title: Laccase electrode for direct electrocatalytic reduction of O2 to H2O with high-operational stability and resistance to chloride inhibition.
abstract: Laccase from Trametes hirsuta basidiomycete has been covalently bound to graphite electrodes electrochemically modified with phenyl derivatives as a way to attach the enzyme molecules with an adequate orientation for direct electron transfer (DET). Current densities up to 0.5mA/cm(2) of electrocatalytic reduction of O(2) to H(2)O were obtained in absence of redox mediators, suggesting preferential orientation of the T1 Cu centre of the laccase towards the electrode. The covalent attachment of the laccase molecules to the functionalized electrodes permitted remarkable operational stability. Moreover, O(2) bioelectroreduction based on DET between the laccase and the electrode was not inhibited by chloride ions, whereas mediated bioelectrocatalysis was. In contrast, fluoride ions inhibited both direct and mediated electron transfers-based bioelectrocatalytic reduction of O(2). Thus, two different modes of laccase inhibition by halides are discussed.
authors.affiliation: Instituto de Catálisis, CSIC, c/Marie Curie 2, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Vaz-Dominguez
authors.forename: Susana
authors.initials: S
authors.lastname: Campuzano
authors.forename: Olaf
authors.initials: O
authors.lastname: Rüdiger
authors.forename: Marcos
authors.initials: M
authors.lastname: Pita
authors.forename: Marina
authors.initials: M
authors.lastname: Gorbacheva
authors.forename: Sergey
authors.initials: S
authors.lastname: Shleev
authors.forename: Victor M
authors.initials: VM
authors.lastname: Fernandez
authors.forename: Antonio L
authors.initials: AL
authors.lastname: De Lacey
mesh_terms: D002384:Catalysis; D002712:Chlorides / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D042845:Laccase / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D002712:Chlorides; D004800:Enzymes, Immobilized; D014867:Water; D042845:Laccase; D010100:Oxygen