A thermostable&苍产蝉辫;β-1,6-别苍诲辞驳濒耻肠补苍补蝉别&苍产蝉辫;or pustulanase (E.C. 3.2.1.75) which catalyses the cleavage of β-1,6 bonds in pustulan and other beta-glucans containing 1,6 linked glucose units. The enzyme is now a component in a standard assay for beta-glucan from Baker’s yeast as documented in US Pharmacopeia Food and Chemicals Index 7th Edition, 3rd Supplement p. 1686-1689.