重组大肠杆菌BL21(DE3)/rbLF-N高密度培养条件优化

High cell-density culture of recombinant E.coli BL21(DE3)/rbLF-N

研究了6种不同培养基,pH值和诱导条件对表达量的影响。结果表明,培养基为2×TY+M9+微量元素溶液,pH值为7.0,在对数生长中后期(OD600=1.96)用浓度为0.1 mmol/L的IPTG诱导4 h,rbLF-N的表达量最高,达到25.2%。在此条件下,用Bioengineering 19 L自控式发酵罐,以pH-stat的培养技术,高密度培养重组E.coli BL21(DE3)/pGEX-4T1,生产重组牛乳铁蛋白N末端多肽(recombinant bovine lactoferrin-N polypeptide,rbLF-N)。通过控制pH值、溶解氧以及补料方式,使工程菌E.coli BL21(DE3)/pGEX-4T1的发酵菌体OD600值达到72.6,发酵菌体干重为31.9 g/L,rbLF-N表达量为菌体总蛋白的26.8%。

Six culture mediums, pH and inductive condition of E. coli BL21 （DE3）/rbLF-N have been optimized. The optimal condition is as follows： the culture medium was 2×TY ＋ M9 ＋ trace elements solution, the pH was 7.0, the time point of induction is OD600= 1.96, the final concentration of IPTG in the culture is 0.1 mmol/L and the induction time is 4 h, the expression level of rbLF-N was 25.2 %. The pH-stat culture process of E, coli BL21 （DE3）/rbLF-N were carried out to produce recombinant bovine lactoferrin-N polypeptide （rbLF-N） in 19 L Bioengineering autocontrol fermentor. High cell-density and high expression were achieved by controlling pH, dissolved oxygen and feeding solution. The final cell-density and cell dry weigh were 72.6OD600 and 31.9 g/L respectively. The expression level of rbLF-N was 26.8 %.