Frontier leaders: Understanding and exploiting hydrogenases

Frontier Leader Seminar

Title: Understanding and exploiting hydrogenases: modular H2-driven and electro-enzymatic approaches to using redox enzymes for chemical synthesis

Speaker: Kylie A. Vincent

Affiliation: Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, UK

Abstract:

Microbial nickel-iron hydrogenases cycle H₂ and H⁺ at negligible overpotential, rivalling platinum both in terms of catalytic rate and in terms of selectivity for H₂ in the face of other small gas molecules such as CO and O₂. We have developed new approaches to coupling IR spectroscopy with electrochemistry to probe the reactions of hydrogenases at high surface-area graphite electrodes in order to better understand the competing chemical and redox reactions of the active site. The efficiency of electrocatalytic H₂ oxidation or H⁺ reduction by hydrogenases has also inspired devices based on hydrogenases, including H₂/O₂ fuel cells, and H₂-production systems. We have exploited hydrogenases in the development of modular enzyme-modified beads which facilitate recycling of the cofactor NADH using electrons supplied from H₂. We further build on this concept to develop enzyme cascades for driving NADH-dependent dehydrogenases and are exploring applications of these cofactor recycling systems to catalyze steps in chemical synthesis.²

1. A.J. Healy, P.A. Ash, O. Lenz, K.A. Vincent, ‘Attenuated total reflectance infrared spectroelectrochemistry at a carbon particle electrode; unmediated redox control of a [NiFe]-hydrogenase solution’ Phys. Chem. Chem. Phys., (2013) 15: 7055.

2. H.A. Reeve, L. Lauterbach, P.A. Ash, O. Lenz, K.A. Vincent, ‘A modular system for regeneration of NAD cofactors using graphite particles modified with hydrogenase and diaphorase moieties’ Chem. Commun., (2012) 48: 1589.