Reactivation of standard [NiFe]-hydrogenase and bioelectrochemical catalysis of proton reduction and hydrogen oxidation in a mediated-electron-transfer system

• Published in: Bioelectrochemistry (Amsterdam, Netherlands) Vol. 123; pp. 156 - 161
• Main Authors: Shiraiwa, Saeko, So, Keisei, Sugimoto, Yu, Kitazumi, Yuki, Shirai, Osamu, Nishikawa, Koji, Higuchi, Yoshiki, Kano, Kenji
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2018; Elsevier BV
• Subjects: Activation; Catalysis; Chemical reactions; Chemical reduction; Deactivation; Electrocatalysis; Electrochemistry; Electrode materials; Electrodes; H2/2H+ interconversion; Hydrogen; Hydrogen production; Hydrogenase; Hydrogenases; Inactivation; Intermetallic compounds; Iron compounds; Membrane reactors; MET-type bioelectrocatalysis; Nickel compounds; Organic chemistry; Oxidation; Oxidative stress; Polymers; Reactivation of Ni-A; Standard hydrogenase; Viologen polymer; Reactivation of Ni-A; H2/2H+ interconversion; MET-type bioelectrocatalysis; Standard hydrogenase; Viologen polymer; H/2H(+) interconversion
• ISSN: 1567-5394; 1878-562X
• DOI: 10.1016/j.bioelechem.2018.05.003

Standard [NiFe]-hydrogenase from Desulfovibrio vulgaris Miyazaki F (DvMF-H2ase) catalyzes the uptake and production of hydrogen (H2) and is a promising biocatalyst for future energy devices. However, DvMF-H2ase experiences oxidative inactivation under oxidative stress to generate Ni-A and Ni-B states. It takes a long time to reactivate the Ni-A state by chemical reduction, whereas the Ni-B state is quickly reactivated under reducing conditions. Oxidative inhibition limits the application of DvMF-H2ase in practical devices. In this research, we constructed a mediated-electron-transfer system by co-immobilizing DvMF-H2ase and a viologen redox polymer (VP) on electrodes. The system can avoid oxidative inactivation into the Ni-B state at high electrode potentials and rapidly reactivate the Ni-A state by electrochemical reduction of VP. H2 oxidation and H+ reduction were realized by adjusting the pH from a thermodynamic viewpoint. Using carbon felt as a working-electrode material, high current densities—up to (200 ± 70) and −(100 ± 9) mA cm−3 for the H2-oxidation and H+-reduction reactions, respectively—were attained. [Display omitted] •DvMF-H2ase- and viologen polymer-co-immobilized MET system was constructed.•Reactivation of Ni-A was realized in a short time in the MET system.•Electrochemical oxidative-inactivation was protected in the MET system.•Bidirectional H2 oxidation and H+ reduction were realized by adjusting pH.•High catalytic-current-densities were achieved by use of carbon felt.