title: Improving the performance of a biofuel cell cathode with laccase-containing culture supernatant from Pycnoporus sanguineus.
abstract: Laccases are multicopper oxidoreductases that can be used in biofuel cells to improve cathode performance by cathodic oxygen reduction. Here we present a laccase from the ligninolytic white-rot fungus Pycnoporus sanguineus that, in contrast to the Trametes versicolor laccase, can be produced in the absence of inducers in a standard culture medium. After 7days of cultivation the activity of this laccase in culture supernatant reached 2.5U/ml, which is high enough for direct application of the supernatant in biofuel cells. The highest current density of 115.0±3.5μA/cm(2) at 400mV vs. SCE was obtained at pH 5 with a buckypaper cathode with a laccase-containing culture supernatant. The enzyme also showed electrocatalytic activity at pH 6 and 7. These results not only present a new cost-efficient laccase for improving cathode performance, but also show that new laccases with different catalytic properties can be suitable for biofuel cells.
authors.affiliation: Institute for Applied Biosciences, Department of Microbiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
authors.forename: Oleksandra
authors.initials: O
authors.lastname: Fokina
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Eipper
authors.affiliation: Institute for Applied Biosciences, Department of Microbiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
authors.forename: Lex
authors.initials: L
authors.lastname: Winandy
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Kerzenmacher
authors.affiliation: Institute for Applied Biosciences, Department of Microbiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. Electronic address: Reinhard.fischer@kit.edu.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fischer
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D056804:Biofuels; D003470:Culture Media / Q000737:chemistry; D004566:Electrodes / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D055494:Pycnoporus / Q000201:enzymology*; D013696:Temperature; D055454:Trametes / Q000201:enzymology
chemical_list: D056804:Biofuels; D003470:Culture Media; D042845:Laccase; D010100:Oxygen
keywords: Biofuel cell; Cathode; Enzyme; Laccase; Pycnoporus