title: Selective natural induction of laccases in Pleurotus sajor-caju, suitable for application at a biofuel cell cathode at neutral pH.
abstract: Laccases are multicopper oxidoreductases with broad substrate specificity and are applied in biofuel cells at the cathode to improve its oxygen reduction performance. However, the production of laccases by e.g. fungi is often accompanied by the need of synthetic growth supplements for increased enzyme production. In this study we present a strategy for the white-rot fungus Pleurotus sajor-caju for natural laccase activity induction using lignocellulose substrates and culture supernatant of Aspergillus nidulans. P. sajor-caju laccases were secreted into the supernatant, which was directly used at a carbon-nanotube buckypaper cathode in a biofuel cell. Maximal current densities of -148±3μAcm(-2) and -102±9μAcm(-2) at 400mV were achieved at pH 5 and 7, respectively. Variations in cathode performance were observed with culture supernatants produced under different conditions due to the induction of specific laccases.
authors.affiliation: Institute for Applied Biosciences - Department of Microbiology, Karlsruhe Institute of Technology (KIT), D-76187 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, D-79110 Freiburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Eipper
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, D-79110 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), D-76187 Karlsruhe, Germany. Electronic address: Reinhard.fischer@kit.edu.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fischer
mesh_terms: D001674:Bioelectric Energy Sources; D056804:Biofuels; D001709:Biotechnology; D004396:Coloring Agents / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry*; D010084:Oxidation-Reduction; D020076:Pleurotus / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D056804:Biofuels; D004396:Coloring Agents; C036909:lignocellulose; D008031:Lignin; D042845:Laccase
keywords: Aspergillus nidulans; Biofuel cell; Enzyme; Induction; Laccase; Pleurotus