Electrolytic regeneration of the reduced from the oxidized form of immobilized NAD

Abstract

A covalently bound adduct of nicotinamide adenine dinucleotide (NAD) with alginic acid has been found to be enzymatically active and to undergo electrochemical oxidation or reduction without significant loss of its enzymatic activity. The preparation of the adduct itself (from NAD+, alginic acid, and 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide metho-p-toluenesulfonate) is also accomplished with substantially complete retention of enzymatic activity. This adduct has been converted from the oxidized to the reduced form by controlled potential electrolysis using mercury and stainless-steel electrodes. This electrolytically produced NADH complex could be oxidized again to the enzymatically active NAD+ complex by enzymatic reaction with the proton acceptor, 2,6-dichlorophenol indophenol, as catalyzed by diaphorase. Using this electrolytic method with immobilized NAD, it is now possible to carry out redox reactions in which NADH is enzymatically oxidized to NAD+, with the simultaneous electrolytic regeneration of the reduced form, NADH, from the oxidized form, NAD+, produced in the enzymatic reaction.

Cofactor Regeneration for Enzyme-Catalysed Synthesis

“…Several strategies improve the electrochemical behaviour of NAD(P). Immobilized NAD, which suppresses coupling of the radical intermediate (Aizawa, Coughlin and Charles, 1976), and coated electrodes (Aizawa, Suzuki and Kubo, 1976) both increase yields of active cofactor. Electron transport agents mediate the indirect reduction of NAD(P) (Day etal., 1978;Wienkamp and Steckhan, 1982).…”

Direct electrochemical regeneration of enzymatic cofactor 1,4‐NADH on a cathode composed of multi‐walled carbon nanotubes decorated with nickel nanoparticles

“…This step is favoured on bare (non-modified) electrodes, therefore, bare electrodes are not a good choice for the electrochemical conversion of NAD þ to 1,4-NADH. [34,[38][39][40][41][42][43][44] In our previous works, we have demonstrated that the use of nano-modified electrodes can increase the yield (recovery) of 1,4-NADH even up to 100 %. [25,30,31,45] Surprisingly, we have also discovered that bare (non-modified) glassy carbon (GC) and carbon nanofibre (CNF) electrodes are quite efficient in producing pure (100 %) 1,4-NADH.…”

“…This step is favoured on bare (non‐modified) electrodes, therefore, bare electrodes are not a good choice for the electrochemical conversion of NAD + to 1,4‐NADH …”

Bioelectrocatalyzed reduction of acetic and butyric acids via direct electron transfer using a mixed culture of sulfate-reducers drives electrosynthesis of alcohols and acetone

“…11 On the other hand, enzyme-mediated systems were earlier developed for reduction of organics. 12,13 Using artificial redox mediators, reduction of fumarate to succinate was achieved with Actinobacillus succinogenes and Shewanella oneidensis. 14,15 Meanwhile, other investigations considered electrochemically-generated H 2 as a reducing equivalent to drive fermentation; for instance, reduction of glucose to boost the production of propionate and butanol.…”