Mediator-less Microbial Fuel Cell Research Articles

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

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

Cobalt ferrite microspheres as a biocompatible anode for higher power generation in microbial fuel cells

In the present study, spinel cobalt ferrite hierarchical flower-like microspheres (CoFe2O4-MS) are fabricated using a hydrothermal method and utilized as a biocompatible anode in microbial fuel cells (MFCs) for power generation. A maximum power density of 1964 mW m−2 is achieved with CoFe2O4-MS in a mediator-less MFC using Escherichia coli as a biocatalyst and glucose as a fuel. The unprecedented power generation by CoFe2O4-MS can be attributed to (i) the morphology of the flower-like CoFe2O4-MS, with a rough surface and large surface area suitable for biofilm formation, (ii) the rapid immobilization of negatively charged E. coli cells on the positively charged CoFe2O4-MS, facilitating stronger bacterial adhesion between the bacterial cells and CoFe2O4-MS, which leads to lower contact resistance and advantageous interfacial properties with rapid electron transfer, and, more importantly, (iii) enhanced interfacial charge transfer due to the presence of multi-valent cations and multiple valence states in the highly electrocapacitive CoFe2O4-MS. Thus, the enrichment of electroactive E. coli on CoFe2O4-MS produces a large number of electron-shuttling endogenous redox mediators, which promotes efficient extracellular electron transfer between E. coli and the electrocapacitive CoFe2O4-MS during the oxidation of the substrate, thus generating higher power output.

Electricity Generation using Carboxymethyl Cellulose and Kitchen Waste as Substrate by Exiguobacterium sp SU-5 in Mediatorless Microbial Fuel Cell

Electricity Generation using Carboxymethyl Cellulose and Kitchen Waste as Substrate by Exiguobacterium sp SU-5 in Mediatorless Microbial Fuel Cell

Evaluation of the Performance of a Mediatorless Microbial Fuel Cell by Electrochemical Impedance Spectroscopy

AbstractA mediatorless microbial fuel cell was developed using Escherichia coli bacteria and platinised titanium mesh as electrodes, producing a maximum power density of 627 mW m−2. The performance characteristics of the fuel cell were evaluated using both electrochemical and optical techniques. Cyclic Voltammetry showed that an anaerobically grown cell suspension of E. coli was electrochemically active, and is consistent with a role for E. coli‐secreted mediators in the functioning of the cell, after the formation of a biofilm on the surface of the electrode. Electrochemical impedance spectroscopy (EIS) data show a variation in the internal resistance during bacterial growth. EIS analysis based on an equivalent circuit revealed that the initial internal resistance of the cell (5.6 MΩ) initially reduces by around 50 % over an 8 hour period; more or less the same time where the fuel cell reaches its maximum potential of 860 mV, whereupon the resistance begins to increase resulting in the corresponding fall in potential; this trend was reversible upon the introduction of further nutrients into the cell.

Treatment of Oil refinery waste water simultaneously with Bioelectricity production in Mediator-less Microbial Fuel cell using native Gram positive Bacillus sp.

Microbial fuel cells standalone effective approach for generating electricity directly from the breakdown of waste organic matter or almost any renewable biomass using diverse metabolic activity of native electrogenic microorganisms. This communication reports effect of various factors on electricity production and efficient treatment of rice bran oil refinery wastewater used as fuel in mediator-less Microbial fuel cells (MFCs). The work represents efficacy of low-cost, simple and easy-to operate microbial fuel cells assisted with isolate WRS-6 for generating electricity to glow LED of 4V using oil refinery wastewater alone; and with combination of starch from cooked rice, sap of rotten fruit, vegetable waste from kitchen for about 10 days.

Influence of Red Pepper (<i>Capsicum annuum</i>) Addition on Bioenergy Production in Microbial Fuel Cells

The current study was performed to evaluate the beneficial effect in the power output of microbial fuel cells (MFCs) through supplementation of dried red pepper (Capsicum annuum) powder into the anodic chamber. Mediator-less H-type MFCs were set up where the anode chamber contained rumen microorganisms as inocula on cellulose (Avicel) and the cathode chamber of phosphate buffered saline (pH 7.4), both separated by cation exchange membrane. Electrical power generation in MFC was monitored daily over a 10-day period and the accumulated amounts and components of gaseous byproducts were measured at the end of 10 d operation of MFC. For both groups of MFCs with red pepper and the control, the head space gases collected were methane and CO2, and its volume and composition were similar between treatments. Methane and CO2 produced for 10 d operation were 210.7 and 106.5 mL, respectively, in MFC. The addition of red pepper powder caused an average power density to increase from 24.0 mW/m2 to 39.6 mW/m2 (P 2 for control and bellflower, respectively. This study provides the strong evidence that red pepper (Capsicum annuum) supplementation might modify the anaerobic fermentation characteristics of rumen microorganisms in anode chamber and improve the cellulosic bioenergy production in MFC.

Conversion of Food Processing Waste to Bioenergy: Bangladesh Perspective

Microbial fuel cell (MFC) is an attractive renewable and sustainable technology to meet up the drastic energy crisis of the world through waste water treatment. This Bioelectrochemical system (BES) converts biomass spontaneously into electricity by the metabolic activity of microorganisms. Food processing industry generally discharges large volume of wastewater, which creates adverse financial and ecological impacts to the industry and environment. In this present contribution, electricity production from food processing industry wastewater that serves as substrates in MFCs was investigated. Dual chambered mediator-less MFC was designed and fabricated using locally available materials. Performance of the MFC was evaluated by measuring potential parameters, such as current generation, current density, change in pH, and change in chemical oxygen demand at different operating conditions. Polarization experiments were conducted to find the maximum power density. Current generation increased with increasing sludge loading, and maximum results were recorded as 90 µA with 9 g of sludge and optimum pH value 8 in the anode chamber. This study documented a maximum power density of 7.42 mW/m 2 with the corresponding current density of 25 mA/m 2 . Citation: Amin, M. S. A., Talukder, M. J., Raju, R. R., and Khan, M. M. R. (2019). Conversion of Food Processing Waste to Bioenergy: Bangladesh Perspective. Trends in Renewable Energy, 5(1), 1-11. DOI: 10.17737/tre.2019.5.1.0080

Development of a High-Performance Mediatorless Microbial Fuel Cell Comprising a Catalytic Steel Anode

The present paper reports for the first time the construction of a sugar cane bagasse-mediated double-chambered microbial fuel cell (MFC), consisting of a novel bioanode of an iron/titanium Ni-P composite. This anode could facilitate uninterrupted extracellular electron transfer (EET) from bacteria (mixed culture). The Ni-P composite anode had a significant corrosion resistance and enhanced electrocatalytic activity. The corrosion rate was reduced to 0.187 mmpy, which was 3 times less than that of the noncomposite anode. A steady decrease in internal resistance from 3.84 × 103 Ω to 2.94 × 102 Ω was achieved with the incorporation of the iron/titanium-based composite on the anode surface. The presence of Fe (III) ion centers in the composite surface favored electroactive biofilm formation and enhanced the capacitive nature of the anode, thereby accelerating EET. The constructed MFC showed an internal resistance as low as 1.12 × 10-2 Ω in comparison with the control MFC. This led to a very high power density of ∼2.1 W/m2, which was 20% higher than that of the control MFC, while a stacked MFC obtained a maximum open-circuit potential of 3.2 V with power density and current density outputs of 6.3 W/m2 and 2.7 mA/m2, respectively. Even though an extensive amount of literature is available in this field, this report is the first of its kind because it includes such a simple reproducible system that can be extended to other similar systems.

Continuous Bioelectricity Generation from Phenol‐Contaminated Water by Mediator‐Less Microbial Fuel Cells: A Comparative Study between Air‐Cathode and Bio‐Cathode Systems

AbstractDue 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.

The Cellulolytic Bacteria <i>R. albus</i> for Improving the Efficiency of Microbial Fuel Cell

The current study has been undertaken to examine the beneficial effect in the power output of a microbial fuel cell (MFC) by adding cellulolytic bacteria Ruminococcus albus (R. albus) into the anodic chamber. Mediator-less H-type MFCs were set up where the anode chamber contained anaerobic digester microorganisms as inocula on finely ground pine tree (Avicel) at 2% (w/v) and the cathode chamber of 10mM phosphate buffered saline conductive solution, both separated by a cation exchange membrane. The functioning of the MFCs for generation of electrical power and the amounts of gaseous byproducts was monitored over a 9-day period. The addition of cellulolytic bacteria caused an increase of average power density from 7.9 m W/m2 to19.5 m W/m2, about 245% increase over a 9-day period. For both groups of MFCs; with R. albus and the control, the head space gases collected were methane and CO2. While the methane: CO2 ratios were found unchanged at 1.7:1 throughout the 9 days of operation, the total gas production increased from 248 mL to 319 mL due to the presence of R. albus addition. This study confirms that whereas the biocatalytic activity of anode microbial population determines the energy production, the addition of external cellulolytic bacteria into anode microbial population can improve and extend the biomass utilization.

Bioelectricity Production and Comparative Evaluation of Electrode Materials in Microbial Fuel Cells Using Indigenous Anode-Reducing Bacterial Community from Wastewater of Rice-Based Industries

Microbial fuel cells (MFCs) are the electrochemical systems that harness the electricity production capacity of certain microbes from the reduction of biodegradable compounds. The present study aimed to develop mediator-less MFC without using expensive proton exchange membrane. In the present study, a triplicate of dual-chamber, mediator-less MFCs was operated with two local rice based industrial wastewater to explore the potential of this wastewater as a fuel option in these electrochemical systems. 30 combinations of 6 electrodes viz. Carbon (14 cm × 1.5 cm), Zn (14.9 cm × 4.9 cm), Cu (14.9 cm × 4.9 cm), Sn (14.1cm × 4.5cm), Fe (14cm × 4cm) and Al (14cm × 4.5 cm) were evaluated for each of the wastewater samples. Zn-C as anode-cathode combination produced a maximum voltage that was 1.084±0.016V and 1.086±0.028 and current of 1.777±0.115mA and 1.503±0.120 for KRM and SSR, respectively. In the present study, thick biofilm has been observed growing in MFC anode. Total 14 bacterial isolates growing in anode were obtained from two of the wastewater. The dual chambered, membrane-less and mediator-less MFCs were employed successfully to improve the economic feasibility of these electrochemical systems to generate bioelectricity and wastewater treatment simultaneously.Keywords: Membrane-less, Microbial Fuel Cells, Biofilm, Wastewater, Electrogenic.Article History: Received June 25th 2016; Received in revised form Dec 15th 2016; Accepted January 5th 2017; Available onlineHow to Cite This Article: Reena, M. and Jadhav, S. K. (2017) Bioelectricity production and Comparative Evaluation of Electrode Materials in Microbial Fuel Cells using Indigenous Anode-reducing Bacterial Community from Wastewater of Rice-based Industries. International Journal of Renewable Energy Develeopment, 6(1), 83-92.http://dx.doi.org/10.14710/ijred.6.1.83-92

Substrate concentration dependence of voltage and power production characteristics in two-chambered mediator-less microbial fuel cells with acetate and peptone substrates.

Power production characteristics and substrate concentration dependence of voltage have been investigated together with the determination of kinetic constants in two-chambered mediator-less microbial fuel cells (MFC) for acetate and peptone substrates. At 500 mg DOC l-1 (dissolved organic carbon), power densities normalized to the anode surface of 112 mW m-2 with acetate and 114 mW m-2 with peptone as electron donor were attained by applying cathodes with a Pt catalyst layer. Related anode surface specific substrate removal rate was 44 g DOC m-2 h-1 for acetate and 52gDOCm-2h-1 for peptone. Substrate concentration dependency of the voltage suggests Monod-like kinetics with extremely low, <1 mg DOC l-1, half saturation constants and with final DOC concentrations of 6-10 mg l-1. Acetate and peptone are equivalent substrates for the exoelectrogenic bacteria both from the point of view of biodegradation kinetics and power production characteristics.

Hierarchically Three-Dimensional Nanofiber Based Textile with High Conductivity and Biocompatibility As a Microbial Fuel Cell Anode.

Microbial fuel cells (MFCs) encompass complex bioelectrocatalytic reactions that converting chemical energy of organic compounds to electrical energy. Improving the anode configuration is thought to be a critical step for enhancing MFCs performance. In present study, a hierarchically structured textile polypyrrole/poly(vinyl alcohol-co-polyethylene) nanofibers/poly(ethylene terephthalate) (referred to PPy/NFs/PET) is shown to be excellent anode for MFCs. This hierarchical PPy/NFs/PET anode affords an open porous and three-dimensional interconnecting conductive scaffold with larger surface roughness, facilitating microbial colonization and electron transfer from exoelectrogens to the anode. The mediator-less MFC equipped with PPy/NFs/PET anode achieves a remarkable maximum power density of 2420 mW m(-2) with Escherichia coli as the microbial catalyst at the current density of 5500 mA m(-2), which is approximately 17 times higher compared to a reference anode PPy/PET (144 mW m(-2)). Considering the low cost, low weight, facile fabrication, and good winding, this PPy/NFs/PET textile anode promises a great potential for high-performance and cost-effective MFCs in a large scale.

Electricity generation through degradation of organic matters in medicinal herbs wastewater using bio-electro-Fenton system

In the present study, the potential application of the bio-electro-Fenton (BEF) process for the treatment of medicinal herbs wastewater in a mediator-less microbial fuel cell (MFC) system is investigated. This process is operated in a dual-chamber MFC with anaerobic seed sludge as biocatalyst in an anode chamber under conditions of neutral pH, an aerobic cathode chamber equipped with a Fe@Fe2O3/graphite composite cathode and a Nafion membrane as a separator. The performance of the MFC is determined in three different mixed liquor suspended solids (MLSS) loadings, Nafions (112, 115) and a salt bridge in an air-cathode BEF process, in terms of power generation, chemical oxygen demand (COD) removal efficiency, columbic and energy efficiencies. Under optimal conditions, the batch experiment results show that the cathode chamber of the BEF reactor, equipped with Nafion 112 and inoculated with seed sludge at 3000 mg L−1 MLSS concentration, produces the maximum power density of 49.76 mW m−2, 0.56 mg L−1 and 29 mol L−1 of H2O2 and Fe2+, respectively. Under these conditions, the MFC achieves COD removal 78.05% in the anaerobic anode chamber and 84.02% as a result of aerobic processes from the air-cathode BEF chamber, whilst the maximum voltage εcb and εE values are 600 mV, 4.09% and 1.37%, respectively.

Mediator-less microbial fuel cell employing Shewanella Oneidensis

ABSTRACTThis study investigated efficient energy harvesting of a mediator-less microbial fuel cell (MFC) using Shewanella Oneidensis bacteria. Synthetic wastewater made from M9 minimal growth medium and carbon source was used to generate electricity. This experiment exhibits how concentration of bacteria in the anodic chamber, different types of carbon sources, and the substance concentration affect electricity generation. The results showed that the mediator-less MFC using Shewanella Oneidensis can produce voltage close to the maximum attainable MFC voltage. The efficient MFC can be used to treat wastewater while reducing energy needs and producing an alternative form of energy.

Evaluating the efficiency of a mixed culture biofilm for the treatment of black liquor and molasses in a mediator-less microbial fuel cell

ABSTRACTA microbial fuel cell (MFC) is an emerging environment-friendly technology to recover the useful energy available in waste by using microorganisms as catalyst. In this study, double chamber mediator-less MFCs separated by proton exchange membrane (PEM; Nafion) were constructed to determine the efficiency of mixed culture in using complex substrates (molasses and black liquor). It was found that activated sludge can serve as efficient source of electricigens for biofilm development on an anode. Power density of 2.425 W/m² was generated from molasses with chemical oxygen demand (COD) removal efficiency of 67% as compared to power density of 3.55 W/m² produced from black liquor along with COD removal efficiency of 78%. Moreover, it was demonstrated that surface area of PEM has a significant effect on power generation. An almost 5- to 8-fold increase in voltage was observed as the size of PEM was increased from 6.5 to 25 cm².

The Influence of Active Carbon Supports Toward the Electrocatalytic Behavior of Fe3O4 Nanoparticles for the Extended Energy Generation of Mediatorless Microbial Fuel Cells.

Magnetite (Fe3O4) nanoparticles anchored over the different active carbon supports were developed by a simple wet solution method. The developed nanostructures were magnetically self-assembled over the electrode surface and exploited as anode catalysts in mediatorless microbial fuel cells (MFC). The morphological characterizations revealed that 3∼8-nm-sized Fe3O4 nanoparticles were homogeneously anchored over the different carbon matrices and the obtained diffraction patterns ensured the cubic inverse spinel structure of prepared Fe3O4 nanoparticles. The morphology, size, and structure of Fe3O4 nanoparticles anchored over the different active carbon supports were maintained identical, and the influence of active carbon support toward the effectual MFC performances was evaluated under various electrochemical regimes and conditions by using Escherichia coli as a catalytic microorganism. The electrochemical characterizations revealed that carbon nanotube (CNT)-supported Fe3O4 nanoparticles exhibited lower charge transfer resistance and high coulombic efficiency in comparison with the graphene and graphite nanofiber-supported composites. Among the studied anode catalysts, Fe3O4/CNT composite exhibited the maximum MFC power density of 865mWm(-2) associated with excellent durability performances, owing to the specific interaction exerted between the microorganisms and the Fe3O4/CNT composite. Thus, the binder-free electrode modification process, mediatorless environment, rapid electron transfer kinetics, high power generation, and long durability performances achieved for the developed system paved futuristic dimensions for the high performance MFCs.

Effect of electric impulse for improved energy generation in mediatorless dual chamber microbial fuel cell through electroevolution of Escherichia coli

The main emphasis of this study is to understand the electroactive behavior of a microbe in microbial fuel cell (MFC) under specific selection pressure. This study explores potential of a non-electrogenic microbe for power production in a mediatorless MFC under the influence of a specific stress. Electric pulse of specific magnitude has been applied to Escherichia coli cells in a MFC and compared the results with unpulsed (control) MFC. Maximum power density of 187.77mW/m2 and 284.44mW/m2 for the control and experimental MFC has been observed at corresponding current density of 1444.44mA/m2 and 1777.77mA/m2. The results show improved performance for the pulsed (experimental) system, despite of initial downfall with respect to the control system. This suggests bacterial adaptation against electrical pulses which leads to evolution of an efficient electrogen. This observation is further confirmed by analyzing the results of Cyclic Voltammetry (CV), Scanning Electron Microscopy (SEM) Electrochemical Impedence Spectroscopy (EIS), enlightening different attributes like electrochemical property, bacterial morphology and impedance. The study is focused on development of a microbial fuel cell catalysed by E. coli, through triggering electroactive property in the microbe by exposing it to external stress. This study is unique in nature as it is mediatorless, economical and describes about a new method of natural bacterial evolution.

Electrochemical Characterization of a Novel Exoelectrogenic Bacterium Strain SCS5, Isolated from a Mediator-Less Microbial Fuel Cell and Phylogenetically Related to Aeromonas jandaei.

A facultative anaerobic bacterium, designated as strain SCS5, was isolated from the anodic biofilm of a mediator-less microbial fuel cell using acetate as the electron donor and α-FeOOH as the electron acceptor. The isolate was Gram-negative, motile, and shaped as short rods (0.9–1.3 μm in length and 0.4–0.5 μm in width). A phylogenetic analysis of the 16S rRNA, gyrB, and rpoD genes suggested that strain SCS5 belonged to the Aeromonas genus in the Aeromonadaceae family and exhibited the highest 16S rRNA gene sequence similarity (99.45%) with Aeromonas jandaei ATCC 49568. However, phenotypic, cellular fatty acid profile, and DNA G+C content analyses revealed that there were some distinctions between strain SCS5 and the type strain A. jandaei ATCC 49568. The optimum growth temperature, pH, and NaCl (%) for strain SCS5 were 35°C, 7.0, and 0.5% respectively. The DNA G+C content of strain SCS5 was 59.18%. The isolate SCS5 was capable of reducing insoluble iron oxide (α-FeOOH) and transferring electrons to extracellular material (the carbon electrode). The electrochemical activity of strain SCS5 was corroborated by cyclic voltammetry and a Raman spectroscopic analysis. The cyclic voltammogram of strain SCS5 revealed two pairs of oxidation-reduction peaks under anaerobic and aerobic conditions. In contrast, no redox pair was observed for A. jandaei ATCC 49568. Thus, isolated strain SCS5 is a novel exoelectrogenic bacterium phylogenetically related to A. jandaei, but shows distinct electrochemical activity from its close relative A. jandaei ATCC 49568.

Conducting Polymers As Electrode Modifiers for the Enhanced Microbial Fuel Cell Performance

The low power density of a microbial fuel cell (MFC) compared to other fuel cells has been a problem for this technology to be implanted in the real world despite the fact that it has many merits as an alternative energy source such as environmental sustainability and carbon neutrality. The main reason lies in the slow electron transfer (ET) kinetics at the anode and the cathode. Electrons produced from the oxidation of organic matters by the bacterial biofilm on the anode are transferred to the cathode where oxygen reduction reaction (ORR) takes place. Thus fast ET at both electrodes is very important to increase current density that leads to enhanced power density. Here we show how polyaniline (PANI) and polypyrrole (Ppy) can be utilized as electrode modifiers to greatly improve MFC performance.First, we have used PANI and Ppy to modify anodes. When Ppy was applied to the anode in a mediator-type MFC using Proteus vulgaris as a biocatalyst, a large enhancement in power density was observed. A dramatic power enhancement was resulted from the electrodeposited Ppy onto the reticulated vitreous carbon (RVC) electrode. Our obtained maximum power density of 1.2 mW cm−3 is the highest value among the reported ones for the similar system. From impedance measurements, enhancement was attributed to the decrease in charge transfer resistance. More practical MFCs are single chamber and mediatorless type MFCs with a biofilm formed from activated sludge. We prepared polyaniline/carbon black (PANI/C) composite and applied it to carbon cloth anode. It shortened start-up period and significantly enhanced power density from 764 mW m-2 to 1277 mW m-2. Enhances performance was also attributed to fast electron transfer to the anode through PANI. The anode surface was characterized by employing various surface characterization techniques such as scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The power output depended upon the amount of PANI/C, showing a highest value at 0.2 mg cm-2. Coulombic efficiency was more than 30% at 4.3 A m-2.Second, PANI was also utilized as an ORR catalyst for an MFC cathode. We used polyaniline nanofibers (PANInf) synthesized by interfacial polymerization and prepared PANInf/Carbon black composite for the cathode. Higher electrocatalytic activity for the oxygen reduction compared to pristine PANInf was resulted, thus leading to a large power density enhancement 185 mW m−2 for the pristine PANInf to 496 mW m−2 for the composite material. Although the power density was still lower than when conventional Pt catalyst was used (604.3 mW m−2), a facile bulk synthesis and cheaper price would make PANInf/C an alternative to Pt when a large scale application comes to an issue.PANI was also used as a support to incorporate compounds that have high catalytic activity toward oxygen reduction. Iron phthalocyanine (FePc) has been known as effective oxygen reduction catalyst. FePc was incorporated into Polyaniline/carbon black (PANI/C) composite. Thus prepared (PANI/C/FePc) was used as a catalyst for the ORR in an air–cathode microbial fuel cell (MFC). The electrocatalytic activity of the PANI/C/FePc toward the ORR was compared with carbon-supported FePc. The ORR overpotential was decreased and current density was greatly increased, indicating that polyaniline plays a key role in ORR reactions. This PANI/FePc/C composite was also well adopted as a cathode material in MFCs. The maximum power density of 630.5 mW m−2 with the PANI/C/FePc cathode was higher than that of 336.6 mW m−2 with the C/FePc cathode because of enhanced ORR activity. We compared monetary aspect per power for these materials. It turned out that the power per cost of the PANI/C/FePc cathode is 7.5 times greater than that of the Pt cathode. Thus, the PANI/C/FePc can be a potential alternative to Pt in MFCs.We found PANInf could be a useful material for modifying the interior of the three-dimensional anode. Reticulated vitreous carbon (RVC) is an ideal material in that it has many interconnected pores inside so that substrate can freely flow through the pores. The PANInf layer was easily formed on the interior surface of the RVC on which a stable and robust bacterial biofilm was formed, giving higher power density.In conclusion, conducting polymers have been proven very promising materials for the MFC power enhancement. Electron transfer barrier at the anode and cathode can be lowered when conducting polymers are used. Modification of these polymers with foreign species can further increase power density.