Power Generation In Microbial Fuel Cells Research Articles

High-performance bacterium-enhanced dual-compartment microbial fuel cells for simultaneous treatment of food waste oil and copper-containing wastewater

Microbial fuel cells (MFCs) use the metabolic actions of microorganisms in an anode chamber to convert the chemical energy from wastewater into electrical energy. To improve the MFC power generation performance and chemical oxygen demand (COD) removal efficiency, Stenotrophomonas acidaminiphila was added to the anode chamber of a dual-compartment MFC. In this process, Stenotrophomonas acidaminiphila promotes the degradation of macromolecules such as bis(2-ethylhexyl) phthalate in food waste oil. Additionally, the generated electrical energy reduced Cu2+ in the copper-containing wastewater in the cathode chamber to Cu monomers. The maximum power density of the MFC was 49.5 ± 3.5 mW/m2, the maximum removal efficiencies of COD and Cu2+ were 63.5 ± 5.8% and 96.5 ± 1.0%, respectively, and Cu2+ was reduced to brick-red Cu monomers. This study provides insights into the simultaneous implementation of food waste oil treatment and metal resource recovery.

Effects of potassium-mediated electrical communication inhibition on nitrogen removal in microbial fuel cells

Potassium ion signaling mediates microbial communication in electroactive biofilms within microbial fuel cells (MFCs), but its role in nitrogen removal remains unclear. This study investigated the impact of inhibiting potassium signaling on nitrogen removal in MFCs using tetraethylammonium chloride (TEA) as an inhibitor. Results demonstrated that 5 mM and 10 mM TEA reduced the maximum power generation of MFCs from 77.95 mW/cm2 to 57.18 mW/cm2 and 48.23 mW/cm2, respectively. Correspondingly, total nitrogen (TN) removal efficiency was decreased from 46.57 ± 1.01% to 35.93 ± 0.63% and 38.97 ± 0.74%, respectively. This decline was attributed to inhibited potassium ion signaling, which compromised the electrochemical performance of the MFC and hindered the nitrogen removal process. The relative abundance of exoelectrogen Geobactor decreased from 15.37% to 5.17% and 8.05%, while the relative abundance of cathodic nitrifying bacteria Nitrosomonas decreased from 17.87% to 4.92% and 3.63% under 5 mM and 10 mM TEA. These findings underscore the crucial role of potassium ion signaling in enhancing the bioelectrochemical nitrogen removal process in MFCs.

Three-dimensional biochar aerogel anode derived from expired yogurt for enhancing power efficiency and electron transfer at the bacteria-anode interface in microbial fuel cells

Microbial fuel cells (MFCs) are a promising and sustainable form of fuel cells that utilize electroactive microorganisms to generate electricity. However, the practical application of MFCs is limited by their low power density, inadequate biocompatibility, and suboptimal electrochemical properties. To overcome these challenges, we developed a three-dimensional high performance biochar aerogel anode (YP) made from a mixture of expired yogurt and polyvinyl alcohol (PVA) and investigated its effect on the performance of the MFC. The incorporation of PVA into the YP anodes resulted in improved electrolyte wettability and hydrophilic surfaces, thereby enhancing biocompatibility and bacterial adhesion, especially with Geobacter, reaching up to 89.6% coverage. The biofilm content reached 68.1 mg, which is 1.7 times that of carbon cloth, which improved the electron transfer efficiency at the bacteria-anode interface. Moreover, the mechanical strength of the YP anodes was increased, improving anode stability and durability. In addition, the aerogel anode exhibited impressive power density and current density values of 15.87 W m−3 and 43.76 A m−3, respectively. These values are 3.16 times and 3.60 times higher than the 5.03 W m−3 and 12.13 A m−3 of carbon cloth. This study makes a significant contribution to improving power generation in MFCs, optimizing electron transfer at the bacteria-anode interface, and paving the way for future practical applications of MFCs.

Enhancement of gaseous chlorobenzene biodegradation and power generation in a microbial fuel cell by bifunctional Acinetobacter sp. HY-99C

The efficient biodegradation of volatile chlorinated hydrocarbons using microbial fuel cells (MFCs) offers a feasible approach for purifying waste gas and alleviating energy crises. However, power generation is limited by poor pollutant biodegradation and slow electron transfer. The bifunctional bacterium Acinetobacter sp. HY-99C was screened and used to improve the performance of a conventional MFC. The inoculation of strain HY-99C into the conventional MFC promoted the formation of a compact biofilm with high metabolic activity and an enriched bifunctional genus (Acinetobacter), which resulted in the accelerated decomposition of chlorinated aromatic compounds into biodegradable organic acids. This led to efficient chlorobenzene removal and power generation from the MFC, with a chlorobenzene elimination capacity of 70.8 g m−3 h−1 and power density of 89.6 mW m−2, which are improved over those of previously reported MFCs. This study provides novel insights into enhancing pollutant removal and power generation in MFCs.

Enhancing microbial fuel cell performance with carbon powder electrode modifications for low-power sensors modules

Microbial Fuel Cell (MFC) is a promising technology for harnessing energy from organic compounds. However, the low power generation of MFCs remains a significant challenge that hinders their commercial viability. In this study, we reported three distinct modifications to the stainless-steel mesh (SSM), carbon cloth, and carbon felt electrodes using carbon powder (CP), a mixture of CP and ferrum, and a blend of CP with sodium citrate and ethanol. The MFC equipped with an SSM and CP anode showed a notable power density of 1046.89 mW.m-2. In comparison, the bare SSM anode achieved a maximum power density of 145.8 mW m-2. Remarkably, the 3D-modified SSM with a CP anode (3D-SSM-CP) MFC exhibited a substantial breakthrough, attaining a maximum power density of 1417.07 mW m-2. This achievement signifies a significant advancement over the performance of the unaltered SSM anode, underscoring the effectiveness of our modification approach. Subsequently, the 3D-SSM-CP electrode was integrated into single-chamber MFCs, which were used to power a LoRaWAN IoT device through a power management system. The modification methods improved the MFC performance while involving low-cost and easy fabricating techniques. The results of this study are expected to contribute to improving MFC's performance, bringing them closer to becoming a practical source of renewable energy.

Investigation of microbial fuel cell performance based on the nickel thin film modified electrodes

Microbial fuel cells (MFCs) are a self-sustaining and environmentally friendly system for the simultaneous was tewater treatment and bioelectricity generation. The type and material of the electrode are critical factors that can influence the efficiency of this treatment process. In this study, graphite plates and carbon felt were modified through the electrodeposition of nickel followed by the formation of a biofilm, resulting in conductive bio-anode thin film electrodes with enhanced power generation capacity. The structural and morphological properties of the electrode surfaces were characterized using X-ray diffraction, energy-dispersive X-ray spectroscopy, elemental mapping, and field-emission scanning electron microscopy techniques. Maximum voltage, current density, and power generation were investigated using a dual-chamber MFC equipped with a Nafion 117 membrane and bio-nickel-doped carbon felt (bio-Ni@CF) and bio-nickel-doped graphite plate (bio-Ni@GP) electrodes under constant temperature conditions. The polarization and power curves obtained using different anode electrodes revealed that the maximum voltage, power and current density achieved with the bio-Ni@CF electrode were 468.0 mV, 130.72 mW/m2 and 760.0 mA/m2 respectively. Moreover, the modified electrodes demonstrated appropriate stability and resistance during successful runs. These results suggest that nickel-doped carbon-based electrodes can serve as suitable and stable supported catalysts and conductors for improving efficiency and increasing power generation in MFCs.

Metabolic regulation boosts bioelectricity generation in Zymomonas mobilis microbial fuel cell, surpassing ethanol production

Zymomonas mobilis (Z. mobilis), a bacterium known for its ethanol production capabilities, can also generate electricity by transitioning from ethanol production to electron generation. The purpose of this study is to investigate the ability of Z. mobilis to produce bioelectricity when utilized as a biocatalyst in a single-chamber microbial fuel cell (MFC). Given the bacterium's strong inclination towards ethanol production, a metabolic engineering strategy was devised to identify key reactions responsible for redirecting electrons from ethanol towards electricity generation. To evaluate the electroactivity of cultured Z. mobilis and its ethanol production in the presence of regulators, the reduction of soluble Fe(III) was utilized. Among the regulators tested, CuCl2 demonstrated superior effectiveness. Consequently, the MFC was employed to analyze the electrochemical properties of Z. mobilis using both a minimal and modified medium. By modifying the bacterial medium, the maximum current and power density of the MFC fed with Z. mobilis increased by more than 5.8- and sixfold, respectively, compared to the minimal medium. These findings highlight the significant impact of metabolic redirection in enhancing the performance of MFCs. Furthermore, they establish Z. mobilis as an active electrogenesis microorganism capable of power generation in MFCs.

Fabrication and Study of 3D Printed ABS-Carbon Composite Anodes for Single Chamber Microbial Fuel Cells

Microbial Fuel Cells (MFCs) are electrochemical devices that exploit microbes for wastewater treatment with simultaneous power production. Concerning reactor design, electrode materials and operation modes, great achievements have been reported with an emphasis on developing anode materials to improve overall MFC performance. Anode materials (carbon cloth, carbon veil, carbon sponges) and their properties such as biocompatibility, electrical conductivity, surface area and efficient transport of waste play a very important role in power generation in MFCs. Despite their low cost, they present structural-based disadvantages eg. Fragility, and low conductivity issues. Additive manufacturing of Fused Deposition Modelling (FDM) due to its tailoring properties, has employed various polymer-based materials such as Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) for manufacturing applications. In addition, carbon-based composites and hybrid materials eg. electrically conductive PLA and ABS have already been fabricated and are commercially available to exploit good electrical conductivity and structural rigidness. In this research, FDM was used to fabricate custom-sized electrodes made of a laboratory-produced electrically conductive ABS filament. A parametric study of conductivity and biocompatibility properties of these electrodes in correlation to 3D printer parameters was investigated and reported. Furthermore, treatment with a combination of thermal, mechanical, and chemical procedures was performed to improve the crucial parameters of anodes for MFCs.

Enhanced Electricity Generation and Heavy Metal Removal by a Rutile–Biochar Cathode MFC

The issue of heavy metal pollution has gradually emerged as a significant global concern. Microbial fuel cells (MFCs) hold immense potential for clean energy production and pollutant treatment. However, their limited power generation efficiency hampers the large-scale implementation of MFCs. The porous microstructure of biochar and the excellent physical and chemical properties of rutile render both materials promising catalysts with positive potential. In this study, we employed biochar as a carrier for rutile to fabricate a novel rutile–biochar (Rut-B) composite material, investigating its efficacy in enhancing MFC power generation efficiency as a cathode catalyst, as well as its application in heavy metal pollutant degradation. Scanning electron microscopy (SEM) results confirmed the successful preparation of biochar-loaded rutile composites. The MFC achieved maximum current density and power density values of 152.26 mA/m2 and 9.88 mW/m2, respectively—an increase of 102.7% and 224% compared to the control group without the addition of Rut-B. Furthermore, the biochar-loaded rutile MFC exhibited excellent performance in degrading heavy metal pollutants; within 7 h, the Pb2+ degradation rate reached 92.4%, while the Zn2+ degradation rate reached 84%. These rates were significantly higher than those observed in the control group, by factors of 437.2% and 345%, respectively. The cyclic degradation experiments also demonstrated the outstanding stability of the system over multiple cycles. In summary, this study successfully combined natural rutile with biochar to create an efficient electrode catalyst that not only enhances electricity generation performance but also provides an environmentally friendly and cost-effective approach for remediating heavy metal pollution.

Stimulation of electron transfer in electricigens by MnxCoySz heterostructure for the enhanced power generation of microbial fuel cell

Microbial fuel cells (MFCs) are an efficient approach to converting energy existing in waste into electricity. However, MFCs still face problems such as low electron transfer rate and low power density. Herein, the anode properties dominate the performance of MFC. This study manufactured a high-performance MnCo2S4–CoS1.097/carbon black carbon felt (T-MCS-CS/CB-CF) anode through a two-step hydrothermal method. T-MCS-CS/CB catalyst exhibited superior surface roughness and mesoporous structure. Besides, the excellent electrocatalytic activity of the T-MCS-CS/CB catalyst with the heterostructure resulted in the higher power output. After biofilm formation, T-MCS-CS/CB-CF anode exhibited lower Rct (9.29 Ω) than MnCo2S4-Co4S3/ carbon black carbon felt (MCS-CS/CB-CF (15.83 Ω)), carbon black carbon felt (CB-CF (29.52 Ω)) and CF anode (116.1 Ω), exhibiting higher electrochemical activity. T-MCS-CS/CB-CF anode enhanced extracellular electron transfer (EET) and improved the power density, which was 12.29 times higher (1299.27 mW/m2) than the bare CF (105.70 mW/m2). The relative abundance of Geobacter for T-MCS-CS/CB-CF (21.65 %) was 7.24 times higher than the control CF anode (2.99 %). Moreover, T-MCS-CS/CB modification enriched exoelectrogens/sulfate-reducing bacteria, Desulfovibrio, 4.69 % higher than the CF anode, which attributed to the introduction of CoS1.097. The excellent electrocatalytic activity, surface properties and biocompatibility of T-MCS-CS/CB-CF promoted the power output in MFC. This study provided an effective way of anodic electrocatalyst fabrication for enhancing the power generation of MFC.

Accelerating Electricity Generation and Cr (VI) Removal Using Anatase–Biochar-Modified Cathode Microbial Fuel Cells

Microbial fuel cells (MFC) have considerable potential in the field of energy production and pollutant treatment. However, a low power generation performance remains a significant bottleneck for MFCs. Biochar and anatase are anticipated to emerge as novel cathode catalytic materials due to their distinctive physicochemical properties and functional group architectures. In this study, biochar was utilized as a support for an anatase cathode to investigate the enhancement of the MFC power generation performance and its environmental impact. The results of the SEM and XPS experiments showed that the biochar-supported anatase composites were successfully prepared. Using the new cathode catalyst, the maximum current density and power density of the MFC reached 164 mA/m2 and 10.34 W/m2, respectively, which increased by 133% and 265% compared to a graphite cathode (70.51 mA/m2 and 2.83 W/m2). The degradation efficiency of Cr (VI) was 3.1 times higher in the biochar-supported anatase MFC than in the graphite cathode. The concentration and pH gradient experiments revealed that the degradation efficiency of Cr (VI) was 97.05% at an initial concentration of 10 mg/L, whereas a pH value of two resulted in a degradation efficiency of 94.275%. The biochar-supported anatase composites avoided anatase agglomeration and provided more active sites, thus accelerating the cathode electron transfer. In this study, natural anatase and biochar were ingeniously combined to fabricate a green and efficient electrode catalyst, offering a novel approach for the preparation of high-performance positive catalysts as well as a sustainable, economical, and environmentally friendly method for Cr (VI) removal in aqueous solutions.

Exploring the use of raw honey as a fuel source for microbial fuel cells

Microbial fuel cell (MFC) technologies are making headway in developing and expanding renewable energy through the conversion of organic matter to electricity. Various substrates can be used in the MFCs technology to enable energy generation, either pure substances or complex mixtures of organic materials. This study aims to consider the feasibility of raw honey as a fuel for mediator-less double-chamber MFC. The cell voltage was monitored in mediator-less double-chamber H2O2 cathode microbial fuel cell. The Mfensi clay partition and the raw honey were analyzed using FTIR-ATR. The results show the highest open-circuit voltage of 1414 mV with a maximum current density of 0.6540 A/m2 and a maximum power density of 247.0 W/m2. These results demonstrate that raw honey can be used for power generation in MFCs and for practical applications.

Investigating the Performance of a Zinc Oxide Impregnated Polyvinyl Alcohol-Based Low-Cost Cation Exchange Membrane in Microbial Fuel Cells.

The current study investigated the development and application of lithium (Li)-doped zinc oxide (ZnO)-impregnated polyvinyl alcohol (PVA) proton exchange membrane separator in a single chambered microbial fuel cell (MFC). Physiochemical analysis was performed via FT-IR, XRD, TEM, and AC impedance analysis to characterize thus synthesized Li-doped ZnO. PVA-ZnO-Li with 2.0% Li incorporation showed higher power generation in MFC. Using coulombic efficiency and current density, the impact of oxygen crossing on the membrane cathode assembly (MCA) area was evaluated. Different amounts of Li were incorporated into the membrane to optimize its electrochemical behavior and to increase proton conductivity while reducing biofouling. When acetate wastewater was treated in MFC using a PVA-ZnO-Li-based MCA, the maximum power density of 6.3 W/m3 was achieved. These observations strongly support our hypothesis that PVA-ZnO-Li can be an efficient and affordable separator for MFC.

Transitional trimetallic alloy embedded polyacrylamide hydrogel derived nitrogen-doped carbon air-cathode for bioenergy generation in microbial fuel cell

Heterometallic carbons are popular materials for application in energy devices due to their high oxygen reduction reaction (ORR) activity and good catalytic stability. Particularly in microbial fuel cells (MFCs), Fe group metal alloys are efficient ORR catalysts. This work has embedded different metallic alloy nanoparticles in polyacrylamide hydrogel derived in-situ nitrogen-doped carbon. All the catalysts (Fe@NC, FeCo@NC, FeNi@NC, and FeCoNi@NC) are used as air cathodes and examined for power generation in single chamber MFCs. Trimetallic composite (FeCoNi@NC) performed better than Pt/C. FeCoNi@NC exhibited superior electrocatalytic activity with an oxygen reduction peak at 0.394 V (vs RHE) and a corresponding peak current density of −0.159 mA. FeCoNi@NC records maximum power output of 963.5 mW m−2 at 2483.2 mA m−2, 3.287 and 1.136 times higher than NC and 10 wt% Pt/C, respectively. This could be due to the uniformly distributed alloy nanoparticles, abundant pyridinic-N, and M−Nx sites that enhance the durability, charge transfer, and power generation in MFCs. These findings suggest that the trimetallic transition metal-carbon (MNC) electrodes could be promising ORR catalysts, justifying their application for energy devices.

Microbial Electrochemical Treatment of Methyl Red Dye Degradation Using Co-Culture Method

Methyl red, a synthetic azo dye, was reported for not only being mutagenic but also its persistence has severe consequences on human health, such as cancer, alongside detrimental environmental effects. In the present study, the Pseudomonas putida OsEnB_HZB_G20 strain was isolated from the soil sample to study the catalytic activity for the degradation of methyl red dye. Another isolated strain, the Pseudomonas aeruginosa PA 1_NCHU strain was used as an electroactive anodophile and mixed with the Pseudomonas putida OsEnB_HZB_G20 strain to see the effect of co-culturing on the power generation in single-chambered microbial fuel cells (MFCs). The Pseudomonas putida OsEnB_HZB_G20 and Pseudomonas aeruginosa PA 1_NCHU strains were used as co-culture inoculum in a 1:1 ratio in MFCs. This work uses isolated bacterial strains in a co-culture to treat wastewater with varying methyl red dye concentrations and anolyte pH to investigate its effect on power output in MFCs. This co-culture produced up to 7.3 W/m3 of power density with a 250 mgL−1 of dye concentration, along with 95% decolorization, indicating that the symbiotic relationship between these bacteria resulted in improved MFC performance simultaneous to dye degradation. Furthermore, the co-culture of Pseudomonas putida and Pseudomonas aeruginosa in a 1:1 ratio demonstrated improved power generation in MFCs at an optimized pH of 7.

The preparation of PANI-doped Co-Ni-ZIF carbonized derivatives and the exploration of EET process by the DFT calculation and the prediction of related functional genes

As a green conversion/energy storage device, the practical application of microbial fuel cell (MFC) was limited with its low power generation. The extracellular electron transfer efficiency was one of the key factors affecting the power generation performance of MFC. This paper reported the carbonized derivative Co-Ni-ZIF@NC derived from PANI-doped Co-Ni-ZIF with conductivity, biocompatibility and high electrocatalytic activity. Density functional theory (DFT) confirmed the strong interaction between the electrode surface and microorganisms. The maximum power density of the MFC with Co-Ni-ZIF@NC anode (8.67 W/m3) was 1.47 time higher than that of Co-Ni-ZIF@C-800 (5.96 W/m3). High-throughput sequencing revealed that Co-Ni-ZIF@NC catalyst facilitated the screening of relevant functional microbial communities in microbial membranes, leading to the reinforcement of power generation in MFC. PICRUSt predicted the relative abundance of functional genes, confirmed the spontaneous enrichment behaviour of functional microorganisms to the electrode surface, and identified cytochrome c552 as the dominant role in the EET process. The above foregoing mainly due to the doping of PANI, improved the content of pyrrolic N on the surface of derivatives, protected the original crystal morphology, promoted the approaching behaviour of conductive flagella to the anode surface and shortened the electron transport distance, thus Co-Ni-ZIF@NC exhibited superb bioelectrocatalytic activity.

Binder-free Fe nano oxides decoration for stimulating power generation in microbial fuel cell: Effects on electrode substrates and function mechanism

Nanomaterials are ideal for electrode modification to improve the power output of microbial fuel cells (MFCs). The nanomaterials decoration usually needs a conductive binder which faces the problem of high cost and low conductivity, significantly constraining further application. This study successfully fabricated the binder-free Fe nano oxides modified anodes through the solvothermal method. MFC assembled with carbon cloth/Fe nano oxides (M−CC/Fe) achieved the highest maximum power density (471.6 mW m−2), dramatically higher than that with carbon cloth (M−CC, 150.4 mW m−2), Ni foam/Fe nano oxides (M−NF/Fe, 130.6 mW m−2) and Ni foam (M−NF, 16.5 mW m−2). The electrochemical catalyzing activity, extracellular electron transfer rate, COD removal efficiency and coulombic efficiency were all improved after Fe nano oxides decoration in MFCs. Fe nano oxides enriched exoelectrogens/iron-reducing bacteria like Geobacter and Comamonas and showed a mutual benefit relationship with them. The formation of stable Fe nano oxide cubes significantly enhanced the electroactive biofilm development and alleviated the corrosion of the electrode substrate. The complementary merits of the carbon-based electrode and Fe nano oxides performed better in stimulating power generation in MFCs. These results provided knowledge of in-situ nanomaterials decoration for advanced anodes, providing suggestions for high-performance resource recovery from wastewater.

Biodegradation of Congo Red Using Co-Culture Anode Inoculum in a Microbial Fuel Cell

Congo red is an azo dye widely used as a colouring agent in textile industries. It is a serious threat due to its carcinogenic effects. Its degradation has been challenging due to its complex yet stable structure. The present study was aimed to investigate the effective degradation of Congo red by bioremediating bacteria isolated from different environments. To investigate predominant microorganisms that degrade Congo red and its functions in microbial fuel cells (MFCs), strains isolated from cow dung (Enterococcus faecalis SUCR1) and soil (Pseudomonas aeruginosa PA1_NCHU) were used as a co-culture inocula. The remarkable results establish that E. faecalis as an excellent microbial source for the biological degradation of dye-contaminated wastewater treatment alongside bioactive treating wastewater with varied concentrations of congo red dye. The highest efficiency percentage of dye degradation was 98% after 3 days of incubation at pH 7 and 37 °C, whereas findings have shown that the decolorization at pH 5 and 6 was lower at 66% and 83.3%, respectively, under the same incubation conditions. Furthermore, the co-culture of E. faecalis SUCR1 and P. aeruginosa at a 1:1 ratio demonstrated improved power generation in MFCs. The maximum power density of 7.4 W/m3 was recorded at a 150 mg L−1 concentration of Congo red, indicating that the symbiotic relation between these bacterium resulted in improved MFCs performance simultaneous to dye degradation.

Fungus-sourced filament-array anode facilitates Geobacter enrichment and promotes anodic bio-capacitance improvement for efficient power generation in microbial fuel cells.

Microbial fuel cells (MFC) are emerging as new generation eco-friendly technology for the superiorities of energy harvest and simultaneous wastewater treatment. However, the power generation performance was strongly restricted by the material/biofilm electron transfer rate. In this research, the fungus-sourced electrode with filament-array structure was firstly proposed and prepared by one-step carbonization method. After 2 h pyrolysis, the functional groups containing N and O elements highly remained in the as-prepared material, which was beneficial to the electron transfer for the current generation. The lowest electron transfer resistance was obtained at 2.2 Ω, which showed a great reduction that compared with graphite sheet anode. With filament-array structure, the lowest mass diffusion resistance was obtained at 26.9 Ω for anodic oxidation reaction, which also supported the highest current generation performance. In addition, the relative abundance of typical electrochemical bacterium Geobacter was highly improved to 45.5% with an extraordinary electroactive biofilm loading of about 1203 ± 256 μg cm-2. More importantly, the high biocatalytic activity biofilm supported a remarkably observed bio-capacitance of about 1.14 F in 3DFfv anode, which exhibited the highest power density in 3.5 ± 0.2 W m-2. In addition, the fungus-sourced material was one kind of economical and readily available material. Overall, this work provided one efficient strategy for electrode preparation and higher power generation in MFCs, which would reduce the capital cost and improve the efficiency in further applications of MFCs.

Mild Alkaline Pretreatment of Rice Straw as a Feedstock in Microbial Fuel Cells for Generation of Bioelectricity.

The dependency on non-renewable fossil fuels as an energy source has drastically increased global temperatures. Their continuous use poses a great threat to the existing energy reserves. Therefore, the energy sector has taken a turn toward developing eco-friendly, sustainable energy generation by using sustainable lignocellulosic wastes, such as rice straw (RS). For lignocellulosic waste to be utilized as an efficient energy source, it needs to be broken down into less complex forms by pretreatment processes, such as alkaline pretreatment using NaOH. Varied NaOH concentrations (0.5%,1.0%,1.5%,2%) for alkaline pretreatment of RS were used for the holocellulose generation. Amongst the four NaOH concentrations tested, RS-1.5% exhibited higher holocellulose generation of 80.1%, whereas 0.5%, 1 5 and 2% pointed 71.9%, 73.8%, and 78.5% holocellulose generation, respectively. Further, microbial fuel cells (MFCs) were tested for voltage generation by utilizing holocellulose generated from untreated (RS-0%) and mildly alkaline pretreated RS (RS-1.5%) as a feedstock. The MFC voltage and maximum power generation using RS-0% were 194mV and 167mW/m2, respectively. With RS-1.5%, the voltage and maximum power generation were 556mV and 583mW/m2, respectively. The power density of RS-1.5% was three-fold higher than that of RS-0%. The increase in MFC power generation suggests that alkaline pretreatment plays a crucial role in enhancing the overall performance.