Electrochemical Peculiarities of Mediator-Assisted Bioelectrocatalytic Oxidation of Glucose by a New Type of Bioelectrocatalyst

A protein extract of microbe cells is studied as a bioelectrocatalyst for glucose oxidation. The microbial protein extract prepared from Escherichia coli BB, which comprises all enzymes of the life cycle of these bacteria, is considered here as a model system. This system demonstrates the mediator mechanism of interaction with an inert glassy-carbon electrode in a buffer containing glucose as the substrate. The efficiency of the bioelectrocatalytic process was shown to depend on the type of mediator system and also on the nature of buffer, its temperature, pH, and ionic strength. The protein extract is shown to contain NAD-dependent Fe-glucosodehydrogenase and demonstrate the current densities in mediator-assisted glucose oxidation well comparable with the known data for pure dehydrogenase enzymes and E. coli microbial systems. The prospects for further studies and practical applications of this new bioelectrocatalyst type are outlined.