Kinetics of redox polymer-mediated enzyme electrodes

Joshua W. Gallaway, Scott A Calabrese Barton

    Research output: Research - peer-reviewArticle

    • 122 Citations

    Abstract

    Oxygen-reducing enzyme electrodes are prepared from laccase of Trametes versicolor and a series of osmium-based redox polymer mediators covering a range of redox potentials from 0.11 to 0.85 V. Experimentally obtained current density generated by the film electrodes is analyzed using a one-dimensional numerical model to obtain kinetic parameters. The bimolecular rate constant for mediation is found to vary with mediator redox potential from 250 s-1 M-1 when mediator and enzyme are close in redox potential to 9.4 × 104 s-1 M-1 when the redox potential difference is large. The value of the bimolecular rate constant for the simultaneously occurring laccase-oxygen reaction is found to be 2.4 × 105 s-1 M-1. The relationship between mediator-enzyme overpotential and bimolecular rate constant is used to determine the optimum mediator redox potential for maximum power output of a hypothetical biofuel cell with a planar cathode and a reversible hydrogen anode. For laccase of T. versicolor (Ee0 = 0.82), the optimum mediator potential is 0.66 V (SHE), and a molecular structure is presented to achieve this result.

    LanguageEnglish (US)
    Pages8527-8536
    Number of pages10
    JournalJournal of the American Chemical Society
    Volume130
    Issue number26
    DOIs
    StatePublished - Jul 2 2008

    Profile

    Enzyme electrodes
    Polymers
    Kinetics
    Oxidation-Reduction
    Biosensing Techniques
    Laccase
    Rate constants
    Electrodes
    Oxygen
    Enzymes
    Biological fuel cells
    Osmium
    Kinetic parameters
    Molecular structure
    Numerical models
    Hydrogen
    Anodes
    Cathodes
    Current density
    Bioelectric Energy Sources

    ASJC Scopus subject areas

    • Chemistry(all)

    Cite this

    Kinetics of redox polymer-mediated enzyme electrodes. / Gallaway, Joshua W.; Barton, Scott A Calabrese.

    In: Journal of the American Chemical Society, Vol. 130, No. 26, 02.07.2008, p. 8527-8536.

    Research output: Research - peer-reviewArticle

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