Population dynamics of electrogenic microbial communities in microbial fuel cells started with three different inoculum sources

By Ishii, Shun'ichi; Suzuki, Shino; Yamanaka, Yuko; Wu, Angela; Nealson, Kenneth H.; Bretschger, Orianna
Published in Bioelectrochemistry NULL 2017

Abstract

Abstract Microbial fuel cells (MFCs) are one of the bioelectrochemical systems that exploit microorganisms as biocatalysts to degrade organic matters and recover energy as electric power. Here, we explored how the established electrogenic microbial communities were influenced by three different inoculum sources; anaerobic sludge of the wastewater plant, rice paddy field soil, and coastal lagoon sediment. We periodically characterized both electricity generation with sucrose consumption and 16S rRNA-basis microbial community composition. The electrochemical features of {MFCs} were slightly different among three inocula, and the lagoon sediment-inoculated {MFC} showed the highest performance in terms of the treatment time. Meanwhile, although the inoculated microbial communities were highly diverse and quite different, only twelve genera affiliated with ?-Proteobacteria, ?-Proteobacteria, Bacilli, Clostridia/Negativicutes or Bacteroidetes were abundantly enriched in all {MFC} anode communities. Within them, several fermentative genera were clearly different due to the inocula, while the inocula-specific phylotypes were identified in an electrogenic genus Geobacter. The relative abundances of phylotypes closely-related to Geobacter metallireducens were increased in later stages of all the sucrose-fed MFCs. These results indicate that key microbial members for the functional electrogenic community widely exist in natural ecosystems, but the community members presenting in inoculum sources affected the {MFC} performances.

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