High Current Density Bioelectrolysis of d-Fructose at Fructose Dehydrogenase-adsorbed and Ketjen Black-modified Electrodes without a Mediator

Abstract d-Fructose dehydrogenase (FDH) has been irreversibly adsorbed without loss of the enzymatic activity on Ketjen black (KB)-modified glassy carbon electrodes, although the adsorption rate is very slow probably owing to the microstructure of KB. The FDH-adsorbed electrode produced the enzyme-kinetic-controlled catalytic oxidation wave of d-fructose at current densities of as high as 10 mA cm−2 without a mediator, in which the electron in FDH seems to be directly transferred to the electrode via the heme c site. No hindrance was observed in the mass transfer of d-fructose to KB-modified electrodes.