PRODUCTION OF HIRUDIN BY RECOMBINANT SACCHAROMYCES-CEREVISIAE IN A MEMBRANE-RECYCLE FERMENTER

Recombinant Saccharomyces cerevisiae was employed to continuously prod uce hirudin in a membrane cell recycle fermenter. The gene coding for the anticoagulant protein was combined with the GAL10 promoter for con trolled expression and the MF alpha 1 signal sequence for secretion to the fermentation broth. A dilution rate of 0.1h(-1) yielded a maximum hirudin concentration of 59mg/l with a specific hirudin concentration of 2.4mg/g cell mass among dilution rates studied ranging from 0.05h( -1) to 0.3h(-1). Cell bleeding gave the same fermentation results as c ell recycle fermentation without cell bleeding. The productivity of th e cell recycle fermentation process was 6.0mg hirudin/l . hr, correspo nding to a 1.7-fold increase compared with a conventional continuous c ulture.