High-density Expression of Recombinant Porcine Insulin Precursor by Pichia pastoris / 微生物学通报

ABSTRACT

The recombinaut porcine insulin precursor(PIP)produced by Pichia pastoris in shake-flask and 501.fermenter was investigated respectively.The results indicated that 60h induction time length and 2.0%～2.5% methanol addition every day was optimum in shake- flask.The process in 50L fermenter was consisted of batch,feed-batch and induction phases.The relationship between dry cell weight(y) and culture time (t) in growth phase(batch and feed-batch phase)could be described by model y=0.6525e~(0.1907t).Glycerol and ammonia were almost used for cell growth and maintain,and no by-product was observed in batch and fed-batch phase Only 80% ammonia and 70% methanol were used by cell in induction phase.By comparison the results of shake-flask and 50L fermenter,it was concluded that the limit- ing factor in the fermentation of shake-flask and 50L fermenter was dissolved oxygen(DO)and.carbon source,respectively.When scaling the result of shake-flask to 501.fermenter,the control strategy was adapted for 50L fermenter by increasing the feed rate of methanol and the maximum PIP concentration reached 1.72 g/L.