Incomplete protein disulphide bond conformation and decreased protein expression result from high cell growth during heterologous protein expression in Pichia pastoris

► The incorrectly folded cIFN in supernatant is produced in cell. ► Cell secretes incorrectly folded recombinant cIFN at high specific growth rate. ► cIFN expression level decreases at high specific growth rate. ► Incorrectly folded cIFN forms aggregates intracellularly. ► These results suggest that the efficient heterologous expression of cIFN is limited by high cell growth.