初步研究了来源于Aspergillus sp.的β-半乳糖苷酶催化人参皂苷Rg3水解的反应.首先采用羟丙基-β-环糊精包合法解决Rg3水溶性差的问题,其溶解度提高了74.6倍.根据相溶解度曲线,Rg3的包合类型属于AL型,即形成1∶1的包合物.以Rg3包合物为底物,来源于Aspergillus sp.的β-半乳糖苷酶能选择性催化水解Rg3分子结构中C3位槐糖基的β-1,2葡萄糖苷键,得到Rh2.当加酶量为500 U/g Rg3,60℃下反应24 h,Rg3的转化率达90.6％,Rh2的产率为88.5％.

Biotransformation of ginsenoside Rg3 using a β-galactosidase from Aspergillus sp.was evaluated preliminarily.To improve the aqueous solubility of Rg3,an inclusion complex with hydroxypropyl-β-cyclodextrin was prepared before enzymatic hydrolysis.The solubility of Rg3 increased 74.6 folds and the phase solubility curve displayed a typical AL type indicating the formation of 1 ∶ 1 inclusion complex.The β-galactosidase from Aspergillus sp.presented specific hydrolytic activity on β-1,2 glucosidic linkage at C3 of ginsenoside Rg3,and converted Rg3 to Rh2.Using an enzyme loading of 500 U/g Rg3,the highest conversion of 90.6％ and yield of 88.5％ were obtained after reaction at at 60 ℃ for 24 h.