Expression and characteristic of β-Glucanase in Escherichia coli induced by lactose

The feasibility of expression of β-Glucanase in recombinant E.coli BL21 induced by lactose instead of IPTG was studied.The main factors of induction such as terminal concentration of lactose,the optimal time of induction,the duration and temperature of induction were analyzed.The results showed that the optimal condition was to add 10mmol/L(terminal concentration)lactose when the cell density achieved to OD600 0.7,changed the temperature from 37℃ to 41℃ and induce 6h.The maximum enzyme activity of 830.7U/mL induced by lactose was higher 2 times than IPTG,and the period of fermentation shortened 70%.The enzyme was stable at pH6～8,and thermal stability,as well as high activity at the physiological temperature(about 70℃).The research demonstrated that lactose could be used as an efficient inducer of genetically engineered strain.