[The effect of fermentation conditions on glycosylation of recombinant human interferon omega in yeast Pichia pastoris].
To investigate the influence of the fermentation conditions on glycosylation of heterologous recombinant protein in yeast Pichia pastoris, the glycosylation of recombinant human interferon omega (rhIFNomega) under various fermentation conditions, e. g., cell density, initial pH, methanol concentration, duration of the induction, and medium volume were studied. The glycosylation of rhIFNomega in the continuous fermentation process under various pH values and in batch fermentation were also investigated. In 250 mL flask, the optimal cell density, initial pH, medium volume, methanol concentration and frequency of methanol induction were 250 g/L (WCW), pH6.0, less than 30 mL, 15 g/L and 3 (in every 24 h), respectively. In the continuous process, the glycosylation of rhIFNomega could be effectively improved by maintaining the pH value at 7.0-7.5. In the batch fermentation process, the expression level of glycosylated and non-glycosylated rhIFNomega were the same, but the specified value of glycosylation/non-glycosylation was significantly lower than that in the flask culture. The reason of this phenomenon will be further studied. This research lay the foundation for the scale-up of production and the enhancement of rhIFNomega glycosylation in Pichia pastoris.