title: Using planktonic microorganisms to supply the unpurified multi-copper oxidases laccase and copper efflux oxidases at a biofuel cell cathode.
abstract: The feasibility to apply crude culture supernatants that contain the multicopper oxidases laccase or copper efflux oxidase (CueO) as oxygen reducing catalysts in a biofuel cell cathode is shown. As enzyme-secreting recombinant planktonic microorganisms, the yeast Yarrowia lipolytica and the bacterium Escherichia coli were investigated. The cultivation and operation conditions (choice of medium, pH) had distinct effects on the electro-catalytic performance. The highest current density of 119 ± 23 μA cm(-2) at 0.400 V vs. NHE was obtained with the crude culture supernatant of E. coli cells overexpressing CueO and tested at pH 5.0. In comparison, at pH 7.4 the electrode potential at 100 μA cm(-2) is 0.25 V lower. Laccase-containing supernatants of Y. lipolytica yielded a maximum current density of 6.7 ± 0.4 μAcm(-2) at 0.644 V vs. NHE. These results open future possibilities to circumvent elaborate enzyme purification procedures and realize cost effective and easy-to-operate enzymatic biofuel cells.
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany. Electronic address: sabine.sane@imtek.uni-freiburg.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Sané
authors.affiliation: Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany. Electronic address: katrin.richter@kit.edu.
authors.forename: Katrin
authors.initials: K
authors.lastname: Richter
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Rubenwolf
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
authors.forename: Nina Joan
authors.initials: NJ
authors.lastname: Matschke
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, UMR 7197 Laboratoire de Réactivité de surface, F-75005 Paris, France; CNRS, UMR 7197 Laboratoire de Réactivité de surface, F-75005 Paris, France. Electronic address: claude.jolivalt@upmc.fr.
authors.forename: Claude
authors.initials: C
authors.lastname: Jolivalt
authors.affiliation: INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France. Electronic address: Catherine.Madzak@grignon.inra.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Madzak
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany; BIOSS - Centre for Biological Signalling Studies, University of Freiburg, 79110 Freiburg, Germany. Electronic address: zengerle@imtek.uni-freiburg.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Zengerle
authors.affiliation: Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany. Electronic address: johannes.gescher@kit.edu.
authors.forename: Johannes
authors.initials: J
authors.lastname: Gescher
authors.affiliation: Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany. Electronic address: kerzenma@imtek.uni-freiburg.de.
authors.forename: Sven
authors.initials: S
authors.lastname: Kerzenmacher
mesh_terms: D001483:Base Sequence; D001674:Bioelectric Energy Sources; D017931:DNA Primers; D004566:Electrodes; D004926:Escherichia coli / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism*; D010933:Plankton / Q000378:metabolism*; D025062:Yarrowia / Q000378:metabolism
chemical_list: D017931:DNA Primers; D010088:Oxidoreductases; C024748:copper oxidase
keywords: Bioelectrochemistry; Biofuel cell; Cathode; Copper efflux oxidase; Laccase