Effect of co‐substrate sorbitol different feeding strategies on human growth hormone production by recombinant Pichia pastoris

Abstract

AbstractBACKGROUNDEffects of co‐substrate sorbitol different feeding strategies on recombinant human growth hormone (rhGH) production by Pichia pastoris hGH‐Mut+ were investigated by eight designed experiments grouped as: (i) fed‐batch methanol feeding without the co‐substrate; (ii) fed‐batch methanol feeding with pulse sorbitol feeding; (iii) fed‐batch methanol feeding together with fed‐batch sorbitol feeding at t = 0–15 h, followed by fed‐batch methanol feeding; and (iv) fed‐batch methanol and sorbitol feeding at t = 0–30 h, followed with fed‐batch methanol feeding.RESULTSThe highest rhGH and cell concentrations were achieved, respectively, as 0.64 g L−1 and 105 g L−1 at t = 42 h of induction phase, with the strategy where methanol was fed to the system at a pre‐determined feeding rate of μM0=0.03 h−1, and sorbitol concentration was kept at 50 g L−1 at t = 0–15 h of the rhGH production phase where the specific growth rate on sorbitol was μS0=0.025 h−1. The overall cell and product yield on total substrate were found as 0.26 g g−1 and 2.26 mg g−1, respectively.CONCLUSIONThis work demonstrates that co‐carbon source, sorbitol, feeding strategy is as important as methanol feeding strategy in recombinant protein production by Mut+ strains of P. pastoris. © 2012 Society of Chemical Industry