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

Anand Jain, Xiaoming Zhang, Gabriele Pastorella, Jack O. Connolly, Niamh Barry, Robert Woolley, Satheesh Krishnamurthy, Enrico Marsili

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)

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 (0.2V 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 90μAcm-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.

Original languageEnglish
Pages (from-to)28-32
Number of pages5
JournalBioelectrochemistry
Volume87
DOIs
Publication statusPublished - Oct 2012
Externally publishedYes

Keywords

  • Electroactive biofilms
  • Extracellular electron transfer
  • Graphite electrode
  • Mediated electron transfer
  • Shewanella loihica PV-4

ASJC Scopus subject areas

  • Biophysics
  • Physical and Theoretical Chemistry
  • Electrochemistry

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