SCREENING OF A YEAST STRAIN WITH LIPASE AND ESTERASE ACTIVITY AND CHARACTERIZATION OF THE ENZYMES

A yeast strain S 9 producing both lipase and esterase was screened. Various factors affecting production of lipase and esterase were studied. The best nitrogen and carbon sources were 2% soybean powder and 1% soluble starch. Optimal initial culture pH and temperature were 6.5 and 28℃,respectively. Different surfactants had different effects on enzymes. The studies on the characteristics of S 9 lipase and esterase showed that the optimal action temperature of them were all 30℃, and optimal pH 7.0 and 8.0,respectively. Both of the enzymes were very stable between 30℃and 40℃. S 9 lipase was alkaline by neutral enzyme,S 9 esterase was alkaline enzyme and was rather stable in the range of pH 7.5～10.5.