Fractionation of the Glucoamylase System from Black‐koji Mold and the Effects of Adding Isoamylase and Alpha‐amylase on Amylolysis by the Glucoamylase Fractions

Abstract

AbstractThe glucoamylase system of black koji mold was fractionated into four kinds of glucoamylase by using the corn starch adsorption technique supplement by DEAE‐cellulose column chromatography. One of these fractions, referred to as glucoamylase I, had a strong debranching activity and is highly active in raw starch digestion.The raw waxy corn starch digestion by glucoamylase I was accelerated by adding α‐amylase or isoamylase. The raw non‐waxy corn starch digestion by glucoamylase I was accelerated by α‐amylase but not so much by isoamylase as by α‐amylase.On the other hand, another fraction, referred to as glucoamylase II, had very weak debranching activity and was most feeble in the digestion of raw starch. The raw waxy corn starch digestion by glucoamylase II was very weak, but was accelerated extremely by adding isoamylase, but not by α‐amylase.