Oxygen-reducing enzyme cathodes produced from SLAC, a small laccase from Streptomyces coelicolor

Joshua Gallaway, Ian Wheeldon, Rosalba Rincon, Plamen Atanassov, Scott Banta, Scott Calabrese Barton

    Research output: Research - peer-reviewArticle

    • 87 Citations

    Abstract

    The bacterially-expressed laccase, small laccase (SLAC) of Streptomyces coelicolor, was incorporated into electrodes of both direct electron transfer (DET) and mediated electron transfer (MET) designs for application in biofuel cells. Using the DET design, enzyme redox kinetics were directly observable using cyclic voltammetry, and a redox potential of 0.43 V (SHE) was observed. When mediated by an osmium redox polymer, the oxygen-reducing cathode retained maximum activity at pH 7, producing 1.5 mA/cm2 in a planar configuration at 900 rpm and 40 °C, thus outperforming enzyme electrodes produced using laccase from fungal Trametes versicolor (0.2 mA/cm2) under similar conditions. This improvement is directly attributable to differences in the kinetics of SLAC and fungal laccases. Maximum stability of the mediated SLAC electrode was observed at pH above the enzyme's relatively high isoelectric point, where the anionic enzyme molecules could form an electrostatic adduct with the cationic mediator. Porous composite SLAC electrodes with increased surface area produced a current density of 6.25 mA/cm2 at 0.3 V (SHE) under the above conditions.

    LanguageEnglish (US)
    Pages1229-1235
    Number of pages7
    JournalBiosensors and Bioelectronics
    Volume23
    Issue number8
    DOIs
    StatePublished - Mar 14 2008

    Profile

    Cathodes
    Enzymes
    Electrodes
    Oxygen
    Electrons
    Oxidation-Reduction
    Laccase
    Streptomyces coelicolor
    Biological fuel cells
    Enzyme electrodes
    Osmium
    Enzyme kinetics
    Cyclic voltammetry
    Electrostatics
    Current density
    Molecules
    Kinetics
    Composite materials
    Polymers
    Bioelectric Energy Sources

    Keywords

    • Biofuel cell
    • Direct electron transfer
    • Laccase
    • Mediated electron transfer
    • Oxygen reduction
    • SLAC

    ASJC Scopus subject areas

    • Biotechnology
    • Analytical Chemistry
    • Electrochemistry

    Cite this

    Oxygen-reducing enzyme cathodes produced from SLAC, a small laccase from Streptomyces coelicolor. / Gallaway, Joshua; Wheeldon, Ian; Rincon, Rosalba; Atanassov, Plamen; Banta, Scott; Barton, Scott Calabrese.

    In: Biosensors and Bioelectronics, Vol. 23, No. 8, 14.03.2008, p. 1229-1235.

    Research output: Research - peer-reviewArticle

    Gallaway J, Wheeldon I, Rincon R, Atanassov P, Banta S, Barton SC. Oxygen-reducing enzyme cathodes produced from SLAC, a small laccase from Streptomyces coelicolor. Biosensors and Bioelectronics. 2008 Mar 14;23(8):1229-1235. Available from, DOI: 10.1016/j.bios.2007.11.004
    Gallaway, Joshua ; Wheeldon, Ian ; Rincon, Rosalba ; Atanassov, Plamen ; Banta, Scott ; Barton, Scott Calabrese. / Oxygen-reducing enzyme cathodes produced from SLAC, a small laccase from Streptomyces coelicolor. In: Biosensors and Bioelectronics. 2008 ; Vol. 23, No. 8. pp. 1229-1235
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