Gas-diffusion and Direct-electron-transfer-type Bioanode for Hydrogen Oxidation with Oxygen-tolerant [NiFe]-hydrogenase as an Electrocatalyst

A membrane-bound [NiFe]-hydrogenase (MBH) from Hydrogenovibrio marinusallows the direct-electron-transfer (DET)-type bioelectrocatalysis for H2oxidation and is an O2-tolerant promising enzyme for the construction of enzymatic H2–O2biofuel cells. However, the oxidative and reversible inactivation called “anaerobic inactivation” limits the H2oxidation at high potentials. In order to avoid this inhibition, we have constructed an MBH-adsorbed gas-diffusion-type electrode, in which H2is spontaneously supplied to the electrode from the gas phase.