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Convergent development of anodic bacterial communities in microbial fuel cells.

Yates MD, Kiely PD, Call DF, Rismani-Yazdi H, Bibby K, Peccia J, Regan JM, Logan BE - ISME J (2012)

Bottom Line: After 16 cycles the predominance of Geobacter spp. in anode communities was identified using 16S rRNA gene clone libraries (58±10%), fluorescent in-situ hybridization (FISH) (63±6%) and pyrosequencing (81±4%).While the clone library analysis for the underperforming UAJA3 had a significantly lower percentage of Geobacter spp. sequences (36%), suggesting that a predominance of this microbe was needed for convergent power densities, the lower percentage of this species was not verified by FISH or pyrosequencing analyses.These results show that the predominance of Geobacter spp. in acetate-fed systems was consistent with good MFC performance and independent of the inoculum source.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA.

ABSTRACT
Microbial fuel cells (MFCs) are often inoculated from a single wastewater source. The extent that the inoculum affects community development or power production is unknown. The stable anodic microbial communities in MFCs were examined using three inocula: a wastewater treatment plant sample known to produce consistent power densities, a second wastewater treatment plant sample, and an anaerobic bog sediment. The bog-inoculated MFCs initially produced higher power densities than the wastewater-inoculated MFCs, but after 20 cycles all MFCs on average converged to similar voltages (470±20 mV) and maximum power densities (590±170 mW m(-2)). The power output from replicate bog-inoculated MFCs was not significantly different, but one wastewater-inoculated MFC (UAJA3 (UAJA, University Area Joint Authority Wastewater Treatment Plant)) produced substantially less power. Denaturing gradient gel electrophoresis profiling showed a stable exoelectrogenic biofilm community in all samples after 11 cycles. After 16 cycles the predominance of Geobacter spp. in anode communities was identified using 16S rRNA gene clone libraries (58±10%), fluorescent in-situ hybridization (FISH) (63±6%) and pyrosequencing (81±4%). While the clone library analysis for the underperforming UAJA3 had a significantly lower percentage of Geobacter spp. sequences (36%), suggesting that a predominance of this microbe was needed for convergent power densities, the lower percentage of this species was not verified by FISH or pyrosequencing analyses. These results show that the predominance of Geobacter spp. in acetate-fed systems was consistent with good MFC performance and independent of the inoculum source.

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Power density curves generated from cycle 16 showing that UAJA replicate 3 produced far less power than all other reactors, including other UAJA replicates. Legend order mimics the order of the curves based on max power density.
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fig2: Power density curves generated from cycle 16 showing that UAJA replicate 3 produced far less power than all other reactors, including other UAJA replicates. Legend order mimics the order of the curves based on max power density.

Mentions: The bog-inoculated reactors initially produced higher maximum voltages on average than the wastewater-inoculated MFCs, but after 20 cycles, all reactors converged to a maximum voltage output of 470±20 mV (Figure 1). Based on polarization tests, maximum power densities on cycle 16 were not significantly different for eight of the nine reactors (P>0.05), but the UAJA3 replicate produced significantly (P=0.005, t-test) less voltage (data not shown) and power (354 mW m−2; Figure 2) than the other samples. The maximum power density was 590±110 mW m−2 based on all nine reactors, and 620±60 mWm−2 excluding the UAJA3 replicate (n=8).


Convergent development of anodic bacterial communities in microbial fuel cells.

Yates MD, Kiely PD, Call DF, Rismani-Yazdi H, Bibby K, Peccia J, Regan JM, Logan BE - ISME J (2012)

Power density curves generated from cycle 16 showing that UAJA replicate 3 produced far less power than all other reactors, including other UAJA replicates. Legend order mimics the order of the curves based on max power density.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475369&req=5

fig2: Power density curves generated from cycle 16 showing that UAJA replicate 3 produced far less power than all other reactors, including other UAJA replicates. Legend order mimics the order of the curves based on max power density.
Mentions: The bog-inoculated reactors initially produced higher maximum voltages on average than the wastewater-inoculated MFCs, but after 20 cycles, all reactors converged to a maximum voltage output of 470±20 mV (Figure 1). Based on polarization tests, maximum power densities on cycle 16 were not significantly different for eight of the nine reactors (P>0.05), but the UAJA3 replicate produced significantly (P=0.005, t-test) less voltage (data not shown) and power (354 mW m−2; Figure 2) than the other samples. The maximum power density was 590±110 mW m−2 based on all nine reactors, and 620±60 mWm−2 excluding the UAJA3 replicate (n=8).

Bottom Line: After 16 cycles the predominance of Geobacter spp. in anode communities was identified using 16S rRNA gene clone libraries (58±10%), fluorescent in-situ hybridization (FISH) (63±6%) and pyrosequencing (81±4%).While the clone library analysis for the underperforming UAJA3 had a significantly lower percentage of Geobacter spp. sequences (36%), suggesting that a predominance of this microbe was needed for convergent power densities, the lower percentage of this species was not verified by FISH or pyrosequencing analyses.These results show that the predominance of Geobacter spp. in acetate-fed systems was consistent with good MFC performance and independent of the inoculum source.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA.

ABSTRACT
Microbial fuel cells (MFCs) are often inoculated from a single wastewater source. The extent that the inoculum affects community development or power production is unknown. The stable anodic microbial communities in MFCs were examined using three inocula: a wastewater treatment plant sample known to produce consistent power densities, a second wastewater treatment plant sample, and an anaerobic bog sediment. The bog-inoculated MFCs initially produced higher power densities than the wastewater-inoculated MFCs, but after 20 cycles all MFCs on average converged to similar voltages (470±20 mV) and maximum power densities (590±170 mW m(-2)). The power output from replicate bog-inoculated MFCs was not significantly different, but one wastewater-inoculated MFC (UAJA3 (UAJA, University Area Joint Authority Wastewater Treatment Plant)) produced substantially less power. Denaturing gradient gel electrophoresis profiling showed a stable exoelectrogenic biofilm community in all samples after 11 cycles. After 16 cycles the predominance of Geobacter spp. in anode communities was identified using 16S rRNA gene clone libraries (58±10%), fluorescent in-situ hybridization (FISH) (63±6%) and pyrosequencing (81±4%). While the clone library analysis for the underperforming UAJA3 had a significantly lower percentage of Geobacter spp. sequences (36%), suggesting that a predominance of this microbe was needed for convergent power densities, the lower percentage of this species was not verified by FISH or pyrosequencing analyses. These results show that the predominance of Geobacter spp. in acetate-fed systems was consistent with good MFC performance and independent of the inoculum source.

Show MeSH