Continuous enzymatic transformation in an enzyme membrane reactor with simultaneous NAD(H) regeneration

✍ Scribed by Rolf Wichmann; Christian Wandrey; Andreas F. Bückmann; Maria-regina Kula

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 541 KB
• Volume: 23
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.260231213

✦ Synopsis

Abstract

Multienzyme reaction systems with simultaneous coenzyme regeneration have been investigated in a continuously operated membrane reactor at bench scale. NAD(H) covalently bound to polyethylene glycol with a molecular weight of 10^4^ [PEG‐10,000‐NAD(H)] was used as coenzyme. It could be retained in the membrane reactor together with the enzymes. L‐leucine dehydrogenase (LEUDH) was used as catalyze for the reductive amination of α‐ketoisocaproate (2‐oxo‐4‐methylpentanoic acid) to L‐leucine. Format dehydrogenease (FDH) was used for the regeneration of NADH. Kinetic experiments were carried out to obtain data which could be used in a kinetic model in order to predict the performance of an enzyme membrane reactor for the continuous production of L‐leucine. The kinetic constants V~max~ and K~m~ of enzymes are all in the same range regardless of whether native NAD(H) or PEG‐10,000‐NAD(H) is used as coenzyme. L‐leucine was produced continuously out of α‐ketoisocaproate for 48 days; a maximal conversion of 99.7% was reached. The space‐time yield was 324 mmol/L day (or 42.5 g/L day).