Enzymatic Preparation of Steviolbioside from Hydrolysis of Stevioside Catalyzed with a β- Galactosidase

Steviolbioside is a terpenoid with biological activity which can be converted to drugs with anti tubereulotie and antibacterial activity. Unfortunately, steviolbioside is a rare component in extract of Stevia rebaudiana Bertoni leaves. In this work, a β-galactosidase from Kluyveromyces lactis presented a strict substrate specifity on converting stevioside to steviolbioside in a stoichiometric yield. It presented specific hydrolytic activity on favors cleavage of glycosyl ester linkage of stevioside. The results showed that the highest stevioside conversion reached to 98.36% accompanying with a steviolbioside yield of 94.88% in 12 h under the optimum conditions.