乳糖诱导大肠杆菌产褐藻胶裂解酶的条件优化

Expression and optimization of alginate lyase in recombinant Escherichia coli induced by lactose

摘要: 本文研究了使用乳糖替代IPTG（异丙基硫代半乳糖苷）诱导褐藻胶裂解酶在重组大肠杆菌中表达的可行性,通过摇瓶实验,分别对诱导终浓度、诱导温度、诱导时机、诱导时间等方面进行了单因素实验并利用响应面对条件进行了优化设计,并使用Ni-NTA亲和柱对粗酶液进行了纯化得到纯酶。结果表明,诱导乳糖终浓度22 mmol/L,诱导温度29℃,诱导22 h,酶活可达到8.552 U/m L。说明乳糖可以作为基因工程菌的高效诱导剂。

Abstract: The feasibility of expression of alginate lyase in recombinant Escherichia coli induced by lactose instead of IPTG was studied.The main factors of induction such as terminal concentration of lactose, inducing temperature, the optimal time of induction, the duration were analyzed. The response surface was used to improve the design and to fabricate pure enzyme by refining crude enzyme with Ni-NTA affinity column. The results showed that the optimal condition was adding 22 mmol/L ( terminal concentration) lactose, 29 ℃ and inducing 22 h.The activity of 8.552 U/m L induced by lactose was basically the same with IPTG.The research demonstrated the lactose could be used as an efficient inducer of genetically engineered strain.