Studies on Enzymatic Liquefaction and Saccharification of Starch

Abstract

Liquefaction of corn starch is generally considered to be difficult to achieve. A double enzyme system, a combination of bacterial alpha-amylase and fungal glucoamylase, was tested for the production of dextrose from corn starch. The former liquefies starch and the latter hydrolyzes further into glucoseParticularly various conditions for liquefaction of corn starch were examined. As criteria of solubilization of starch molecule, turbidity of filtrate obtained while the solution was hot, iodine coloration value, filterability and turbidity of the saccharified solution after the addition of alcohol were measured.Starch slurry containing bacterial alpha-amylase was poured continuously in fine stream into hot water with vigorous agitation. Liquefaction at 92°C was better than at 87°C for dissolving corn starch. It was indispensable to apply heat treatment under high pressure after liquefaction followed by the second addition of bacterial alpha-amylase at 90°C to render remaining tightly bound starch micelle t...