title: Microbial population and functional dynamics associated with surface potential and carbon metabolism.
abstract: Microbial extracellular electron transfer (EET) to solid surfaces is an important reaction for metal reduction occurring in various anoxic environments. However, it is challenging to accurately characterize EET-active microbial communities and each member's contribution to EET reactions because of changes in composition and concentrations of electron donors and solid-phase acceptors. Here, we used bioelectrochemical systems to systematically evaluate the synergistic effects of carbon source and surface redox potential on EET-active microbial community development, metabolic networks and overall electron transfer rates. The results indicate that faster biocatalytic rates were observed under electropositive electrode surface potential conditions, and under fatty acid-fed conditions. Temporal 16S rRNA-based microbial community analyses showed that Geobacter phylotypes were highly diverse and apparently dependent on surface potentials. The well-known electrogenic microbes affiliated with the Geobacter metallireducens clade were associated with lower surface potentials and less current generation, whereas Geobacter subsurface clades 1 and 2 were associated with higher surface potentials and greater current generation. An association was also observed between specific fermentative phylotypes and Geobacter phylotypes at specific surface potentials. When sugars were present, Tolumonas and Aeromonas phylotypes were preferentially associated with lower surface potentials, whereas Lactococcus phylotypes were found to be closely associated with Geobacter subsurface clades 1 and 2 phylotypes under higher surface potential conditions. Collectively, these results suggest that surface potentials provide a strong selective pressure, at the species and strain level, for both solid surface respirators and fermentative microbes throughout the EET-active community development.
authors.affiliation: 1] J. Craig Venter Institute, La Jolla, CA, USA [2] Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan [3] Japan Society for the Promotion of Science (JSPS), Chiyoda-ku, Tokyo, Japan.
authors.forename: Shun'ichi
authors.initials: S
authors.lastname: Ishii
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA.
authors.forename: Shino
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA.
authors.forename: Trina M
authors.initials: TM
authors.lastname: Norden-Krichmar
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Phan
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA.
authors.forename: Greg
authors.initials: G
authors.lastname: Wanger
authors.affiliation: 1] J. Craig Venter Institute, La Jolla, CA, USA [2] Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA.
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Nealson
authors.affiliation: Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sekiguchi
authors.affiliation: 1] J. Craig Venter Institute, La Jolla, CA, USA [2] Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA.
authors.forename: Yuri A
authors.initials: YA
authors.lastname: Gorby
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA.
authors.forename: Orianna
authors.initials: O
authors.lastname: Bretschger
mesh_terms: D002244:Carbon / Q000378:metabolism*; D004579:Electron Transport; D045302:Geobacter / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D008670:Metals / Q000378:metabolism; D010084:Oxidation-Reduction; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D008670:Metals; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D002244:Carbon