title: The conjugated oligoelectrolyte DSSN+ enables exceptional coulombic efficiency via direct electron transfer for anode-respiring Shewanella oneidensis MR-1-a mechanistic study.
abstract: Shewanella oneidensis MR-1 was cultivated on lactate with poised graphite electrode acceptors (E = +0.2 V vs. Ag/AgCl) in order to explore the basis for sustained increases in anodic current output following the addition of the lipid-intercalating conjugated oligoelectrolyte (COE), 4,4'-bis(4'-(N,N-bis(6''-(N,N,N-trimethylammonium)hexyl)amino)-styryl)stilbene tetraiodide (DSSN+). Microbial cultures, which were spiked with DSSN+, exhibit a ∼2.2-fold increase in charge collected, a ∼3.1-fold increase in electrode colonization by S. oneidensis, and a ∼1.7-fold increase in coulombic efficiency from 51 ± 10% to an exceptional 84 ± 7% without obvious toxicity effects. Direct microbial biofilm voltammetry reveals that DSSN+ rapidly and sustainably increases cytochrome-based direct electron transfer and subsequently increases flavin-based mediated electron transfer. Control experiments indicate that DSSN+ does not contribute to the current in the absence of bacteria.
authors.affiliation: Department of Materials, University of California, Santa Barbara, California CA 93106, USA. bazan@chem.ucsb.edu.
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Kirchhofer
authors.forename: Xiaofen
authors.initials: X
authors.lastname: Chen
authors.forename: Enrico
authors.initials: E
authors.lastname: Marsili
authors.forename: James J
authors.initials: JJ
authors.lastname: Sumner
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Dahlquist
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D004566:Electrodes / Q000382:microbiology*; D004573:Electrolytes / Q000737:chemistry*; D004579:Electron Transport; D004735:Energy Transfer / Q000502:physiology; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020592:Shewanella / Q000502:physiology*; D055672:Static Electricity
chemical_list: D004573:Electrolytes