A rational approach to improving productivity in recombinant Pichia pastoris fermentation

Abstract: A MutS Pichia pastoris strain that had been genetically modified to produce and secrete sea raven antifreeze protein was used as a model system to dem-onstrate the implementation of a rational, model-based approach to improve process productivity. A set of glyc-erol/methanol mixed-feed continuous stirred-tank reac-tor (CSTR) experiments was performed at the 5-L scale to characterize the relationship between the specific growth rate and the cell yield on methanol, the specific methanol consumption rate, the specific recombinant protein for-mation rate, and the productivity based on secreted pro-tein levels. The range of dilution rates studied was 0.01 to 0.10 h−1, and the residual methanol concentration was kept constant at approximately 2 g/L (below the inhibi-tory level). With the assumption that the cell yield o