Purification of β-d-glucosidase from Aspergillus niger

Abstract

Publisher Summary β-D-Glucosidases have been isolated and purified from a number of fungal culture filtrates. A number of β-glucosidases, including those from almond emulsin and from Aspergillus niger 15, do not have a strict requirement for a D-gluco configuration. The enzyme from almond emulsin catalyzes hydrolysis of both β-D-glucopyranosides and β-D-galactopyranosides and evidence has been obtained for the involvement of different enzyme active sites. An enzyme purified to homogeneity from culture filtrates of Aspergillus niger 15 has a very broad specificity with activity on β-D-glucosides, β-D-xylosides, β-D-galactosides, and β-L-arabinosides. β-glucosidase in combination with a specific endo-β-glucanase could find widespread application in the quantification of a range of β-D-glucans such as (1→4)-β-D-glucan, (1→3)-β-D-glucan, (1→3),(1→4)-β-D-glucan, and (1→3),1→6)-β-D-glucan. Together with endo-1,4-β-D-mannanase and β-D-mannosidase it may also prove useful in the measurement of β-D-glucomannans. A method for the assay of (1→3),(1→4)-β-D-glucan has already been developed using a highly purified β-D-glucosidase from a commercially available Aspergillus niger enzyme preparation. This chapter describes the purification of this enzyme and report on some of its properties.