Estimation of kinetic parameters for rice starch hydrolysis inhibited by added materials

Abstract

In the present study, glucose, maltose, and glycerol inhibition effects for alpha-amylase hydrolyzing rice starch were investigated. For the enzymatic hydrolyzsis of rice starch, alpha-amylase enzyme produced from Bacillus licheniformis was used. During the starch hydrolysis experiments, the temperature and pH were kept constant at 60 degrees C and 6.5 respectively. The reactions were carried out in 0.5 L of aqueous solutions containing 1, 2, 4, and 8% (w/v) rice starch. The amount of alpha-amylase enzyme added to this solution was 5 mL per liter ( approximately 130500 units/L). The amounts of glucose, maltose, and glycerol added to the reaction solution were 4 and 8% (w/v), 4 and 8% (w/v), and 5 and 10% (v/v), respectively. An emprical model effectively simulated the data of residual starch concentration as a function of processing time for each condition. The Lineweaver-Burk plots showed that the inhibition effects of these added materials were uncompetitive.