乳糖诱导酸性木聚糖酶基因在大肠杆菌中的表达

目的]以融合酸性木聚糖酶基因的大肠杆菌（E．coli）B121（DE3）为研究对象，研究以乳糖作为诱导剂时重组目的产物的表达规律。方法]以重组木聚糖酶比酶活为评价指标，利用单因素试验和k（3。）正交试验考察摇瓶发酵条件下诱导剂浓度、诱导时机、诱导培养时间和诱导培养温度对木聚糖酶表达的影响。结果]各因素影响程度依次为：诱导时机〉诱导温度〉诱导时间〉诱导剂浓度；最优表达条件为：诱导剂浓度5∥L、诱导时机0．5h、诱导培养时间4．5h、诱导培养温度32℃；在此工艺条件下，重组木聚糖酶比酶活可达49．69U／mg。结论]乳糖作为诱导剂能够成功诱导酸性木聚糖酶在大肠杆菌中的表达。

Expression of Acid Xylanase in Escherichia coli Induced by Lactose

Objective]Cells of E.coli BL21 bearing the acid xylanase from Aspergillus usamii under the control of the lacDE3 promoter were induced with lactose.Method] With the specific activity of recombinant xylanase as the evaluation index,the effects of culture conditions such as concentration of the inducer,the time of culture before induction,the time and the temperature of induction culture on the expression of the recombinant protein of E.coli BL21(DE3) were investigated by using single factor experiment and ...