A New Insight into Potential Regulation on Growth and Power Generation of <i>Geobacter sulfurreducens</i> in Microbial Fuel Cells Based on Energy Viewpoint

Wei, Jincheng; Liang, Peng; Cao, Xun; Huang, Xia

doi:10.1021/es903758m

Cited by 154 publications

(110 citation statements)

References 22 publications

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“…n ¼ 1). 22 The use of a first order reaction for Step 3 follows directly from models of redox enzyme electrodes 25,29,30,[38][39][40] and is consistent with the supposition that mediators in Step 3 are bound to the microbe surface (e.g. outer membrane cytochromes).…”

Section: Resultsmentioning

confidence: 58%

Application of cyclic voltammetry to investigate enhanced catalytic current generation by biofilm-modified anodes of Geobacter sulfurreducens strain DL1vs. variant strain KN400

Strycharz

Malanoski

Snider

et al. 2011

Energy Environ. Sci.

189

178

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A biofilm of Geobacter sulfurreducens will grow on an anode surface and catalyze the generation of an electrical current by oxidizing acetate and utilizing the anode as its metabolic terminal electron acceptor. Here we report qualitative analysis of cyclic voltammetry of anodes modified with biofilms of G. sulfurreducens strains DL1 and KN400 to predict possible rate-limiting steps in current generation. Strain KN400 generates approximately 2 to 8-fold greater current than strain DL1 depending upon the electrode material, enabling comparative electrochemical analysis to study the mechanism of current generation. This analysis is based on our recently reported electrochemical model for biofilm-catalyzed current generation expanded here to a five step model; Step 1 is mass transport of acetate, carbon dioxide and protons into and out of the biofilm, Step 2 is microbial turnover of acetate to carbon dioxide and protons, Step 3 is the non-concerted, 1-electron reduction of 8 equivalents of electron transfer (ET) mediator, Step 4 is extracellular electron transfer (EET) through the biofilm to the electrode surface, and Step 5 is the reversible oxidation of reduced mediator by the electrode. Five idealized voltammetric current vs. potential dependencies (voltammograms) are derived, one for when each step in the model is assumed to limit catalytic current. Comparison to experimental voltammetry of DL1 and KN400 biofilm-modified anodes suggests that for both strains, the microbial oxidation of acetate (Step 2) is fast compared to microbial reduction of ET mediator (Step 3), and either Step 3 or EET through the biofilm (Step 4) limits catalytic current generation. The possible limitation of catalytic current by Step 4 is consistent with proton concentration gradients observed within these biofilms and finite thicknesses achieved by these biofilms. The model presented here has been universally designed for application to biofilms other than G. sulfurreducens and could serve as a platform for future quantitative voltammetric analysis of non-corrosive anode and cathode reactions catalyzed by microorganisms.

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Section: Resultsmentioning

confidence: 58%

Application of cyclic voltammetry to investigate enhanced catalytic current generation by biofilm-modified anodes of Geobacter sulfurreducens strain DL1vs. variant strain KN400

Strycharz

Malanoski

Snider

et al. 2011

Energy Environ. Sci.

189

178

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“…With microorganisms functioning as catalysts in BESs, their growth and activity is inextricably linked to the performance of these systems. Biomass growth and activity in BESs is known to be dynamic and highly adaptive to changing operational conditions 27, 28. Although biomass growth and activity has been studied by using different techniques,29, 30 little quantitative information is available regarding the relation between specific growth rates, activities, and biomass yields on one hand, and operational conditions (e.g., electrode potential, substrate availability, or shear stress) on the other.…”

Section: Introductionmentioning

confidence: 99%

In situ Biofilm Quantification in Bioelectrochemical Systems by using Optical Coherence Tomography

Molenaar

Sleutels²,

Pereirã³

et al. 2018

ChemSusChem

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Detailed studies of microbial growth in bioelectrochemical systems (BESs) are required for their suitable design and operation. Here, we report the use of optical coherence tomography (OCT) as a tool for in situ and noninvasive quantification of biofilm growth on electrodes (bioanodes). An experimental platform is designed and described in which transparent electrodes are used to allow real‐time, 3D biofilm imaging. The accuracy and precision of the developed method is assessed by relating the OCT results to well‐established standards for biofilm quantification (chemical oxygen demand (COD) and total N content) and show high correspondence to these standards. Biofilm thickness observed by OCT ranged between 3 and 90 μm for experimental durations ranging from 1 to 24 days. This translated to growth yields between 38 and 42 mgCODbiomass gCODacetate −1 at an anode potential of −0.35 V versus Ag/AgCl. Time‐lapse observations of an experimental run performed in duplicate show high reproducibility in obtained microbial growth yield by the developed method. As such, we identify OCT as a powerful tool for conducting in‐depth characterizations of microbial growth dynamics in BESs. Additionally, the presented platform allows concomitant application of this method with various optical and electrochemical techniques.

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“…When anodes in MFCs were acclimated to different set anode potentials they showed differences in startup time, power production, and electrochemical performance (Sun et al, 2012;Torres et al, 2009;Wang et al, 2009;Zhang et al, 2013;Zhu et al, 2013), likely due to the selection of different bacteria species with different anode potentials during the acclimation. Even with pure cultures the set potential can alter expression of different electron transport systems, thus affecting the actual reactions (Dumas et al, 2008;Wei et al, 2010). These changes in the electrochemical behavior or composition of the microorganisms are much different than that of abiotic electrochemical systems where the reaction pathways and potentials are not altered.…”

Section: Introductionmentioning

confidence: 99%

Reference and counter electrode positions affect electrochemical characterization of bioanodes in different bioelectrochemical systems

Zhang

Liu²,

Ivanov³

et al. 2014

Biotech & Bioengineering

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The placement of the reference electrode (RE) in various bioelectrochemical systems is often varied to accommodate different reactor configurations. While the effect of the RE placement is well understood from a strictly electrochemistry perspective, there are impacts on exoelectrogenic biofilms in engineered systems that have not been adequately addressed. Varying distances between the working electrode (WE) and the RE, or the RE and the counter electrode (CE) in microbial fuel cells (MFCs) can alter bioanode characteristics. With well-spaced anode and cathode distances in an MFC, increasing the distance between the RE and anode (WE) altered bioanode cyclic voltammograms (CVs) due to the uncompensated ohmic drop. Electrochemical impedance spectra (EIS) also changed with RE distances, resulting in a calculated increase in anode resistance that varied between 17 and 31 V (À0.2 V). While WE potentials could be corrected with ohmic drop compensation during the CV tests, they could not be automatically corrected by the potentiostat in the EIS tests. The electrochemical characteristics of bioanodes were altered by their acclimation to different anode potentials that resulted from varying the distance between the RE and the CE (cathode). These differences were true changes in biofilm characteristics because the CVs were electrochemically independent of conditions resulting from changing CE to RE distances. Placing the RE outside of the current path enabled accurate bioanode characterization using CVs and EIS due to negligible ohmic resistances (0.4 V). It is therefore concluded for bioelectrochemical systems that when possible, the RE should be placed outside the current path and near the WE, as this will result in more accurate representation of bioanode characteristics.

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A New Insight into Potential Regulation on Growth and Power Generation of Geobacter sulfurreducens in Microbial Fuel Cells Based on Energy Viewpoint

Cited by 154 publications

References 22 publications

Application of cyclic voltammetry to investigate enhanced catalytic current generation by biofilm-modified anodes of Geobacter sulfurreducens strain DL1vs. variant strain KN400

Application of cyclic voltammetry to investigate enhanced catalytic current generation by biofilm-modified anodes of Geobacter sulfurreducens strain DL1vs. variant strain KN400

In situ Biofilm Quantification in Bioelectrochemical Systems by using Optical Coherence Tomography

Reference and counter electrode positions affect electrochemical characterization of bioanodes in different bioelectrochemical systems

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