Optimum pH and temperature were determined in an extractive fermentation system using Ca-alginate entrapped Saccharomyces cerevisiae. The highest ethanol concentration and productivity of the extractive fermenta-tion system were observed at pH5.8 and 25℃. Meanwhile, the optimum pH and temperature of a fermentation system usingS.cerevisiae were determined to be pH4.5 and 30℃. The reason for this shift is that a product inhibition effect is less due to the improved extraction capacity of the solvent at new optimum pH and temperature and the immobilized cells have relatively constant activity over the pH and temperature range. Extractive fermentation at new pH and tem-perature present higher productivity and maximum ethanol concentration, 1.9g/l-hr and 180g/l, respectively than their counterparts, 1.6g/l-hr and 110g/l, at pH4.5 and 30℃. Shift of new optimum pH and temperature is possible for any extractive fermentation by using immobilized cells in which product inhibition is significant.