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From mud to microbial electrode catalysts and conductive nanomaterials
Published online by Cambridge University Press: 20 October 2011
Abstract
Dissimilatory metal-reducing bacteria (DMRB) are a fascinating group of microorganisms that inhabit many natural environments. They possess a distinct capability wherein they can acquire energy by coupling oxidation of organic matter with reduction of insoluble oxidants such as mineral deposits. This capability requires that DMRB transfer respired electrons to their outer surface where electron transfer can occur to an insoluble oxidant. This is distinct from the dominant paradigm, wherein soluble oxidants are transported into microbes for reduction during metabolism. This unique extracellular electron transfer (EET) capability of DMRB extends to reduction of electrodes on which they can proliferate and form persistent films (biofilms). This capability makes DMRB useful as anode catalysts in microbial fuel cells for alternative energy generation and for degradation of organic wastes. In the case of Geobacter spp., anode biofilms can grow to be many microbes thick. In such biofilms, individual microbes contribute to a flux of electrons to the underlying electrode surface, which may be many cell lengths away, confounding long-held notions about the inability of microbes to engage in such long-range EET. This article describes the electrode-reducing ability of DMRB and the latest results describing the mechanism of long-range extracellular electron transfer, which appears to involve filamentous appendages termed nanowires.
- Type
- Research Article
- Information
- MRS Bulletin , Volume 36 , Issue 10: Solution-processed transparent electrodes , October 2011 , pp. 800 - 805
- Copyright
- Copyright © Materials Research Society 2011
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