| 摘要 |
Continuous prodn. of L-alpha-amino acids (I) comprises (1) culturing a Bacillus strain so that the cells contain amino acid dehydrogenase and an enzyme able to catalyse regeneration of NAD; (2) keeping these cells in a reaction zone, then (3) supplying this zone with at least one alpha-keto acid (II), or salt, an NH4 ion source and reducing agent, and reaction with the cells in presence of NAD-type coenzyme (oxidised or reduced). The new feature is that (I)-contg. effluent is withdrawn and the (II) supply rate, (II) concn. and rate of withdrawal are controlled so that, in the reactin zone, the (I) concn. is 1-200 mM and the (II) concn. at least 150 mM. More specifically the cells are esp. of B. megaterium ATCC 39118 and the (II) feed rate is 0.01-25 (esp. 0.1-10) mmole/hr/l of reaction vol. USE/ADVANTAGE - Compared with known procedures, this method provides higher (I) yields for a given wt. of cells; does not require use of polymer-fixed coenzyme and uses only one type of cell culture. Long-term continuous operation is possible since coenzyme is not lost from the cells and is repeatedly reused. (I) are useful in the chemical and pharmaceutical industries.
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