In this work, ultrasonic treatment was used for improving the catalytic activity of glucoamylase preparation Dextrozyme GA. The ultrasonic temperature, power and time were optimized by a Central Composite Circumscribed design for maximizing of the catalytic activity of the preparation. | SCIENCE & TECHNOLOGY DEVELOPMENT, , - 2015 Optimization of the ultrasonic treatment for improving catalytic activity of glucoamylase preparation Tran Thi Thu Tra Le Van Viet Man Department of Food Technology, Ho Chi Minh city University of Technology, VNU-HCM (Manuscript Received on March 12nd, 2015, Manuscript Revised September 04nd, 2015) ABSTRACT In this work, ultrasonic treatment was used for improving the catalytic activity of glucoamylase preparation Dextrozyme GA. The ultrasonic temperature, power and time were optimized by a Central Composite Circumscribed design for maximizing of the catalytic activity of the preparation. The optimal ultrasonic temperature, power and time were 30oC, 20 W/mL and 33 sec, respectively. Under these conditions, the maximum glucoamylase activity was ± KU/mL and this value increased 11 % in comparison with that in the control without ultrasonic treatment. Our results also showed that Vmax and KM of the sonicated Dextrozyme GA preparation were higher than those of the control. The ultrasonic treatment would be a potential method for improving the catalytic activity of the glucoamylase preparation in starch hydrolysis. Keyword: glucoamylase, optimization, ultrasonic treatment, 1. INTRODUCTION In food industry, ultrasonic treatment can be considered as a potential method for enzyme inactivation. Ultrasound generated cavitation that could cause the change in protein structure and reduce enzyme activity [1]. Under mild treatment conditions, however, ultrasound could increase enzyme activity. This phenomenon was observed for different enzymes including amylase [2], [3], cellulase [4], dextranase [5], TRANG 52 pectinase [6]. It was explained that slight modification of protein conformation facilitated the formation of enzyme-substrate complex and that resulted in an improved catalytic activity of the sonicated enzyme preparation [1]. Recently, our study showed that .
