title: Functional and taxonomic dynamics of an electricity-consuming methane-producing microbial community.
abstract: The functional and taxonomic microbial dynamics of duplicate electricity-consuming methanogenic communities were observed over a 6 months period to characterize the reproducibility, stability and recovery of electromethanogenic consortia. The highest rate of methanogenesis was 0.72 mg-CH4/L/day, which occurred during the third month of enrichment when multiple methanogenic phylotypes and associated Desulfovibrionaceae phylotypes were present in the electrode-associated microbial community. Results also suggest that electromethanogenic microbial communities are very sensitive to electron donor-limiting open-circuit conditions. A 45 min exposure to open-circuit conditions induced an 87% drop in volumetric methane production rates. Methanogenic performance recovered after 4 months to a maximum value of 0.30 mg-CH4/L/day under set potential operation (-700 mV vs Ag/AgCl); however, current consumption and biomass production was variable over time. Long-term functional and taxonomic analyses from experimental replicates provide new knowledge toward understanding how to enrich electromethanogenic communities and operate bioelectrochemical systems for stable and reproducible performance.
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA. Electronic address: obretschger@jcvi.org.
authors.forename: Orianna
authors.initials: O
authors.lastname: Bretschger
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA.
authors.forename: Kayla
authors.initials: K
authors.lastname: Carpenter
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; Japan Agency for Marine-Earth Science and Technology, Kochi, Japan.
authors.forename: Shino
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: J. Craig Venter Institute, La Jolla, CA, USA; Japan Agency for Marine-Earth Science and Technology, Kochi, Japan.
authors.forename: Shun'ichi
authors.initials: S
authors.lastname: Ishii
authors.affiliation: University Affiliated Research Center, UC Santa Cruz, Moffett Field, CA, USA; Stanford University, Stanford, CA, USA; NASA Ames Research Center, Moffett Field, CA, USA.
authors.forename: Elysse
authors.initials: E
authors.lastname: Grossi-Soyster
authors.affiliation: NASA Ames Research Center, Moffett Field, CA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Flynn
authors.affiliation: NASA Ames Research Center, Moffett Field, CA, USA.
authors.forename: John
authors.initials: J
authors.lastname: Hogan
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics; D018533:Biomass; D019149:Bioreactors; D004560:Electricity; D019605:Euryarchaeota / Q000145:classification* / Q000235:genetics; D008697:Methane / Q000096:biosynthesis*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S; D008697:Methane
keywords: Bioelectrochemical systems; Electromethanogenesis; Microbial community dynamics