Optimization of fermentation conditions for the production of recombinant hpdgf-bb in Pichia pastoris

Abstract

hPDGF-BB (human Platelet-derived Growth Factor BB) is a growth factor that plays an important role in wound healing. It is indicated for treatment of foot ulcers in diabetic patients by FDA. Besides, hPDGF-BB also stimulates the recruitment and proliferation of a variety of cell types, including bone cells and mesenchymal stem cells, and used to enhance bone graft. In order to produce rhPDGF-BB for therapeutic purposes, we conducted the research on production of rhPDGF-BB in Pichia pastoris. In this study, we applied the fed-batch fermentation in 1-liter scale including glycerol batch, glycerol fed-batch and induction the expression of rhPDGF-BB by feeding methanol. The induction stage was carried out at different temperature (25oC, 30oC) and different pH (3.5; 5.0; 6.5). The result showed that fermentation at different temperature and different pH did not affect the growth of the recombinant Pichia pastoris X33::pdgf-b clone. Induction at low temperature and low pH will decrease the amount of secreted protein. Fermentation at 30oC and pH 6.5 produced the highest amount of rhPDGF-BB with 686.69 mg/l which was 7.63-fold higher than that of shake flask batch culture.