The microbe electric: conversion of organic matter to electricity

Lovley, Derek R.

doi:10.1016/j.copbio.2008.10.005

Cited by 777 publications

(448 citation statements)

References 74 publications

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“…In BESs, exoelectrogenic bacteria oxidize organic matter and donate electrons to the anode (Lovley, 2006), while different electron acceptors can be reduced biologically or abiotically at the cathode depending on the purpose of the system (Logan and Rabaey, 2012;Lovley, 2008). Air cathode microbial fuel cells (MFCs) are one type of BES that use oxygen as the final electron acceptor, and convert chemical energy directly to electrical power .…”

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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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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“…This suggested that cells at a substantial distance from the anode surface (that is, 50-100 mm) contributed to current production. The mechanisms for this potential long-range electron transfer have been intensively investigated and are still a matter of considerable debate (Lovley, 2006(Lovley, , 2008Rittmann et al, 2008;Logan, 2009).…”

Section: Introductionmentioning

confidence: 99%

Microtoming coupled to microarray analysis to evaluate the spatial metabolic status of Geobacter sulfurreducens biofilms

et al. 2009

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Further insight into the metabolic status of cells within anode biofilms is essential for understanding the functioning of microbial fuel cells and developing strategies to optimize their power output. Cells throughout anode biofilms of Geobacter sulfurreducens reduced the metabolic stains: 5-cyano-2,3-ditolyl tetrazolium chloride and Redox Green, suggesting metabolic activity throughout the biofilm. To compare the metabolic status of cells growing close to the anode versus cells in the outer portion of the anode biofilm, anode biofilms were encased in resin and sectioned into inner (0-20 lm from anode surface) and outer (30-60 lm) fractions. Transcriptional analysis revealed that, at a twofold threshold, 146 genes had significant (Po0.05) differences in transcript abundance between the inner and outer biofilm sections. Only 1 gene, GSU0093, a hypothetical ATP-binding cassette transporter, had significantly higher transcript abundances in the outer biofilm. Genes with lower transcript abundance in the outer biofilm included genes for ribosomal proteins and NADH dehydrogenase, suggesting lower metabolic rates. However, differences in transcript abundance were relatively low (othreefold) and the expression of genes for the tricarboxylic acid cycle enzymes was not significantly lower. Lower expression of genes involved in stress responses in the outer biofilm may reflect the development of low pH near the surface of the anode. The results of this study suggest that cells throughout the biofilm are metabolically active and can potentially contribute to current production. The microtoming/microarray strategy described here may be useful for evaluating gene expression with depth in a diversity of microbial biofilms.

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“…This large energy consumption can be potentially compensated by extracting energy from wastewater, which contains an average energy density of ≈1.9 kW h m −3 stored as chemical energies in the form of various organic compounds 1. Microbial fuel cells (MFCs) are devices that can recover and transform these chemical energies to bioelectricity via bio‐oxidation with the help of electrogenic bacteria (e.g., Shewanella oneidensis and Escherichia coli ) 2. However, the relatively low power density of MFCs (typically in the order of several W m −3 for milliliter‐scale device)3 and the high capital cost associated with fabrication and operation processes severely hinders their potentials for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Boosting Power Density of Microbial Fuel Cells with 3D Nitrogen‐Doped Graphene Aerogel Electrode

et al. 2016

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A 3D nitrogen‐doped graphene aerogel (N‐GA) as an anode material for microbial fuel cells (MFCs) is reported. Electron microscopy images reveal that the N‐GA possesses hierarchical porous structure that allows efficient diffusion of both bacterial cells and electron mediators in the interior space of 3D electrode, and thus, the colonization of bacterial communities. Electrochemical impedance spectroscopic measurements further show that nitrogen doping considerably reduces the charge transfer resistance and internal resistance of GA, which helps to enhance the MFC power density. Importantly, the dual‐chamber milliliter‐scale MFC with N‐GA anode yields an outstanding volumetric power density of 225 ± 12 W m−3 normalized to the total volume of the anodic chamber (750 ± 40 W m−3 normalized to the volume of the anode). These power densities are the highest values report for milliliter‐scale MFCs with similar chamber size (25 mL) under the similar measurement conditions. The 3D N‐GA electrode shows great promise for improving the power generation of MFC devices.

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The microbe electric: conversion of organic matter to electricity

Cited by 777 publications

References 74 publications

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

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

Microtoming coupled to microarray analysis to evaluate the spatial metabolic status of Geobacter sulfurreducens biofilms

Boosting Power Density of Microbial Fuel Cells with 3D Nitrogen‐Doped Graphene Aerogel Electrode

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