Identification of glucose tolerant acid active β-glucosidases from thermophilic and thermotolerant fungi

摘要

Thirteen thermophilic and thermotolerant fungal cultures isolated from composting soils produced diverse β-glucosidases as indicated by zymograms of PAGE developed using 4-methylumbelliferyl-β-d-glucoside. IEF profiling revealed the presence of 28 β-glucosidases separated on the basis of their pI. Eleven of the β-glucosidases were active under acidic conditions. Two β-glucosidase isoforms, ASCβG-II of Aspergillus caespitosus and HIβG-I of Humicola insolens were resistant to inhibition by glucose and were active in the presence of 300 and 100 (mM) glucose, respectively.