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Graphite Electrodes as Electron Donors for Anaerobic Respiration
Environ Microbiol (2004)
  • Derek Lovley, University of Massachusetts - Amherst
  • Kelvin B Gregory
  • Daniel R Bond
Abstract

It has been demonstrated previously that Geobacter species can transfer electrons directly to electrodes. In order to determine whether electrodes could serve as electron donors for microbial respiration, enrichment cultures were established from a sediment inoculum with a potentiostat-poised graphite electrode as the sole electron donor and nitrate as the electron acceptor. Nitrate was reduced to nitrite with the consumption of electrical current. The stoichiometry of electron and nitrate consumption and nitrite accumulation were consistent with the electrode serving as the sole electron donor for nitrate reduction. Analysis of 16 rRNA gene sequences demonstrated that the electrodes supplied with current were specifically enriched in microorganisms with sequences most closely related to the sequences of known Geobacter species. A pure culture of Geobacter metallireducens was shown to reduce nitrate to nitrite with the electrode as the sole electron donor with the expected stoichiometry of electron consumption. Cells attached to the electrode appeared to be responsible for the nitrate reduction. Attached cells of Geobacter sulfurreducens reduced fumarate to succinate with the electrode as an electron donor. These results demonstrate for the first time that electrodes may serve as a direct electron donor for anaerobic respiration. This finding has implications for the harvesting of electricity from anaerobic sediments and the bioremediation of oxidized contaminants.

Disciplines
Publication Date
2004
Publisher Statement
DOI: 10.1111/j.1462-2920.2004.00593.x
Citation Information
Derek Lovley, Kelvin B Gregory and Daniel R Bond. "Graphite Electrodes as Electron Donors for Anaerobic Respiration" Environ Microbiol Vol. 6 (2004)
Available at: http://works.bepress.com/derek_lovley/168/