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Study of the Mechanism of Catalytic Activity of G. Sulfurreducens Biofilm Anodes during Biofilm Growth

Authors

  • Dr. Sarah M. Strycharz-Glaven,

    Corresponding author
    1. Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Ave., SW, Washington DC, 20375 (USA)
    • Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Ave., SW, Washington DC, 20375 (USA)
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  • Prof. Leonard M. Tender

    1. Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, 4555 Overlook Ave., SW, Washington DC, 20375 (USA)
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Abstract

The number of investigations involving bioelectrochemical systems (BES), processes in which microorganisms catalyze electrode reactions, is increasing while their mechanisms remain unresolved. Geobacter sulfurreducens strain DL1 is a model electrode catalyst that forms multimicrobe-thick biofilms on anodes that catalyze the oxidation of acetate to result in an electric current. Here, we report the characterization by cyclic voltammetry (CV) of DL1 biofilm-modified anodes (biofilm anodes) performed during biofilm development. This characterization, based on our recently reported model of biofilm anode catalytic activity, indicates the following. 1) As a biofilm grows, catalytic activity scales linearly with the amount of anode-accessible redox cofactor in the biofilm. This observation is consistent with a catalytic activity that is limited during biofilm growth by electron transport from within cells to the extracellular redox cofactor. 2) Distinct voltammetric features are exhibited that reflect the presence of a redox cofactor expressed by cells that initially colonize an anode that is not involved in catalytic current generation

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