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Extracellular electron transfer mechanism in Shewanella loihica PV- 4 biofilms formed at indium tin oxide and graphite electrodes

Jain, Anand; O Connolly, Jack; Woolley, Richard; Krishnamurthy, Satheesh and Marsili, Enrico (2013). Extracellular electron transfer mechanism in Shewanella loihica PV- 4 biofilms formed at indium tin oxide and graphite electrodes. International Journal of Electrochemical Science, 8 pp. 1778–1793.

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URL: http://www.electrochemsci.org/papers/vol8/80201778...
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Abstract

Electroactive biofilms are capable of extracellular electron transfer to insoluble metal oxides and electrodes; such biofilms are relevant to biogeochemistry, bioremediation, and bioelectricity production. We investigated the extracellular electron transfer mechanisms in Shewanella loihica PV-4 viable biofilms grown at indium tin oxide (ITO) and graphite electrodes in potentiostat-controlled electrochemical cells poised at 0.2 V vs. Ag/AgCl. Chronoamperometry and confocal microscopy showed higher biofilm growth at graphite compared to the ITO electrode. Cyclic voltammetry, differential pulse voltammetry, along with fluorescence spectroscopy showed that direct electron transfer through outer membrane c type cytochromes (Omcs) prevailed at the biofilm/ITO interface, while biofilms formed at graphite electrode reduced the electrode also via secreted redox mediators, such as flavins and quinones. The biofilm age does not affect the prevalent transfer mechanism at ITO electrodes. On the other hand, secreted redox mediators accumulated at biofilm/graphite interface, thus increasing mediated electron transfer as the biofilm grows over five days. Our results showed that the electrode material determined the prevalent electron transfer mechanism and the dynamic of secreted redox mediators in S. loihica PV-4 biofilms. These observations have implications for the optimization of biofilm-based electrochemical systems, such as biosensors and microbial fuel cells.

Item Type: Journal Item
Copyright Holders: 2013 Not known
ISSN: 1452-3981
Keywords: extracellular electron transfer; Shewanella loihica PV- 4; electroactive biofilms; ITO electrode; graphite electrode
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Engineering and Innovation
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Item ID: 36671
Depositing User: Satheesh Krishnamurthy
Date Deposited: 21 Feb 2013 10:25
Last Modified: 16 Mar 2017 13:33
URI: http://oro.open.ac.uk/id/eprint/36671
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