重组巴氏毕赤酵母高密度发酵表达rHSA

对基因工程菌Pichiapastoris的摇瓶发酵条件进行了试验 ,并根据摇瓶发酵的优化结果进行了补料分批高密度发酵。在摇瓶发酵时 ,甲醇诱导基因工程菌P .pastoris表达重组人血清白蛋白的发酵周期为 96h ;甲醇的最佳诱导浓度为 1 0g L ;发酵pH范围为 5 72～ 6 5 9;在摇瓶培养时 ,随着接种量的增加 ,虽然目的蛋白表达量缓慢增加 ,但单位细胞光密度的蛋白产率却明显下降 ,符合y =1 2 941x- 0 50 59方程 (线性相关系数r=0 9789) ,其限制性因子很可能为溶氧。在分批发酵 ,接种量为 1 0 %且种子细胞光密度 (OD60 0 )为 2 0左右时 ,细胞生长的延迟期为 2 1 1h左右 ,细胞生长光密度与培养时间的关系模型为 :y =0 7841e0 .2 3 19t(线性相关系数r=0 .993 6 ) ;在补料发酵时细胞干重浓度可达到 1 1 5g L— 1 6 0g L ,在 1 2 0h重组人血清白蛋白表达量最大达到 3 6g L。

Expression of Recombinant Human Serun Albumin in Genetically Engineered Pichia pastoris in High-density Fermentation

The optimum culture conditions of genetically engineered Pichia pastoris in shake-flask cultivation and in fed-batch fermentation were investigated respectively in this paper. It showed that the cultural period induced with 5 g/L methanol is 96 h, optimum methanol concentration is 10 g/L, and pH range is 5.72-6.59 in shake-flask culture. Although the seed inoculum amount increased, the target protein productivity per cell optical density was decreased. Their relationship fit the equeation Y = 12.941x(-0.5059) (r = 0.9789, where x is inoculating OD600, Y is protein productivity per cell optical density), we postulated that the restricting factor may be dissolved oxygen (DO) at shake-flask culture. With the 10% inoculum and 20 OD600 of seed, the lag phase of cell growth is 2.11 h in batch cultivation, and the relationship between cell optical density (Y) and culture time (t) is Y = 0.7841e0.2319t (r = 0.9936); The cell dry weight of broth reached 115-160 g/L and the maximum rHSA concentration was 3.6 g/L at the 120th at the fed-batch fermentation phase.