High Expression Of β-Galactosidase In Pichia Pastoris And Application In Low-Lactose Milk Preparation

Lactose malabsorption is one of the factors which influence the development of milk-market. Adding the lactose to the milk is the most effective method to solve the question .But lactase production has following questions: low yields,complicate process and narrow applied range.However the genetic engineering technology effectively promotes the development of lactase.In this paper ,the lacO gene was modified and syntheeized to the lacM gene which could high-efficiently express in pichia pastori, The IacM gene was cloned to vector of pPIC9 and recombinant pPIC-lacM was obtainded and expression in pichia pastoris. And the expression yields increased by 3-5 times.When pH was 5.8 and the temperature 55℃, the activity of lactase could keep more than 60%.Metal ions and chemical reagents have little effects on enzymic reaction..Through adding lactase in milk in variouse conditions with 2 hours , 60℃and adding lactase 3000U/ml, hydrolysis rate of lactase could be reached 92%.