Central Composite Statistical Design of Tapioca Starch Hydrolysis using Immobilized Glucoamylase on Mesostructured Cellular Foam Silica (MCF-9.2T-3D)

Abstract

Bioethanol is a renewable fuel that can be produced from tapioca starch via fermentation pathway. This substrate must be reduced either by enzymatic or acidic hydrolysis. As the hydrolysis of tapioca starch employing immobilised glucoamylase enzyme increase reusability of the enzyme, the process catalysed by the glucoamylase immobilised on/in mesostructured cellular foam silica (MCF-9.2T-3D) was optimised.  Effects of temperature, pH of acetate buffer, and agitation speed were studied using response surface methodology based-on central composite design.  The saccharification results were analyzed using Design-Expert^®6.0.6 software.  The model is validated by the F-test for analysis of variance (ANOVA) where p is 0.001. The ANOVA indicated that the acetate buffer pH and agitation speed were not significant, while temperature of hydrolysis showed significant effect.  The optimum condition was found at 70⁰C, 4.6, and 140 rpm. The glucose yield at this optimum condition was 2.06 mg/ml, which was equivalent to 68.05% dextrose value.