutes to keep the double chambers in an anaerobic environment.

[0067] Take 10 mL of the thermocellum Acetovibrio seed solution and inoculate it directly into the anode chamber;

[0068] The anode and cathode of the microbial fuel cell were connected with a 2 kΩ resistor load (4), and the two ends of the resistor load (4) were connected to a data acquisition device (5). The cells were then cultured in a constant temperature shaker at 55°C and 150 rpm for 72 h. At 24 h and 48 h of culture, 90 mL of anode culture medium and cathode liquid were respectively replaced with fresh anode culture medium and cathode liquid, and nitrogen was refilled to test the real-time output voltage. The output voltage curve results are shown in Figure 2. Figure 3 shown.

[0069] The output voltage of the microbial fuel cell constructed above can reach 318.4 mV after working for 24 hours. After running for 3 cycles, the output voltage can reach 369.2 mV.

[0070] When the output voltage of the third power generation cycle reaches a stable stage, remove the resistance load (4) and stabilize for a period of time. Then use a resistance box to connect different resistance loads (0 to 100,000 Ω) to the external circuit in turn. After stabilization for a period of time, record the output voltage across the resistor at this time, calculate the current density and power density corresponding to each output voltage, and draw the electrode polarization curve and power density curve (the results are shown in Figure 2). Figure 4 shown).

[0071] The maximum power density of the microbial fuel cell constructed above is 21.6 mW / m 2 .

[0072] Example 3: The difference from Example 2 is that sodium carboxymethyl cellulose is used instead of the pretreated substrate in Example 2

[0073] This embodiment provides a Figure 2 The microbial fuel cell shown in the figure comprises an anode chamber (1), a proton exchange membrane (DuPont Nafion-117) (3), and a cathode chamber (2), and the volume of both chambers is 150 mL;

[0074] The anode chamber includes an anode solution (8) and a carbon paper anode electrode (6); wherein the anode solution (8) is composed of 90 mL of anode culture medium and 10 mL of the thermocellulosic vibrio seed solution obtained in Example 1. The anode culture medium is composed of the following components: 10 g / L sodium carboxymethyl cellulose, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium dihydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast powder, 0.5 mL / L 0.1% (w / v) resazurin and 1.1 mL / L 0.1% (w / v) ferrous sulfate heptahydrate, the solvent is water, and the pH is 7.0. The size of the carbon paper anode electrode (6) is 15×15×0.2 mm.

[0075] The cathode chamber contains 100 mL of cathode liquid (9) and a carbon paper cathode electrode (7). The cathode liquid is a 50 mM potassium ferrocyanide solution (the solute is potassium ferrocyanide; the solvent is a phosphate buffer solution with a pH value of 7.0); the size of the carbon paper cathode is 15×15×0.2 mm.

[0076] The construction method and voltage testing method of the microbial fuel cell are the same as those in Example 2.

[0077] The output voltage of the microbial fuel cell constructed above can reach 407.2 mV after working for 24 hours. After running for 3 cycles, the output voltage can reach 493.1 mV, and the maximum power density is 55.8 mW / m 2 , the electrode polarization curve and power density curve are as follows Figure 5 shown.

[0078] Example 4: The difference from Example 2 is that cellobiose is used instead of the pretreated substrate in Example 2

[0079] This embodiment provides a Figure 2 The microbial fuel cell shown in the figure comprises an anode chamber (1), a proton exchange membrane (DuPont Nafion-117) (3), and a cathode chamber (2), and the volume of both chambers is 150 mL;

[0080] The anode chamber includes an anode solution (8) and a carbon paper anode electrode (6); wherein the anode solution (8) is composed of 90 mL anode culture medium and 10 mL thermocellulosic bacteria seed solution obtained in Example 1. The anode culture medium is composed of the following components: 10 g / L cellobiose, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium dihydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast powder, 0.5 mL / L 0.1% (w / v) resazurin and 1.1 mL / L 0.1% (w / v) ferrous sulfate heptahydrate, the solvent is water, and the pH is 7.0. The size of the carbon paper anode electrode (6) is 15×15×0.2 mm.

[0081] The cathode chamber contains 100 mL of cathode liquid (9) and a carbon paper cathode electrode (7). The cathode liquid is a 50 mM potassium ferrocyanide solution (the solute is potassium ferrocyanide; the solvent is a phosphate buffer solution with a pH value of 7.0); the size of the carbon paper cathode is 15×15×0.2 mm.

[0082] The construction method and voltage testing method of the microbial fuel cell are the same as those in Example 2.

[0083] The output voltage of the microbial fuel cell constructed above can reach 619.3 mV after working for 24 hours. After running for 3 cycles, the output voltage can reach 661.5 mV, and the maximum power density is 88.5 mW / m 2 , the electrode polarization curve and power density curve are as follows Figure 6 shown.

[0084] Comparative Example 1

[0085] This comparative example provides a microbial fuel cell, which is the same as Example 2 except that the substrate in the anolyte is a lignocellulosic raw material treated with a 3% (w / v) sodium hydroxide pretreatment solution. The lignocellulosic raw material after sodium hydroxide pretreatment was observed using a scanning electron microscope. The results are as follows: Figure 1 Although the surface structure of the raw material was also destroyed when it was pretreated with sodium hydroxide alone, no scaly debris was observed and the surface roughness was not high.

[0086] The preparation of the Acetovibrio thermocellum seed solution is the same as that in Example 1.

[0087] The construction of the microbial fuel cell is the same as that of Example 2.

[0088] The anode and cathode of the microbial fuel cell were connected with a 2 kΩ resistor load, and both ends of the load were connected to a data acquisition device. The cells were then cultured in a constant temperature shaker at 55°C and 150 rpm for 72 h. At 24 and 48 h of culture, the anode culture medium and cathode liquid were replaced and nitrogen was refilled. The real-time output voltage was tested. The output voltage curve results are shown in Figure 2. Figure 3 shown.

[0089] The output voltage of the microbial fuel cell constructed above was only 193.1 mV after working for 24 hours. After running for 3 cycles, the maximum output voltage was 289.9 mV.

[0090] When the output voltage of the third power generation cycle reaches a stable stage, remove the resistance load (4) and stabilize for a period of time. Then use a resistance box to connect different resistance loads (0 to 100,000 Ω) to the external circuit in turn. After stabilization for a period of time, record the output voltage across the resistor at this time, calculate the current density and power density corresponding to each output voltage, and draw the electrode polarization curve and power density curve (the results are shown in Figure 2). Figure 7 shown).

[0091] The maximum power density of the microbial fuel cell constructed above is only 11.3 mW / m 2 .

[0092] Comparative Example 2

[0093] This comparative example provides a microbial fuel cell. The microbial fuel cell is the same as Example 2 except that the substrate in the anolyte is an untreated lignocellulose raw material.

[0094] The preparation of the Acetovibrio thermocellum seed solution is the same as that in Example 1.

[0095] The construction of the microbial fuel cell is the same as that of Example 2.

[0096] The anode and cathode of the microbial fuel cell were connected with a 2 kΩ resistor load, and both ends of the load were connected to a data acquisition device. The cells were then cultured in a constant temperature shaker at 55°C and 150 rpm for 72 h. At 24 and 48 h of culture, the anode culture medium and cathode liquid were replaced, and nitrogen was refilled to test the real-time output voltage.

[0097] The lignocellulose raw materials before and after pretreatment were observed using a scanning electron microscope. Figure 1 The surface of the raw material without pretreatment is smooth and dense, while the surface of the substrate after pretreatment is full of gullies and the surface roughness is significantly improved, indicating that the pretreatment can effectively destroy the surface structure of the raw material. The output voltage curve results are shown in Figure 3As shown, the output voltage curve of the microbial fuel cell constructed above did not change, indicating that it failed to utilize the substrate to generate electricity.

[0098] As demonstrated in Examples 2, 3, and 4, the Acetovibrio thermocellum provided by the present invention exhibits high electricity production, not only using soluble substrates as electron donors but also capable of degrading lignocellulosic substrates to generate electricity, thus possessing application value in microbial fuel cells. As demonstrated in Example 2 and the comparative examples, the pretreatment method provided by the present invention can effectively destroy the natural structure of lignocellulose, allowing it to directly serve as an electron donor in microbial fuel cells, thereby achieving efficient energy utilization of waste biomass.

[0099] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any improvement, modification, substitution, combination, or simplification to a certain extent without departing from the spirit and principle of the present invention should be regarded as an equivalent replacement method of the present invention and should be included in the scope of protection of the present invention.

Claims

1. A method for directly generating electricity from lignocellulose, characterized in that: The following steps are involved: (1) Pretreating the lignocellulosic raw material to obtain a pretreated substrate; (2) Activating and culturing Vibrio thermocellum to obtain seed liquid; (3) inoculating the seed solution obtained in step (2) into a dual-chamber fuel cell using the pretreated substrate obtained in step (1) as an electron donor, culturing, and outputting electrical energy from the electrodes of the dual-chamber fuel cell; The pretreatment steps described in step (1) are as follows: adding a pretreatment solution containing H2O2 and NaOH to react; The composition of the pretreatment solution containing H2O2 and NaOH is as follows: 1-3% (w / v) H2O2, 0.5-1.5% (w / v) NaOH, and the solvent is water; The usage amount of the pretreatment liquid containing H2O2 and NaOH is 20-30 mL of the pretreatment liquid containing H2O2 and NaOH per 1 g of lignocellulose; The reaction conditions are as follows: temperature of 30-80° C., reaction at 100-200 rpm for 4-8 h.

2. The method for directly utilizing lignocellulose to generate electricity according to claim 1, characterized in that: The activation culture described in step (2) is to inoculate the thermocellum Acetovibrio into a seed culture medium for cultivation; The seed culture medium is composed of: 8-11 g / L microcrystalline cellulose, 1-1.5 g / L ammonium sulfate, 2.5-3 g / L magnesium chloride hexahydrate, 1.4-1.5 g / L potassium dihydrogen phosphate, 5-6 g / L potassium hydrogen phosphate trihydrate, 0.1-0.15 g / L calcium chloride dihydrate, 5-7 g / L sodium β-glycerophosphate pentahydrate, 0.2-0.3 g / L reduced glutathione, 4-5 g / L yeast extract, 0.4-0.6 mL / L 0.1% w / v resazurin, 0.5-1.5 g / L ferric chloride hexahydrate, and 1-1.5 mL / L 0.1% w / v ferrous sulfate heptahydrate, and the solvent is water; The pH value of the seed culture medium is 6.8-7.

2.

3. The method for directly generating electricity from lignocellulose according to claim 2, characterized in that: The culture is shaken under inert gas; The shaking culture conditions are: temperature of 50-60° C., rotation speed of 120-180 rpm, and shaking culture for 12-18 hours.

4. The method for directly utilizing lignocellulose to generate electricity according to claim 1, characterized in that: The dual-chamber fuel cell in step (3) using the pretreated substrate obtained in step (1) as an electron donor comprises an anode chamber and a cathode chamber separated by a proton exchange membrane; The anode chamber and the cathode chamber are both filled with inert gas; The anode chamber contains an anolyte, which contains an anode culture medium and Acetovibrio thermocellum; The cathode chamber contains cathode liquid; the cathode liquid uses potassium ferrocyanide as an electron acceptor.

5. The method for directly generating electricity from lignocellulose according to claim 4, characterized in that: The components of the anode culture medium are as follows: 8-11 g / L pretreated substrate, 1-1.5 g / L ammonium sulfate, 2.5-3 g / L magnesium chloride hexahydrate, 1.4-1.5 g / L potassium dihydrogen phosphate, 5-6 g / L potassium hydrogen phosphate trihydrate, 0.1-0.15 g / L calcium chloride dihydrate, 5-7 g / L sodium β-glycerophosphate pentahydrate, 0.2-0.3 g / L reduced glutathione, 4-5 g / L yeast powder, 0.4-0.6 mL / L 0.1% w / v resazurin, and 1-1.5 mL / L 0.1% w / v ferrous sulfate heptahydrate, and the solvent is water; The pH value of the anode culture medium is 6.8 to 7.2; The cathode liquid comprises the following components: 40-60 mM potassium ferrocyanide and a phosphate buffer solution with a pH value of 6.8-7.

2.

6. The method for directly generating electricity from lignocellulose according to claim 5, characterized in that: The components of the anode culture medium are as follows: 10 g / L pretreated substrate, 1.3 g / L ammonium sulfate, 2.6 g / L magnesium chloride hexahydrate, 1.43 g / L potassium dihydrogen phosphate, 5.5 g / L potassium hydrogen phosphate trihydrate, 0.13 g / L calcium chloride dihydrate, 6 g / L sodium β-glycerophosphate pentahydrate, 0.25 g / L reduced glutathione, 4.5 g / L yeast powder, 0.5 mL / L 0.1% w / v resazurin, and 1.1 mL / L 0.1% w / v ferrous sulfate heptahydrate, and the solvent is water; The pH value of the anolyte is 7.

0.

7. The method for directly generating electricity from lignocellulose according to claim 1, characterized in that: The dual-chamber fuel cell described in step (3) using the pretreated substrate obtained in step (1) as an electron donor further comprises an anode electrode and a cathode electrode; The anode electrode and the cathode electrode are made of conductive carbon paper.

8. The method for directly utilizing lignocellulose to generate electricity according to claim 1, characterized in that: The inoculation in step (3) is to inoculate the thermocellum seed solution into the anode chamber of the battery; The culture described in step (3) is a shaking culture under inert gas; The shaking culture conditions are: temperature of 50-60°C, rotation speed of 120-180 rpm, and culture for 20-28 hours.

9. Use of the method for directly utilizing lignocellulose to generate electricity according to any one of claims 1 to 8 in microbial energy conversion of waste biomass.

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