重组Microdochium nivale还原糖氧化酶用于制备乳糖酸方法的研究

摘要

Microdochium nivale(M,nivale)还原糖氧化酶可以催化乳糖转化为乳糖酸,作者采用实验室保存的重组M.nivale还原糖氧化酶基因工程菌X33-pPICZαA-MnCO,通过诱导在毕赤酵母中表达并制备了重组M.nivale还原糖氧化酶,通过单因素和正交实验考查了乳糖浓度,重组M.nivale还原糖氧化酶用量,反应温度,反应时间对乳糖酸转化率的影响.结果表明:重组M.nivale还原糖氧化酶催化乳糖制备乳糖酸的最适转化条件为:乳糖浓度5 mmol/L,酶的添加量为1.5 U/ml,反应温度为55℃,反应时间为48 h,最终反应乳糖酸的转化率接近100％.%The carbohydrate oxidase from Microdochium nivale (MnCO)can catalyze the oxidation of lactose to produce lactobionic acid.In this study,we used the recombinant MnCO which expressed in Pichia pastoris from the genetically engineered bacteria X33-pPICZαA-MnCO stored in our lab.The production of lactobionic acid was optimized by single factor experiment and orthogonal test.The optimal fermentation conditions for the production of lactobionic acid were as follows:the concentration of lactose solution of 5 mmol/L,the amount of enzyme of 1.5 U/ml,the reaction temperature of 55 ℃,the reaction time of 48 h,the conversion rate of lactose to lactobionic acid could reach to 100％.