Hong Guo, Huiming Yin, Xiuling Yan et al.

Scientific Reports • 2016

Abstract Binary PtBi decorated nanoporous gold (NPG-PtBi) electrocatalyst is specially designed and prepared for the anode in direct glucose fuel cells (DGFCs). By using electroless and electrochemical plating methods, a dense Pt layer and scattered Bi particles are sequentially coated on NPG. A simple DGFC with NPG-PtBi as anode and commercial Pt/C as cathode is constructed and operated to study the effect of operating temperatures and concentrations of glucose and NaOH. With an anode noble metal loading of only 0.45 mg cm −2 (Au 0.3 mg and Pt 0.15 mg), an open circuit voltage (OCV) of 0.9 V is obtained with a maximum power density of 8 mW cm −2 . Furthermore, the maximum gravimetric power density of NPG-PtBi is 18 mW mg −1 , about 4.5 times higher than that of commercial Pt/C.

Santiago Erazo, Lina María Agudelo-Escobar

Processes • 2023

Microbial fuel cells (MFCs) are an alternative to conventional wastewater treatments that allow for the removal of organic matter and cogeneration of electrical energy, taking advantage of the oxidation–reduction metabolism of organic compounds conducted by microorganisms. In this study, the electrogenic potential and the capacity for the reduction of the organic matter of native microbial communities in wastewater from the wet processing of coffee were evaluated using open-cathode MFCs. To determine the electrogenic potential, a factorial experimental design was proposed in which the origin of the residual water and the source of the inoculum were evaluated as factors. The MFCs operated for 21 days in both open-circuit and closed-circuit operation modes. Voltage records, current determinations, and chemical oxygen demand (COD) analyses were used to establish the power reached in the electrochemical system and the degree of the decontamination of the wastewater. During the MFC operation, voltages from 200–400 mV and power and current densities from 300–900 mW·m−2 and 10–22 mA·m−2, respectively, were reached. The inoculum used, with a statistical significance of α < 0.05, influenced the electrogenic performance of the microbial fuel cell. The previous process of adaptation to the operational conditions of the MFCs of the native microbial community positively influenced the current generation in the system. The degradation rates reached 500–600 mg·L−1·day−1, indicating the metabolic capacity of the microbial community in the MFCs to achieve the decontamination of wastewater from the coffee agroindustry. It was shown the implementation of bioelectrochemical systems constituted a viable option for the treatment of agricultural waste in Colombia. In addition, it was observed the capacity to cogenerate electrical energy from the biotransformation of the polluting organic matter in the effluents of the coffee industry.

Paweł Piotr Włodarczyk, Barbara Janina Włodarczyk

Civil and Environmental Engineering Reports • 2024

Wastewater has high potential as an energy source. Therefore, it is important to recover even the smallest part of this energy, e.g., in microbial fuel cells (MFCs). The obtained electricity production depends on the process rate of the electrodes. In MFC, the microorganisms are the catalyst of anode, and the cathode is usually made of carbon material. To increase the MFC efficiency it is necessary to search the new cathode materials. In this work, the electricity production from yeast wastewater in membrane-less microbial fuel cells with a carbon felt, Ni-Co, Cu-B, and Cu-Ag cathodes has been analyzed. In the first place, the measurements of the stationary potential of the electrodes (with Cu-Ag catalyst obtained by the electrochemical deposition technique) were performed. Next, the analysis of the electric energy production during the operation of the membrane-less microbial fuel cell (ML-MFC). The highest parameters were obtained for the Ni-Co and Cu-Ag catalysts. The cell voltage of 607 mV for Ni-Co and 605 mV for Cu-Ag was obtained. Additionally, the power of 4.29 mW for both cathodes - Ni-Co and Cu-Ag was obtained. Moreover, Ni-Co and Cu-Ag allow the shortest time of COD reduction. Based on the test results (with selected MFC design, wastewater, temperature, etc.), it can be concluded that of all the analyzed electrodes, Cu-Ag and Ni-Co electrodes have the best parameters for use as cathodes in ML-MFC. However, based on the results of this study, it can be concluded that all the tested electrodes can be used as cathode material in MFC.

Raudzah Mohd Zahir, Huzairy Hassan, Ahmad Anas Nagoor Gunny

IOP Conference Series: Earth and Environmental Science • 2021

Abstract Microbial fuel cell (MFC) has emerged as one of the potential technologies for sustainable bioelectrical energy recovery and reduction of recalcitrant wastes. The MFC performance is greatly influenced by the anode materials which serve as the support for exoelectrogenic bacteria attachment. In this study, oil palm empty fruit bunch (OPEFB) is proposed as an alternative anode material prepared via a direct carbonization process using tube furnace owing to its good conductivity property. The carbonization process was conducted under nitrogen gas flow at 900°C with a constant heating rate of 5°C/min. The anode was prepared by mixing the carbonized OPEFB with polytetrafluoroethylene (PTFE) binder. When used in MFC, the OPEFB-anode generated a maximum current density of 97.30 mA/m 2 , which is comparatively higher than that of the conventional carbon cloth anode (76.24 mA/m 2 ). Our MFC system had also resulted considerable chemical oxygen demand (COD) and 2-chlorophenol reductions of 77% and 75%, respectively. This study could support future research on freely-available OPEFB materials for high performance MFC anode.

Jiating Wang, Xinmin Liu

The Canadian Journal of Chemical Engineering • 2019

A single chambered air cathode anaerobic fluidized bed microbial fuel cell (AFB‐MFC) was simultaneously used to dispose of the real boiler cleaning wastewater (BCW) containing a high concentration of citric acid and to generate renewable energy. At the temperature of 40 °C and flow rate of 5.22 mL/s, the removal efficiency and power density were improved in AFB‐MFC with the abiotic cathode of the Pt/C modified carbon cloth. With the real boiler cleaning wastewater fed as substrate, the maximal removal efficiency of chemical oxygen demand (COD) in AFB‐MFC was up to 90 %, which was higher than the corresponding value of 84 % obtained in the anaerobic biological fluidized bed reactor (ABFBR). The maximum voltage and the maximum power density were 424.6 mV and 18.68 mW/m 2 , respectively, when the external resistance was 5000 Ω. Furthermore, the Haldane inhibition model was well fitted with experiment data (R 2 = 0.97–0.98) in AFB‐MFC/ABFBR. The inhibition of citric acid degradation in ABFBR was stronger than that of AFB‐MFC. The bioelectrochemical system of AFB‐MFC not only improved the charge transfer and but also accelerated the reaction rate of citric acid. The reduction of the ferric ion and oxidation of ferrous ion in AFB‐MFC played important roles in the degradation reaction of critic acid.

Yinghui Mo, Peng Liang, Xia Huang et al.

Journal of Chemical Technology & Biotechnology • 2009

Abstract BACKGROUD: A decreased power density could be observed in a single‐chamber microbial fuel cell (MFC) with a cation exchange membrane (CEM), as a result of pH‐associated problem and a precipitated salt‐associated problem, due to the transport of cations other than protons through the membrane to the cathode. To inhibit cation transport and enhance the stability of power generation, an anion exchange membranes (AEM) was applied in a single‐chamber MFC. RESULTS: After 70 days' operation, the power density dropped 29% in the MFC with an AEM (AMFC), smaller than 48% in the MFC with a cation exchange membrane (CMFC). The reason for this difference lay in internal resistance development. Membrane resistance in the AMFC remained the same but that in the CMFC was increased by 67 Ω, and the cathode resistance increase in the AMFC was 54 Ω, while that in the CMFC was 123 Ω. The precipitated cations on the cathode catalyst surface in the CMFC, which accounted for the resistance increase, were up to 84 times larger than that in the AMFC. CONCLUSION: Because of its capacity for inhibiting cations, the AMFC possessed more stable membrane and cathode resistances; thus an enhanced power generation was obtained. Copyright © 2009 Society of Chemical Industry

Abdul Sirajudeen, M. Annuar

Journal of the Serbian Chemical Society • 2020

Practical application of microbial fuel cell (MFC), a sustainable energy device, is hampered by low power output. Its principal components i.e., anode, cathode and proton exchange membrane (PEM) are the focus of enhancement and modification in terms of their functional design and material. The anode surface conduciveness as electron sink is crucial to the power output magnitude, while the cathode electrode should be reactive for efficient oxygen reduction at tri-phase junction. PEM is solely responsible for unidirectional proton flow concomitantly completing the electrical circuit. Polymeric nanocomposites as electrode modifier improved significantly anode/cathode/PEM functions thus overall MFC performance. The review highlights the progress made in polymer-based modifications to anode, cathode and PEM material and function between year 2014 to 2019. The effects to biocompatibility, surface area, internal resistance, electrochemical activities, environmental sustainability and overall MFC performance are discussed.

Haiying Guo, Shuixiang Xie, Hao Deng et al.

Environmental Progress & Sustainable Energy • 2020

Abstract Oily sludge is a major problem affecting the quality of oil fields and surrounding environment. Microbial fuel cell (MFC) technology is a simple way to treat the oily sludge while generating electricity. To investigate the electrochemical properties of such MFC and the characteristics of bacteria attached to anode, a single‐chamber MFC supplemented with oily sludge was constructed. The electrochemical results showed that the oily sludge is suitable for MFC operation, with a maximum output voltage of 299.13 mV and a maximum output power ( P max ) of 2,255.52 mW/m 2 . The cyclic voltammetry curve of MFC anode displayed an “S” shape, whereas the main peaks were at 0 and 0.1 V, indicating a strong redox reaction on the anode carbon felt. The limiting current was 0.08 A/cm 2 . The scanning electron microscopy (SEM) of the bacteria on the anode surface showed that most of bacteria displayed a rod‐shaped morphology, whereas the biological metagenomic classification sequencing showed that the predominant electricity‐producing bacteria were Proteiniciclasticum (15.83%) from Firmicutes and Pseudomonas (11.9%) from Gammaproteobacteria. MFC can effectively utilize the oily sludge to generate electricity at the same time, which provides a theoretical basis for the research of MFCs' pollution control and electricity production.

Fikret Kargi, Serkan Eker

Journal of Chemical Technology & Biotechnology • 2007

Abstract Background: A microbial fuel cell (MFC) consisting of anaerobic and aerobic chambers separated by a salt‐agar slab was used for electricity generation with simultaneous wastewater treatment where copper and gold covered copper wires were used as anode and cathode, respectively. The electrons produced from degradation of carbohydrates in anaerobic chamber traveled through the copper wire generating electricity and the protons were transferred from cathode to anode through the salt‐agar slab. Variation of the current intensity (mA) and the electrical power (mW) were investigated as function of the surface area of anode and also the chemical oxygen demand (COD) content of the synthetic wastewater. Results: The generated power density (mW m −2 ) increased with increasing surface area of the electrodes and also with the COD content of the wastewater. Both the current intensity (mA) and the power generated (mW) increased with time and reached maximum levels at the end of batch operation. More than 80% COD removal was achieved in the aerobic chamber with an electricity generation of 2.9 mW m −2 when the initial COD content was 6000 mg l −1 . Conclusion: The MFC configuration and the use of Cu and Cu‐Au electrodes instead of graphite were proven to be effective for electricity generation with simultaneous wastewater treatment. The electrical current (0.24 mA) and power (2.9 mW m −2 ) obtained in our microbial fuel cell are comparable with the literature studies utilizing salt bridge. The microbial fuel cell developed in this study can be improved further to yield higher power generations by modifications. Copyright © 2007 Society of Chemical Industry

Sumaya Sarmin, Asmida Binti Ideris, Baranitharan Ethiraj et al.

IOP Conference Series: Materials Science and Engineering • 2019

Abstract The petrochemical wastewater (PCW) from acrylic acid plant possesses very high chemical oxygen demand (COD) due to presence of acrylic acid along with other organic acids. The treatment of PCW by conventional methods is energy intensive. The treatment of PCW with concurrent power generation by employing microbial fuel cell (MFC) could be a potential alternative solving the problem of energy and environment. The goal of the present paper is to evaluate the viability of treating the wastewater using anaerobic sludge as biocatalyst in a dual- chamber MFC for simultaneous power generation and wastewater treatment. This study demonstrates that anaerobic sludge (AS) could work as a biocatalyst producing maximum power density of 0.75 W/m3at current density and open circuit voltage (OCV) of 412 mA/m2 and 0.45 V respectively using PCW with an initial COD of 45,000 mg/L. The COD removal efficiency and the columbic efficiency (CE) were found 40% and 13.11%, respectively. The mechanism of electron transfer in the anode was analyzed by cyclic voltammetry (CV) and the resistances across the electrode/biofilm/solution interface were investigated by employing impedance spectroscopy (EIS). The current work proves the capability of the MFC for the treatment of acrylic acid plant PCW using anaerobic sludge (AS) as biocatalyst.

Nancy González-Gamboa, Xochitl Domínguez-Benetton, Daniella Pacheco-Catalán et al.

Sustainability • 2018

Benthic microbial fuel cells (BMFC) are devices that remove organic matter (OM) and generate energy from sediments rich in organic nutrients. They are composed of electrodes with adequate different distances and floating air cathodes in an aqueous medium with saturated oxygen. In this study we proposed to design, build, analyze and evaluate a set of BMFCs with floating air cathodes to test the optimal distance between the electrodes, using sediment from the Bay of Campeche as a substrate. For the analysis of OM removal, COD tests, volatile solids (VS), E4/E6 study and FTIR analysis were performed. Power generation was evaluated through polarization curves, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). We achieved a current density and power density at 10 cm depth of 929.7 ± 9.5 mA/m2 and 109.6 ± 7.5 mW/m2 respectively, with 54% removal of OM from the sediment, obtaining formation of aliphatic structures. BMFCs are proposed as adequate systems for bioremediation and power generation. The system at 10 cm depth and 100 cm distance between sediment and the floating air cathode had a good performance and therefore the potential for possible scaling.

Hong‐Liang Sun

Journal of Chemical Technology & Biotechnology • 2012

Abstract BACKGROUND: To make the treatment of seafood wastewater more economical and sustainable, this study aims to examine electricity generation and simultaneous degradation of organic substances from seafood wastewater in single‐chamber (SC) and dual‐chamber (DC) microbial fuel cell (MFC). RESULTS: By supplying the MFCs with seafood wastewater, the maximum power density produced from the SCMFC was higher than that produced from the DCMFC, which is a consequence of the difference in internal resistance of the two systems. The electrochemical reduction of oxygen catalyzed by C/CoTMPP was comparable with that promoted by commercial C/Pt catalyst. The SCMFC achieved higher organic degradation than the DCMFC, which corresponded to less accumulation of volatile fatty acids being decomposed aerobically promoted by the oxygen diffused from the cathode in the absence of the membrane. Owing to electron losses via aerobic decomposition rather than the electricity‐producing pathway, the higher removal efficiency was in line with the low coulombic efficiency. In addition, the DCMFC having a membrane had a more severe pH polarization than the SCMFC without the membrane. CONCLUSIONS: This study provides a conceptual demonstration of sustainable utilization of seafood wastewater while carrying out biological decomposition in an MFC system in an economical manner. Copyright © 2012 Society of Chemical Industry

Tri Mulyono, Diah Meirendi Hutamia, Imam Rofi’i et al.

Jurnal ILMU DASAR • 2024

The growth in population is not adequately matched by the corresponding increase in energy demand. The imperative for prioritizing the exploration of alternative energy sources that possess attributes of safety, affordability, and ample access to raw materials cannot be overstated. An energy source with significant potential is a microbial fuel cell (MFC)-based energy source. This study aims to investigate the utilization of cow rumen as a substrate and source of nutrition in the bioenergy system of microbial fuel cells (MFCs). The present study aims to investigate the impact of substrate concentration and bacterial incubation duration derived from bovine rumen bacteria on the attainment of optimal power density. The research employed a Dual Chamber Microbial Fuel Cell (MFC) device using a Proton Exchange Membrane (PEM) constructed from ceramic materials. Daily observations were conducted over a period of 30 days. The performance of MFC was assessed utilizing the polarization technique. The findings indicated that altering the proportion of bovine rumen bacterial substrates and the duration of bacterial incubation had an impact on the power density seen in the Microbial Fuel Cell (MFC) system. The optimal conditions were attained when the substrate concentration reached 3640 ppm and after 7 days, resulting in a maximum power density of 864 mW/m2.

Asimina Tremouli, Pavlos K. Pandis, Theofilos Kamperidis et al.

Water • 2023

The effect of different cathode strategies (mullite/MnO2, Plexiglas/Gore-Tex/MnO2, mullite/coal fly ash, mullite/biochar, mullite/activated carbon) on the performance of air-cathode microbial fuel cells (MFCs) was investigated. The highest maximum power output was observed using MnO2 catalyst pasted on Gore-Tex cloth (7.7 mW/m3), yet the highest coulombic efficiencies (CEs) were achieved using MnO2 (CE 23.5 ± 2.7%) and coal fly ash (CE 20 ± 3.3%) pasted on ceramic. The results showed that the utilization of coal fly ash and biochar as catalysts in MFC technology can be a sustainable and cost-effective solution.

Mohamed E. Osman, Om-Kolthoum H. Khattab, Abo Elnasr A.A. et al.

Biosciences Biotechnology Research Asia • 2018

A microbial fuel cell (MFC) has great potential for azo dyes decolorization and electricity generation by using filamentous fungi as biocatalysts. In this study, Aspergillus niger and Trichoderma harzianum were inoculated in anode chamber of double-chamber MFC to decolorize azo dye acid black 172 with Potassium Ferricyanide in the cathode chamber. During MFC operations, Acid black 172 oxidized and produced a maximum open-circuit voltage of 890 mV, and maximum current density of 163 mA/m2 with an external resistance of 1000Ω. Also, variable parameters such as dye concentration, Co-substrate and dye as a sole carbon source were studied to improve microbial fuel cell performance.

A. Ziaedini, H. Rashedi, E. Alaie et al.

Fuel Cells • 2018

Abstract Due to metabolic activity of bacteria, microbial fuel cells (MFCs) can directly generate electricity by converting chemical energy of a biodegradable substrate to electrical energy. Simultaneous production of clean energy and wastewater treatment can be accomplished in these systems. In this study, phenol (100 ‐ 1,000 ppm) as a toxic model of wastewater pollutant compounds was used as the sole source of carbon and energy for growth of bacteria and concomitant power generation in a dual‐chamber MFC. Experiments were conducted in two lab‐scale systems including an air‐cathode and a bio‐cathode MFC operating in continuous mode. Anode and bio‐cathode chambers were inoculated with aerobic activated sludge from an industrial wastewater treatment plant. The highest output power was obtained at a phenol concentration of 700 ppm in both air‐cathode (25 mW m −2 ) and bio‐cathode (5 mW m −2 ) MFCs without using any co‐substrate for the first time confirming the higher performance of the air‐cathode electrode in oxygen reduction reaction. Phenol removal efficiency for an influent concentration of 700 ,ppm with an HRT of 125 min was 59.0% and 71.8% in bio‐cathode and air‐cathode MFCs, respectively. Cyclic voltammetry results confirmed involvement of both soluble and membrane‐bound mediator components in electrochemical activity of anodic biofilm.

Strahinja Zecevic, Edward M. Patton, Parviz Parhami

2nd International Conference on Fuel Cell Science, Engineering and Technology • 2003

Historically, despite its compelling cost and performance advantages, the use of molten hydroxide electrolytes has been ignored by DCFC researches, primarily due to the potential for formation of carbonate salt in the cell. This paper describes the electrochemistry of a patented medium-temperature DCFC based on molten hydroxide electrolyte, which overcomes the historical carbonate formation. An important technique discovered for significantly reducing carbonate formation is to ensure high water content of the electrolyte. Water helps hydrolysis of the carbonates and reduces formation of peroxide and superoxide ions that may react with carbon dioxide producing carbonate ions. High water content can be achieved by maintaining a humid atmosphere above the melt. To date, four successive generations of medium temperature DCFC prototypes have been built and tested at SARA Inc. to demonstrate the technology, all using graphite rods as their fuel source. The cells all used a simple design in which the cell containers served as the air cathodes and successfully demonstrated delivering more than 40 A at 0.3 V with the current density exceeding 200 mA/cm2. The basic feature of this simple cell design is that the cathode is not traditional gas fed electrode type. It is a non-porous electrode structure made of an inexpensive Fe-Ti alloy and gaseous oxygen is introduced into the cell by bubbling humid air through the electrolyte. Results obtained indicated that the cell operation was under a mixed activation-Ohmic-mass transfer control. The activation control is mainly due to slow anode oxidation of carbon, the Ohmic control is mainly due to a large electrode spacing whereas the mass transfer control is most likely because of slow diffusion of oxygen species (O2, O22−, O2−, and H2O) to the cathode surface. Cell performances are improved in the new generation cell design, which has been recently built, and which enables faster mass transfer of the reaction species and a lower voltage drop across the electrolyte. In the new design, the cathode is a separate perforated component of the cell that allows the use of a larger surface area electrode and for the electrode spacing to be varied.

David Ewusi-Mensah, Jingyu Huang, Laura Katherin Chaparro et al.

Processes • 2021

Algae-assisted microbial desalination cells represent a sustainable technology for low-energy fresh water production in which microalgae culture is integrated into the system to enhance oxygen reduction reaction in the cathode chamber. However, the water production (desalination rate) is low compared to conventional technologies (i.e., reverse osmosis and/or electrodialysis), as biocathodes provide low current generation to sustain the desalination process. In this sense, more research efforts on this topic are necessary to address this bottleneck. Thus, this study provides analysis, from the electrochemical point of view, on the cathode performance of an algae-assisted microbial desalination cell (MDC) using Chlorella vulgaris. Firstly, the system was run with a pure culture of Chlorella vulgaris suspension in the cathode under conditions of an abiotic anode to assess the cathodic behavior (i.e., cathode polarization curves in light-dark conditions and oxygen depletion). Secondly, Geobacter sulfurreducens was inoculated in the anode compartment of the MDC, and the desalination cycle was carried out. The results showed that microalgae could generate an average of 9–11.5 mg/L of dissolved oxygen during the light phase, providing enough dissolved oxygen to drive the migration of ions (i.e., desalination) in the MDC system. Moreover, during the dark phase, a residual concentration of oxygen (ca. 5.5–8 mg/L) was measured, indicating that oxygen was not wholly depleted under our experimental conditions. Interestingly, the oxygen concentration was restored (after complete depletion of dissolved oxygen by flushing with N2) as soon as microalgae were exposed to the light phase again. After a 31 h desalination cycle, the cell generated a current density of 0.12 mA/cm2 at an efficiency of 60.15%, 77.37% salt was removed at a nominal desalination rate of 0.63 L/m2/h, coulombic efficiency was 9%, and 0.11 kWh/m3 of electric power was generated. The microalgae-assisted biocathode has an advantage over the air diffusion and bubbling as it can self-sustain a steady and higher concentration of oxygen, cost-effectively regenerate or recover from loss and sustainably retain the system’s performance under naturally occurring conditions. Thus, our study provides insights into implementing the algae-assisted cathode for sustainable desalination using MDC technology and subsequent optimization.

Mehmet S Yazici, Sumeyye Dursun

ECS Meeting Abstracts • 2021

Cobalt (II) phthalocyanine (CoPc) is investigated as an alternative catalyst to Pt to decrease the cost of polymer electrolyte membrane (PEM) fuel cell. Carbon nanotube (CNT), VulcanXC72 (V), graphene (G) and their hybridization (CNT/G, V/G, CNT/V) are used as catalyst support. Carbon supported CoPc is prepared by impregnation method using THF. Different support materials and back pressure effect are investigated for better catalytic activity and stability. Single fuel cell tests were carried out. Higher heat treatment temperatures and higher operational backpressure improves fuel cell performance. Hybridization of graphene with Vulcan gives lower performance. Hybridization of carbon nanotube and Vulcan XC72 as a catalyst support gives the best fuel cell performance. Operational parameters provided maximum power density of CNT-Vulcan 303 mW/cm 2 with 0.3 mgCo/cm 2 loading, 5-psi backpressure, 100% RH and 60 °C operational temperature. Figure 1

Junjira Thipraksa, Panisa Michu, Pimprapa Chaijak

Journal of Degraded and Mining Lands Management • 2023

The microbial fuel cell (MFC) is a device that harnesses microbial metabolism to convert chemical energy into bio-electrical energy. Extensive research has demonstrated its efficacy in both wastewater treatment and power generation applications. This study focused on the integration of a microbial fuel cell (MFC) with a biocathode constructed using the oxidoreductase-producing bacterium <em>Bacillus</em> sp. MCO22 and rice straw as a cost-effective substrate. The MFC utilized palm oil mill effluent (POME) as a chemical energy source for electricity generation in the anodic chamber. The ability of the MFC was evaluated by monitoring biochemical oxygen demand (BOD) activity and electrochemical properties. Post-operation, chemical oxygen demand (COD) and color removal were measured. The results revealed that the MFC with the BOD-based cathode achieved a maximum current density and power density of 0.58±0.01 A/m<sup>2</sup> and 0.17±0.00 W/m<sup>2</sup>, respectively. Furthermore, it exhibited high COD and color removal rates of 95.10±0.10% and 98.53±0.33%, respectively, without requiring an external power supply. This study presents novel insights into utilizing a BOD-producing bacterium as a whole-cell biocatalyst on the MFC cathodic surface for both electricity generation and agricultural wastewater treatment.

Kyungmi Chung, Satoshi Okabe

Biotechnology and Bioengineering • 2009

Abstract The microbial communities associated with electrodes in closed and open circuit microbial fuel cells (MFCs) fed with glucose were analyzed by 16S rRNA approach and compared. The comparison revealed that bacteria affiliated with the Aeromonas sp. within the Gammaproteobacteria constituted the major population in the closed circuit MFC (harvesting electricity) and considered to play important roles in current generation. We, therefore, attempted to isolate the dominant bacteria from the anode biofilm, successfully isolated a Fe (III)‐reducing bacterium phylogenetically related to Aeromonas sp. and designated as strain ISO2‐3. The isolated strain ISO2‐3 could grow and concomitantly produce current (max. 0.24 A/m 2 ) via oxidation of glucose or hydrogen with an electrode serving as the sole electron acceptor. The strain could ferment glucose, but generate less electrical current. Cyclic voltammetry supported the strain ISO2‐3 was electrically active and likely to transfer electrons to the electrode though membrane‐associated compounds (most likely c‐type cytochrome). This mechanism requires intimate contact with the anode surface. Scanning electron microscopy revealed that the strain ISO2‐3 developed multiplayer biofilms on the anode surface and also produced anchor‐like filamentous appendages (most likely pili) that may promote long‐range electron transport across the thick biofilm. Biotechnol. Bioeng. 2009; 104: 901–910. © 2009 Wiley Periodicals, Inc.

Gee Jay C Bartolome, Lemmuel L Tayo

IOP Conference Series: Earth and Environmental Science • 2020

Abstract In this study, the decolorization of methyl orange was carried out in a double chamber microbial fuel cell. Microbial fuel cells (MFC’s) have been widely studied using various materials and operating conditions, these bioelectrochemical devices that use exoelectrogenic bacteria as biocatalysts have shown great potential to oxidize a variety of substrates while simultaneously generating electricity. Soil microorganisms consisting of lactic acid bacteria, Saccharomyces , Rhizobium , Rhodopseudomonas , Rhodobacter , Actinomycete s, and fungi were obtained from a concentrated soil microbial inoculant. Comparatively, the results of the experiments showed that using titanium mesh, the open circuit voltage and the power density of the MFC in close-circuit condition were 1.005 V and 1.223 Wm −2 while using carbon fiber brushes, values were 0.992 V and 0.338 Wm − 2. On the other hand, results also revealed that the system with carbon fiber brush electrodes is more effective in decolorizing methyl orange at a maximum of 78 percent removal efficiency. In 10 hours of continuous operation, the concentration of methyl orange reduced from 0.10-0.022 mM.

Ardiyan Harimawan, Hary Devianto, Nicholas Khodiyat et al.

Journal of Engineering and Technological Sciences • 2024

Microbial fuel cells (MFCs) can potentially be used to overcome issues with battery powered light buoys and their frequent maintenance. In this study, a phototrophic sediment microbial fuel cell (PSMFC) was chosen, as the microalgae provide oxygen to be reduced on the cathode and to release the necessary nutrients for the bacteria on the anode. To achieve this, we studied the effect of illumination, the period of the illumination, and the distance between 9-cm2 stainless steel mesh electrodes on the performance of the MFC. The illuminated cells were able to produce higher OCP (max. 205.2 mV) and higher power density (max. 0.68 mW/m2). However, the highest current was achieved during the unilluminated variation (max. 5.3 μA unilluminated and 3.3 μA illuminated). Prolonged illumination produced a higher OCP, current, and power density. A longer electrode distance produced a higher OCP, power density, and current. SEM analysis showed that biofilm formation tended to be scattered at lower electrode distance and more clumped (filling the anode area) at higher electrode distance. Through FTIR analysis, it was found that all MFC variations had the same organic matter, but a more concentrated organic content was found in the MFC at longer electrode distances.

Tong Lin, Xue Bai, Yidan Hu et al.

AIChE Journal • 2016

Microbial fuel cells (MFCs) were green and sustainable bio‐electrochemical reactors for simultaneous wastewater treatment and electricity harvest from organic wastes. However, exoelectrogens, such as Shewanella and Geobacter being widely studied in MFCs, could only use a limited spectrum of carbon sources. To expand the carbon source range being used in MFCs, we herein rationally designed a glucose‐fed fungus‐bacteria microbial consortium including a fermenter (Saccharomyces cerevisiae) in which the ethanol pathway was knocked out and the lactic acid biosynthesis pathway from Bovin was introduced into S. cerevisiae, and an exoelectrogen (Shewanella oneidensis MR‐1). We optimized the co‐culturing conditions of the microbial consortium to achieve an optimal coordination between carbon source metabolism of the fermenter and extracellular electron transfer of the exoelectrogen, such that lactate, the metabolic product of glucose by the recombinant S. cerevisiae, was continuously supplied to S. oneidensis in a constant level until glucose exhaustion. This metabolic coordination between the fermenter and the exoelectrogen enabled bioelectricity production in a glucose‐fed MFC. Furthermore, a porin protein encoded by oprF gene from Pseudomonas aeruginosa was incorporated into the outer membrane of S. oneidensis to enhance membrane permeability and its hydrophobicity, which in turn facilitated its biofilm formation and power generation. The glucose‐fed MFC inoculated with the recombinant S. cerevisiae‐recombinant S. oneidensis generated a maximum power density of 123.4 mW/m 2 , significantly higher than that of recombinant S. cerevisiae‐wild‐type S. oneidensis (71.5 mW/m 2 ). Our design strategy of synthetic microbial consortia was highly scalable to empower the possibility of a wide range of carbon sources being used in MFCs, e.g., xylose, cellulosic biomass, and recalcitrant wastes. © 2016 American Institute of Chemical Engineers AIChE J , 63: 1830–1838, 2017

Wulin Yang, Bruce E. Logan

ChemSusChem • 2016

Abstract Applications of microbial fuel cells (MFCs) are limited in part by low power densities mainly due to cathode performance. Successful immobilization of an Fe–N–C co‐catalyst on activated carbon (Fe–N–C/AC) improved the oxygen reduction reaction to nearly a four‐electron transfer, compared to a twoelectron transfer achieved using AC. With acetate as the fuel, the maximum power density was 4.7±0.2 W m −2 , which is higher than any previous report for an air‐cathode MFC. With domestic wastewater as a fuel, MFCs with the Fe–N–C/AC cathode produced up to 0.8±0.03 W m −2 , which was twice that obtained with a Pt‐catalyzed cathode. The use of this Fe–N–C/AC catalyst can therefore substantially increase power production, and enable broader applications of MFCs for renewable electricity generation using waste materials.

Ivy Ai Wei Tan, J.R. Selvanathan, M.O. Abdullah et al.

Defect and Diffusion Forum • 2021

Palm oil mill effluent (POME) discharged without treatment into watercourses can pollute the water source. Microbial fuel cell (MFC) has gained high attention as a green technology of converting organic wastewater into bio-energy. As an approach to overcome the limitations of the existing POME treatment methods, air-cathode MFC-Adsorption system is introduced as an innovative technology to treat POME and generate bio-electricity simultaneously. However, the use of conventional MFC with proton exchange membrane in large scale applications is restricted by the high cost and low power generation. Addition of mediator in MFC is essential in order to increase the electron transfer efficiency, hence enhancing the system performance. This study therefore aims to investigate the effect of different type of mediators i.e. congo red (CR), crystal violet (CV) and methylene blue (MB) on the performance of an affordable air-cathode MFC-Adsorption system made from earthen pot with POME as the substrate. The addition of different mediators altered the pH of the MFC-Adsorption system, in which more alkaline system showed better performance. The voltage generated in the system with CR, CV and MB mediator was 120.58 mV, 168.63 mV and 189.25 mV whereas the current generated was 2.41 mA, 3.37 mA and 3.79 mA, respectively. The power density of 290.79 mW/m3, 568.72 mW/m3 and 716.31 mW/m3 was produced in the MFC-Adsorption system with CR, CV and MB mediator, respectively. The highest POME treatment efficiency was achieved in MFC-Adsorption system with MB mediator, which resulted in biochemical oxygen demand, chemical oxygen demand, total suspended solids, turbidity and ammoniacal nitrogen removal of 75.3%, 84.8%, 91.5%, 86.1% and 23.31%, respectively. Overall, the air-cathode MFC-Adsorption system with addition of MB mediator was feasible for POME treatment and simultaneous bio-energy generation.

Mathias Gerard, Jean-Philippe Poirot-Crouvezier, Daniel Hissel et al.

Journal of Fuel Cell Science and Technology • 2010

In a fuel cell system the stack is strongly coupled with the main system components, among which the compressor is one of the most important. Malfunction of this auxiliary device (delay during peak power, low stoichiometry operation, emergency stop, etc.) is directly responsible for bad oxygen distribution in the cathode (substoichiometry reactants feeding). This phenomenon is usually called oxygen starvation. In this study we want to identify the consequences of oxygen starvation on the performance and durability of polymer electrolyte membrane fuel cell stacks, and more particularly, on the current distribution along the cell. The oxygen concentration decreases along the channel and induces a change in the local electrochemical response; it means that the local current density on the cell is redistributed on the surface. This bad distribution of reactive gas (in a transient time or long time) decreases the performance but may also have an effect on cathode degradation such as carbon corrosion and platinum dissolution/oxidation. The current distribution along the cell is studied by two approaches (modeling and experiments). The 3D model using serpentine bipolar plate meshing is adapted to dynamically compute for the catalyst layer local conditions (local current, temperature, gases partial pressure, and water activity). It is able to reproduce the conditions of low or high oxygen concentration in the cathode side. The experiments are performed with a bi-cell stack developed by CEA with specific design for the magnetic sensors (the local current is computed by measuring the local induced magnetic field and using the Maxwell equations).

Ryosuke Ichikawa, Yutaka Tabe, Takemi Chikahisa

ECS Transactions • 2011

In polymer electrolyte fuel cells (PEFCs), the freezing of produced water induces the extreme deterioration of the cell performance below zero. This phenomenon is serious problem in cold regions and is needed to be solved to achieve the practical use of PEFCs. In this study, we investigated the ice formation and the reaction rate in the cathode catalyst layer (CL) using a CRYO-SEM and a three-phase boundary model to clarify the freezing mechanism in the cold start at -20oC. The observation results showed that the ice distribution formed in the CL is changed by the operation time and the current density. In particular, in a case of large current density, it was shown that ice grows from the membrane side to the gas diffusion layer (GDL) side. This process can also be analyzed in detail by the model that calculates the reaction rate in the CL.

Pil Hyong Lee, Sang Soon Hwang

Sensors • 2009

In fuel cells flow configuration and operating conditions such as cell temperature, humidity at each electrode and stoichiometric number are very crucial for improving performance. Too many flow channels could enhance the performance but result in high parasite loss. Therefore a trade-off between pressure drop and efficiency of a fuel cell should be considered for optimum design. This work focused on numerical simulation of the effects of operating conditions, especially cathode humidity, with simple micro parallel flow channels. It is known that the humidity at the cathode flow channel becomes very important for enhancing the ion conductivity of polymer membrane because fully humidified condition was normally set at anode. To investigate the effect of humidity on the performance of a fuel cell, in this study humidification was set to 100% at the anode flow channel and was changed by 0–100% at the cathode flow channel. Results showed that the maximum power density could be obtained under 60% humidified condition at the cathode where oxygen concentration was moderately high while maintaining high ion conductivity at a membrane.

Hui Xu, Chao Lei, Yu Seung Kim et al.

ECS Meeting Abstracts • 2018

Conventional polymer electrolyte membrane (PEM) fuel cell electrodes using aqueous ionomer dispersion suffer from high manufacturing costs and rapid performance degradation. We have investigated an innovative method of designing fuel cell electrodes to reduce manufacturing costs and extend the lifetime. Our approach to obtaining good fuel cell performance is to; 1) understand ionomer particle morphology in dispersion; 2) investigate the electrode morphology, catalyst, and ionomer binder distributions in the electrodes; 3) evaluate the electrode performance using various electrodes prepared from different dispersing agents. First, laser diffraction particle size analysis was used to understand the various solvents’ impacts on catalyst ink structure. It can be seen that nPA/H 2 O and ethylene glycol (EG) solvent systems provide better ink structure, implied by much smaller agglomeration sizes. IPA/H 2 O and pentanediol based solvent systems exhibit large agglomerations in the ink, which may account for their poor quality. The laser diffraction particle size will be correlated with electrode structure and fuel cell performance later. Low magnification transmission electron microscopy element mapping was then used to characterize the ionomer distribution in these cathode layers. The best ionomer distribution was found in the EG based sample, with ionomer aggregates <50 nm. The porosity and pore size distribution of the electrode layers were also obtained from transmission electron microscopy image analysis. The EG-based electrode shows the lowest porosity (i.e., 13%). It also contains the smallest pore sizes and the highest number of pores. The effect of the dispersing agents on initial fuel cell performance was investigated. In this experiment, four ionomer dispersions were used and compared with nPA/H 2 O and IPA/H 2 O. All MEAs had a Pt loading of ~0.20 mg Pt /cm 2 . The IPA/H 2 O baseline shows very low performance especially in the mass transport region, which is probably attributed to its poor coating quality. The ionomer dispersions have shown significant influence on the fuel cell performance, with a general ranking as: nPA/H 2 O > ethylene glycol > butanediol > pentanediol). The ethylene glycol based sample displays the best performance of all the non-aqueous samples, and its performance is very comparable to the nPA/H 2 O baseline.

Zhihua Liu, Xiaoming Li, Bin Jia et al.

Water Science and Technology • 2009

A single-chamber, membrane-less and floating-cathode microbial fuel cells (MFC) was successfully started up using surplus sludge as fuel without adding carbohydrate after 20 days. The electricity generation of the MFC was investigated. The results showed that the obtained maximum voltage was 440.7 mV when external resistance was 1,000 Ω. There were four phases (rapid fall phase, stationary phase, fall phase and stationary phase of low voltage) in the periodic time of MFC, and the output voltage range of 150–300 mV lasted for 107 hours during stationary phase. In addition, the obtained maximum power density was 220.7 mW m−2 and internal resistance was 368.13 Ω in the MFC. Consequently, surplus sludge could be used to generate electricity in MFC, which could provide a novel process for sludge recycling.

Shota Tochigi, Kiyoshi Dowaki

Energies • 2023

Recently, fuel cell combined heat and power systems (FC-CGSs) for residential applications have received increasing attention. The International Electrotechnical Commission has issued a technical specification (TS 62282-9-101) for environmental impact assessment procedures of FC-CGSs based on the life cycle assessment, which considers global warming during the utilization stage and abiotic depletion during the manufacturing stage. In proton exchange membrane fuel cells (PEMFCs), platinum (Pt) used in the catalyst layer is a major contributor to abiotic depletion, and Pt loading affects power generation performance. In the present study, based on TS 62282-9-101, we evaluated the environmental impact of a 700 W scale PEMFC-CGS considering cathode catalyst degradation. Through Pt dissolution and Ostwald ripening modeling, the electrochemical surface area transition of the Pt catalyst was calculated. As a result of the 10-year evaluation, the daily power generation of the PEMFC-CGS decreased by 11% to 26%, and the annual global warming value increased by 5% due to the increased use of grid electricity. In addition, when Pt loading was varied between 0.2 mg/cm2 and 0.4 mg/cm2, the 10-year global warming values were reduced by 6.5% to 7.8% compared to the case without a FC-CGS.

O. Marconot, N. Pauc, D. Buttard et al.

Fuel Cells • 2018

Abstract This paper describes the elaboration via an electrochemistry route of a PEM carbon‐free cathode made of a periodic array of vertically aligned platinum copper nanotubes. Nanotubes synthesis is assisted with a porous alumina mold made on a silicon substrate to perform growth of copper nanowires. After optimization of an original confined galvanic displacement with H 2 PtCl 6 salt, PtCu nanotubes are embedded into porous alumina template and directly integrated onto a Nafion ® membrane. Therefore, our process does not need any step of purification or catalyst dispersion. The performances in fuel cell of these new electrodes are compared to conventional structures made of Tanaka Pt/C with the same electrocatalytic surface area. Significant improvement in the specific activity at 0.9 V and reduction in mass transport limitations are observed compared with standard Tanaka Pt/C catalyst in real operating conditions.

Shambhoo Sharan, Prateek Khare, Ravi Shankar et al.

International Journal of Chemical Reactor Engineering • 2021

Abstract In this study, membrane less double chambered microbial fuel cell has been used for the simultaneous electricity generation and organics removal from glucose and glutamic acid (mole ratio 1:1) based synthetic solution in the presence of municipal wastewater activated sludge-based microbes using graphite as an electrode. A central composite design technique has been employed to optimize the experimental conditions using design expert software for modeling input–output model as surface function of various input parameters like initial COD, anodic pH, and run time for voltage and current density generation. The predicted model suggests that maximum voltage and current density generation of ∼14.8 mV and ∼41.11 μA/m 2 , respectively are obtained at COD: 1500 mg/L, pH: 7, run time: 7 days. Further, methylene blue is used as mediator for voltage and current density production at optimum condition. Experimental result depicts the substantial role of mediator concentration and showing maximum current and voltage production, approximately 10 times higher than that without meditator under similar conditions. In addition to bioenergy production, values of BOD and COD in the wastewater simulant are found to be reduced after each run which exists below the permissible limits. The developed model equations give better prediction on the voltage and current density generation which lies within the error limits of −12 to +12% and −2 to 14%, respectively to their corresponding experimental values. Overall, the process can generate simultaneously bioenergy along with wastewater treatment and the empirical model gives better prediction with experimental values.

Huanhuan Liang, Jiali Han, Xingai Yang et al.

Nanomaterials and Nanotechnology • 2021

In microbial fuel cell (MFC), the anode is the carrier of microbial attachment and growth, and its material and surface structure play a vital role in MFC electricity generation. Therefore, anode surface optimization is an effective way to improve MFC performance. Although the power generation of bacteria has been confirmed and studied as early as the beginning of the 20th century, up to now, MFC still has the extremely challenging problem of low current and low power output in practical application. To improve the performance of MFC, several strategies have been applied to enhance the bacterial extracellular electron transfer. One promising technology is the genetic engineering approach, and some outstanding research results have been obtained. Another effective strategy is to design and fabricate a high-performance electrode because anode material is the essential factor affecting MFC performance, which provides surface active sites for microbial adhesion, reproduction and interfacial electron transfer. At present, the MFC anodes mainly include carbon-based electrodes and a variety of metal electrodes, but untreated anodes have always been unable to overcome the obstacle of low power output. Anode modification, a common and effective method, is employed for improving the power output of MFC. For this reason, this review is primarily focused on the applications of various anode materials and its nanoscale modification in the field of MFC, including the influence of different anode materials on the power output of MFC, and analyzes the reasons why anode modification enhances output performance. Furthermore, the influence of anode research on the practical application of MFC in the future is prospected.

Junxian Shi, Wenyan Zhao, Chang Liu et al.

Water • 2017

Here we reported the investigation of enhanced performance for the removal of hexavalent chromium (Cr (VI)) by a new microbial fuel cell (MFC) with natural pyrrhotite-coated cathode. By comparisons of the graphite-cathode, the MFCs equipped with a pyrrhotite-coated cathode generated the maximum power density of 45.4 mW·m−2 that was 1.3 times higher than that of with bare graphite cathode (35.5 mW·m−2). Moreover, the Cr (VI) removal efficiency of 97.5% achieved after 4.5 h compared with only 46.1% by graphite cathode MFC. In addition, Cr (VI) removal rate with different initial Cr (VI) concentrations for 10 mg/L and 30 mg/L was investigated and a decreased removal percentage with increasing Cr (VI) concentration was observed. Batches of experiments of different pH values from 3.0 to 9.0 in catholyte were carried out to optimize system performance. The complete Cr (VI) removal was achieved at pH 3.0 and 99.59% of Cr (VI) was removed after 10.5 h, which met the requirement of the Cr (VI) National Emission Standard. When the value of pH was decreasing, the removal rate was obviously increased and Cr (VI) could be removed successfully with a broad pH range indicating pyrrhotite-coated cathode MFC had more extensive usage scope. Furthermore, cathode treatment products were studied by X-ray photoelectron spectroscopy (XPS), Cr2O3, Cr (III)-acetate were detected on the cathode by the XPS Cr2p spectra and no Cr (VI) founded, indicating that the Cr on the surface of cathode was Cr (III) and Cr (VI) were reduced. On cathode, pyrrhotite not only played a significant role for catalyst of MFCs, but also acted as reactive sites for Cr (VI) reduction. Our research demonstrated that pyrrhotite, an earth-abundant and low-cost natural mineral was promised as an effective cathode material. Which had great potential applications in MFCs for reduction of wastewater containing heavy metals and other environmental contaminants in the future.

H. Bouzidi, L. Otmani, R. Doufnoune et al.

Engineering, Technology & Applied Science Research • 2022

The effects of different parameters on the electric output of air-cathode microbial fuel cells were investigated in this work. The single microbial fuel cell was equipped by modifying Proton Exchange Membranes (PEM). Two membrane types were prepared: first by using the combination of Poly Vinyl Alcohol (PVA) with Polystyrene Sulfonate (PSSNa), while the second membrane was elaborated by mixing Poly Vinyl Chloride (PVC) with Methyl Tri-Octyl Ammonium (MTOA) chloride. The PEMs were incorporated into the air-cathode to form a Membrane Electrode Assembly (MEA) to promote electricity generation. PVA/PSSNa and PVC-MTOA membranes were synthesized by solution casting method. Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet (UV) Visible spectroscopy, Scanning Electronique Microscope (SEM), Differential Scanning Calorimetry (DSC), and water Contact Angle (CA) were used as characterization techniques to explore the membrane structure and properties. The performance and the electric capacity of the microbial fuel cell in real time were operated using an external resistance of 5kΩ. Impedance and resistance capacity were determined using the polarization method. It was found that the internal resistance of the PVA/PSSNa and PVC-MTOA membranes were 50 and 350Ω respectively. The voltage values at open circuit of the cells using PVA/PSSNa and PVC-MTOA membranes were 600mV and 150mV respectively. The values of power, current, and power density, are quite interesting. Cells with PVA/PSSNa and PVC-MTOA membranes gave values of 18.24 and 9.64mW.cm-2 respectively.

Kabo Benedict Jongman, Girum Ayalneh, Getachew Dagnew

Advances in Science and Technology • 2025

The increasing demand for energy and the growing concern for environment pollution have led to the exploration of sustainable and efficient methods for wastewater treatment coupled with energy recovery. This study was focusing on the application of clay based (MFC) microbial fuel cell as a novel approach to treat petroleum wastewater while simultaneously generating electrical energy by using microorganisms extracted from diesel oil-contaminated soil collected from old garage. In this study, microbial fuel cells (MFCs) were constructed using low cost ceramic cylindrical pot (900ml) as an ion exchange membrane. An inoculum derived from oil-contaminated soil, 10% of the volume of the anode inoculum was fed to the anode chamber for MFC1, MFC2 and no inoculation was added to the MFC control. The cathode chamber was filled with 1M potassium ferricyanide in a 1M phosphate buffer solution at a ratio of 1:1. All MFCs were operated in batch mode with synthetic petroleum wastewater containing (810 ml) for 30 days for open circuit voltage and at an external resistance of 10Ω, 100Ω, and 1000 Ω for 14 days for closed circuit voltage. Carbon cloth (projected surface area of 546cm2and 455.22 cm2) was used as both the cathode and anode respectively. The treatment efficiency of clay-based MFCs were evaluated by the removal efficiencies of COD and BOD. For MFC1, BOD removal efficiency of 89%, COD removal efficiency was 96%, and maximum daily open circuit voltage of 188.92 mV. MFC2 demonstrated BOD removal efficiency of 91%, COD removal efficiency of 98%, and a maximum average daily open circuit voltage of 210.35 mV. In contrast, MFC control displayed lower removal efficiencies with BOD removal efficiency of 49%, COD removal efficiency of 30%, and a maximum average daily open circuit voltage of 58.28 mV. The maximum power density achieved was 9.99µW/cm2 for the highest performing MFC2.These results highlights the effectiveness of MFC1 and MFC2 in terms of organic matter removal and power generation compared to MFC control, displaying the potential of clay-based MFCs for wastewater treatment and energy production. This research just laid a foundation for the use of clay based MFC in treatment of petroleum wastewater and energy recovery, more studies have to be carried out to optimize and maximise its efficiency.

Tania Surya Utami, Rita Arbianti, M Mariana et al.

Reaktor • 2018

Microbial Fuel Cell (MFC) technology is highly prospective to be developed because it could be utilized as the alternative electricity sources and simultaneously as the wastewater treatment unit using microorganism as catalyst. Industrial Tempe wastewater has the potential to be used as MFC substrate since it still contains high nutrition for microbe and could pollute the environment if it disposed before being processed first. This study focused on investigating the effect of selective mixed culture addition and biofilm formation on the electricity production and the wastewater treatment aspects with tubular single chamber membranless reactor and industrial Tempe wastewater substrate. The result showed that, with the addition of selective mixed culture, the optimum electricity production obtained with addition of 1 ml gram-negative bacteria with increase in electricity production up to 92.14% and average voltage of 17.91 mV, while the optimum decreased levels of COD and BOD obtained with addition of 5 ml gram-negative bacteria which are 29.32% and 51.32%. On the biofilm formation experiment, optimum electricity production obtained from biofilm formation time for 14 days with increase in electricity production up to 10-folds and average voltage of 30.52 mV, while the optimum decreased levels of COD and BOD obtained from biofilm formation time for 7 days which are 18.2% and 35.9%.Keywords : biofilm, Microbial Fuel Cell, selective mixed culture, Tempe wastewater, tubular reactor

Peng Li, Wenfeng Yuan, Yitie Huang et al.

BMC Microbiology • 2022

Abstract Background Pseudomonas stutzeri S116 is a sulfur-oxidizing bacteria isolated from marine sludge. It exhibited excellent electricity generation as bioanode and biocathode applied in microbial fuel cells (MFCs). Complete genome sequencing of P. stutzeri and cyclic voltammetry method were performed to reveal its mechanism in microbial fuel cells system. Results This study indicated that the MFCs generated a maximum output voltage of 254.2 mV and 226.0 mV, and maximum power density of 765 mW/m 2 and 656.6 mW/m 2 respectively. Complete genome sequencing of P. stutzeri S116 was performed to indicate that most function genes showed high similarities with P. stutzeri , and its primary annotations were associated with energy production and conversion (6.84%), amino acid transport and metabolism (6.82%) and inorganic ion transport and metabolism (6.77%). Homology of 36 genes involved in oxidative phosphorylation was detected, which suggests the strain S116 possesses an integrated electron transport chain. Additionally, many genes encoding pilus-assembly proteins and redox mediators (riboflavin and phenazine) were detected in the databases. Thiosulfate oxidization and dissimilatory nitrate reduction were annotated in the sulfur metabolism pathway and nitrogen metabolism pathway, respectively. Gene function analysis and cyclic voltammetry indicated that P. stutzeri probably possesses cellular machinery such as cytochrome c and redox mediators and can perform extracellular electron transfer and produce electricity in MFCs. Conclusion The redox mediators secreted by P. stutzeri S116 were probably responsible for performance of MFCs. The critical genes and metabolic pathways involved in thiosulfate oxide and nitrate reduction were detected, which indicated that the strain can treat wastewater containing sulfide and nitrite efficiently.