Figure 3.

Response surface curves for pH and temperature effects and thermal stabilities of β-glucosidase (a), β-xylosidase (b) and xylanase (c) activities. The fungus was cultured under optimal conditions for the production of each enzyme. For thermal stability studies, aliquots of the crude extracts were incubated at (○) 50 °C, (■) 55 °C, (△) 60 °C, (●) 65 °C or (□) 70 °C. One hundred percent specific activities corresponded to 48.5 ± 1.4 U mg⁻¹ for β-glucosidase, 33.2 ± 0.8 U mg⁻¹ for β-xylosidase and 47.0 ± 1.4 U mg⁻¹ for xylanase. Residual activities were estimated in duplicate aliquots, and the values shown represent averages from triplicate experiments (n = 3).