Enhanced porcine interferon-α production by recombinant Pichia pastoris with a combinational control strategy of low induction temperature and high dissolved oxygen concentration

Porcine interferon-α (pIFN-α) production by recombinant Pichia pastoris with standard induction strategy at 30 °C often suffers problems such as low antiviral activity, long cells adaptation period, etc. To solve these problems, a combinational induction strategy by simultaneously controlling induction temperature at 20 °C and dissolved oxygen concentration (DO) over 50% was proposed and the relevant fermentation runs were conducted in a 5 l bioreactor. With this control strategy, pIFN-α antiviral activity could be continuously enhanced and eventually reached a level of 3.62 × 107 IU/ml, which was about 16-fold of the maximum obtained when induction was done at 20 °C but without DO control, and more than 100-fold of the maximum obtained with the standard induction strategy at 30 °C. The novel control strategy could enhance alcohol oxidase (AOX) activity and relieve oxygen supply limitation in oxidative phosphorylation reaction to accelerate ATP regeneration simultaneously. As a result, the metabolic flux towards pIFN-α synthesis was enhanced and the adaptation period was shortened, enabling the entire system to be operated in a most efficient way.