Enantioselective enzymatic reduction of prochiral ketones in one-phase and two-phase systems

TL;DRAbstract

Within this thesis a strategy for the enantioselective synthesis of chiral short chain alcohols using biocatalysis is developed. This is realized in close collaboration with an industrial partner. The biocatalysts used are alcohol dehydrogenases (ADH) which need nicotinamide cofactors (NAD+/NADH and NADP+/NADPH) as redox equivalents. The regeneration of the cofactors is done substrate dependent by addition of 2-propanol which is oxidized by the ADH while the cofactor is reduced, and enzyme dependent. Here, a malate dehydrogenase(MDH) as second enzyme and L-malic acid as specific substrate are used for in situ cofactor reduction. The kinetic characterization of the different ADH preparations and of a NAD- and a NADP-dependent MDH shows strong dependence of activity on the substrate, on reaction parameters like concentrations of buffer, substrate, and cofactor, on the type of ADH and on the kind of preparation, i.e. lyophilized or purified. The obtained results are transferred to one-pha

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