Process for the continuous enzymatic change of water soluble .alpha.-ketocarboxylic acids into the corresponding .alpha.-hydroxycarboxylic acids

US4326031A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Christian Wandrey · Jülich, DE
• Rolf Wichmann · Jülich, DE
• Wolfgang Leuchtenberger
• Maria-Regina Kula · Jülich, DE
• Andreas Buckmann · Braunschweig, DE

Key dates

• Filing date: Jul 25, 1980
• Grant date: Apr 20, 1982
• Expiry date: Jul 25, 2000

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C12P7/56
• WIPO field: Biotechnology
• WIPO sector: Chemistry

Abstract

Water soluble .alpha.-ketocarboxylic acids are continuously converted in a membrane reactor into the corresponding .alpha.-hydrocarboxylic acids. The conversion takes place in the presence of a substrate specific dehydrogenase and of a nicotinamide-adenine-dinucleotide (NAD.sup.+ /NADH) enlarged in molecular weight through linkage to a water soluble polymer as coenzyme. Simultaneously NADH is regenerated continuously from NAD.sup.+ in presence of a formate dehydrogenase and from formate ion. The membrane must have a mean pore diameter of 1 to 3 nm. As coenzyme there is employed 0.1 to 10 mmol/l of NAD.sup.+ /NADH present bound to a water soluble polymer having an average molecular weight between 500 and 50,000. There is continuously supplied to the reactor a substrate stream which contains 50 to 100% of the maximum amount soluble, but not over 2,000 mmol/l, of the reacting .alpha.-ketocarboxylic acid in the form of a water soluble salt and 100 to 6,000 mmol/l of a formate. There is maintained over the membrane a differential pressure of 0.1 to 15 bar. There is continuously drawn off behind the membrane a filtrate stream containing the .alpha.-hydroxy acid formed.