Selection of a variant of Geobacter sulfurreducens with enhanced capacity for current production in microbial fuel cells

Hana Yi, Kelly P. Nevin, Byoung Chan Kim, Ashely E. Franks, Anna Klimes, Leonard M. Tender, Derek R. Lovley

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360 Citations (Scopus)


Geobacter sulfurreducens produces current densities in microbial fuel cells that are among the highest known for pure cultures. The possibility of adapting this organism to produce even higher current densities was evaluated. A system in which a graphite anode was poised at -400 mV (versus Ag/AgCl) was inoculated with the wild-type strain of G. sulfurreducens, strain DL-1. An isolate, designated strain KN400, was recovered from the biofilm after 5 months of growth on the electrode. KN400 was much more effective in current production than strain DL-1. This was apparent with anodes poised at -400 mV, as well as in systems run in true fuel cell mode. KN400 had current (7.6 A/m2) and power (3.9 W/m2) densities that respectively were substantially higher than those of DL1 (1.4 A/m2 and 0.5 W/m2). On a per cell basis KN400 was more effective in current production than DL1, requiring thinner biofilms to make equivalent current. The enhanced capacity for current production in KN400 was associated with a greater abundance of electrically conductive microbial nanowires than DL1 and lower internal resistance (0.015 versus 0.130 Ω/m2) and mass transfer limitation in KN400 fuel cells. KN400 produced flagella, whereas DL1 does not. Surprisingly, KN400 had much less outer-surface c-type cytochromes than DL1. KN400 also had a greater propensity to form biofilms on glass or graphite than DL1, even when growing with the soluble electron acceptor, fumarate. These results demonstrate that it is possible to enhance the ability of microorganisms to electrochemically interact with electrodes with the appropriate selective pressure and that improved current production is associated with clear differences in the properties of the outer surface of the cell that may provide insights into the mechanisms for microbe-electrode interactions.

Original languageEnglish
Pages (from-to)3498-3503
Number of pages6
JournalBiosensors and Bioelectronics
Issue number12
Publication statusPublished - 2009 Aug 15
Externally publishedYes

Bibliographical note

Funding Information:
This research was supported by the Office of Science (BER), U. S. Department of Energy, Cooperative Agreement No. DE-FC02-02ER63446 and Office of Naval Research Award No. N00014-07-1-0966. HY was partially supported by the Korean Research Foundation Grant funded by the Korean Government (MOEHRD) KFR-2007-357-C00104. We thank Marianne Schiffer and Yuri Y. Londer (Biosciences Divison, Argonne National Laboratory, Argonne, IL, USA) for providing pilA antibody.


  • Biofilm
  • Current density
  • Geobacter sulfurreducens
  • Microbial fuel cell
  • Power density
  • Selective pressure

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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