BETA-GLUCOSIDASE IN THE CELLULOLYTIC FUNGUS SPOROTRICHUM-THERMOPHILE APINIS

Sporotrichum (Chrysosporium) thermophile was shown to produce β-glucosidase during growth on cellulose, cellobiose, laminaribiose, and arbutin. Enzyme synthesis was regulated by induction, the exact identity of the natural inducers being, at present, unknown. The β-glucosidase was not derepressed, either during growth on glucose after total substrate exhaustion from the culture medium or during growth on nonsugar substrates. An intracellular trehalase was, however, synthesized under such conditions. β-Glucosidase preparations were active against cellobiose, laminaribiose, sophorose and o-nitrophenyl-β-d-glucoside. Other β-linked glucosides or cellobiose derivatives were hydrolyzed at a much lower rate. Such preparations did not show a great deal of exo-glucanase activity when tested with laminarin. No evidence was found in favor of the presence of more than one isofunctional β-glucosidase in this organism. Moreover, unlike for other cellulolytic fungi, the β-glucosidase of Sporotrichum thermophile was essentially intracellular, suggesting an intracellular function. © 1979 Academic Press, Inc. All rights reserved.