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

BACKGROUNDEffects 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=0-15h, followed by fed-batch methanol feeding; and (iv) fed-batch methanol and sorbitol feeding at t=0-30h, followed with fed-batch methanol feeding. RESULTSThe highest rhGH and cell concentrations were achieved, respectively, as 0.64gL(-1) and 105gL(-1) at t=42h of induction phase, with the strategy where methanol was fed to the system at a pre-determined feeding rate of (M0)=0.03h(-1), and sorbitol concentration was kept at 50gL(-1) at t=0-15h of the rhGH production phase where the specific growth rate on sorbitol was (S0)=0.025h(-1). The overall cell and product yield on total substrate were found as 0.26gg(-1) and 2.26mgg(-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. (c) 2012 Society of Chemical Industry