Bioelectrocatalysis has been attracting great attention over the last five decades. It has become one of important research fields in electrochemistry and provided a firm base for 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 mediated- and direct electron transfer (DET)-type bioelectrocatalysis. Important progresses made on how to improve the performance of bioelectrocatalysis are presented and applications to bioelectrochemical devices are briefed. Some prospective aspects are also described.

The rotating disk electrode (RDE) technique is one of the most powerful methods for studying electrode reaction kinetics. Koutecký–Levich equation is frequently applied to the analysis of RDE curves of electrocatalytic reactions. Here, we take careful note of the negative aspect of the situation that the electrocatalytic kinetic-controlled current term in the equations is often expressed by Butler–Volmer-type equation. More rigid analytical expressions are proposed and some examples of the analysis of current-potential curves are also detailed by taking the oxygen reduction reaction.