Recombinant Protein Expression in P. pastoris in a bioreactor via a semicontinuous mode
Pichia pastoris has been successfully used as an efficient expression system for heterologous protein production.Herein, we report the development of a semicontinuous process to improve the production of recombinant proteins in P.pastoris by its cultivation in a BIONET’ s F1 benchtop bioreactor of 3 L equipped with a continuous process module(CPM). Six repetitive batches were conducted in a semicontinuous process by replacing 2 / 3 of the culture every 72-96 h.The overall process in a volume of 3 L of culture yielded a protein concentration of 0.28± 0.13 mg· mL-1, taking 650 h to obtain 6± 0.5 g of total target protein. On the contrary, the obtention of the equivalent amount of protein with a fedbatch mode require around 1100 h of total time, including the inoculum preparation, the non induced fermentation stage and the expression stage. Therefore, a reduction of the operation time and of the operation cost is evident when using a semi continuous fermentation strategy. These results suggest the interesting gap for the development of costeffective processes for the expression of recombinant proteins in P.pastoris in semicontinuous mode as an alternative to the productive continuous process mode that is not available when low dilution rates are required(due to the lack of available pumping technology).