Isolation and Identification of a Novel Aspergillus sydowii F5 Producing a-Galactosidase and Statistical Optimization for the Enzyme Production

Abstract

A novel strain F5, producing a-galactosidase, was isolated from Chinese wheat Qu. According to the morphological characteristics and ITS gene sequence analysis, it was identified as Aspergillus sydowii F5. Statistically based experimental designs were applied to the optimization of cultural medium for the a-galactosidase production by A. sydowii F5. Plackett-Burman design was used to evaluate the effects of variables of the fermentation medium. Among these variables, soybean meal, MgSO₄ and KH₂PO₄ were identified to have the significant effects. Subsequently, the concentrations of soybean meal, MgSO₄ and KH₂PO₄ were optimized using central composite design. The optimum concentration of soybean meal, MgSO₄ and KH₂PO₄ was 22.4 g/L, 2.23 g/ L and 0.91 g/L, respectively. The optimization strategy led to a 5.1-fold increase in the a-galactosidase production.