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.

Leonor Morgado, Joana M. Dantas, Telma Simões et al.

Bioscience Reports • 2013

The bacterium Gs (Geobacter sulfurreducens) is capable of oxidizing a large variety of compounds relaying electrons out of the cytoplasm and across the membranes in a process designated as extracellular electron transfer. The trihaem cytochrome PpcA is highly abundant in Gs and is most probably the reservoir of electrons destined for the outer surface. In addition to its role in electron transfer pathways, we have previously shown that this protein could perform e−/H+ energy transduction. This mechanism is achieved by selecting the specific redox states that the protein can access during the redox cycle and might be related to the formation of proton electrochemical potential gradient across the periplasmic membrane. The regulatory role of haem III in the functional mechanism of PpcA was probed by replacing Met58, a residue that controls the solvent accessibility of haem III, with serine, aspartic acid, asparagine or lysine. The data obtained from the mutants showed that the preferred e−/H+ transfer pathway observed for PpcA is strongly dependent on the reduction potential of haem III. It is striking to note that one residue can fine tune the redox states that can be accessed by the trihaem cytochrome enough to alter the functional pathways.

Akihiro Okamoto, Ryuhei Nakamura, Kenneth H. Nealson et al.

ChemElectroChem • 2014

AbstractCertain microbes are capable of transporting electrons from the cell interior‐respiratory electron chain to insoluble electron acceptors located outside of the cell, a process referred to as extracellular electron transport (EET). Bacteria capable of EET are currently utilized as “living anode catalysts” in microbial fuel cells. Several EET mechanisms have been proposed, yet they lack molecular‐level consistency. Here, we review our recent work, presenting a “bound‐flavin cofactor” model, which we believe provides a suitable explanation for all of the published data to date for the model EET microbes of Shewanella oneidensis and Geobacter sulfurreducens. We discuss the interaction between free flavin and outer‐membrane c‐type cytochromes based on a protein–ligand binding model, the accumulation of cell‐secreted flavins in nanostructured electrodes, and EET through intermittent direct contacts or conductive extracellular appendages.

Jessica E Butler, Nelson D Young, Derek R Lovley

BMC Genomics • 2010

Geobacter species grow by transferring electrons out of the cell--either to Fe(III)-oxides or to man-made substances like energy-harvesting electrodes. Study of Geobacter sulfurreducens has shown that TCA cycle enzymes, inner-membrane respiratory enzymes, and periplasmic and outer-membrane cytochromes are required. Here we present comparative analysis of six Geobacter genomes, including species from the clade that predominates in the subsurface. Conservation of proteins across the genomes was determined to better understand the evolution of Geobacter species and to create a metabolic model applicable to subsurface environments.

Gemma Reguera

Biochemical Society Transactions • 2012

The in situ stimulation of Fe(III) oxide reduction in the subsurface stimulates the growth of Geobacter spp. and the precipitation of U(VI) from groundwater. As with Fe(III) oxide reduction, the reduction of uranium by Geobacter spp. requires the expression of their conductive pili. The pili bind the soluble uranium and catalyse its extracellular reductive precipitation along the pili filaments as a mononuclear U(IV) complexed by carbon-containing ligands. Although most of the uranium is immobilized by the pili, some uranium deposits are also observed in discreet regions of the outer membrane, consistent with the participation of redox-active foci, presumably c-type cytochromes, in the extracellular reduction of uranium. It is unlikely that cytochromes released from the outer membrane could associate with the pili and contribute to the catalysis, because scanning tunnelling microscopy spectroscopy did not reveal any haem-specific electronic features in the pili, but, rather, showed topographic and electronic features intrinsic to the pilus shaft. Pili not only enhance the rate and extent of uranium reduction per cell, but also prevent the uranium from traversing the outer membrane and mineralizing the cell envelope. As a result, pili expression preserves the essential respiratory activities of the cell envelope and the cell's viability. Hence the results support a model in which the conductive pili function as the primary mechanism for the reduction of uranium and cellular protection in Geobacter spp.

S. Veer Raghavulu, P.N. Sarma, S. Venkata Mohan

Journal of Applied Microbiology • 2011

To study the bioelectrochemical behaviour of Pseudomonas aeruginosa (MTCC 17702) and Escherichia coli (MTCC 10436) and to assess their potential to act as anodic biocatalyst with the function of anaerobic consortia for microbial (bio) fuel cell (BFC) application.

Kengo Sasaki, Masahiko Morita, Norio Matsumoto et al.

Journal of Bioscience and Bioengineering • 2012

The aim of this study was to show the effectiveness of the membrane free bioelectrochemical system (BES) using three electrodes on inhibition of methanogenesis and construction of hydrogen fermentation from the artificial garbage slurry. The electrical redox-potential on the working electrode was adjusted to -1.0V (vs. Ag/AgCl) that has positive effect on methanogenesis. The redox-potential on the counter electrode was measured to be 1.6V. The pH in the effluents was 5.5-6.4. Hydrogen production rate at the cathode side was similar to that at the anode side and much higher than that calculated from current, and reached a maximum of 2445±815 (average±standard deviation) mL L(-1) d(-1) at an organic loading rate of 58.7g dichromate chemical oxygen demand per L d(-1). Methane production was negligible throughout the experiment. Acetate and butyrate were the main products of the fermentation using a BES; these offered favorable conditions for hydrogen production. The bacterial community in the bioelectrochemical hydrogen fermentor differed from that in the methanogenic seed sludge and included hitherto unknown species. These results show that high redox-potential on the anodic electrode and acidic pH in the membrane free BES can be utilized for hydrogen fermentation from the artificial garbage slurry by avoiding methanogenesis.

Iain S. Michie, Jung Rae Kim, Richard M. Dinsdale et al.

Bioresource Technology • 2014

In this study three different tubular helical anode designs are compared, for each helical design the pitch and nominal sectional area/liquid flow channel between the helicoids was varied and this produced maximum power densities of 11.63, 9.2 and 6.73Wm(-3) (small, medium and large helical flow channel cross-sections). It is found that the level of mixing and the associated shear rates present in the anodes affects both the power development and biofilm formation. The small helical flow channel carbon anode produced 40% more biofilm and this result was related to modelling data which determined a system shear rate of 237s(-1), compared to 52s(-1) and 47s(-1) for the other reactor configurations. The results from computational fluid dynamic modelling further distinguishes between convective flow conditions and supports the influence of helical structure on system performance, so establishing the importance of anodic design on the overall electrogenic biofilm activity.

Stephen J. Andersen, Ilje Pikaar, Stefano Freguia et al.

Environmental Science & Technology • 2013

Microbial bioelectrochemical systems (BESs) use microorganisms as catalysts for electrode reactions. They have emerging applications in bioenergy, bioproduction, and bioremediation. BESs can be scaled up as a linked series of units or cells; however, this may lead to so-called cell reversal. Here, we demonstrate a cell balance system (CBS) that controls individual BES cells connected electrically in series by dynamically adapting the applied potential in the kilohertz frequency range relative to the performance of the bioanode. The CBS maintains the cell voltage of individual BES cells at or below a maximum set point by bypassing a portion of applied current with a high-frequency metal oxide semiconductor field-effect transistor switch control system. We demonstrate (i) multiple serially connected BES cells started simultaneously and rapidly from a single power source, as the CBS imparts no current limitation, (ii) continuous, stable, and independent performance of each stacked BES cell, and (iii) stable BES cell and stack performance under excessive applied currents. This control system has applications for not only serially stacked BESs in scaled-up stacks but also rapidly starting individual- and/or lab-scale BESs.

Ahmed ElMekawy, Sandipam Srikanth, Karolien Vanbroekhoven et al.

Journal of Power Sources • 2014

Deyong Kong, Bin Liang, Duu-Jong Lee et al.

Journal of Environmental Sciences • 2014

Exposure to chloramphenicol (CAP), a chlorinated nitroaromatic antibiotic, can induce CAP-resistant bacteria/genes in diverse environments. A biocathode bioelectrochemical system (BES) was applied to reduce CAP under switched operational temperatures. When switching from 25 to 10°C, the CAP reduction rate (kCAP) and the maximum amount of the dechlorinated reduced amine product (AMCl, with no antibacterial activity) by the biocathode communities were both markedly decreased. The acetate and ethanol yield from cathodophilic microbial glucose fermentation (with release of electrons) was also reduced. Formation of the product AMCl was enhanced by the biocathode dechloridation reaction compared with that produced from pure electrochemical or microbial dechloridation processes. The electrochemical and morphological analyses of cathode biofilms demonstrated that some cathodophilic microbes could adapt to low temperature and play a key role in CAP degradation. The resilient biocathode BES has a potential for the treatment of CAP-containing wastewater in temperature fluctuating environments.

Sanath Kondaveeti, Sang-Hoon Lee, Hee-Deung Park et al.

Water Research • 2014

Pan Yu Wong, Ka Yu Cheng, Anna H. Kaksonen et al.

Water Research • 2014

We demonstrated the ability of a bio-anode to fix dinitrogen (N2), and confirmed that diazotrophs can be used to treat N-deficient wastewater in a bioelectrochemical system (BES). A two-compartment BES was fed with an N-deficient medium containing glucose for >200 days. The average glucose and COD removal at an anodic potential of +200 mV vs. Ag/AgCl was 100% and 76%, respectively. Glucose removal occurred via fermentation under open circuit (OC), with acetate as the key byproduct. Closing circuit remarkably reduced acetate accumulation, suggesting the biofilm could oxidise acetate under N-deficient conditions. Nitrogen fixation required an anode and glucose; removing either reduced N2 fixation significantly. This suggests that diazotroph utilised glucose directly at the anode or indirectly through syntrophic interaction of an N2-fixing fermenter and an anodophile. The enriched biofilm was dominated (68%) by the genus Clostridium, members of which are known to be electrochemically active and capable of fixing N2.

Tao Bo, Lixia Zhang, Xiaoyu Zhu et al.

RSC Adv. • 2014

Nikolaos Xafenias, Valeria Mapelli

International Journal of Hydrogen Energy • 2014

Fanying Kong, Aijie Wang, Hong-Yu Ren

Bioresource Technology • 2014

This study developed and optimized a modular biocathode materials design in bioelectrochemical system (BES) using composite metal and carbon-based materials. The 4-chlorophenol (4-CP) dechlorination could be improved with such composite materials. Results showed that stainless steel basket (SSB) filled with graphite granules (GG) and carbon brush (CB) (SSB/GG/CB) was optimum for dechlorination, followed by SSB/CB and SSB/GG, with rate constant k of 0.0418 ± 0.0002, 0.0374 ± 0.0004, and 0.0239 ± 0.0002 h(-1), respectively. Electrochemical impedance spectroscopy (EIS) demonstrated that the composite materials with metal can benefit the electron transfer and decrease the charge transfer resistance to be 80.4 Ω in BES-SSB/GG/CB, much lower than that in BES-SSB (1674.3 Ω), BES-GG (387.3 Ω), and BES-CB (193.8 Ω). This modular cathode design would be scalable with successive modules for BES scale-up, and may offer useful information to guide the selection and design of BES materials towards dechlorination improvement in wastewater treatment.

Fei Sun, Hao Liu, Bin Liang et al.

Bioresource Technology • 2013

Reductive degradation of choramphenicol (CAP) using Bioelectrochemical system (BES) with both abiotic cathode and biocathode was investigated. It was found that the CAP reduction efficiency during the first 24 h reached 86.3% of the biocathode group, while which was only 62.9% in the case of abiotic cathode. Except for the cathode potential, other indicators of the cathode performance as the cathode current, the current response of the cyclic voltammetry, the ohm resistance, and the polarization resistance of the biocathode group were all better than those of the abiotic group. Moreover, specific CAP reductive rate of the biocathode with sludge fermentation liquid (0.199 h(-1)) as carbon source was close to that of the glucose (0.215 h(-1)), but was about 3.2 times of the abiotic cathode group (0.062 h(-1)). It suggested that the introduction of biocathode would better the cathode performance, and then further increase the CAP reduction.

Li Xiao, Erica B. Young, John A. Berges et al.

Environmental Science & Technology • 2012

An integrated photobioelectrochemical (IPB) system was developed by installing a microbial fuel cell (MFC) inside an algal bioreactor. This system achieves the simultaneous removal from a synthetic solution of organics (in the MFC) and nutrients (in the algal bioreactor), and the production of bioenergy in electricity and algal biomass through bioelectrochemical and microbiological processes. During the one-year operation, the IPB system removed more than 92% of chemical oxygen demand, 98% of ammonium nitrogen, and 82% of phosphate and produced a maximum power density of 2.2 W/m(3) and 128 mg/L of algal biomass. The algal growth provided dissolved oxygen to the cathode reaction of the MFC, whereas electrochemical oxygen reduction on the MFC cathode buffered the pH of the algal growth medium (which was also the catholyte). The system performance was affected by illumination and dissolved oxygen. Initial energy analysis showed that the IPB system could theoretically produce enough energy to cover its consumption; however, further improvement of electricity production is desired. An analysis of the attached and suspended microbes in the cathode revealed diverse bacterial taxa typical of aquatic and soil bacterial communities with functional roles in contaminant degradation and nutrient cycling.

S. Srikanth, M. Venkateswar Reddy, S. Venkata Mohan

Bioresource Technology • 2012

Microaerophilic microenvironment at biocathode was evaluated for electrogenesis along with the polyhydroxyalkanoates (PHA) accumulation in bio-electrochemical system (BES). The electrogenic activity (512 mV; 15.2 mW/m(2)) was extended for longer periods (144 h) which might be attributed to the lowering of losses due to the controlled microbial metabolism. Growth limiting stress at cathode due to lower oxygen levels and its effective utilization by the protons and electrons coming from anode, might have diverted the microbial metabolism towards PHA synthesis instead of oxidation. PHA accumulation (19% of dry cell weight (DCW)) was observed with higher hydroxy butyrate (HB) (89%) concentration at 48 th h in the cathodic biocatalyst and was re-utilized by the end of experiment. Bio-electro kinetics studied through voltammetry and Tafel analysis further supported the observed electrogenesis in microaerophilic reduction microenvironment, in terms of redox catalytic currents, Tafel slopes, exchange current densities and polarization resistance.

Suyun Zeng, Sujun Wang, Li Wang et al.

Sensors • 2012

CD105 is a well-known tumor metastasis marker and useful for early monitoring of metastasis and cancer relapse. It is important to generate rapid, reliable and precise analytical information regarding CD105 levels. To establish a simple, selective and sensitive detection method, we prepared an immunosensor with novel bioconjugates based on Pt nanoparticles, thionin acetate and antibodies. The proposed immunosensor displayed a broader linear response to CD105, with a working range of 1.3 to 200.0 ng/mL and a detection limit of 0.9 ng/mL under optimal conditions. Moreover, the studied immunosensor exhibited high sensitivity, fast analysis and adequate stability. The proposed methodology could readily be extended to other clinical- or environment-related biospecies.

Sanath Kondaveeti, Booki Min

Bioprocess and Biosystems Engineering • 2013

Electrochemical treatment of nitrate ions was attempted using different catalysts on the cathode in bioelectrochemical denitrification systems. The carbon cathode coated by biofilm (biocathode) could remove 91 % of nitrate ions at 1.0 V, which was almost same as the Pt-coated electrode (90 %). The exchange current density of biocathode was 0.0083 A/m(2), which was almost 22 times higher than with an abiotic plain carbon cathode. The formation of intermediate products in nitrate reduction varied depending on the cell voltage. At 0.5 V, a large portion of nitrate was converted to ammonia, but at more increased cell voltage (0.7 and 1 V) a high amount of nitrite ions was found with little ammonia formation in cathodic solution. The maximum nitrate removal rate was 0.204 mg NO(3)-N/cm(2)d by biocathode, while plain carbon paper showed only 0.176 mg NO(3)-N/cm(2)d. Electrochemical analysis of chronoamperometry showed a higher stable current generation for biocathode (3.1 mA) and Pt-coated cathode (2.8 mA) as compared to plain carbon (0.6 mA) at 0.7 V of poised voltage.

Sanath Kondaveeti, Sang-Hoon Lee, Hee-Deung Park et al.

Water Research • 2014

Electrochemical treatment of nitrate (NO3(-)), nitrite (NO2(-)) and mixtures of nitrate and nitrite was evaluated with microbial catalysts on a cathode in three different bioelectrochemical denitrification systems (BEDS). The removal rates and removal percentage of nitrogen (N) compounds varied during biotic and abiotic operations. The biotic cathode using NO3(-)-N as an electron acceptor showed enhanced removal percentages (88%) compared to the operation with NO2(-)-N (85%). The simultaneous reduction of NO3(-)-N and NO2(-)-N occurred in the operation with a mixture of N compounds. The bacterial diversity from the initial inoculum (return sludge) changed at the end of bioelectrochemical denitrification operation after 55 days. The microbial community composition was different depending on the type of electron acceptor. BEDS operation with NO3(-)-N and NO2(-)-N was enriched with Proteobacteria and Firmicutes respectively. BEDS with a mixture of N electron acceptors showed enrichment with Proteobacteria. There was no clear, distinct microbial community between the cathode biofilm and suspended biomass.

The Hai Pham, Peter Aelterman, Willy Verstraete

Trends in Biotechnology • 2009

In a bioelectrochemical system (BES) operated with a bioanode, the anode performance plays an important part in the overall performance. Fundamental aspects of bioanodes have been intensively investigated, enabling us to better understand the growth, kinetics functioning and interactions of anodophilic microorganisms. Recently, various technological advances have improved the properties and operation of anodes and have increased bioanode performance by up to tenfold. To further boost the performance of bioanodes by several orders of magnitude, practical microbiological approaches deserve more investigation. This article reviews the factors affecting bioanode performance, the recent advances and the prospective strategies for improving it. Future application perspectives of bioanodes are also proposed.

A. Bonmatí, A. Sotres, Y. Mu et al.

Bioresource Technology • 2013

The aim of this work was to investigate the feasibility of using oxalate at the anode in a continuous reactor. Complete oxalate removal was observed, albeit at a maximum coulombic efficiency of 33.9±0.4%. At the cathode side, there was an increase in pH from 8 to 11 showing production of caustic. Analysis of the microbial community demonstrated a clear shift during reactor start-up, resulting in enrichment of microorganisms belonging to Bacteroidetes, Firmicutes, Mollicutes, and β and γ-Proteobacteria. Methane was produced throughout the experiment; Archaea belonging to the Methanosarcinacea, Methanomicrobiaceae and Methanosaetaceae were identified as key representatives.

S. Venkata Mohan, S. Veer Raghavulu, P.N. Sarma

Biosensors and Bioelectronics • 2008

Biochemical functioning of single chambered microbial fuel cell (MFC) using glass wool as proton exchange membrane (PEM) operated with selectively enriched acidogenic mixed culture was evaluated in terms of bioelectricity production and wastewater treatment. Performance of MFC was studied at two different organic/substrate loading rates (OLR) (2.64 and 3.54 kg COD/m(3)) and operating pH 6 and 7 using non-coated plain graphite electrodes (mediatorless anode; air cathode). Applied OLR in association with operating pH showed marked influence on the power output and substrate degradation efficiency. Higher current density was observed at acidophilic conditions [pH 6; 98.13 mA/m(2) (2.64 kg COD/m(3)-day; 100 Omega) and 111.29 mA/m(2) (3.54 kg COD/m(3)-day; 100 Omega)] rather than neutral conditions [pH 7; 100.52 mA/m(2) (2.64 kg COD/m(3)-day; 100 Omega) and 98.13 mA/m(2) (3.54 kg COD/m(3)-day; 100 Omega)]. On the contrary, effective substrate degradation was observed at neutral pH. MFC performance was evaluated employing polarization curve, impedance analysis, cell potential, Coulombic efficiency and bioprocess monitoring. Sustainable power yield was calculated at stable cell potential.

Sunil A. Patil, Venkata Prasad Surakasi, Sandeep Koul et al.

Bioresource Technology • 2009

Feasibility of using chocolate industry wastewater as a substrate for electricity generation using activated sludge as a source of microorganisms was investigated in two-chambered microbial fuel cell. The maximum current generated with membrane and salt bridge MFCs was 3.02 and 2.3 A/m(2), respectively, at 100 ohms external resistance, whereas the maximum current generated in glucose powered MFC was 3.1 A/m(2). The use of chocolate industry wastewater in cathode chamber was promising with 4.1 mA current output. Significant reduction in COD, BOD, total solids and total dissolved solids of wastewater by 75%, 65%, 68%, 50%, respectively, indicated effective wastewater treatment in batch experiments. The 16S rDNA analysis of anode biofilm and suspended cells revealed predominance of beta-Proteobacteria clones with 50.6% followed by unclassified bacteria (9.9%), alpha-Proteobacteria (9.1%), other Proteobacteria (9%), Planctomycetes (5.8%), Firmicutes (4.9%), Nitrospora (3.3%), Spirochaetes (3.3%), Bacteroides (2.4%) and gamma-Proteobacteria (0.8%). Diverse bacterial groups represented as members of the anode chamber community.

S. Venkata Mohan, R. Saravanan, S. Veer Raghavulu et al.

Bioresource Technology • 2008

The performance of aerated and ferricyanide catholytes on the bioelectricity production was evaluated in dual chambered microbial fuel cell (MFC) (mediatroless anode; graphite electrodes) employing selectively enriched H(2) producing mixed consortia as anodic inoculum. Two MFCs with aerated catholyte (MFC(AC)) and ferricyanide catholyte (MFC(FC)) were operated separately to elucidate the difference in power generation potential and carbon removal efficiency under similar operating conditions [ambient pressure; room temperature (28+/-2 degrees C); acidophilic microenvironment (pH 6)]. The experimental data demonstrated the feasibility of in situ bioelectricity generation along with wastewater treatment. Effective power generation and substrate removal efficiency was documented in the fuel cell operated with ferricyanide catholyte (586 mV; 2.37 mA; 0.559 kg COD/m(3) day) than aerated catholyte (572 mV; 1.68 mA; 0.464 kg COD/m(3) day). Maximum power yield (0.635 W/kg COD(R) and 0.440 W/kg COD(R)) and current density (222.59 mA/m(2) and 190.28 mA/m(2)) was observed at 100 Omega resistor with ferricyanide and aerated catholytes, respectively. The study documented both wastewater treatment and electricity production through direct conversion of H(2) in a single system.

Anil Ghadge, M.M. Ghangrekar, Soumya Pandit et al.

International Journal of Environmental Technology and Management • 2014

Surajbhan Sevda, Xochitl Dominguez-Benetton, Karolien Vanbroekhoven et al.

Applied Energy • 2013

Ho Il Park, Chenjie Wu, Lian-Shin Lin

Biotechnology and Bioprocess Engineering • 2012