合成己酸乙酯酯化酶产生菌的鉴定及产酶条件优化

Identification of Ethyl Hexanoate Synthesis Esterifying Enzymes Production Strain and Its Enzyme Production Conditions Optimization

筛选到1株浓香型酒曲来源且己酸乙酯酯化性能较强的红曲霉并进行菌种鉴定。在形态学鉴定的基础上,通过ITS序列和β-微管蛋白基因序列构建系统发育树,初步鉴定为紫色红曲霉,编号为YJX-8。研究菌株YJX-8最佳产酯化酶条件及酯化酶底物特异性,结果表明,其最适液态培养基组分是:蔗糖90 g/L、黄豆饼粉25 g/L、MgSO41 g/L、NaH2PO41 g/L;最适培养条件是:pH 4.5、30℃、180 r/min、6 d;在最优条件下,酯化酶酶活达到(1.177±0.009)U/mL,酶活提高4.56倍。红曲霉酯化酶对己酸具有很强的选择性。

A fungal strain was isolated with the capability for efficient production of ethyl hexanoate.The strain was identified as Monascus purpureus by ITS and beta-tubulin sequence analysis after morphological identification,and numbered as YJX-8.The culture conditions of YJX-8 for enzyme production were optimized for enhanced production of ethyl hexanoate,and the substrate specificity was also investigated.The results showed that the optimal culture medium components were sucrose 90 g/L,soybean cake powder 25 g/L,MgSO41 g/L,NaH2PO41 g/L.The optimal culture conditions were pH 4.5,30℃,180 r/min,6 d.Under the optimized conditions,the esterifying enzymes activity was(1.177±0.009)U/mL,which enhanced by 4.56 folds.The esterifying enzyme had an obvious substrate specificity to hexanoic acid.