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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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PCA plot of the dominant (darkest) bands from the DGGE gels representing the communities at cycle 1 and cycle 16. This plot contrasts the initial community of wastewater-inoculated reactors (P=PSU and U=UAJA) with the bog-inoculated reactors (B). Over the duration of the experiment all communities converged irrespective of inoculum source.
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fig5: PCA plot of the dominant (darkest) bands from the DGGE gels representing the communities at cycle 1 and cycle 16. This plot contrasts the initial community of wastewater-inoculated reactors (P=PSU and U=UAJA) with the bog-inoculated reactors (B). Over the duration of the experiment all communities converged irrespective of inoculum source.

Mentions: Analysis of predominant bands in DGGE gels using PCA showed convergence of the final microbial communities at cycle 16 (Supplementary Figure S1). During the first cycle, the Bog results clustered separately (quadrant 1) from the two wastewater inoculum sources (quadrant 4) (Figure 5). By the end of the study, all of the data clustered in quadrant 2. The computer-generated PCA (Warmink and van Elsas, 2008) produced the same results as manual scoring, indicating no bias in the manual scoring method (Supplementary Figure S2).


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)

PCA plot of the dominant (darkest) bands from the DGGE gels representing the communities at cycle 1 and cycle 16. This plot contrasts the initial community of wastewater-inoculated reactors (P=PSU and U=UAJA) with the bog-inoculated reactors (B). Over the duration of the experiment all communities converged irrespective of inoculum source.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig5: PCA plot of the dominant (darkest) bands from the DGGE gels representing the communities at cycle 1 and cycle 16. This plot contrasts the initial community of wastewater-inoculated reactors (P=PSU and U=UAJA) with the bog-inoculated reactors (B). Over the duration of the experiment all communities converged irrespective of inoculum source.
Mentions: Analysis of predominant bands in DGGE gels using PCA showed convergence of the final microbial communities at cycle 16 (Supplementary Figure S1). During the first cycle, the Bog results clustered separately (quadrant 1) from the two wastewater inoculum sources (quadrant 4) (Figure 5). By the end of the study, all of the data clustered in quadrant 2. The computer-generated PCA (Warmink and van Elsas, 2008) produced the same results as manual scoring, indicating no bias in the manual scoring method (Supplementary Figure S2).

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