多表位恶性疟疾疫苗M.RCAg-1在大肠杆菌表达的条件优化和大规模培养

The optimal condition for expression and large-scale culture of candidate vaccine against Plasmodium falciparum in E. coli

通过以培养基配方、IPTG浓度、金属离子复合液浓度、镁离子浓度、表达时间、接种量、诱导时间点等发酵的重要条件对重组蛋白表达量影响的研究,确定多表位恶性疟疾疫苗M.RCAg-1蛋白最佳表达条件为以改良TB培养基培养、最优Mg2+,诱导剂IPTG和金属离子复合液浓度分别为10mmol/L,0.5mmol/L,6μl/ml,接种量为10%,表达时间为4.5h,将优化后的参数用于50L发酵罐进行连续3批中试规模的发酵,最终收获菌体湿重平均为31.8±1.78g/L,目的蛋白表达量可占菌体总蛋白的50%左右,试验确定了恶性疟疾多表位随机组合蛋白M.RCAg-1在大肠杆菌中的最优表达条件,该条件能够适合大规模培养需要。

The factors influencing the expression of recombination protein and vaccine culture were detected these factors inelude the medium composition, concentration of IPTG, the concentration of metalions compound liquid, ionic strength of Mg^2＋ , expression time, inoculum dose, induction time and induction dose. The results showed that the optimal conditions for the expression of recombination protein and vaccine culture are as follows ： the modified TB culture medium is the best, the optimal concentration of Mg^2＋ , inducer IPTG and ions compound liquid was 10mmol / L, 0.5mmol / L, 6μl/ml respectively, the inoculum dose is 10% and the induction time is 4.5 h. three consecutive bathes of fermentation culture in a polot scale were carried out at the conditions of the above mentioned optimal parameters. The yield of bacteria reaches the average value of 31.8 ± 1.78g/L and the expressing level of recombinant M. RCAg-1 is about 50% of the host protein in 50 liter fermentor. These conditions can be suitable for large scale culture.