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

Abstract

Abstract Water soluble α-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 + /NADH) enlarged in molecular weight through linkage to a water soluble polymer as coenzyme. Simultaneously NADH is regenerated continuously from NAD + 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 + /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 α-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 stream containing the aminoacid formed.

Inventors

• 👤 Christian Wandrey
• 👤 Rolf Wichmann
• 👤 Wolfgang Leuchtenberger
• 👤 Maria-Regina Kula
• 👤 Andreas Buckmann

Bibliographic Details