重组大肠杆菌产Streptomyces sp.FA1来源木聚糖酶的摇瓶发酵优化

Optimization of Fermentation in Shake Flasks for the Xylanase in Recombinant E.coli

为了实现来源于Streptomyces sp.FA1的木聚糖酶的高效胞外分泌表达,对E.coli BL21(DE3)/pET20b(+)/coe/xynA基因工程菌的发酵产酶诱导条件进行优化,获得最优的诱导条件为25℃发酵6 h后添加终浓度为0.4 mmol/L的IPTG。在此基础上对发酵培养基进一步优化,得到最优培养基成分为:甘油11 g/L,酵母粉24 g/L,蛋白胨8 g/L,磷酸盐浓度89 mmol/L,镁离子4mmol/L。最终酶活达到780.2 U/ml,为未优化前的2.2倍,是目前大肠杆菌摇瓶发酵产木聚糖酶的最高表达水平,为实现该酶的工业化生产奠定基础。

In order to achieve high production of the xylanase, the optimization of culture medium was investigated in E. coli BI21 （DE3） harboring the plasmid pET20b （ ＋ ）/coe/xynA. The optimized medium and induction condition were as follows ： 11 g/L glycerol, 24 g/L yeast extract, 8 g/L peptone, 89 mmol/L P043, 4 mmol/L Mg2＋ , induced by 0.4 mmol/L IPTG at 6h of culture. Under this condition, the enzyme activity increased from 346.8 U/ml to 780.2 U/ml, which Was 2.2 times as high as that when it was not optimized.