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

Abstract:

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 corn flour，2 g yeast extract，1 %（v/v）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.