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Figure 3 | Biotechnology for Biofuels

Figure 3

From: Predominance of Trichoderma and Penicillium in cellulolytic aerobic filamentous fungi from subtropical and tropical forests in China, and their use in finding highly efficient β-glucosidase

Figure 3

Identification of purified β-glucosidase from Trichoderma koningiopsis FCD3-1. (A) (Left) SDS-PAGE analyses of the β-glucosidase. Lane M, protein molecular marker; lane 1, the purified β-glucosidase. (Right) Native PAGE analyses of the β-glucosidase. Lane 2, the gel stained with Coomassie blue; lane 3, the gel soaked in a 50°C solution containing 0.1% esculin and 0.25% ammonium iron (III) citrate (pH 4.5) for 30 minutes. (B) Effect of pH on TkBgl3A activity and stability toward substrate pNPG. For effect of pH on TkBgl3A activity (filled circles), enzyme activity was measured in 0.1 M citrate–phosphate buffer (CPB) pH 3.0 to 7.0 for 10 minutes at 50°C. For effect of pH on TkBgl3A stability, the enzyme was incubated in CPB, pH 3.0 to 7.0 (open circles), or 0.1 M Tris–HCl buffer, pH 7.0 to 9.0 (open squares), or 0.1 M glycine–NaOH buffer, pH 8.5 to 10.0 (open triangles) at 4°C for 24 hours. The residual activity was measured under optimal conditions. All values are expressed as percentages of the activity of untreated sample. (C) Effect of temperature on TkBgl3A activity and stability toward substrate pNPG. To assess the effect of temperature on TkBgl3A activity (filled circles), enzyme activity was measured at pH 4.5 in 0.1 M CPB at the indicated temperature for 10 minutes. To assess the effect of temperature on TkBgl3A stability (open circles), the enzyme was incubated in 0.1 M CPB (pH 4.5) at various temperatures for 1 hour; the residual enzyme activity was measured under optimal conditions. All values are expressed as percentages of the activity of untreated sample. (D) Stability of TkBgl3A under SSF conditions (30°C and pH 4.0); 100 μl of purified enzyme was added to 4.9 ml of 0.1 M CPB (pH 4.0) , followed by incubating the enzyme mixture at 30°C for varying times before checking the remaining enzyme activity.

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