酶法转化L-谷氨酸生产a-酮戊二酸

Enzymatic production of a-ketoglutaric acid by L-glutamate oxidase from L-glutamic acid

摘要:

利用L-谷氨酸氧化酶 (LGOX)，对酶法转化L-谷氨酸生产a-酮戊二酸 (a-KG) 的工艺条件进行了研究。首先对野生菌链霉菌Streptomyces sp. FMME066进行亚硝基胍诱变，获得一株遗传性状稳定的突变株Streptomyces sp. FMME067；突变株在最优培养基 (g/L)：果糖10，蛋白胨7.5，KH2PO4 1，CaCl2 0.05条件下，LGOX酶活为0.14 U/mL。LGOX的生化特征为最适pH 8.5、温度35 ℃，Mn2+是激活剂。对LGOX转化L-谷氨酸生产a-KG的条件进行优化，在最优条件下转化24 h，a-KG产量为38.1 g/L，转化率为81.4%。研究结果为开发LGOX酶法转化生产a-KG的工业化奠定了坚实的基础。

关键词:L-谷氨酸氧化酶，生化特征，发酵优化，酶法转化

Abstract:

We produced a-ketoglutaric acid (a-KG) from L-glutamic acid, using enzymatic transformation approach with L-glutamate oxidase (LGOX). First, wild strain Streptomyces sp. FMME066 was mutated with NTG, a genetically stable mutant Streptomyces sp. FMME067 was obtained. Under the optimal nutrition conditions with fructose 10 g/L, peptone 7.5 g/L, KH2PO4 1 g/L and CaCl2 0.05 g/L, the maximum LGOX activity reached 0.14 U/mL. The LGOX was stable to pH and temperature, and Mn2+ had a stimulating effect. Finally, after 24 h enzymatic conversion under the optimal conditions, the maximum titer of a-KG reached 38.1 g/L from 47 g/L L-glutamic acid. Enzymatic transformation by LGOX is a potential approach for a-KG production.

Key words:L-glutamate oxidase, biochemical properties, fermentation optimization, enzymatic transformation