大曲中产酯化酶菌株的分离鉴定及固体发酵工艺优化

Isolation and Identification of Ethyl Caproate Esterifying Enzyme in Daqu and its Fermentative Technology Optimization

为提高大曲中己酸乙酯含量,从汾酒大曲中分离得到1株高产己酸乙酯酯化酶的霉菌SXG-Z-6,结合形态学特征和分子鉴定方法对其进行鉴定,确定为黑曲霉。以酯化力为指标,对该菌株的固体发酵培养基和培养条件进行优化,得到最适培养基:以10 g麸皮为基质,添加1.5g玉米粉,2 g酵母粉,体积分数1%大豆油,0.2 g(NH4)2SO4和10 m L蒸馏水。最适培养条件为36℃恒温静置培养44 h,酯化力最高达到615.8 mg/d L,比优化前提高了35.7%。

To improve the ethyl caproate in daqu. A hyper ethyl caproate esterifying enzyme producer-SXG-Z-6, was isolated from Fen-Daqu. The analysis of morphological and molecular characteristics showed that this wild-type strain was closest to Aspergillus niger. The culture media and conditions were optimized using esterifying power as the reference index. As a result,the optimal culture conditions were summed up as follows： 10 g wheat bran as culture substrate, 1.5 g com flour,2 g yeast extract, 1 %（ y/y ） soybean oil ,0.2 g（NH4）2SO4 and 10 mL H2O ,at 36 ℃ for 44 h. The highest esterifying power could reach 615.8 mg/dL,which was improved by 35.7% than the control.