Optimization of Operating Variables for Corn Flour Starch Hydrolysis using Immobilized a-amylase by Response Surface Methodology

摘要

The major concern in an enzymatic process is the instability of the enzyme under repetitive or prolonged use and inhibition by high substrate and product concentration. Immobilization is a very effective alternative in overcoming problems of instability of enzymes. Entrapment method of immobilization is advantageous over other . methods as they do not involve chemical modification of the enzyme, a -amylase was immobilized in sodium alginate beads and used for the effective hydrolysis of soluble and raw corn starch. In this study the effect of starch concentration, temperature, time and enzyme concentration were studied and optimized for hydrolysis of corn flour starch powder (of mesh size 80/120) into glucose syrup by immobilized (using sodium alginate ) a-amylase using central composite design. Considering the individual effect and interaction effect of independent variables, a statistical central composite design was conducted including starch concentration, enzyme concentration, temperature andtime as operational variables and reducing sugar concentration released as dependent variable. The conditions to obtain the maximum response were 8.07% of starch concentration, 1.92 % of Enzyme concentration, temperature 60°C and time 93.07 min, where 1.19 mg/ml of reducing sugar concentration was predicted.