Determination of Optimum Reaction Velocity for Glucose Production from Cassava Starch Using Gluco Amylase Sourced from Rice

Abstract

In an attempt to produce glucose from locally sourced materials to boost glucose syrup production and other applications, the optimum reaction velocity which enzyme becomes saturated with the substrate was investigated. In this study, cassava starch (substrate) and glucoamylase (enzyme) from rice were sourced and prepared. The time course of the enzyme hydrolysis was studied at pH 5 and temperature of 400C as optimum conditions. The hydrolysis was carried out at various substrate concentrations. The time course of the reaction for glucose production was monitored at 10 minutes interval for a period of one hour. The glucose concentration produced was plotted against reaction time to evaluate the optimum glucose amount and its corresponding substrate concentration. The reaction velocity was then computed. Also, the experimental data were fitted into Michaelis-Menten model using Statistical Package for Social Scientists to compare the yield of glucose. Results showed optimum yield of glucose concentration was 0.253 g DE L-1 achieved with 2.5 and 3.0% w/v substrate concentration at 50 and 40 minutes respectively. Further analysis gave the optimum reaction velocity range of 0.00506 to 0.00625 of g DE per litre-min.  This range when compared with the model equation result (0.0052 to 0.0068 g DE litre-min) is reasonably close; hence the results from this study are valid. Technical evaluation to standardize the reaction velocity with respect to substrate concentration which may be referred to as specific reaction velocity gave 0.00205 ±0.00005 g D per litre-min per substrate concentration %w/v.