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

Jain, Anand; Zhang, Xiaoming; Pastorella, Gabriele; Connolly, Jack O.; Barry, Niamh; Woolley, Robert; Krishnamurthy, Satheesh and Marsili, Enrico (2012). Electron transfer mechanism in Shewanella loihica PV-4 biofilms formed at graphite electrode. Bioelectrochemistry, 87 pp. 28–32.

DOI: https://doi.org/10.1016/j.bioelechem.2011.12.012


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.

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  • Item ORO ID
  • 35403
  • Item Type
  • Journal Item
  • ISSN
  • 1878-562X
  • Extra Information
  • International Symposium on Bioelectrochemistry and Bioenergetics, 21st BES 2011
  • Keywords
  • Ag/AgCl; anodic current density; biofilm growth; cell-free; differential pulse voltammetry; direct electron transfer; electroactive; electron transfer mechanisms; extracellular electron transfer; first derivative; fluorescence emission spectra; graphite interfaces; incubation periods; mediated electron transfer; oxidative potential; Shewanella; anodic oxidation; biofilms; chronoamperometry; cyclic voltammetry; electron transitions; emission spectroscopy; graphite; voltage regulators; graphite electrodes, quinone derivative; riboflavin; amperometry; bacterial growth; bacterial strain; bacterium culture; bioaccumulation; cell free system; cyclic potentiometry; electric current; electrochemistry; electrode; electron transport; fluorescence spectroscopy; incubation time; oxidation reduction potential; scanning electron microscopy; Shewanella loihica; supernatant
  • Academic Unit or School
  • Faculty of Science, Technology, Engineering and Mathematics (STEM) > Engineering and Innovation
    Faculty of Science, Technology, Engineering and Mathematics (STEM)
  • Copyright Holders
  • © 2012 Elsevier B.V.
  • Depositing User
  • Satheesh Krishnamurthy