title: Study of the mechanism of catalytic activity of G. sulfurreducens biofilm anodes during biofilm growth.
abstract: The number of investigations involving bioelectrochemical systems (BES), processes in which microorganisms catalyze electrode reactions, is increasing while their mechanisms remain unresolved. Geobacter sulfurreducens strain DL1 is a model electrode catalyst that forms multimicrobe-thick biofilms on anodes that catalyze the oxidation of acetate to result in an electric current. Here, we report the characterization by cyclic voltammetry (CV) of DL1 biofilm-modified anodes (biofilm anodes) performed during biofilm development. This characterization, based on our recently reported model of biofilm anode catalytic activity, indicates the following. 1) As a biofilm grows, catalytic activity scales linearly with the amount of anode-accessible redox cofactor in the biofilm. This observation is consistent with a catalytic activity that is limited during biofilm growth by electron transport from within cells to the extracellular redox cofactor. 2) Distinct voltammetric features are exhibited that reflect the presence of a redox cofactor expressed by cells that initially colonize an anode that is not involved in catalytic current generation.
authors.affiliation: Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Ave., SW, Washington DC, 20375, USA. sarah.glaven@nrl.navy.mil
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Strycharz-Glaven
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Tender
mesh_terms: D001674:Bioelectric Energy Sources; D018441:Biofilms / Q000254:growth & development*; D002384:Catalysis; D004566:Electrodes / Q000382:microbiology; D004579:Electron Transport; D045302:Geobacter / Q000502:physiology*; D010084:Oxidation-Reduction