Improvement of porcine interferon-α production by recombinant Pichia pastoris via induction at low methanol concentration and low temperature.

Improved porcine interferon-α (pIFN-α) production by recombinant Pichia pastoris was achieved by culture conditions optimization in a 5-l bioreactor. The results indicated that the pIFN-α concentration, specific methanol consumption rate, specific activities of alcohol oxidase, formaldehyde dehydrogenase, and formate dehydrogenase could be significantly enhanced by decreasing induction temperature. The highest pIFN-α concentration (1.35 g l(-1)) was obtained by simultaneously controlling methanol concentration at 5 g l(-1) and induction temperature at 20 °C, which was about 1.6-fold higher than the maximum obtained with previous optimal methanol concentration level (about 10 g l(-1)) when inducing at 30 °C. The potential mechanisms behind low temperature and low methanol concentration effect on pIFN-α production may be ascribed to higher cell metabolic activity, more carbon flux towards pIFN-α production, and less intracellular/extracellular protease release.