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RESEARCH PRODUCT

Electron transfer mechanism in Shewanella loihica PV-4 biofilms formed at graphite electrode

Niamh BarrySatheesh KrishnamurthyAnand JainXiaoming ZhangRobert WoolleyGabriele PastorellaJ. ConnollyEnrico Marsili

subject

ShewanellaElectroactive biofilmBioelectric Energy SourcesExtracellular Electron TransferRiboflavinInorganic chemistryBiophysicsElectrochemical cellElectron TransportElectron transferGraphite electrodeElectrochemistryGraphitePhysical and Theoretical ChemistryElectrodesMicroscopy ConfocalChemistryQuinonesBiofilmmediated electron transferElectrochemical TechniquesGeneral MedicineChronoamperometryAnodeSpectrometry FluorescenceShewanella loihica PV- 4Extracellular Electron Transfer; Shewanella loihica PV- 4; Electroactive biofilms; Graphite electrode; mediated electron transferBiofilmsMicroscopy Electron ScanningGraphiteDifferential pulse voltammetryCyclic voltammetryOxidation-Reduction

description

Abstract Electron transfer mechanisms in Shewanella loihica PV-4 viable biofilms formed at graphite electrodes were investigated in potentiostat-controlled electrochemical cells poised at oxidative potentials (0.2 V vs. Ag/AgCl). Chronoamperometry (CA) showed a repeatable biofilm growth of S. loihica PV-4 on graphite electrode. CA, cyclic voltammetry (CV) and its first derivative shows that both direct electron transfer (DET) mediated electron transfer (MET) mechanism contributes to the overall anodic (oxidation) current. The maximum anodic current density recorded on graphite was 90 μA cm − 2 . Fluorescence emission spectra shows increased concentration of quinone derivatives and riboflavin in the cell-free supernatant as the biofilm grows. Differential pulse voltammetry (DPV) show accumulation of riboflavin at the graphite interface, with the increase in incubation period. This is the first study to observe a gradual shift from DET to MET mechanism in viable S. loihica PV-4 biofilms.

yearjournalcountryeditionlanguage
2012-01-01Bioelectrochemistry
https://doi.org/10.1016/j.bioelechem.2011.12.012