Preliminary studies showed in Aspergillus versicolor that the carbon source utilized for growth could affect the degree of glycosylation of ß-xylosidases (Andrade et al. Process Biochemistry 39, 1931-1938, 2004). The aim of this work was to investigate in this fungus whether the carbon source would also affect the glycosylation of ß-glucosidase. The organism was grown in several carbon sources. Wheat straw, a complex material containing cellulose and hemycellulose, was the substrate that produced the larger variety of ß-glucosidases. The two main mycelial forms of ß-glucosidase produced in wheat straw were purified using DEAE-Sephacel and DEAE-cellulose chromatography. ß-glucosidase I exhibited 51% of carbohydrate while ß-glucosidase II had 43%. Their apparent molecular masses, estimated by gel filtration and SDS-PAGE, were respectively 146 kDa, 123 kDa, 131 kDa and 123 kDa, for ß-glucosidase I and ß-glucosidase II. However, ß-glucosidase II moved faster in PAGE than ß-glucosidase I. The pI values were 5.8 and 4.9 for ß-glucosidase I and II, respectively. Both enzymes exhibited maximal activity at 50 ºC. However, ß-glucosidase I exhibited a half-live of 16 min when incubated at 45 ºC in water, while ß-glucosidase II exhibited a half-life of only 7 min under the same conditions.  ß-Glucosidase I exhibited optimum pH of 5.0, while that of ß-glucosidase II was 5.5. The enzymes could not be distinguished by the values of Km, Vmax and both were specific for cellobiose and pNP-glucopyranoside. However, ß-glucosidase I was more drastically inhibited by silver, cooper, iron and cobalt than ß-glucosidase II. After treatment with endo-H both enzymes migrated identically in PAGE, suggesting that the different electrophoretic mobility observed for ß-glucosidase I and II resulted of differences in the amount of carbohydrate present in the protein. Also, slight biochemical differences (thermal resistance, optimum pH and sensitivity to metals) observed for ß-glucosidase I and II might be attributed to differential glycosylation.