Production of hirudin by recombinant Saccharomyces cerevisiae in a membrane-recycle fermentor

Recombinant Saccharomyces cerevisiae was employed to continuously produce hirudin in a membrane cell recycle fermenter. The gene coding for the anticoagulant protein was combined with the GAL10 promoter for controlled expression and the MF α1 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 rates studied ranging from 0.05h-1 to 0.3h-1. Cell bleeding gave the same fermentation results as cell recycle fermentation without cell bleeding. The productivity of the cell recycle fermentation process was 6.0mg hirudin/l·hr, corresponding to a 1.7-fold increase compared with a conventional continuous culture.ope