Membranverfahren für Redoxenzyme : Gasversorgung, Reaktion, Produktextraktion

Oxidoreductases are enzymes that catalyse the oxidation or reduction of chemical compounds. Their application in chemical synthesis offers the access to a multitude of chiral synthons of high opticai purity. In the scope of this thesis two interesting enzymes were selected, which offen the access to two different ciasses of compounds. The nicotinamide-cofactors needed were regenerated effectively using formate dehydrogenases (FDI-I). The enzymatic Baeyer-Villiger-Oxidation of prochiral ketones to form the corresponding lactones was performed enantiospeciflcally using cyciohexanone monooxygenase (CHMO). For the problem of cofactor regeneration - using a FDH obtained by site-directed mutagenesis - and for the bubble-free aeration - by means of diffusive gas transfer through a silicone membrane - elegant solutions have been found. {Abb.] A carbonyl reductase from Candida parapsilosis (CPCR) reduces numerous ketones to form the corresponding enantiopure alcohols. As model substrates the poorly soluble 3,4- methylenedioxyphenylacetone (MDA, first step in the synthesis of a promising AIV1PA-biocker at Eli Lilly) and the readiiy soluble 2,5-hexanedione (precursor of the DuPHOS-Ligand) were selected. With MDA as a substrate the extraordinary operational stability of the system was demonstrated and the cofactor consumption minimised by use of a biphasic membrane reactor with integrated product extraction. For the production of (2S,5S)-hexanediol an economic and scalable biocatalytic process was developed