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: Contribution to journalArticle

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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

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

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: Contribution to journalArticle

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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