title: Cyclic voltammetric analysis of the electron transfer of Shewanella oneidensis MR-1 and nanofilament and cytochrome knock-out mutants.
abstract: Shewanella is frequently used as a model microorganism for microbial bioelectrochemical systems. In this study, we used cyclic voltammetry (CV) to investigate extracellular electron transfer mechanisms from S. oneidensis MR-1 (WT) and five deletion mutants: membrane bound cytochrome (∆mtrC/ΔomcA), transmembrane pili (ΔpilM-Q, ΔmshH-Q, and ΔpilM-Q/ΔmshH-Q) and flagella (∆flg). We demonstrate that the formal potentials of mediated and direct electron transfer sites of the derived biofilms can be gained from CVs of the respective biofilms recorded at bioelectrocatlytic (i.e. turnover) and lactate depleted (i.e. non-turnover) conditions. As the biofilms possess only a limited bioelectrocatalytic activity, an advanced data processing procedure, using the open-source software SOAS, was applied. The obtained results indicate that S. oneidensis mutants used in this study are able to bypass hindered direct electron transfer by alternative redox proteins as well as self-mediated pathways.
authors.affiliation: Sustainable Chemistry and Energy Research, Institute of Environmental and Sustainable Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
authors.forename: Alessandro A
authors.initials: AA
authors.lastname: Carmona-Martinez
authors.forename: Falk
authors.initials: F
authors.lastname: Harnisch
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Fitzgerald
authors.forename: Justin C
authors.initials: JC
authors.lastname: Biffinger
authors.forename: Bradley R
authors.initials: BR
authors.lastname: Ringeisen
authors.forename: Uwe
authors.initials: U
authors.lastname: Schröder
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001674:Bioelectric Energy Sources; D018441:Biofilms; D003574:Cytochrome c Group / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D003580:Cytochromes / Q000737:chemistry / Q000378:metabolism; D004566:Electrodes; D004579:Electron Transport; D010861:Fimbriae, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005407:Flagella / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D055786:Gene Knockout Techniques; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D011199:Potentiometry / Q000379:methods*; D011485:Protein Binding; D020592:Shewanella / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D003574:Cytochrome c Group; D003580:Cytochromes; C114590:omc A protein, Shewanella putrefaciens; C433527:MtrC protein, Shewanella