类产碱假单胞菌XW-40发酵-生物转化级联产生D-脯氨酸

建立了一个新颖的用于产生D-脯氨酸的发酵-生物转化过程.发酵过程中,以DL-脯氨酸为发酵前体,类产碱假单胞菌XW-40利用L-对映体诱导产生脯氨酸脱氢酶,D-对映体完全保留.在最优条件下,发酵阶段产生6 g/L D-脯氨酸.生物转化过程中,细胞不经分离,发酵液直接作为反应介质.采用分批补料策略实现DL-脯氨酸中L-对映体的转化.DL-脯氨酸单批补料浓度为10 g/L,补料次数达到5批.通过发酵和生物转化的级联,累积的D-脯氨酸浓度达到31 g/L,ee99%.推测了生物转化过程中D-脯氨酸产生的反应机理.

Fermentation-biotransformation Cascade for the Production of D-proline by Pseudomonas pseudolcaligenes XW-40

A novel fermentation-biotransformation cascade was developed for the production of D-proline. In the fermentation process with DL-proline as the precursor, the L-enantiomer was used to induce the production of proline dehydrogenase by Pseudomonas pseudoalcaligenes XW-40, while the D-enantiomer was completely retained. Under the optimal conditions, 6 g/L D-proline was produced in the fermentation stage. In the biotransformation process, the fermentation broth is directly used as the reaction medium without further separation of cells. The conversion of L-enantiomer in DL-proline was realized by fed-batch strategy. The feeding concentration of DL-proline in a single batch was 10g / L, and the feeding times reached 5 batches. Through the cascade of fermentation and biotransformation, the D-proline was accumulated with 31g/L and more than 99% enantiomeric excess. The mechanism of D-proline production in biotransformation was also postulated.