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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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Community analysis results obtained from pyrosequencing. No significant difference in the amount of Proteobacteria was seen in any reactor. Insert: the Deltaproteobacteria was made up almost entirely of Geobacter and Trichlorobacter (95%). Other minor genera were detected by pyrosequencing that were not detected in the clone libraries.
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fig4: Community analysis results obtained from pyrosequencing. No significant difference in the amount of Proteobacteria was seen in any reactor. Insert: the Deltaproteobacteria was made up almost entirely of Geobacter and Trichlorobacter (95%). Other minor genera were detected by pyrosequencing that were not detected in the clone libraries.

Mentions: A higher relative abundance of sequences with similarity to Deltaproteobacteria (81±4%) (Figure 4) was identified by pyrosequencing compared with 16S rRNA gene clone libraries. Bacteroidetes (10±5%) and Firmicutes (8±3%) were the other two most prominent phyla present. The Deltaproteobacteria sequences obtained by pyrosequencing were dominated by the closely related genera Geobacter and Trichlorobacter, as identified by the RDP II classifier (Cole et al., 2005). It has been proposed that Trichlorobacter be reclassified as Geobacter (Nevin et al., 2007), so the two genera are grouped together in this analysis. The main difference between the two results is that pyrosequencing analysis did not confirm the clone library result that showed a lower abundance of clones with sequence similarity to G. sulfurreducens in the UAJA3 replicate.


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)

Community analysis results obtained from pyrosequencing. No significant difference in the amount of Proteobacteria was seen in any reactor. Insert: the Deltaproteobacteria was made up almost entirely of Geobacter and Trichlorobacter (95%). Other minor genera were detected by pyrosequencing that were not detected in the clone libraries.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig4: Community analysis results obtained from pyrosequencing. No significant difference in the amount of Proteobacteria was seen in any reactor. Insert: the Deltaproteobacteria was made up almost entirely of Geobacter and Trichlorobacter (95%). Other minor genera were detected by pyrosequencing that were not detected in the clone libraries.
Mentions: A higher relative abundance of sequences with similarity to Deltaproteobacteria (81±4%) (Figure 4) was identified by pyrosequencing compared with 16S rRNA gene clone libraries. Bacteroidetes (10±5%) and Firmicutes (8±3%) were the other two most prominent phyla present. The Deltaproteobacteria sequences obtained by pyrosequencing were dominated by the closely related genera Geobacter and Trichlorobacter, as identified by the RDP II classifier (Cole et al., 2005). It has been proposed that Trichlorobacter be reclassified as Geobacter (Nevin et al., 2007), so the two genera are grouped together in this analysis. The main difference between the two results is that pyrosequencing analysis did not confirm the clone library result that showed a lower abundance of clones with sequence similarity to G. sulfurreducens in the UAJA3 replicate.

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
Related in: MedlinePlus