Exoelectrogens: Recent advances in molecular drivers involved in extracellular electron transfer and strategies used to improve it for microbial fuel cell applications

Kumar, Ravinder; Singh, Lakhveer; Zularisam, A. W.

doi:10.1016/j.rser.2015.12.029

Cited by 376 publications

(166 citation statements)

References 112 publications

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“…Growth and kinetics of exoelectrogens in MFCs are not well understood (Torres, 2014), an issue further complicated by uncertainty over the mechanisms of electron transfer (Kumar et al, 2016). Measurements of exoelectrogen numbers, growth rates and growth yields are inherently difficult in MFCs for a series of reasons, which includes a lack of suitable primers and probes, because it is not known which organisms are electrogenic or indeed what makes them electrogenic (see below) and also because sampling of biomass on the electrodes destroys the biofilm required for successful operation (Freguia et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Quantification of effective exoelectrogens by most probable number (MPN) in a microbial fuel cell

Heidrich

Curtis

Woodcock

et al. 2016

Bioresource Technology

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The objective of this work was to quantify the number of exoelectrogens in wastewater capable of producing current in a microbial fuel cell by adapting the classical most probable number (MPN) methodology using current production as end point. Inoculating a series of microbial fuel cells with various dilutions of domestic wastewater and with acetate as test substrate yielded an apparent number of exoelectrogens of 17perml. Using current as a proxy for activity the apparent exoelectrogen growth rate was 0.03h(-1). With starch or wastewater as more complex test substrates similar apparent growth rates were obtained, but the apparent MPN based numbers of exoelectrogens in wastewater were significantly lower, probably because in contrast to acetate, complex substrates require complex food chains to deliver the electrons to the electrodes. Consequently, the apparent MPN is a function of the combined probabilities of members of the food chain being present.

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Section: Introductionmentioning

confidence: 99%

Quantification of effective exoelectrogens by most probable number (MPN) in a microbial fuel cell

Heidrich

Curtis

Woodcock

et al. 2016

Bioresource Technology

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“…In the recent years, He et al (2017), Kumar et al (2016), Hernandez-Fernandez et al (2015), He et al (2015), and Solanki et al (2013) provided detailed and prolific reviews with thorough implications of microbial fuel cell (MFC) for wastewater treatment, bioenergy production, azo dye treatment, selection of electron acceptors, and exoelectrogens transfer, respectively. The concept of exoelectrogens of two dissimilatory metal reducing genera as electroactive bacteria (e.g., genomics, proteomics, and metabolomics of nanowire-generating Shewanella and Geobacter spp.…”

Section: Glimpse Of Microbial Fuel Cellsmentioning

confidence: 99%

“…The concept of exoelectrogens of two dissimilatory metal reducing genera as electroactive bacteria (e.g., genomics, proteomics, and metabolomics of nanowire-generating Shewanella and Geobacter spp. ; Table 1 in Kumar et al 2016) has been well established for bioelectricity-generating applications. However, as aforementioned, sole expression of wild-type or genetically modified "superstar" bioelectricity-generating bacteria (e.g., nanowire-generating Shewanella sp.)…”

Section: Glimpse Of Microbial Fuel Cellsmentioning

confidence: 99%

“…Then, bioelectricity generation would be taken place at (bio)cathode coupled with water formation (i.e., 1 2 O 2 + 2H + + 2e − → H 2 O). In fact, there were at least several mechanisms in levels of genomics and proteomics for biofilm formation, direct electron transfer, mediator electron transport, and direct interspecies electron transfer dealing with performance of power generation in MFCs (Kumar et al 2016). Regarding (bio)cathode, selecting appropriate electron acceptor could significantly attenuate the potential loss present on the cathode, effectively augmenting power generation in MFCs (He et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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Electron transport phenomena of electroactive bacteria in microbial fuel cells: a review of Proteus hauseri

Hsueh

Chen

2017

Bioresour. Bioprocess.

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This review tended to decipher the expression of electron transfer capability (e.g., biofilm formation, electron shuttles, swarming motility, dye decolorization, bioelectricity generation) to microbial fuel cells (MFCs). As mixed culture were known to perform better than pure microbial cultures for optimal expression of electrochemically stable activities to pollutant degradation and bioenergy recycling, Proteus hauseri isolated as a "keystone species" to maintain such ecologically stable potential for power generation in MFCs was characterized. P. hauseri expressed outstanding performance of electron transfer (ET)-associated characteristics [e.g., reductive decolorization (RD) and bioelectricity generation (BG)] for electrochemically steered bioremediation even though it is not a nanowire-generating bacterium. This review tended to uncover taxonomic classification, genetic or genomic characteristics, enzymatic functions, and bioelectricity-generating capabilities of Proteus spp. with perspectives for electrochemical practicability. As a matter of fact, using MFCs as a tool to evaluate ET capabilities, dye decolorizer(s) could clearly express excellent performance of simultaneous bioelectricity generation and reductive decolorization (SBG and RD) due to feedback catalysis of residual decolorized metabolites (DMs) as electron shuttles (ESs). Moreover, the presence of reduced intermediates of nitroaromatics or DMs as ESs could synergistically augment efficiency of reductive decolorization and power generation. With swarming mobility, P. hauseri could own significant biofilm-forming capability to sustain ecologically stable consortia for RD and BG. This mini-review evidently provided lost episodes of great significance about bioenergysteered applications in myriads of fields (e.g., biodegradation, biorefinery, and electro-fermentation). Keywords

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“…The diverse populations developed in the biofilms in MECs have been widely analyzed (Mei et al, 2015). Geobacter as a typical dissimilatory metal-reducing bacterium (DMRB) is commonly identified in MFCs (Mohan et al, 2014; Zhu et al, 2014; Kumar et al, 2016). Hence, to understand and optimize ecological conditions that facilitate exoelectrogens enrichment and electron transfer are essential for MEC application.…”

Section: Introductionmentioning

confidence: 99%

Impact of Ferrous Iron on Microbial Community of the Biofilm in Microbial Fuel Cells

Liu

et al. 2017

Front. Microbiol.

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The performance of microbial electrochemical cells depends upon microbial community structure and metabolic activity of the electrode biofilms. Iron as a signal affects biofilm development and enrichment of exoelectrogenic bacteria. In this study, the effect of ferrous iron on microbial communities of the electrode biofilms in microbial fuel cells (MFCs) was investigated. Voltage production showed that ferrous iron of 100 μM facilitated MFC start-up compared to 150 μM, 200 μM, and without supplement of ferrous iron. However, higher concentration of ferrous iron had an inhibitive influence on current generation after 30 days of operation. Illumina Hiseq sequencing of 16S rRNA gene amplicons indicated that ferrous iron substantially changed microbial community structures of both anode and cathode biofilms. Principal component analysis showed that the response of microbial communities of the anode biofilms to higher concentration of ferrous iron was more sensitive. The majority of predominant populations of the anode biofilms in MFCs belonged to Geobacter, which was different from the populations of the cathode biofilms. An obvious shift of community structures of the cathode biofilms occurred after ferrous iron addition. This study implied that ferrous iron influenced the power output and microbial community of MFCs.

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Exoelectrogens: Recent advances in molecular drivers involved in extracellular electron transfer and strategies used to improve it for microbial fuel cell applications

Cited by 376 publications

References 112 publications

Quantification of effective exoelectrogens by most probable number (MPN) in a microbial fuel cell

Quantification of effective exoelectrogens by most probable number (MPN) in a microbial fuel cell

Electron transport phenomena of electroactive bacteria in microbial fuel cells: a review of Proteus hauseri

Impact of Ferrous Iron on Microbial Community of the Biofilm in Microbial Fuel Cells

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