重组大肠杆菌产淀粉分支酶的发酵条件探索
Optimizations of fermentation production of starch branching enzyme in recombinant Escherichia coli
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摘要: 淀粉分支酶可增加淀粉的α-1,6-糖苷键,从而改善淀粉的理化特性和生理功能。本文以可胞内表达Geobacillus thermoglucosidans淀粉分支酶的重组大肠杆菌BL21（DE3）（pET-20b（+）/be）为研究对象,首先研究了超声波提取胞内淀粉分支酶的条件,结果显示,当超声波输出功率为325W,总工作时间为15min,菌液OD600为1.4时,超声波破壁效果最佳。在此基础上,对重组大肠杆菌产淀粉分支酶的摇瓶发酵条件进行了探索,结果表明,最适发酵培养基为TB,初始pH为7.0,在25℃、IPTG浓度为0.01mmol/L下诱导培养12h,发酵所得菌体经超声后产生的淀粉分支酶总酶活最高为222.4U/mL。Abstract: Starch branching enzyme can increase the α- 1, 6- glycosidic bond to improve the physicochemical properties and functions of starch.In this paper, the recombinant Escherichia coli BL21 ( DE3) ( pET-20b ( +) /be) was used to produce intracellularly starch branching enzyme from Geobacillus thermoglucosidans. Firstly, the ultrasound conditions for extracting the recombinant enzyme were optimized.The results showed that the optimized conditions were as follows: the ultrasonic power output of 325 W, total working time of 15 min and OD600 of 1.4. In addition, the shaking flask fermentation conditions for the production of the recombinant enzyme was optimized achieving highest activity 222.4U /mL, and the optimized conditions were as follows: TB medium, pH7.0, induced by0.01 mmol /L IPTG at 25℃ for 12 h.
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