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

US4304858A · 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: Dec 8, 1981
• Expiry date: Jul 25, 2000

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S435/813
• WIPO field: Biotechnology
• WIPO sector: Chemistry

Abstract

Water soluble .alpha.-ketocarboxylic acids are continuously converted in a membrane reactor into the corresponding aminoacids. The conversion takes place in the presence of a substrate specific dehydrogenase, of ammonium ions 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 polyoxyethylene 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, an ammonium ion in an amount about equimolar to the amount of substrate 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 str…