title: High Biofilm Conductivity Maintained Despite Anode Potential Changes in a Geobacter-Enriched Biofilm.
abstract: This study systematically assessed intracellular electron transfer (IET) and extracellular electron transfer (EET) kinetics with respect to anode potential (Eanode) in a mixed-culture biofilm anode enriched with Geobacter spp. High biofilm conductivity (0.96-1.24 mS cm-1) was maintained during Eanodechanges from -0.2 to +0.2 V versus the standard hydrogen electrode (SHE), although the steady-state current density significantly decreased from 2.05 to 0.35 A m-2in a microbial electrochemical cell. Substantial increase of the Treponema population was observed in the biofilm anode at Eanode=+0.2 V, which reduced intracellular electron-transfer kinetics associated with the maximum specific substrate-utilization rate by a factor of ten. This result suggests that fast EET kinetics can be maintained under dynamic Eanodeconditions in a highly conductive biofilm anode as a result of shift of main EET players in the biofilm anode, although Eanodechanges can influence IET kinetics.
authors.affiliation: Civil and Environmental Engineering, University of Alberta, 9211-116 Street NW, Edmonton, Alberta, T6G 1H9, Canada.
authors.forename: Bipro Ranjan
authors.initials: BR
authors.lastname: Dhar
authors.affiliation: National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA.
authors.forename: Hodon
authors.initials: H
authors.lastname: Ryu
authors.affiliation: School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Ren
authors.affiliation: National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, USA.
authors.forename: Jorge W Santo
authors.initials: JW
authors.lastname: Domingo
authors.affiliation: School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA.
authors.forename: Junkseck
authors.initials: J
authors.lastname: Chae
authors.affiliation: Civil and Environmental Engineering, University of Waterloo, 200 University Avenue, West Waterloo, Ontario, N2L 3G, Canada.
authors.forename: Hyung-Sool
authors.initials: HS
authors.lastname: Lee
mesh_terms: D001674:Bioelectric Energy Sources; D018441:Biofilms; D004553:Electric Conductivity; D004566:Electrodes; D004579:Electron Transport; D005110:Extracellular Space / Q000378:metabolism; D045302:Geobacter / Q000378:metabolism* / Q000502:physiology; D007700:Kinetics
keywords: anode potential; biofilm; conductivity; electron transfer; microbial electrochemical cell