Principles of direct (mediator free) bioelectrocatalysis.

Current mini-review is devoted to principles and focuses on the most important trends of bioelectrocatalysis, i.e. acceleration of electrochemical reactions with the use of biological catalysts. The history of direct bioelectrocatalysis, starting from electrochemistry of redox enzymes is presented. The direct bioelectrocatalysis presumes the direct electron exchange (tunneling) between the enzyme active site and the electrode without any redox mediators. Special attention is paid to the novel approach: enzyme orientation during immobilization to improve efficiency of bioelectrocatalysis. Using this particular approach the limiting performance characteristics of the enzymes in bioelectrocatalysis are achieved. The phenomenon of the direct bioelectrocatalysis by intact cells is discussed.