HIGH-PROTEIN EXPRESSION IN FERMENTATION OF RECOMBINANT PICHIA-PASTORIS BY A FED-BATCH PROCESS

A fed-batch fermentation process was developed to culture recombinant Pichia pastoris at high cell density and with high protein expression. High levels of the thrombomodulin fragment were obtained from an SMD1 168 strain (pep4(-)) that had a methanol utilization slow (mut(s)) phe notype. Dissolved oxygen concentration (DO) was controlled by cascadin g DO with agitation and pure oxygen supplementation, thereby avoiding oxygen limitation during the entire process. Wet cell density reached 420 g/litre and the concentration of protein, an 86 amino acid thrombo modulin fragment, was 360 mg/litre. Copyright (C) 1996 Elsevier Scienc e Ltd