Seiya Tsujimura, Akira Wadano, Kenji Kano et al.

Enzyme and Microbial Technology • 2001

Falk Harnisch, Robert Warmbier, Ralf Schneider et al.

Bioelectrochemistry • 2009

Masaki Torimura, Hideto Yoshida, Kenji Kano et al.

Journal of Molecular Catalysis B: Enzymatic • 2000

I. Roche, K. Katuri, K. Scott

Journal of Applied Electrochemistry • 2009

Suzanne T Read, Paritam Dutta, Phillip L Bond et al.

BMC Microbiology • 2010

Abstract Background Microbial fuel cells (MFCs) rely on electrochemically active bacteria to capture the chemical energy contained in organics and convert it to electrical energy. Bacteria develop biofilms on the MFC electrodes, allowing considerable conversion capacity and opportunities for extracellular electron transfer (EET). The present knowledge on EET is centred around two Gram-negative models, i.e. Shewanella and Geobacter species, as it is believed that Gram-positives cannot perform EET by themselves as the Gram-negatives can. To understand how bacteria form biofilms within MFCs and how their development, structure and viability affects electron transfer, we performed pure and co-culture experiments. Results Biofilm viability was maintained highest nearer the anode during closed circuit operation (current flowing), in contrast to when the anode was in open circuit (soluble electron acceptor) where viability was highest on top of the biofilm, furthest from the anode. Closed circuit anode Pseudomonas aeruginosa biofilms were considerably thinner compared to the open circuit anode (30 ± 3 μm and 42 ± 3 μm respectively), which is likely due to the higher energetic gain of soluble electron acceptors used. The two Gram-positive bacteria used only provided a fraction of current produced by the Gram-negative organisms. Power output of co-cultures Gram-positive Enterococcus faecium and either Gram-negative organisms, increased by 30-70% relative to the single cultures. Over time the co-culture biofilms segregated, in particular, Pseudomonas aeruginosa creating towers piercing through a thin, uniform layer of Enterococcus faecium. P. aeruginosa and E. faecium together generated a current of 1.8 ± 0.4 mA while alone they produced 0.9 ± 0.01 and 0.2 ± 0.05 mA respectively. Conclusion We postulate that this segregation may be an essential difference in strategy for electron transfer and substrate capture between the Gram-negative and the Gram-positive bacteria used here.

Aswin K. Manohar, Orianna Bretschger, Kenneth H. Nealson et al.

Electrochimica Acta • 2008

Eileen HaoYu, Shaoan Cheng, Keith Scott et al.

Journal of Power Sources • 2007

Maria Smolander, Harry Boer, Matti Valkiainen et al.

Enzyme and Microbial Technology • 2008

Guo-Wei Chen, Soo-Jung Choi, Tae-Ho Lee et al.

Applied Microbiology and Biotechnology • 2008

Olivier Schaetzle, Frédéric Barrière, Uwe Schröder

Energy Environ. Sci. • 2008

X. Wang, Y. J. Feng, H. Lee

Water Science and Technology • 2008

The performance of electricity production from beer brewery wastewater in a single chamber membrane-free microbial fuel cell (MFC) was investigated. Experimental results showed that the MFCs could generate electricity from full-strength wastewater (2,239 mg-COD/L, 50 mM PBS added) with the maximum power density of 483 mW/m2 (12 W/m3) at 30°C and 435 mW/m2 (11 W/m3) at 20°C, respectively. Temperature was found to have bigger impact on cathode potential than anode potential. Results suggested that it is feasible to generate electricity with the treatment of beer brewery wastewater.

J NIESSEN, U SCHRODER, F SCHOLZ

Electrochemistry Communications • 2004

Justin Biffinger, Ricky Ray, Brenda Little et al.

ECS Meeting Abstracts • 2006

Abstract not Available.

Shun'ichi Ishii, Takefumi Shimoyama, Yasuaki Hotta et al.

BMC Microbiology • 2008

Abstract Background Microbial fuel cells (MFCs) are devices that exploit microorganisms to generate electric power from organic matter. Despite the development of efficient MFC reactors, the microbiology of electricity generation remains to be sufficiently understood. Results A laboratory-scale two-chamber microbial fuel cell (MFC) was inoculated with rice paddy field soil and fed cellulose as the carbon and energy source. Electricity-generating microorganisms were enriched by subculturing biofilms that attached onto anode electrodes. An electric current of 0.2 mA was generated from the first enrichment culture, and ratios of the major metabolites (e.g., electric current, methane and acetate) became stable after the forth enrichment. In order to investigate the electrogenic microbial community in the anode biofilm, it was morphologically analyzed by electron microscopy, and community members were phylogenetically identified by 16S rRNA gene clone-library analyses. Electron microscopy revealed that filamentous cells and rod-shaped cells with prosthecae-like filamentous appendages were abundantly present in the biofilm. Filamentous cells and appendages were interconnected via thin filaments. The clone library analyses frequently detected phylotypes affiliated with Clostridiales , Chloroflexi , Rhizobiales and Methanobacterium . Fluorescence in-situ hybridization revealed that the Rhizobiales population represented rod-shaped cells with filamentous appendages and constituted over 30% of the total population. Conclusion Bacteria affiliated with the Rhizobiales constituted the major population in the cellulose-fed MFC and exhibited unique morphology with filamentous appendages. They are considered to play important roles in the cellulose-degrading electrogenic community.

Daniel Aguirre de Cárcer, Phuc Thi Ha, Jae Kyung Jang et al.

Applied Microbiology and Biotechnology • 2010

Ashley E Franks, Nikhil Malvankar, Kelly P Nevin

Biofuels • 2010

T.T. More, M.M. Ghangrekar

Bioresource Technology • 2009

Effect of low-frequency ultrasound pre-treatment to inoculum on performance of microbial fuel cell (MFC) was evaluated. Mixed anaerobic sludge was pre-treated with ultrasonication duration of 2.5, 5, 7.5, and 15 min, and the performance of MFC using this inoculum was compared with the MFC inoculated without any pre-treatment to the sludge. The effect of combined pre-treatment, using ultrasonication and heating of the inoculum, on performance of the MFC was also evaluated. Maximum power density during polarization in a MFC inoculated with ultrasonication pre-treatment to the sludge for 5 min (40 kHz, 120 W) was 2.5 times higher than that obtained without any pre-treatment to the inoculum sludge. Substrate removal was higher in the MFC with ultrasonicated inoculum, than inoculum without any pre-treatment and combined pre-treated with ultrasonication and heating. These results evidently demonstrated the advantages of ultrasonication pre-treatment to the inoculum for enhancing power and organic matter removal of the MFC.

V. Fedorovich, S. D. Varfolomeev, A. Sizov et al.

Water Science and Technology • 2009

A plug flow multi-electrode bioelectrochemical reactor for wastewater treatment and simultaneous generation of electricity has been developed and its efficiency investigated. It employs a horizontally located anodic zone in which the anodic electrodes comprise porous graphite plates coated with palladium. The aerated immersed cathodic electrodes contain iron(II) phthalocyanine as a catalyst. The parameters of the device were obtained using glycerol and acetate as fuels and anaerobic sludge as an inoculum. The maximal volumetric power and current densities obtained, relative to the total volume of the anodic zone, were: glycerol: 73±1 mA/L; 43±1 mW/L; acetate: 75±1 mA/L; 40±1 mW/L. It was shown that biotransformation of glycerol into volatile fatty acids does not depend on the presence of anodic electrodes in the reaction zone, while acetate degradation takes place only if the reaction zone contains anodic electrodes as a final electron acceptor.

Vinay Sharma, P.P. Kundu

Enzyme and Microbial Technology • 2010

Bin Wang, Jong-In Han

Biotechnology Letters • 2008

K. Scott, C. Murano, G. Rimbu

Journal of Applied Electrochemistry • 2007

Hai The Pham, Nico Boon, Peter Aelterman et al.

Microbial Biotechnology • 2008

Summary In many microbial bioreactors, high shear rates result in strong attachment of microbes and dense biofilms. In this study, high shear rates were applied to enrich an anodophilic microbial consortium in a microbial fuel cell (MFC). Enrichment at a shear rate of about 120 s −1 resulted in the production of a current and power output two to three times higher than those in the case of low shear rates (around 0.3 s −1 ). Biomass and biofilm analyses showed that the anodic biofilm from the MFC enriched under high shear rate conditions, in comparison with that under low shear rate conditions, had a doubled average thickness and the biomass density increased with a factor 5. The microbial community of the former, as analysed by DGGE, was significantly different from that of the latter. The results showed that enrichment by applying high shear rates in an MFC can result in a specific electrochemically active biofilm that is thicker and denser and attaches better, and hence has a better performance.

S.‐J. You, N.‐Q. Ren, Q.‐L. Zhao et al.

Fuel Cells • 2009

Abstract To improve cathodic efficiency and sustainability of microbial fuel cell (MFC), graphite fibre brush (GFB) was examined as cathode material for power production in biocatalysed‐cathode MFC. Following 133‐h mixed culturing of electricity‐producing bacteria, the MFC could generate a reproducible voltage of 0.4 V at external resistance ( R EX ) of 100 Ω. Maximum volumetric power density of 68.4 W m –3 was obtained at a current density of 178.6 A m –3 . Upon aerobic inoculation of electrochemically active bacteria, charge transfer resistance of the cathode was decreased from 188 to 17 Ω as indicated by electrochemical impedance spectroscopy (EIS) analysis. Comparing investigations of different cathode materials demonstrated that biocatalysed GFB had better performance in terms of half‐cell polarisation, power and Coulombic efficiency (CE) over other tested materials. Additionally, pH deviation of electrolyte in anode and cathode was also observed. This study provides a demonstration of GFB used as biocathode material in MFC for more efficient and sustainable electricity recovery from organic substances.

Naroa Uría, David Sánchez, Roser Mas et al.

Procedia Engineering • 2009

Kyungmi Chung, Satoshi Okabe

Applied Microbiology and Biotechnology • 2009

Lewis Hsu, Orianna Bretschger, Kenneth Nealson et al.

ECS Meeting Abstracts • 2008

Abstract not Available.

Youngjin Choi, Eunkyoung Jung, Sunghyun Kim et al.

Bioelectrochemistry • 2003

A study has been performed to examine the effect of temperature and ethanolic stresses on the coulombic efficiency of a microbial fuel cell. The conventional-type fuel cell containing Gram-negative bacteria, Proteus vulgaris, was investigated as a model system. From current output measurements, it was found that the coulombic yields were altered by environmental stresses such as temperature shock or ethanol treatment to the bacteria. While high-temperature or ethanolic shock led to a remarkable decrement in coulombic output, the low-temperature shock induced a slight increase in microbial fuel cell efficiency. These results indicate that the membrane fluidity is affected considerably by environmental stress, which in turn affects the electron transfer process through the bacterial cell membrane to and from the electrode. This interpretation was confirmed by the cyclic voltammetric study of a mediator on an electrode surface modified with the lipids extracted from the membrane of P. vulgaris under the given stress. Markedly different electrochemical behaviors were observed depending on the environmental stress. A reciprocal relationship between coulomb output and the ratio of saturation/unsaturation of fatty acids has been observed. This is the first report, to our knowledge, that the structural adaptation of membrane fatty acids in response to the environmental shock can regulate the coulombic efficiency of a microbial fuel cell.

Hyung Joo Kim, Hyung Soo Park, Moon Sik Hyun et al.

Enzyme and Microbial Technology • 2002

R. Ganguli, B. S. Dunn

Fuel Cells • 2009

Abstract Chronoamperometric investigations with rotating disc electrodes (RDEs) were used to characterise the anodic half‐cell of yeast powered microbial fuel cells using methylene blue (MB) as a mediator. Both convection and mediator adsorption were shown to affect the anodic current. A microbe–mediator limited reaction model was developed and shown to agree well with the experimental data. A power density of ∼150 μW cm –2 was achieved in a full cell, which represented a significant increase from prior reports on yeast‐catalysed fuel cells. The increased power density was enabled by using high mediator concentrations and by controlling the mediator adsorption.

Wenguo Wu, Zhongze Gu, Xing Liu et al.

Sensor Letters • 2013

Michaela A. TerAvest, Largus T. Angenent

ChemElectroChem • 2014

AbstractPrevious transcriptomic profiling of Shewanella oneidensis MR‐1 had suggested that electron transfer to an anode in a bioelectrochemical system may induce a general stress response (similar to a heat‐shock response) and/or an increase in protein turnover rates. Analysis of this microbe grown with a wide variety of electron acceptors also indicated that protein turnover may be related to the redox potential of the terminal electron acceptor. To investigate whether electrodes can induce stress and increase protein turnover, S. oneidensis was grown at potentiostatically poised electrodes at five redox potentials versus the standard hydrogen electrode (SHE) between −3 and +797 mVSHE. Subsequently, current production, coulombic efficiency, and transcription levels of marker genes for general stress and protein turnover were measured. Maximal current production was found at +397 mVSHE, and maximal coulombic efficiency was observed at +197 mVSHE. Both values decreased at more positive (oxidizing) potentials, that is, extracellular electron transfer of S. oneidensis is optimal at moderate electrode potentials. In contrast to previous findings, transcript measurements of a stress‐marker gene indicate that extracellular electron transfer does not increase general stress in comparison with aerobic respiration. Although overall protein turnover is not related to electrode potential, increased expression of a protease suggests that protein degradation increases at oxidizing electrode potentials. Cyclic voltammetry revealed decreased activity of c‐type cytochromes at the higher potentials, which indicates that oxidizing electrodes directly damage electron‐transfer proteins at the electrode surface.

Anand Jain, Xiaoming Zhang, Gabriele Pastorella et al.

Bioelectrochemistry • 2012

Electron transfer mechanisms in Shewanella loihica PV-4 viable biofilms formed at graphite electrodes were investigated in potentiostat-controlled electrochemical cells poised at oxidative potentials (0.2V vs. Ag/AgCl). Chronoamperometry (CA) showed a repeatable biofilm growth of S. loihica PV-4 on graphite electrode. CA, cyclic voltammetry (CV) and its first derivative shows that both direct electron transfer (DET) mediated electron transfer (MET) mechanism contributes to the overall anodic (oxidation) current. The maximum anodic current density recorded on graphite was 90 μA cm(-2). Fluorescence emission spectra shows increased concentration of quinone derivatives and riboflavin in the cell-free supernatant as the biofilm grows. Differential pulse voltammetry (DPV) show accumulation of riboflavin at the graphite interface, with the increase in incubation period. This is the first study to observe a gradual shift from DET to MET mechanism in viable S. loihica PV-4 biofilms.

Justin C. Biffinger, Jeremy Pietron, Ricky Ray et al.

Biosensors and Bioelectronics • 2007

A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m2). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250W/m3), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50mM ferricyanide catholyte solution. The Pt/C-GF (2-4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150W/m3) than bare graphite felt (12W/m3) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.

Yang-Yang Yu, Hai-lan Chen, Yang-Chun Yong et al.

Chemical Communications • 2011

Luo Peng, Shi-Jie You, Jing-Yuan Wang

Biosensors and Bioelectronics • 2010

This study compared voltammetric behavior and catalytic current generation of Shewanella oneidensis on glassy carbon electrode (GCE) with and without carbon nanotube (CNT) modifier. A bare GCE in an electrochemical cell inoculated with S. oneidensis delivered a low current density of 0.117+/-0.006 microA/cm(2) after being anodically polarized for 15h. Cyclic voltammogram suggested current generation could be attributed to S. oneidensis's cell surface cytochromes. But the cytochromes demonstrated irreversible electrochemistry, where electro-oxidation was inhibited. Modification of the working electrode with CNTs transformed such rectification behavior. Additionally, the kinetics of electron transfer (ET) between cell surface cytochrome and electrode was enhanced, it was characterized by reduced oxidative/reductive peak separation. The heterogeneous ET rate constant was estimated to be 1.25 s(-1) with the modified electrode. The promoting effect of CNTs directly raised current density to 9.70+/-0.40 microA/cm(2), a level 82 times greater than that of the original. The CNTs may have similar promoting effects towards exocellular ET of other exoelectrogens.

Amelia-Elena Rotaru, Pravin Malla Shrestha, Fanghua Liu et al.

Applied and Environmental Microbiology • 2014

ABSTRACT Direct interspecies electron transfer (DIET) is potentially an effective form of syntrophy in methanogenic communities, but little is known about the diversity of methanogens capable of DIET. The ability of Methanosarcina barkeri to participate in DIET was evaluated in coculture with Geobacter metallireducens . Cocultures formed aggregates that shared electrons via DIET during the stoichiometric conversion of ethanol to methane. Cocultures could not be initiated with a pilin-deficient G. metallireducens strain, suggesting that long-range electron transfer along pili was important for DIET. Amendments of granular activated carbon permitted the pilin-deficient G. metallireducens isolates to share electrons with M. barkeri , demonstrating that this conductive material could substitute for pili in promoting DIET. When M. barkeri was grown in coculture with the H 2 -producing Pelobacter carbinolicus , incapable of DIET, M. barkeri utilized H 2 as an electron donor but metabolized little of the acetate that P. carbinolicus produced. This suggested that H 2 , but not electrons derived from DIET, inhibited acetate metabolism. P. carbinolicus-M. barkeri cocultures did not aggregate, demonstrating that, unlike DIET, close physical contact was not necessary for interspecies H 2 transfer. M. barkeri is the second methanogen found to accept electrons via DIET and the first methanogen known to be capable of using either H 2 or electrons derived from DIET for CO 2 reduction. Furthermore, M. barkeri is genetically tractable, making it a model organism for elucidating mechanisms by which methanogens make biological electrical connections with other cells.

Sarah M. Strycharz, Richard H. Glaven, Maddalena V. Coppi et al.

Bioelectrochemistry • 2011

Liang Shi, David J. Richardson, Zheming Wang et al.

ChemInform • 2010

AbstractReview: 49 refs.

Joana M. Dantas, Diogo M. Tomaz, Leonor Morgado et al.

FEBS Letters • 2013

The cytochrome PccH from Geobacter sulfurreducens (Gs) plays a crucial role in current‐consuming fumarate‐reducing biofilms. Deletion of pccH gene inhibited completely electron transfer from electrodes toward Gs cells. The pccH gene was cloned and the protein heterologously expressed in Escherichia coli. Complementary biophysical techniques including CD, UV–visible and NMR spectroscopy were used to characterize PccH. This cytochrome contains one low‐spin c‐type heme with His–Met axial coordination and unusual low‐reduction potential. This reduction potential is pH‐dependent, within the Gs physiological pH range, and is discussed within the context of the electron transfer mechanisms from electrodes to Gs cells.

Akihiro Okamoto, Koichiro Saito, Kengo Inoue et al.

Energy Environ. Sci. • 2014

Geobacter cells utilize self-secreted riboflavin as a bound-cofactor in outer-membrane c-type cytochromes to enhance the rate of bacterial electron transport.