engleski

Enantioselective enzymatic oxidation with indirect electrochemical NAD+ regeneration

For production of 2-hydroxyketones and racemic resolution of vicinal diols glycerol dehydrogenase (GDH) [EC 1.1.1.6] from Cellulomonas species was used as production enzyme.1 Since GDH is NAD + dependent and strongly inhibited by its reduced form NADH, an effective and cost efficient cofactor regeneration is necessary. For this regeneration ABTS+.was used as oxidizing agent, which itself was prepared in situ by anodic oxidation. Though electrochemical cofactor regeneration needs no cosubstrate nor additional enzymes, until now it is not used in industrial biotransformations.2, 3 The kinetic parameters were determined and a kinetic model for the electrochemically driven enzymatic reaction was developed. Based on this model the ratios of the reactants were optimized and the model proved by experiments. Synthesis of 2-hydroxyketones and racemic resolution were performed in different reactor types, avoiding product inhibition by continuous extraction of the formed 2-hydroxyketones. GDH was retained by using ultrafiltration membranes. Lit: 1 A. Liese, M. Karutz, J. Kamphuis, C. Wandrey, U. Kragl, Biotech. Bioeng. 1996, 51, 544-550 2 A. Liese, K. Seelbach, C. Wandrey, Industrial Biotransformations, VCH Weinheim 2000 3 E. Steckhan, Top. Curr. Chem 1994, 170, 83-111 Financial support by BASF AG Ludwigshafen (Germany) is gratefully acknowledged.

enantioselective enzymatic oxidation; electrochemical NAD regeneration

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