Bioelectrocatalytic Reduction of Oxygen in the Presence of Laccase Adsorbed on Carbon Electrodes

The kinetics of electroreduction of molecular oxygen on isotropic pyrocarbon with adsorbed laccase or a laccase–Nafion composite is studied. Kinetic parameters thus obtained are compared with those determined previously for electrodes of carbon black with adsorbed laccase. The closeness of kinetic parameters of the reaction of bioelectrocatalytic reduction of oxygen by laccase adsorbed on smooth (pyrocarbon) and disperse (carbon black) carbon materials led to a refined reaction mechanism. The slow stage of the reaction of bioelectrocatalytic reduction of oxygen is a synchronous transfer of two first electrons onto the oxygen molecule, similar to the mechanism of enzymatic catalysis by laccase.