β-glucan hydrolases from Aspergillus niger. Isolation of a β-(1→4)-glucan hydrolase and some properties of the β-(1→3)-glucan-hydrolase components

Abstract

The components of an enzyme preparation from Aspergillus niger, which hydrolysed substrates containing [beta]-(l[forward arrow]3)- and [beta] -(1[forward arrow]4)- glucosidic linkages, were separated by calcium phosphate and Dowex 1 column chromato-graphy. The hydrolytic activity of each fraction from both types of column towards laminaribiose, laminarin, carboxymethylpachyman, pachydextrins, salicin, cellobiose, cellopentaose and swollen cellulose was tested. The activity towards the [beta] -(1[forward arrow]3)-glucosidic substrates was found in three well-separated groups of fractions. The differences in action pattern of these groups is discussed. Preparative-scale chromatography that enabled the separation of a [beta]-(1[forward arrow]4)-glucan-glucanohydrolase component substantially free of activity towards [beta]-(l[forward arrow]3)-glucosidic substrates is described. Residual [beta]-(1[forward arrow]3)-glucan-hydrolase activity was removed by adsorption on to insoluble laminarin at pH3. 5.