Effect of galactose feeding on the improved production of hirudin in fed-batch cultures of recombinant Saccharomyces cerevisiae

Different feeding strategies of galactose were employed to improve the prod uction of anticoagulant, hirudin, by fed-batch mode of cultivation from rec ombinant Saccharomyces cerevisiae. The structural gene coding for hirudin w as harboured with GAL10 promoter for controlled expression of hirudin and t he MF alpha 1 signal sequence for secretion into the growth medium. A stepw ise feeding of galactose was found as more suitable feeding strategy of gal actose which resulted in the final hirudin volumetric productivity of 6,840 mu g/l . h, than intermittent, continuous and ethanol controlled feeding o f galactose. The final volumetric productivity of hirudin obtained by step- wise feeding of galactose was 3.88 fold higher compared with simple batch f ermentation.