title: Alamethicin suppresses methanogenesis and promotes acetogenesis in bioelectrochemical systems.
abstract: Microbial electrosynthesis (MES) systems with mixed cultures often generate a variety of gaseous and soluble chemicals. Methane is the primary end product in mixed-culture MES because it is the thermodynamically most favorable reduction product of CO2. Here, we show that the peptaibol alamethicin selectively suppressed the growth of methanogens in mixed-culture MES systems, resulting in a shift of the solution and cathode communities to an acetate-producing system dominated by Sporomusa, a known acetogenic genus in MES systems. Archaea in the methane-producing control were dominated by Methanobrevibacter species, but no Archaea were detected in the alamethicin-treated reactors. No methane was detected in the mixed-culture reactors treated with alamethicin over 10 cycles (∼ 3 days each). Instead, acetate was produced at an average rate of 115 nmol ml(-1) day(-1), similar to the rate reported previously for pure cultures of Sporomusa ovata on biocathodes. Mixed-culture control reactors without alamethicin generated methane at nearly 100% coulombic recovery, and no acetate was detected. These results show that alamethicin is effective for the suppression of methanogen growth in MES systems and that its use enables the production of industrially relevant organic compounds by the inhibition of methanogenesis.
authors.affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Siegert
authors.affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Yates
authors.affiliation: Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA blogan@psu.edu.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Logan
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000408:Alamethicin / Q000378:metabolism*; D000890:Anti-Infective Agents / Q000378:metabolism*; D001105:Archaea / Q000187:drug effects / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D001674:Bioelectric Energy Sources; D004566:Electrodes / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D041581:Methanobrevibacter / Q000302:isolation & purification / Q000378:metabolism; D059013:Microbial Consortia / Q000187:drug effects*; D045854:Veillonellaceae / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000085:Acetates; D000890:Anti-Infective Agents; D000408:Alamethicin; D008697:Methane
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