| Autor: |
Wichmann R, Wandrey C, Bückmann AF, Kula MR |
| Jazyk: |
angličtina |
| Zdroj: |
Biotechnology and bioengineering [Biotechnol Bioeng] 2000 Mar 20; Vol. 67 (6), pp. 791-804. |
| DOI: |
10.1002/(sici)1097-0290(20000320)67:6<791::aid-bit15>3.0.co;2-i |
| Abstrakt: |
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). |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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