Sago starch as a biomass source: Raw sago starch hydrolysis by commercial enzymes

Raw sago starch and sago starch pretreated by heating at 60°C for 2 hours in sodium acetate buffer (pH 3•5) were hydrolysed using commercial glucoamylase-AMG (EC 3•2•1•3), α-amylases-BAN, Fungamyl and Termamyl (EC 3•2•1•1), debranching amylase-Promozyme (EC 3•2•1•41), and their mixtures in sodium acetate buffer, pH 5•0 at 35°C. Raw sago starch was a poor substrate for enzyme action compared to corn and tapioca starches tested under the same conditions, although pretreating the starch increased the extent and rate of hydrolysis. A strong synergism between glucoamylase and α-amylase on the hydrolysis of both untreated and pretreated sago starch was observed. The hydrolysis products were characterized by high-performance size-exclusion chromatography (HPSEC). The total carbohydrate concentration of hydrolysed sago starch decreased but the amylose and amylopectin ratios in the residues remained the same.