Fundamentals and Applications of Redox Enzyme-Functionalized Electrode Reactions

Electrochemical coupling of redox enzyme reactions, called bioelectrocatalysis, has been attracting great attention over the last four decades. It has become an important technology that can be applied to a wide range of bioelectrochemical devices including biosensors, biofuel cells, and bioreactors. This article presents an overview of the basic concepts of steady-state catalytic waves of mediated- and direct electron transfer (DET)-type bioelectrocatalysis. Several equations that can be used for the analysis of steady-state waves are introduced. The analysis may provide important thermodynamic and kinetic parameters that can be used not only for performance evaluation of the devices but also for fundamental research on the enzymes. Important progress made on how to tune electrode surfaces and enzymes for DET-type reactions are presented. Applications to bioelectrochemical devices are also summarized with emphasis on the achievements recorded in our research group.