title: Bioelectrochemical reduction of CO(2) to CH(4) via direct and indirect extracellular electron transfer by a hydrogenophilic methanogenic culture.
abstract: This study describes the performance of a microbial biocathode, based on a hydrogenophilic methanogenic culture, capable of reducing carbon dioxide to methane, at high rates (up to 0.055 + or - 0.002 mmol d(-1) mgVSS(-1)) and electron capture efficiencies (over 80%). Methane was produced, at potentials more negative than -650 mV vs. SHE, both via abiotically produced hydrogen gas (i.e., via hydrogenophilic methanogenesis) and via direct extracellular electron transfer. The relative contribution of these two mechanisms was highly dependent on the set cathode potential. Both cyclic voltammetry tests and batch potentiostatic experiments indicated that the capacity for extracellular electron transfer was a constitutive trait of the hydrogenophilic methanogenic culture. In principle, both electrons and carbon dioxide required for methane production could be obtained from a bioanode carrying out the oxidation of waste organic substrates.
authors.affiliation: Department of Chemistry, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Villano
authors.forename: Federico
authors.initials: F
authors.lastname: Aulenta
authors.forename: Costanza
authors.initials: C
authors.lastname: Ciucci
authors.forename: Tommaso
authors.initials: T
authors.lastname: Ferri
authors.forename: Antonio
authors.initials: A
authors.lastname: Giuliano
authors.forename: Mauro
authors.initials: M
authors.lastname: Majone
mesh_terms: D001419:Bacteria / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002245:Carbon Dioxide / Q000378:metabolism*; D055664:Electrochemical Techniques / Q000379:methods*; D004583:Electrons; D005110:Extracellular Space / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D008697:Methane / Q000378:metabolism*; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D002245:Carbon Dioxide; D006859:Hydrogen; D008697:Methane