突变芳香基硫酸酯酶H260L工程菌的发酵条件优化

Optimization of Fermentation for the Mutant Arylsulfatase H260L from Engineering Escherichia coli

通过摇瓶培养对突变芳香基硫酸酯酶H260L工程菌的发酵条件进行初步优化,研究不同发酵条件包括接种量、诱导时期、诱导剂浓度、发酵时间、诱导剂加入方式、发酵温度及培养基初始pH值对重组芳香基硫酸酯酶表达的影响。结果表明,重组芳香基硫酸酯酶工程菌发酵的乳糖诱导表达优化条件为:以5%接种量培养3 h后,加入乳糖诱导剂至5 g/L,诱导表达7 h;当发酵温度为25℃、培养基的初始pH值为7.5时,重组芳香基硫酸酯酶活性最高。在优化条件下,工程菌芳香基硫酸酯酶活性达到2.63 U/m L,是未优化酶活性的46.9倍。突变酶H260L对龙须菜粗多糖硫酸基团的脱硫率为82.1%。

The fermentation conditions for the mutant arylsulfatase produced by engineering Escherichia coli were studied in the shake flask. I t included the effects of inoculation size, induction period, inducer concentration, fermentation time, addition method of inducer, fermentation temperature and original pH value of medium on the expression of the recombinant arylsulfatase. The results revealed that the optimized lactose inducer concentration was 5 g^L added to liquid medium after 3 h in it ia l culture inoculation with 5 % （ V / V） . The highest enzyme specific activity （2. 63 U/ml） was achieved after further 7 h fermentation at temperature of 25 ^ and an original pH 7. 5. Compared with the original condition, the enzyme activity was increased by 46.9 times. The desulfation ratio against the crude polysaccharides from Gracilaria lemaneiformis was 82. 1%.