Gunda Mohanakrishna, Ibrahim M. Abu-Reesh, Deepak Pant

Scientific Reports • 2020

Abstract Petroleum refinery wastewater (PRW) that contains recalcitrant components as the major portion of constituents is difficult to treat by conventional biological processes. Microbial fuel cells (MFCs) which also produce renewable energy were found to be promising for the treatment of PRW. However, due to the high total dissolved solids and low organic matter content, the efficiency of the process is limited. Labaneh whey (LW) wastewater, having higher biodegradability and high organic matter was evaluated as co-substrate along with PRW in standard dual chambered MFC to achieve improved power generation and treatment efficiency. Among several concentrations of LW as co-substrate in the range of 5–30% (v/v) with PRW, 85:15 (PRW:LW) showed to have the highest power generation (power density (PD), 832 mW/m 2 ), which is two times higher than the control with PRW as sole substrate (PD, 420 mW/m 2 ). On the contrary, a maximum substrate degradation rate of 0.420 kg COD/m 3 -day (ξCOD, 63.10%), was registered with 80:20 feed. Higher LW ratios in PRW lead to the production of VFA which in turn gradually decreased the anolyte pH to below 4.5 (70:30 feed). This resulted in a drop in the performance of MFC with respect to power generation (274 mW/m 2 , 70:30 feed) and substrate degradation (ξCOD, 17.84%).

Cynthia J. Castro, Varun Srinivasan, Joshua Jack et al.

Journal of Water, Sanitation and Hygiene for Development • 2016

Biological electrochemical systems (BESs) have the potential for decentralized treatment in developing countries. A 46 L, two-chamber, hydraulically partitioned microbial fuel cell (MFC) was designed to replicate low-flow scenarios leaving a composting toilet. The co-evolution of electricity and methane in this MFC was evaluated by testing two distinct waste streams: synthetic feces (Case F) and municipal primary effluent (Case W). Oxidation of organic matter was 76 ± 24% during Case F and 67 ± 21% during Case W. Methanogenesis was dominant in the anode, yielding potential power of 3.3 ± 0.64 W/m3 during Case F and 0.40 ± 0.07 W/m3 during Case W. Electrical power production was marginal, Case F = 4.7 ± 0.46 and Case W = 10.6 ± 0.39 μW/m3, although potentially useful in energy-limited areas. Complimentary batch cultivations with anode inocula yielded greater methane production in the presence of graphite. 74 ± 11% more methane was produced with graphite than suspended growth enrichments and 58 ± 10% more than enrichments with non-conductive plastic beads. The co-production of methane and electricity in an MFC may have utility in decentralized treatment. Further work is needed to optimize power from both electricity and methane.

Pranav H. Nakhate, Nandkumar T. Joshi, Kumudini V. Marathe

Reviews in Chemical Engineering • 2017

Abstract Reclamation of wastewater along with minimum energy utilization has been the paramount concern today. Tremendous industrialization and corresponding demographic resulted in elevated water and energy demand; however, scarcity of sufficient water and energy resource triggers rigorous research for sustainable water treatment technology. Recent technologies like activated sludge, filtration, adsorption, coagulation, and oxidation have been considered as promising sustainable technologies, but high cost, low efficiency, and efficacy are the major concerns so far. Wastewater is food for billions of bacteria, where some exceptional bacterial species have the ability to transport electrons that are produced during metabolism to outside the cell membrane. Indeed, wastewater can itself be considered as a prominent candidate to resolve the problem of sustainability. Bioelectrochemical membrane reactor is a promising technology, which is an integration of microbial fuel cell (MFC) to membrane bioreactor (MBR). It promises the benefit of harvesting electricity while biologically treating any type of wastewater to the highest extent while passing wastewater through anaerobic, aerobic, and integrated membrane compartments in successive manner. In this review, we provide critical rethinking to take this idea of integration of MFC-MBR and apply them to produce a fully functional prototype of bioelectrochemical membrane reactor that could be used commercially.

Daniele Molognoni, Stefania Chiarolla, Daniele Cecconet et al.

Water Science and Technology • 2018

Abstract Development of renewable energy sources, efficient industrial processes, energy/chemicals recovery from wastes are research issues that are quite contemporary. Bioelectrochemical processes represent an eco-innovative technology for energy and resources recovery from both domestic and industrial wastewaters. The current study was conducted to: (i) assess bioelectrochemical treatability of industrial (dairy) wastewater by microbial fuel cells (MFCs); (ii) determine the effects of the applied organic loading rate (OLR) on MFC performance; (iii) identify factors responsible for reactor energy recovery losses (i.e. overpotentials). For this purpose, an MFC was built and continuously operated for 72 days, during which the anodic chamber was fed with dairy wastewater and the cathodic chamber with an aerated mineral solution. The study demonstrated that industrial effluents from agrifood facilities can be treated by bioelectrochemical systems (BESs) with >85% (average) organic matter removal, recovering power at an observed maximum density of 27 W m−3. Outcomes were better than in previous (shorter) analogous experiences, and demonstrate that this type of process could be successfully used for dairy wastewater with several advantages.

Sitao Fei, Hao Ren

Micromachines • 2022

Nowadays, the development of real-time water quality monitoring sensors is critical. However, traditional water monitoring technologies, such as enzyme-linked immunosorbent assay (ELISA), liquid chromatography, mass spectroscopy, luminescence screening, surface plasma resonance (SPR), and analysis of living bioindicators, are either time consuming or require expensive equipment and special laboratories. Because of the low cost, self-sustainability, direct current output and real-time response, microbial fuel cells (MFCs) have been implemented as biosensors for water toxicity monitoring. In this paper, we report a microscale MFC biosensor to study the dose–response curve of exoelectrogen to toxic compounds in water. The microscale MFC biosensor has an anode chamber volume of 200 μL, which requires less sample consumption for water toxicity monitoring compared with macroscale or mesoscale MFC biosensors. For the first time, the MFC biosensor is exposed to a large formaldehyde concentration range of more than 3 orders of magnitudes, from a low concentration of 1 × 10−6 g/L to a high concentration of 3 × 10−3 g/L in water, while prior studies investigated limited formaldehyde concentration ranges, such as a small concentration range of 1 × 10−4 g/L to 2 × 10−3 g/L or only one high concentration of 0.1 g/L. As a result, for the first time, a sigmoid dose–response relationship of normalized dose–response versus formaldehyde concentration in water is observed, in agreement with traditional toxicology dose–response curve obtained by other measurement techniques. The biosensor has potential applications in determining dose–response curves for toxic compounds and detecting toxic compounds in water.

Cheng Liu, Liang Cheng, Hui Jia

Electroanalysis • 2024

Abstract Microbial Fuel Cells (MFCs) represent an innovative approach for transforming biomass energy directly into electricity, which showed great promise in various applications beyond energy generation and wastewater treatment. The use of MFCs as biosensors for in‐situ and online monitoring has garnered increasing interest. These biosensors stand out for their compactness, ease of operation, affordability, and portability. They have proven effectively in the detection of various water quality indicators, including organic matter, nitrogen, heavy metals, pH levels, and dissolved oxygen. This comprehensive review aims to provide a critical analysis of the current research landscape and the latest advancements in MFC technology, with special emphasis on the challenges encountered in its application for wastewater and water quality monitoring. Moreover, strategies for performance improvement, such as the adoption of miniaturized structures, the exploration of innovative materials, and the application of mathematical modelling for analysis, are also discussed. The review also explores potential avenues for future research, especially in the realm of detecting mixed pollutants. Thus, it provides insightful perspectives on the evolving field of biosensor technology based on MFCs.

Ademola Adekunle, Stefano Bambace, Fabrice Tanguay-Rioux et al.

Sensors • 2023

A microbial fuel cell (MFC) biosensor with an anode as a sensing element is often unreliable at low or significantly fluctuating organic matter concentrations. To remove this limitation, this work demonstrates capillary action-aided carbon source delivery to an anode-sensing MFC biosensor for use in carbon-depleted environments, e.g., potable water. First, different carbon source delivery configurations using several thread types, silk, nylon, cotton, and polyester, are evaluated. Silk thread was determined to be the most suitable material for passive delivery of a 40 g L−1 acetate solution. This carbon source delivery system was then incorporated into the design of an MFC biosensor for real-time detection of toxicity spikes in tap water, providing an organic matter concentration of 56 ± 15 mg L−1. The biosensor was subsequently able to detect spikes of toxicants such as chlorine, formaldehyde, mercury, and cyanobacterial microcystins. The 16S sequencing results demonstrated the proliferation of Desulfatirhabdium (10.7% of the total population), Pelobacter (10.3%), and Geobacter (10.2%) genera. Overall, this work shows that the proposed approach can be used to achieve real-time toxicant detection by MFC biosensors in carbon-depleted environments.

Trang Nakamoto, Dung Nakamoto, Kozo Taguchi

Biosensors • 2024

Wastewater pipelines are present everywhere in urban areas. Wastewater is a preferable fuel for renewable electricity generation from microbial fuel cells. Here, we created an integrated microbial fuel cell pipeline (MFCP) that could be connected to wastewater pipelines and work as an organic content biosensor and energy harvesting device at domestic waste-treatment plants. The MFCP used a pipeline-like terracotta-based membrane, which provided structural support for the MFCP. In addition, the anode and cathode were attached to the inside and outside of the terracotta membrane, respectively. Co−MnO2 was used as a catalyst to improve the performance of the MFCP cathode. The experimental data showed a good linear relationship between wastewater chemical oxygen demand (COD) concentration and the MFCP output voltage in a COD range of 200–1900 mg/L. This result implies the potential of using the MFCP as a sensor to detect the organic content of the wastewater inside the wastewater pipeline. Furthermore, the MFCP can be used as a long-lasting sustainable energy harvester with a maximum power density of 400 mW/m2 harvested from 1900 mg/L COD wastewater at 25 °C.

Baoguo Wu, Hui Yu, Chong Lin et al.

ChemElectroChem • 2015

Abstract The maximum current density ( j max ) is of importance to the modeling of current produced in a bioelectrochemical system (BES). This study explores an alternative to biomass and biofilm thickness, the accumulated charge density ( τ ) of electroactive bacteria on the bioanode, to estimate the j max value. The τ values of five carbon‐based bioanodes are chronoamperometrically determined in a substrate‐depleted solution. The graphite felt bioanode acclimated for 1, 2, 4, and 6 batches exhibits τ values of 6.14, 11.80, 22.23, and 30.24 C m −2 , respectively, and j max values of 5.31, 6.69, 14.01, and 19.62 A m −2 , respectively. A linear correlation between τ and j max is achieved and can be expressed as j max =0.64 τ . The τ and j max values of four other carbon‐based bioanodes also follow a linear relationship, with coefficients of approximately 0.64. These results imply that τ is a key parameter for estimating j max in the BES without the need to determine biomass and biofilm thickness.

Alana Danielle Dunne, Madalyn D. Puckett, Nicole Elizabeth Yuede et al.

ECS Meeting Abstracts • 2019

Microbial fuel cells (MFCs) have gained attention as a renewable energy option due to the utilization of microbes as catalysts for the oxidation of natural substrates. In order to increase the practical application of MFC technology, the overall system must enhance power output and lower operational costs. More specifically, the bacteria must dock on the electrode surface to allow for efficient electron transfer mechanisms. In efforts to increase productive bacteria-surface interactions, this work focuses on the synthesis of a conductive, cellulose-based nanocomposite for use as anodic electrodes. The nanocomposite material was non-covalently modified through the incorporation of sugar-functionalized TiO 2 nanoparticles. The relationship between conductivity and biocompatibility was explored in order to optimize the interactions between the synthesized electrodes and Escherichia coli ( E. Coli ). Power production using the composite electrodes was correlated to biofilm formation and cell proliferation via atomic force microscopy (AFM) and live/dead stain, respectively. The composite electrode materials have shown increased electrical response over traditional carbon cloth when used as anodes under dye-mediated conditions. Additionally, the sugar-functionalized composites showed increased bacterial adsorption and enhanced cell viability indicating more intimate contact between the microbes and the electrode surface. Initial results also suggest photochemical activity using sugar, polyaniline modified TiO 2 nanoparticles embedded within the cellulose matrix resulting in responsive fuel cell behavior. Future work aims to incorporate supramolecular structures, such as β-cyclodextrin, to constrain dye absorption to the material surface and potentially increase the electrical response and longevity of the fuel cell system.

Hengliang Zhang, Fei Xing, Liang Duan et al.

Bioresource Technology • 2025

To solve the problems of antibiotic pollution, water resources and energy shortage, an osmotic microbial fuel cell (OsMFC) was adopted innovatively to treat antibiotic wastewater containing sulfamethoxazole (SMX), and achieved SMX removal, water production and electricity generation. Substrate concentration was one of the key factors affecting the performances of OsMFC, but there were few relevant studies This study explored the effect of substrate concentration on system performances, clarified the dynamic changes of membrane fouling under different substrate concentrations, and further revealed the response of microbial communities. The results showed that the stable removal efficiency of SMX exceeded 98.8 % due to the efficient interception of forward osmosis (FO) membrane. Compared with the 1.0 g/L NaAc system, the SMX degradation efficiency and maximum output voltage in the 2.0 g/L NaAc system were only increased by 3.9 % and 6.3 %, respectively. However, the initial water flux decreased by 30.1 % in the 7th cycle due to more serious FO membrane fouling. In addition, there were significant differences in the dynamic formation process of FO membrane fouling. Higher substrate concentration increased the relative abundance of Desulfobacterota and Geobacter. Functional prediction analysis showed that increasing substrate concentration promoted carbohydrate metabolism pathways and relative abundance of sulfur respiration functional groups, thereby improving COD and SMX removal rates. However, the biosynthesis of other secondary metabolites was significantly improved, resulting in increased contents of EPS and SMP, which aggravated membrane fouling. Overall, the system performed better when the substrate concentration was 1.0 g/L. This study would provide certain guidance for the performance optimization and membrane fouling mitigation of OsMFC, thereby promoting its practical application in antibiotic wastewater treatment.

Yating Guo, Guozhen Wang, Hao Zhang et al.

Biotechnology for Biofuels • 2020

Abstract Background Extracellular electron transfer (EET) is essential in improving the power generation performance of electrochemically active bacteria (EAB) in microbial fuel cells (MFCs). Currently, the EET mechanisms of dissimilatory metal-reducing (DMR) model bacteria Shewanella oneidensis and Geobacter sulfurreducens have been thoroughly studied. Klebsiella has also been proved to be an EAB capable of EET, but the EET mechanism has not been perfected. This study investigated the effects of biofilm transfer and electron mediators transfer on Klebsiella quasipneumoniae sp. 203 electricity generation performance in MFCs. Results Herein, we covered the anode of MFC with a layer of microfiltration membrane to block the effect of the biofilm mechanism, and then explore the EET of the electron mediator mechanism of K. quasipneumoniae sp. 203 and electricity generation performance. In the absence of short-range electron transfer, we found that K. quasipneumoniae sp. 203 can still produce a certain power generation performance, and coated-MFC reached 40.26 mW/m 2 at a current density of 770.9 mA/m 2, whereas the uncoated-MFC reached 90.69 mW/m 2 at a current density of 1224.49 mA/m 2 . The difference in the electricity generation performance between coated-MFC and uncoated-MFC was probably due to the microfiltration membrane covered in anode, which inhibited the growth of EAB on the anode. Therefore, we speculated that K. quasipneumoniae sp. 203 can also perform EET through the biofilm mechanism. The protein content, the integrity of biofilm and the biofilm activity all proved that the difference in the electricity generation performance between coated-MFC and uncoated-MFC was due to the extremely little biomass of the anode biofilm. To further verify the effect of electron mediators on electricity generation performance of MFCs, 10 µM 2,6-DTBBQ, 2,6-DTBHQ and DHNA were added to coated-MFC and uncoated-MFC. Combining the time–voltage curve and CV curve, we found that 2,6-DTBBQ and 2,6-DTBHQ had high electrocatalytic activity toward the redox reaction of K. quasipneumoniae sp. 203-inoculated MFCs. It was also speculated that K. quasipneumoniae sp. 203 produced 2,6-DTBHQ and 2,6-DTBBQ. Conclusions To the best of our knowledge, the three modes of EET did not exist separately. K. quasipneumoniae sp.203 will adopt the corresponding electron transfer mode or multiple ways to realize EET according to the living environment to improve electricity generation performance.

Shaoqin Liu

ECS Meeting Abstracts • 2025

Electrochemically active bacteria can transport their metabolically generated electrons to anodes, or accept electrons from cathodes to synthesize high-value chemicals and fuels, via a process known as extracellular electron transfer (EET). Harnessing of this microbial EET process has led to various microbial bioelectrochemical systems such as bioenergy through microbial fuel cells (MFCs). Despite great progress that has been made in terms of the efficiency and applicability of MFCs in recent years, many issues are waiting to be tackled for practical applications of MFCs. The most important challenges included the relatively low power density and poor energy conversion efficiency of MFCs, which mainly arise from low extracellular electron transfer (EET) efficiency between microorganisms and electrode, and the cost of electrode materials. Thus, how to improve the electron transfer rate at the bacteria/electrode interface is an extremely important issue in MFCs. Herein, we designed and fabricated several nanostructured anodes to increase physical contact between electrode and outer-membrane proteins or microbial nanowires and promote efficient EET efficiency between microorganisms and electrode, leading to a steep improvement in MFC performance. For example, our group fabricated a three-dimensional graphene aerogel electrode coated with platinum nanoparticles. Benefited from the continuous 3D macroporous structure with suitable pore size, both the surface and interior of the electrode were covered with a thin biofilm of S. oneidensis MR-1 after pre-inoculation. The graphene aerogel scaffold decorated with highly conductive platinum nanoparticles resulted in an outstanding maximum power density of 1460 mW/m 2 , 5.3 folds of carbon cloth. The MFCs equipped with the graphene/FeS 2 NPs not only benefits bacterial adhesion and enrichment of electrochemically active Geobacter species on the electrode surface but also promotes efficient extracellular electron transfer, thus giving rise to a fast start-up time of 2 days, an unprecedented power density of 3220 mW m -2 in the acetate-feeding and mixed bacteria-based MFCs and 310 mW m -2 with simultaneous removal of 1319 ± 28 mg L -1 chemical oxygen demand in effluents from a beer factory wastewater. The 3D hierarchical porous carbon foam anodes prepared by pyrolyzing nanoscale Fe-MIL-88b-NH 2 modified seitan composite deliver a maximum power density of 11.21 W m -3 and current density of 23.11 A m -3 , outperforming most previously reported 3D porous anodes. The characteristics of improved power generation and enhanced pollutant removal efficiency open door towards development of high-performance MFCs via rational anode design for practical application.

Divya Naradasu

Access Microbiology • 2022

Polymicrobial oral biofilms, which consist of fermentative-bacteria, are associated with periodontitis, gingivitis and cause systemic diseases 1 . Unlike aerobic-respiration, fermentation does not require electron acceptors like O2; and redox-cycling of biological electron-carriers, like NADH, drives the intracellular oxidation and reduction of organic-substrates 2 . Thus, the energy gain is potentially lower than that of respiratory metabolism; however, the high pathogenic activity in anaerobic conditions remained ambiguous 3 . Afew studies have shown that fermentative gut microbes are capable ofreducing external electron acceptors viaextracellular electron transfer (EET) 4-7 . EET, a phenomenon initially found in environmental-bacteria, where metabolically generated electrons are transferred to external electron-acceptors through an outer-membraneredoxprotein complex 8-9 . Thus, the pathogens colonization in the human microbiome may be supported by their EET capability and is important to explore such potentiality. Here, we electrochemically characterized oral-biofilm pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, to examine their EET ability with lactate/glucose. Both strains showed current production on an electrode surface, associated with consumption of substrate 10 . The addition of antibiotics that suppress the biosynthesis of membrane or protein showed a significant current decrease, demonstrating that current production reflects the cellular-activity. Further, transmission-electron-microscopy of 3,3‡-diaminobenzidine (DAB) stained cells revealed the presence of redox-enzymes on the cell-membrane suggesting a potential EET mechanism via membrane proteins9. These results could be a basis to reevaluate human oral pathogens from an electroactive point of view. The identified EET activity of the two strains can be utilized for an effective test for assessing the impact of antibacterial compounds on the pathogen cellular-activity on an electrode 11 .

Tahseena Naaz, Ankit Kumar, Anusha Vempaty et al.

Environmental Engineering Research • 2023

Over the last two decades, scientific communities have been more interested in turning organic waste materials into bioenergy. Microbial fuel cells (MFC) can degrade organic wastewater and produce electrical power. Many constraints have limited the development of MFC. Among them, the anode biofilm development is one of the significant constraints that need to be improved. This review delineates the role of various biological components in the development of electroactive biofilm. The current article focuses on the numerous electron exchange methods for microbiome-induced electron transfer activity, the different proteins, and secretory chemicals involved in electron transfer. This study also focuses on several proteomics and genomics methodologies that have been adopted and developed to improve the extra electron transfer mechanism in electroactive bacteria. Recent advances and publications on synthetic biology and genetic engineering in investigating the direct and indirect electron transport phenomena have also been highlighted. This review helps the reader to understand the recent development in the genetic manipulations of the biofilm, electrode material modifications, EET mechanisms, and operational strategies for improving anode performance. This review also discusses the challenges in present technology and the future direction for improving biofilm production at the anode.

Alberto Hernández-Eligio, Leticia Vega-Alvarado, Xinying Liu et al.

Frontiers in Microbiology • 2025

CsrA is a post-transcriptional regulator that controls biofilm formation, virulence, carbon metabolism, and motility, among other phenotypes in bacteria. CsrA has been extensively studied in γ-proteobacteria and firmicutes, However the cellular processes controlled for regulation in δ-proteobacteria remain unknown. In this work, we constructed and characterized the Δ csrA mutant strain in Geobacter sulfurreducens to determine the involvement of the CsrA protein in the regulation of biofilm and extracellular electron transfer. The Δ csrA mutant strain shows higher rates of insoluble Fe(III) reduction than the wild type using acetate as electron donor and the growth with fumarate and soluble (Fe(III)) was similar to wild type. Biofilm quantification and characterization by confocal laser scanning microscopy, showed that the Δ csrA mutant produces up to twice as much biofilm as the wild type strain and more than 95% viable cells. Transcriptome analysis by RNA-seq showed that in Δ csrA biofilms developed on an inert support, differentially expressed 244 genes (103 upregulated and 141 downregulated), including those related to extracellular electron transfer, exopolysaccharide synthesis, c-di-GMP synthesis and degradation. To validate the transcriptome data, RT-qPCR confirmed the differential expression of several selected genes in the Δ csrA strain. Also, current production in microbial fuel cells was performed and the Δ csrA strain produced 45–50% more current than the wild type. To identify the genes that changed expression in the Δ csrA strain in the graphite electrodes in an MFC, a transcriptome analysis was performed 181 genes changed their expression in the Δ csrA biofilms, of which 113 genes were differentially expressed only in MFC and 68 genes changed their expression as well as the transcriptome of biofilms grown on glass. In silico analysis of the 5′-UTR regions revealed that 76 genes that changed expression in the RNA-seq analysis have a consensus sequence for CsrA binding. To our knowledge this is the first report describing the involvement of CsrA in the regulation of extracellular electron transfer and biofilm in a member of the δ-proteobacteria.

O. O. Oluyide, J. K. Oloke, V. Adenigba et al.

Nigerian Journal of Biotechnology • 2025

The global energy crisis is caused by high energy demand and insufficient resources. Non-renewable energy sources are diminishing, while renewable energy sources are underutilized. An urgent search for alternative energy generation routes is necessary. A microbial fuel cell is a process that makes use of microorganisms like bacteria or fungi as biocatalysts that oxidize waste organic matter to release electrons which in turn are used to produce electricity. An MFC reactor is made of a cathode, an anode, and a substrate onto which microorganisms are fed so that electrons are released for bioelectricity generation .A two-chamber cathode was fabricated in this study. The chamber has a total volume of 120ml and a working volume of 100ml. The chamber was used to investigate the influence of substrate enrichment and type of electrode on electricity production by some selected bacteria (Pseudomonas Tawanensis (PT), Myroides Odoratimimus (MO), Sphingobacterium Mizutaii (SM). The substrate used is locust beans wastewater. The substrate was enriched with either sucrose or acetate. The electrodes include copper, aluminum, aluminum-zinc alloy, soft zinc, and zinc. To determine the most suitable enrichment sources (sucrose and acetate) a mixed culture of the three bacteria was inoculated in the substrate (locust bean wastewater) with a standard graphite electrode. Cellulose acetate was used as the membrane for the chamber in place of the cation exchange membrane. The setup was operated for 20 days. The effect of substrate enrichment and electrode use on bioelectricity and stability was later analyzed. The results from the mixed culture showed that the substrate enriched with sucrose generated a higher voltage (2.15x10-3 mA) when compared with an acetate-enriched substrate (this generated a voltage of 1.62x10-3 mA) with graphite as the electrode. Following this result, we selected sucrose as the enrichment source in the remaining experiment. Each bacterium used in this study generated electricity in the chamber containing sucrose-enriched substrate with each of the electrodes used. This implies that all the adopted electrodes are sufficient site for the formation of biofilm through which bioelectricity can be generated. However, the highest voltage (1.72mA) was recorded in the chamber containing Pseudomonas taiwanensis with zinc as the electrode in the chamber. We noted that in all the bacteria used in this study, bioeletricity generation was more stable and consistent with copper as the electrode of choice.

Sari Sekar Ningrum, Aidha Zulaika, Wike Handini et al.

Jurnal Penelitian Pendidikan IPA • 2023

Electricity consumption is increasing, causing fossil fuels to run out more quickly. Various efforts are needed to develop renewable energy, including generating electricity. One of the developments in renewable energy comes from biomass. There are various types of biomass developed, one of which is biomass of microorganisms which carry out metabolic activities by utilizing organic material to produce metabolites which include energy. Microbial fuel cell (MFC) is a technology that produces electrical energy with the help of microorganisms that degrade organic materials through catalytic reactions or bioelectrochemical mechanisms from microorganisms. In this research, bioelectricity produced from MFC was tested using Aspergillus Niger with sugarcane bagasse as a substrate. The voltage value obtained from observations carried out for 15 days obtained a voltage in the range of 1.3-4.2 mV

Abid Ali, M. I. Anis, S. S. Mohani et al.

Pakistan Journal of Engineering, Technology and Science • 2024

The exploration of sustainable and renewable energy sources parallels the computational modeling and simulation of biological systems, both driven by the increasing energy demands of modern society. One promising area of research is the utilization of microorganisms for electricity generation, leveraging their inherent metabolic processes. This study investigates two innovative approaches: Microbial Fuel Cells (MFCs) and Plant Microbial Fuel Cells (PMFCs). MFCs harness the electron transfer capabilities of certain bacteria to generate electricity directly from organic matter. This bio-electrochemical system offers a sustainable and environmentally friendly method of energy production. However, the performance of MFCs can be enhanced by incorporating plant-based systems, leading to the development of PMFCs. In this research, we introduce a novel PMFC design based on the Aloe vera plant, which demonstrates improved stability and increased bioelectricity generation compared to traditional PMFCs. We evaluate the impact of incorporating plants and compost on bioenergy production in PMFCs and present an automated testing framework for the electrical characterization of these systems. By harnessing the synergy between microorganisms and plant systems, this study aims to contribute to the ongoing efforts in developing clean and sustainable energy solutions. The proposed approaches not only address the depletion of fossil resources but also mitigate environmental degradation, aligning with the global sustainability goals.

Muhamad Maulana Azimatun Nur, Raden Herjun Desta K. H, Ryan Keane Mahardika Pratama et al.

International Journal of Marine Engineering Innovation and Research • 2024

⎯ This review investigates the role of microalgae in bioelectricity production through biophotovoltaic (BPV) systems, focusing on their dual benefits of generating renewable energy and treating wastewater while capturing CO 2 . The objective of this paper is to conduct a bibliometric analysis of publications from 2013 to 2024 to understand research trends, key contributors, and research hotspots in the field of microalgae-based BPV systems. Methods used include statistical analysis through VOSviewer to visualize the connections between articles and authors. The results show significant advancements in integrating of nanomaterials and microbial fuel cell technologies for bioelectricity generation, as well as ongoing challenges in scalability, voltage balance, and material optimization. This review provides insights into future research directions for improving BPV systems.

Shravan Kumar, N. Shenode, Yashavant Jeph et al.

International Journal for Research in Applied Science and Engineering Technology • 2024

Abstract: Microbial Fuel Cells (MFCs) have emerged as a compelling technological advancement that utilizes microbial metabolic processes to produce electricity from organic waste substrates. This review examines the latest advancements, prevailing challenges, and prospective developments of MFCs in relation to renewable energy generation and ecological sustainability. MFCs present a dual benefit by facilitating wastewater treatment while concurrently generating bioelectricity, thereby rendering them appealing for decentralized energy frameworks and waste management strategies. Recent progress in the fields of genetic engineering and synthetic biology has culminated in the development of optimized microbial strains and improved biofilm stability, which significantly enhances the efficiency of electron transfer. Innovations in electrode materials, including carbon nanotubes and graphene, have further augmented the performance metrics of these systems. Nevertheless, obstacles persist in augmenting power output, minimizing material costs, and scaling MFCs for larger industrial applications. This review also elucidates the environmental and economic implications of MFCs, particularly their capacity to mitigate carbon emissions and generate financial savings in the domain of wastewater treatment. Lastly, we delineate future research trajectories, concentrating on synthetic biology, hybrid renewable systems, and commercialization strategies that will catalyze the scalability and wider acceptance of MFC technology. The prospects for MFCs are indeed promising, providing innovative solutions to the pressing global challenges of energy production and waste management.

A. K. Lembon, P. Lestari, A. A. Ramadhani et al.

IOP Conference Series: Earth and Environmental Science • 2025

High reliance on petroleum and coal-based energy poses a significant challenge for environmental sustainability. To address this issue, it is crucial to explore renewable and sustainable energy alternatives. One promising solution is the use of microbial fuel cells (MFC), which are bio-electrochemical systems capable of generating electrical energy through conversion and catalyzation reactions by microorganisms under anaerobic conditions. MFCs can utilize acidic biomass substrates to produce bioelectricity, including waste from agricultural and domestic sectors. In Indonesia, cocoa and oranges are major agricultural commodities, but their production also leads to significant waste generation. Cocoa processing results in solid waste and cocoa fermentation wastewater, while high orange consumption leads to substantial peel waste. This study aimed to investigate the potential of using microbial fuel cells to produce energy from orange peel waste and cocoa fermentation wastewater. It is expected that the use of both wastes enhanced the production of electrical energy due to their high conductivity. The waste is converted into bioelectricity using MFCs with sustainable waste management technology. The dual chamber MFC system is connected by a salt bridge made of 0.1 M KCl and 12.5 g of agar powder. The electrode materials used Cu as the cathode (+) and Zn as the anode (-), cut into pieces measuring 9 x 4 cm. Solution testing consisted of voltage, current, temperature, pH, and organic acids. The solutions tested included 100% cocoa bean fermentation waste, 100% orange peel extract, cocoa bean fermentation wastewater, and various mixtures of orange peel extract and cocoa bean fermentation waste. The study results indicated that the most optimal MFC composition was achieved through the stability of the voltage and current values, resulting from the metabolism of a mixed substrate of cocoa bean fermentation waste and orange peel extract in equal proportions (50:50). Microbial metabolic activity through a fermentation process could break down complex compounds into simpler compounds, which then generating energy. The increase in voltage value is attributed to the lower pH solution, resulting in a larger electric current, particularly in waste mixtures with equal composition of ingredients.

Rojas-Flores Segundo, Cabanillas-Chirinos Luis, N. M. Otiniano et al.

Sustainability • 2025

Corn is one of the most widely produced cereals worldwide, generating large amounts of waste, represents an environmental and economic challenge. In regions such as Africa and rural areas of Peru, access to electricity is limited, affecting quality of life and economic development. This study proposes using microbial fuel cells (MFCs) to convert chicha de jora waste—a traditional fermented beverage made from corn—into electrical energy. Single-chamber MFCs with activated carbon (anode) and zinc (cathode) electrodes were used. A total of 100 ml of chicha de jora waste was added in each MFC, and three MFCs were used in total. The MFCs demonstrated the viability of chicha de jora waste as a substrate for bioelectricity generation. Key findings include a notable peak in voltage (0.833 ± 0.041 V) and current (2.794 ± 0.241 mA) on day 14, with a maximum power density of 5.651 ± 0.817 mW/cm2. The pH increased from 3.689 ± 0.001 to 5.407 ± 0.071, indicating microorganisms’ degradation of organic acids. Electrical conductivity rose from 43.647 ± 1.025 mS/cm to 186.474 ± 6.517 mS/cm, suggesting ion release due to microbial activity. Chemical oxygen demand (COD) decreased from 957.32 ± 5.18 mg/L to 251.62 ± 61.15 mg/L by day 18, showing efficient degradation of organic matter. Oxidation-reduction potential (ORP) increased, reaching a maximum of 115.891 ± 4.918 mV on day 14, indicating more oxidizing conditions due to electrogenic microbial activity. Metagenomic analysis revealed Bacteroidota (48.47%) and Proteobacteria (29.83%) as the predominant phyla. This research demonstrates the potential of chicha de jora waste for bioelectricity generation in MFCs, offering a sustainable method for waste management and renewable energy production. Implementing MFC technology can reduce environmental pollution caused by corn waste and provide alternative energy sources for regions with limited access to electricity.

Longxin Li, Xinyuan He, Huahua Li et al.

ACS Applied Bio Materials • 2024

As the core component of microbial fuel cells, the conductivity and biocompatibility of anode are hard to achieve simultaneously but significantly influence the power generation performance and the overall cost of microbial fuel cells. Stainless steel felt has a low price and high conductivity, making it a potential anode for the large-scale application of microbial fuel cells. However, its poor biocompatibility limits its application. This study provides a one-step binder-free modification method of a stainless steel felt anode with reduced graphene oxide to retain the high conductivity while greatly improving biocompatibility. The maximum power density achieved by reduced graphene oxide modified stainless steel felt was 951.89 mW/m2, 5.49 and 1.91 times higher than the unmodified stainless steel felt anode and reduced graphene oxide coated stainless steel felt by Nafion, respectively. The robust reduced graphene oxide modification markedly improved the biocompatibility by forming a uniform biofilm and utilizing the high conductivity of reduced graphene oxide to enhance the charge transfer rate. It led to 92.7 and 37.9% decreases in charge transfer resistance of reduced graphene oxide modified stainless steel felt compared to the unmodified one and the anode modified with reduced graphene oxide by Nafion, respectively. The excellent performance and green synthesis method of the anode validated its potential as a high-performance anode material for scaled-up microbial fuel cell applications.

Priya Dharshini Palanivel, Samsudeen Naina Mohamed, G. Mohanakrishna et al.

Journal of Chemical Technology & Biotechnology • 2024

Microbial fuel cells (MFCs) are sustainable energy technologies that could resolve pollution challenges brought by various activities. It can meet energy demand by producing bioelectricity through catabolizing organic matter. Over the past two decades, research on many microbes have been used in MFCs, which intrigued researchers to explore the underlying electron transfer mechanism between microbe and anode. Electron transfer between electrode and microorganism occurs via different pathways: direct, indirect electron transfer and interspecies electron transfer. Shewanella and Geobacter are well‐known for microbe–electrode and microbe–microbe electron transfer. This review provides an overview of the significant varieties of microbes utilized in MFCs for simultaneous bioelectricity generation and wastewater treatment. Mechanisms of different modes of electron transfer involved during the oxidation of organic wastes in the anode section of MFCs are highlighted. Furthermore, this review also details some of the techniques to promote extracellular electron transfer efficiency which is important for the enhanced performance of MFC in terms of power, current generation and wastewater remediation. A perspective of challenges to be addressed for the effective functioning of these technologies, opportunities for MFC systems to be scaled up and associated techno‐economic analysis are discussed. © 2024 Society of Chemical Industry (SCI).

Rongdi An, Jiunian Guan, Gaoxiang Li et al.

Carbon Research • 2024

The electrode played an essential role in the operation of CW-MFC system due to its synergistic effect, and the development of electrode strategy has promoted the application of CW-MFC since 2012. In this paper, according to the material and the quantity, the electrode types in CW-MFC were distinctly divided into unified model, composited model, modified model, and multi-electrodes model combined with non-conductive or conductive particle. Different electrode strategies were provided to improve the performance of CW-MFC towards electricity generation, removal of pollutants, and control of greenhouse gas emission, and the coordination mechanism was further reviewed. Furthermore, the development process of the electrode strategy was summarized, and the low-cost, sustainable, and innovated electrode materials were emphatically recommended. For the scale-up application, multi-electrode model was systematically reviewed based on the optimizing of the material, shape, spacing distance, and connection type of electrode. This review may provide guidance to maximize the advantages of CW-MFC applications. Graphical Abstract

Arjan Dekker, A. ter Heijne, M. Saakes et al.

Environmental Science & Technology • 2009

Scaling up microbial fuel cells (MFCs) is inevitable when power outputs have to be obtained that can power electrical devices other than small sensors. This research has used a bipolar plate MFC stack of four cells with a total working volume of 20 L and a total membrane surface area of 2 m(2). The cathode limited MFC performance due to oxygen reduction rate and cell reversal. Furthermore, residence time distribution curves showed that bending membranes resulted in flow paths through which the catholyte could flow from inlet to outlet, while leaving the reactants unconverted. The cathode was improved by decreasing the pH, purging pure oxygen, and increasing the flow rate, which resulted in a 13-fold power density increase to 144 W m(-3) and a volumetric resistivity of only 1.2 mOmega m(3) per cell. Both results are major achievements compared to results currently published for laboratory and scaled-up MFCs. When designing a scaled-up MFC, it is important to ensure optimal contact between electrodes and substrate and to minimize the distances between electrodes.

Karnapa Ajit, J. John, H. Krishnan

Environmental Science and Pollution Research • 2023

The cathode catalyst in microbial fuel cell (MFC) plays a crucial role in scaling up. Activity of biomass-derived activated carbon catalysts with appropriate precursor selection in a natural clay membrane-based MFC of 250 mL was studied. The performance of scaled up MFC of 1.5 L capacity with two different configurations was monitored. Rod-shaped particles with slit-type pores and amorphous graphitic nature with a surface area of 800.37 m2/g was synthesized. The intrinsic doping of heteroatoms N and P in the catalyst was with atomic weight percentages of 4.5 and 3.5, respectively and the deconvolution of N1 spectra confirmed pyridinic N and graphitic N content of 17.3% and 34.1% validating its suitability as a cathode catalyst. Electrochemical characterization of the catalyst coated SS mesh electrode confirmed that a loading of 5 mg/cm2 rendered higher catalytic activity compared to bare SS mesh. The maximum power density in catalyst modified cell was 0.91 W/m3 compared to 0.02 W/m3 as obtained in a plain stainless steel electrode cell at a COD removal efficiency of 93.3%. Series, parallel, and parallel-series combinations of 6 cells showed a maximum voltage of 4.15 V when connected in series and a maximum power density of 1.54 W/m3 when connected in parallel. System with multielectrode assembly achieved better power and current density (0.84 W/m3 and 1.97 A/m3) than the mixed parallel series circuitry (0.7 W/m3 and 0.57 A/m3). These performance results confirm that the catalyst is effective in both stacked and hydraulically connected system.

Pau Rodenas Motos, Gonzalo Molina, A. ter Heijne et al.

Journal of Chemical Technology & Biotechnology • 2017

Abstract Background Bioelectrochemical systems (BESs) enable recovery of electrical energy through oxidation of a wide range of substrates at an anode and simultaneous recovery of metals at a cathode. Scale‐up of BESs from the laboratory to pilot scale is a challenging step in the development of the process, and there are only a few successful experiences to build on. This paper presents a prototype BES for the recovery of copper. Results The cell design presented here had removable electrodes, similar to those in electroplating baths. The anode and cathode in this design could be replaced independently. The prototype bioelectrochemical cell consisted of an 835 cm2 bioanode fed with acetate, and a 700 cm2 cathode fed with copper. A current density of 1.2 A/−2 was achieved with 48 mW m−2 of power production. The contribution of each component (anode, electrolytes, cathode and membrane) was evaluated through the analysis of the internal resistance distribution. This revealed that major losses occurred at the anode, and that the design with removable electrodes results in higher internal resistance compared with other systems. To further assess the practical applicability of BES for copper recovery, an economic evaluation was performed. Conclusion Analysis shows that the internal resistance of several lab‐scale BESs is already sufficiently low to make the system economic, while the internal resistance for scaled‐up systems still needs to be improved considerably to become economically applicable.© 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Fei Zhang, Kristen S. Brastad, Zhen He

Environmental Science & Technology • 2011

A novel osmotic microbial fuel cell (OsMFC) was developed by using a forward osmosis (FO) membrane as a separator. The performance of the OsMFC was examined with either NaCl solution or artificial seawater as a catholyte (draw solution). A conventional MFC with a cation exchange membrane was also operated in parallel for comparison. It was found that the OsMFC produced more electricity than the MFC in both batch operation (NaCl solution) and continuous operation (seawater), likely due to better proton transport with water flux through the FO membrane. Water flux from the anode into the cathode was clearly observed with the OsMFC but not in the MFC. The solute concentration of the catholyte affected both electricity generation and water flux. These results provide a proof of concept that an OsMFC can simultaneously accomplish wastewater treatment, water extraction (from the wastewater), and electricity generation. The potential applications of the OsMFC are proposed for either water reuse (linking to reverse osmosis for reconcentration of draw solution) or seawater desalination (connecting with microbial desalination cells for further wastewater treatment and desalination).

A. Heijne, Fei Liu, R. D. Weijden et al.

Environmental Science & Technology • 2010

A metallurgical microbial fuel cell (MFC) is an attractive alternative for recovery of copper from copper containing waste streams, as the metal is recovered in its metallic form at the cathode, while the energy for metal reduction can be obtained from oxidation of organic materials at the anode with possible additional production of electricity. We studied the recovery of copper in an MFC using a bipolar membrane as a pH separator. Under anaerobic conditions, the maximum power density was 0.43 W/m(2) at a current density of 1.7 A/m(2). In the presence of oxygen, MFC performance improved considerably to a maximum power density of 0.80 W/m(2) at a current density of 3.2 A/m(2). Pure copper crystals were formed on the cathode, and no CuO or Cu(2)O was detected. Removal efficiencies of >99.88% were obtained. The cathodic recovery of copper compared to the produced electricity was 84% (anaerobic) and 43% (aerobic). The metallurgy MFC with the Cu(2+) reducing cathode further enlarges the application range of MFCs.

A. Rahmani, Nahid Navidjouy, M. Rahimnejad et al.

Environmental Technology • 2020

ABSTRACT Microbial fuel cells (MFCS) is a promising and expanding technology able to eliminate various pollutants of wastewater while converting its chemical energy into power energy using biocatalysts. The potential application of double-chamber microbial fuel cell (DC-MFC) for chemical oxygen demand (COD) removal and generated power from wastewater in the different conditions is investigated. DC-MFC is operated with anaerobic sludge as an active biocatalyst in an anode section, an aerobic cathode section and a Nafion117 membrane as a separator. The performance of the bioreactor is determined with different concentrations of chemical oxygen demand (COD) loadings in the MFC process, in terms of COD removal, power generation and columbic efficiencies. The results illustrated that COD removal efficiency increased at the high concentrations of organic matter. So that at COD concentration of 2000.0 mg/L the highest COD removal efficiency (84%) was obtained. But with increasing substrate initial concentration to 10000.0 mg/L the efficiency decreased to 79%. The important outputs of the system like the highest voltage, maximum generated power, current density, and energy efficiency with the 100,000 mg/L COD are 447 mV, 50.7 mW/m2, 570.0 mA/m2, and 18.6%, respectively. The optical density levels increased due to bacterial growth while pH severely decreased in the anode chamber when using high-concentration substrates in the MFC. GRAPHICAL ABSTRACT

I. Gajda, A. Stinchcombe, Irene Merino-Jimenez et al.

Frontiers in Energy Research • 2018

One of the challenges in Microbial Fuel Cell (MFC) technology is the improvement of the power output and the lowering of the cost required to scale up the system to reach usable energy levels for real life applications. This can be achieved by stacking multiple MFC units in modules and using cost effective ceramic as a membrane/chassis for the reactor architecture. The main aim of this work is to increase the power output efficiency of the ceramic based MFCs by compacting the design and exploring the ceramic support as the building block for small scale modular multi-unit systems. The comparison of the power output showed that the small reactors outperform the large MFCs by improving the power density reaching up to 20.4 W/m3 (mean value) and 25.7 W/m3 (maximum). This can be related to the increased surface-area-to-volume ratio of the ceramic membrane and a decreased electrode distance. The power performance was also influenced by the type and thickness of the ceramic separator as well as the total surface area of the anode electrode. The study showed that the larger anode electrode area gives an increased power output. The miniaturized design implemented in 560-units MFC stack showed an output up to 245 mW of power and increased power density. Such strategy would allow to utilize the energy locked in urine more efficiently, making MFCs more applicable in industrial and municipal wastewater treatment facilities, and scale-up-ready for real world implementation.

Dan Sun, Bin Xie, Jiahao Li et al.

SSRN Electronic Journal • 2022

In order to address the need for long-term, in-situ and inexpensive monitoring of dissolved oxygen (DO), a chitin-carrying microbial fuel cell (MFC) based DO sensor was developed using sediment anolyte, which had an extremely low cost of US$12.17 and comparable performance to certain commercial sensors. The MFC based DO sensor had a long lifetime of over half a year with chitin as the fuel, attributed to the syntrophic interactions between fermentative and exoelectrogenic microbes that were well developed for chitin degradation in anaerobic condition with sediment filling in the anode chamber. The use of sediment anolyte introduced hindered diffusion in the porous media, enabling the use of glass fiber as the separator to replace the ion exchange membrane and thus resulting in a much lower cost. Field tests of this MFC based DO sensor were conducted in fresh and saline waters respectively. Excellent performance was achieved with average deviations of <4.5% to three commercial methods of fiber optic sensor (HQ40d, HACH company, USA), Clark type sensor (Pro20i, YSI company, USA) and iodometry. This low-cost MFC sensor also showed a high reliability, with the same response of current generation to different DO levels in random 17-times tests, indicating its great market potentials for in-situ DO monitoring.

M. J. González-Pabón, F. Figueredo, D. Martínez-Casillas et al.

PLOS ONE • 2019

Microbial fuel cells (MFCs) can evolve in a viable technology if environmentally sound materials are developed and became available at low cost for these devices. This is especially important not only for the designing of large wastewater treatment systems, but also for the fabrication of low-cost, single-use devices. In this work we synthesized membranes by a simple procedure involving easily-biodegradable and economic materials such as poly (vinyl alcohol) (PVA), chitosan (CS) and the composite PVA:CS. Membranes were chemical and physically characterized and compared to Nafion®. Performance was studied using the membrane as separator in a typical H-Type MFCs showing that PVA:CS membrane outperform Nafion® 4 times (power production) while being 75 times more economic. We found that performance in MFC depends over interactions among several membrane characteristics such as oxygen permeability and ion conductivity. Moreover, we design a paper-based micro-scale MFC, which was used as a toxicity assay using 16 μL samples containing formaldehyde as a model toxicant. The PVA:CS membrane presented here can offer low environmental impact and become a very interesting option for point of need single-use analytical devices, especially in low-income countries where burning is used as disposal method, and toxic fluoride fumes (from Nafion®) can be released to the environment.

S. Chauhan, Amit Kumar, Soumya Pandit et al.

Membranes • 2023

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.

Aryama Raychaudhuri, R. Sahoo, M. Behera

Water Science and Technology • 2021

Ceramic separators have recently been investigated as low-cost, robust, and sustainable separators for application in microbial fuel cells (MFC). In the present study, an attempt was made to develop a low-cost MFC employing a clayware ceramic separator modified with silica. The properties of separators with varying silica content (10%-40% w/w) were evaluated in terms of oxygen and proton diffusion. The membrane containing 30% silica exhibited improved performance compared to the unmodified membrane. Two identical MFCs, fabricated using ceramic separators with 30% silica content (MFCS-30) and without silica (MFCC), were operated at hydraulic retention time of 12 h with real rice mill wastewater with a chemical oxygen demand (COD) of 3,200 ± 50 mg/L. The maximum volumetric power density of 791.72 mW/m3 and coulombic efficiency of 35.77% was obtained in MFCS-30, which was 60.4% and 48.5%, respectively, higher than that of MFCC. The maximum COD and phenol removal efficiency of 76.2% and 58.2%, respectively, were obtained in MFCS-30. MFC fabricated with modified ceramic separator demonstrated higher power generation and pollutant removal. The presence of hygroscopic silica in the ceramic separator improved its performance in terms of hydration properties and proton transport.

Thirutamil Sachin A, Prajin Raja J, Ranjith S et al.

international journal of engineering technology and management sciences • 2025

Microbial Fuel Cells (MFCs) represent an innovative bioelectrochemical technology thatharnesses the metabolic activities of electroactive bacteria, particularly Shewanella oneidensisandGeobacter sulfurreducens, to generate electricity. These bacteria transfer electrons to an anodewhile breaking down organic matter, enabling sustainable energy production. This paper exploresthe principles behind MFCs, the electron transfer mechanisms of ShewanellaandGeobacter, andtheir practical applications. Experimental results demonstrate their potential for renewable energygeneration in wastewater treatment, agricultural applications, and remote sensing. The study alsodiscusses the challenges of scaling up MFCs, their environmental impact, and future prospects.

Yidan Hu, Yinghui Wang, Xi Han et al.

Frontiers in Bioengineering and Biotechnology • 2021

Geobacter and Shewanella spp. were discovered in late 1980s as dissimilatory metal-reducing microorganisms that can transfer electrons from cytoplasmic respiratory oxidation reactions to external metal-containing minerals. In addition to mineral-based electron acceptors, Geobacter and Shewanella spp. also can transfer electrons to electrodes. The microorganisms that have abilities to transfer electrons to electrodes are known as exoelectrogens. Because of their remarkable abilities of electron transfer, Geobacter and Shewanella spp. have been the two most well studied groups of exoelectrogens. They are widely used in bioelectrochemical systems (BESs) for various biotechnological applications, such as bioelectricity generation via microbial fuel cells. These applications mostly associate with Geobacter and Shewanella biofilms grown on the surfaces of electrodes. Geobacter and Shewanella biofilms are electrically conductive, which is conferred by matrix-associated electroactive components such as c -type cytochromes and electrically conductive nanowires. The thickness and electroactivity of Geobacter and Shewanella biofilms have a significant impact on electron transfer efficiency in BESs. In this review, we first briefly discuss the roles of planktonic and biofilm-forming Geobacter and Shewanella cells in BESs, and then review biofilm biology with the focus on biofilm development, biofilm matrix, heterogeneity in biofilm and signaling regulatory systems mediating formation of Geobacter and Shewanella biofilms. Finally, we discuss strategies of Geobacter and Shewanella biofilm engineering for improving electron transfer efficiency to obtain enhanced BES performance.

Tomás M. Fernandes, Leonor Morgado, David L. Turner et al.

Antioxidants • 2021

Electrogenic microorganisms possess unique redox biological features, being capable of transferring electrons to the cell exterior and converting highly toxic compounds into nonhazardous forms. These microorganisms have led to the development of Microbial Electrochemical Technologies (METs), which include applications in the fields of bioremediation and bioenergy production. The optimization of these technologies involves efforts from several different disciplines, ranging from microbiology to materials science. Geobacter bacteria have served as a model for understanding the mechanisms underlying the phenomenon of extracellular electron transfer, which is highly dependent on a multitude of multiheme cytochromes (MCs). MCs are, therefore, logical targets for rational protein engineering to improve the extracellular electron transfer rates of these bacteria. However, the presence of several heme groups complicates the detailed redox characterization of MCs. In this Review, the main characteristics of electroactive Geobacter bacteria, their potential to develop microbial electrochemical technologies and the main features of MCs are initially highlighted. This is followed by a detailed description of the current methodologies that assist the characterization of the functional redox networks in MCs. Finally, it is discussed how this information can be explored to design optimal Geobacter-mutated strains with improved capabilities in METs.