Optimization of Saccharomyces cerevisiae sp.Strain by1.1b Culture Conditions for Efficient Biosynthesis of D-(-)-mandelate Dehydrogenase / 微生物学通报

The culture conditions of Saccharomyces cerevisiae sp.strain by 1.1 b were optimized for the production of D-(-)-mandelate dehydrogenase which is useful for the asymmetric bioreduction of benzoylformate to form D-(-)-mandelate.The optimum medium(per liter)consistes of 60 g peptone,30 g maltose, 0.5 g MgSO_4,0.01 g ZnSO_4,1.0 g KCl.After optimization of the culture medium,the enzyme production in shake flasks is enhanced from 2.56 to 20.21 U/L.The optimum fermentation conditions were determined as follows:medium volume 100 mL(i.e.,40%for a 250-mL shake flask),pH 6.5,inoculum size 10%,temperature 30℃,and cultivation time 25 h.