Study of brewer yeast autolysis for invertase extraction

Abstract

This research focussed on brewer yeast autolysis for invertase extraction. Firstly, classical method was used for determination of autolytic conditions of brewer yeast. One parameter was varied while the others were fixed. The results were as follows: ratio of yeast and solven (acetate buffer): 1/6 (w/w), autolytic temperature: 50oC, initial pH: 5.5 and autolytic time: 50 hours. In these conditions, the recovery invertase activity was 94.7 activity units/gram of yeast dry matter. Then, the central composite design method was used to optimize the temperature and initial pH factors of brewer yeast autolysis for invertase extraction. Our results showed that optimal temperature and pH for yeast autolysis were 45oC and 5.5 respectively. The obtained invertase activity in the autolysate was 120.9 units/gram of yeast dry matter; the specific activity of the crude invertase was 0.7 units/mg protein.