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: 2000
• Tongue: English
• Weight: 887 KB
• Volume: 67
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/(sici)1097-0290(20000320)67:6<791::aid-bit15>3.0.co;2-i

✦ Synopsis

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 catalyst for the reductive amination of alpha-ketoisocaproate (2-oxo-4-methylpentanoic acid) to L-leucine. Formate dehydrogenase (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 the 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 alpha-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).