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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/232664
- Cathodic oxygen reduction catalyzed by bacteria in microbial fuel cells
- Rabaey, Korneel; Read, Suzanne T.; Clauwaert, Peter; Freguia, Stefano; Bond, Philip L.; Blackall, Linda L.; Keller, Juerg
- Microbial fuel cells (MFCs) have the potential to combine wastewater treatment efficiency with energetic efficiency. One of the major impediments to MFC implementation is the operation of the cathode compartment, as it employs environmentally unfriendly catalysts such as platinum. As recently shown, bacteria can facilitate sustainable and cost-effective cathode catalysis for nitrate and also oxygen. Here we describe a carbon cathode open to the air, on which attached bacteria catalyzed oxygen reduction. The bacteria present were able to reduce oxygen as the ultimate electron acceptor using electrons provided by the solid-phase cathode. Current densities of up to 2.2 A m-2 cathode projected surface were obtained (0.303+/-0.017 W m-2, 15 W m-3 total reactor volume). The cathodic microbial community was dominated by Sphingobacterium, Acinetobacter and Acidovorax sp., according to 16S rRNA gene clone library analysis. Isolates of Sphingobacterium sp. and Acinetobacter sp. were obtained using H2/O2 mixtures. Some of the pure culture isolates obtained from the cathode showed an increase in the power output of up to three-fold compared to a non-inoculated control, that is, from 0.015+/-0.001 to 0.049+/-0.025 W m-2 cathode projected surface. The strong decrease in activation losses indicates that bacteria function as true catalysts for oxygen reduction. Owing to the high overpotential for non-catalyzed reduction, oxygen is only to a limited extent competitive toward the electron donor, that is, the cathode. Further research to refine the operational parameters and increase the current density by modifying the electrode surface and elucidating the bacterial metabolism is warranted.
- Publication type
- Journal article
- ISME Journal, Vol. 2, no. 5 (May 2008), pp. 519-527
- Publication year
- FOR Code(s)
- 05 Environmental Sciences; 06 Biological Sciences; 10 Technology
- Acetate; Acidovorax; Acinetobacter; Bacteria microorganisms; Bacterium; Bio-electrochemical system; Bioelectric energy sources; Bioenergy; Biofuel cell; Bioreactors; Bioremediation; Conservation of energy resources; Electrodes; Energy conservation; Environmental biodegradation; Metabolism; Oxygen; Renewable energy; Sphingobacterium; Wastewater treatment
- Nature Publishing Group
- Publisher URL
- Copyright © 2008 International Society for Microbial Ecology. All rights reserved.
- Peer reviewed