EFFECTS OF MEDIUM COMPOSITION ON HIRUDIN PRODUCTION IN RECOMBINANT SACCHAROMYCES-CEREVISIAE

The enriched medium based on Yeast nitrogen base(YNB)increased hirudin synthesis and secretion in recombinant Saccharomyces cerevisiae in ba tch and fed-batch cultures. Fed-batch fermentation with the defined me dium ridded 342mg hirudin/l but supplementation of yeast extract incre ased the final hirudin concentration to 461mg hirudin/l. The defined m edium, however, produced the product protein with higher purity of 21% and hence will allow easy separation of secreted hirudin from other c ontaminated polypeptides present in the growth medium. In a continuous culuture, the defined medium yielded higher concentrations of cell ma ss and hirudin than the complex medium.