高产α-半乳糖苷酶菌株的筛选鉴定及发酵培养基的优化

Screening, identification and fermentation medium optimization of high α-galactosidase-producing strain

从紫花苜蓿草种植土壤中筛选得到一株产α-半乳糖苷酶的菌株A1-19,结合形态学特征及分子生物学对其鉴定,并优化其发酵培养基。结果表明,菌株A1-19被鉴定为黑曲霉(Aspergillus niger)。对基础发酵培养基中碳源、氮源、无机盐及诱导物进行单因素优化,结果显示,其最佳碳源为乳糖,氮源为牛肉膏,无机盐为MgSO4、Na2HPO4、MnCl2,诱导物为水苏糖。最佳培养基配方为乳糖15.0 g/L,牛肉膏10.0 g/L,MgSO4·7H2O 1.0 g/L,Na2HPO40.5 g/L,MnCl21.0 g/L,水苏糖0.8 g/L。在此优化的培养基下,菌株A1-19产α-半乳糖苷酶酶活力7.85 U/mL,是优化前发酵酶活力的6.77倍。

Anα-galactosidase-producing strain A1-19 was screened from alfalfa planting soil,and identified by morphological characteristics and molecular biology,and its fermentation medium was optimized.The results showed that the optimal carbon source and nitrogen source was lactose and beef extract,respectively.The optimal inorganic salts were MgSO4,Na2HPO4 and MnCl2,and the optimal inducer was stachyose.The optimum medium formula was lactose 15.0 g/L,beef extract 10.0 g/L,MgSO4·7H2O 1.0 g/L,Na2HPO40.5 g/L,MnCl21.0 g/L,and stachyose 0.8 g/L.Under the optimal medium,theα-galactosidase activity of the strain A1-19 was 7.85 U/ml,which was 6.77 times higher than that before optimization.