重组大肠杆菌Bgl2238的发酵优化

Fermentation Optimization of Recombinant Escherichia coli Bgl2238

本研究对前期实验室从黑龙江玉米土壤中筛选并构建的β-葡萄糖苷酶Bgl2238的重组大肠杆菌（E.coliBL21（DE3）-pET32a-bgl2238）采用响应面（Box-Behnken）优化的方法进行摇瓶发酵,优化培养基组分,而培养条件即温度、pH值、接种量及装液量则采用单因素法优化。结果显示最佳培养基配比为：甘油9.32g/L、酵母提取粉12g/L、胰蛋白胨19.13g/L、NaCl8g/L、K_2HPO_4·3H_2O 19.13g/L、KH_2PO_42g/L、柠檬酸高铁胺0.2g/L和微量元素母液6mL/L。重组大肠杆菌Bgl2238最佳的发酵条件为：发酵温度37℃、起始pH8.0、3%接种量、25mL装液量、IPTG终浓度为0.25mmol/L。在250mL锥形瓶对重组子Bgl2238进行发酵,在最优化的发酵培养基成分和培养条件下,Bgl2238的酶活力可以达到2910U/L,比起始培养基中的酶活提高了61.77%。

In this study, β-glucosidase recombinant Escherichia coli （E. coli BL21 （DE3）-pET32a-bg12238） was screened and constructed from the maize soil of Heilongjiang previously by the laboratory, and the Box-Behnken optimization method was used to carry out the shake flask fermentation and to optimize the components of medium. Its culture conditions including temperature, pH value, inoculation amount and liquid loading were optimized by single factor method. The results showed that the optimum medium ratio were glycerol 9.32 g/L, yeast extract powder 12 g/L, tryptone 19.13 g/L, NaC1 8 g/L, K2HPO4·3H2O 19.13 g/L, KH2PO4 2 g/L, lemon Acid high iron by 0.2 g/L and trace element mother liquor 6 mL/L. The best fermentation conditions of recombinant Escherichia coli Bg12238 were as follows： fermentation temperature 37℃, initial pH 8.0, 3% inoculation amount, 25 mL liquid loading, and IPTG final concentration of 0.25 mmol/L. When the recombinant Bg12238 was fermented in a 250 mL Erlenmeyer flask, the enzyme activity of Bg12238 was up to 2 910 U/L under the optimum fermentation medium and culture conditions, which was 61.77% higher than that in the initial culture medium.