DOI:
Authors:
Wassim El Housseini, François Lapicque, Alain Walcarius, Mathieu Etienne
Abstract:
Abstract Beta‐nicotinamide adenine dinucleotide (NAD + /NADH) is an important enzymatic co‐factor that can be efficiently regenerated using a rhodium‐based catalyst as electron transfer mediator ( ie , [Cp*Rh(bpy)Cl] + , where Cp* = pentamethylcyclopentadienyl and bpy = 2,2‐bipyridine). Here, the above mediated regeneration of NADH is implemented in a redox flow bioreactor hybridized with a gas diffusion electrode for hydrogen oxidation. The reactor was initially optimized with respect to rhodium complex and NAD + concentrations, humidification of the hydrogen gas, flow rates of both H 2 gas and electrolytic solution, and solution pH. The integration of an enzymatic reaction consuming the generated NADH was then investigated in a flow process, combining in series the electrochemical reactor to a biochemical cell with immobilized l ‐lactic dehydrogenase for the conversion of pyruvate to lactate. A high activity was achieved with a turnover number up to 370 h −1 for NADH regeneration. Coupled electrochemical regeneration to enzymatic reaction led to total turnover number values of 2000 and 6.3 × 10 6 for NADH electrochemical regeneration and bioconversion, respectively.