| Abstrakt: |
Ethyl (R) -2-hydroxy-4-phenylbutyrate is a key chiral building block for the synthesis of angiotensin-converting enzyme inhibitors. A wild type microbial stain DY99 with the activity of asymmetric reducing ethyl 2-oxy-4-phenylbutyrate to ethyl (R) -2-hydroxy-4-phenylbutyrate was isolated, and identified as Kazachstania naganishii. A carbonyl reductase gene was extracted and cloned from the genome sequence of this strain, and a recombinant bacteria Escherichia coli-pET28-kncr has been constructed. The induction conditions were optimized, under the optimal conditions (when OD600 reached 0. 8, lactose was added as inducer to the final concentration of 6. 0 g/L and cultivated at 28 °C, 150 r/min for 12 h), the activity reached 330. 61 U/L fermentation broth. The optimum conditions of preparing ethyl (R) -2-hydroxyl-4-phenylbutyrate using whole cells of E. coli-pET28-krwr were determined. Under the optimal reaction conditions (30 °C, pH7. 5, ethyl 2-oxy-4-phenylbutyrate, glucose and cells added at concentration of 15 g/L, 15 g/L and 20 g/L, respectively), ethyl (R) -2-hydroxyl-4-phenylbutyrate was accumulated up to 11. 2 g/L, with e. e. > 99%, the space-time yield reached 26. 88 g/(L*h), showing a good application prospect. [ABSTRACT FROM AUTHOR] |
