The reaction mixture contained 0.2 mL of enzyme sample, 0.3 mL of buffer and 0.5 mL of p-nitrophenyl-β-D-glucopyranoside (1.0 mM) prepared in 100 mM buffer as the substrate. The reaction was terminated after 30 min of incubation at 70 °C by adding 2 mL of sodium carbonate-bicarbonate buffer (0.1 M, pH 10.0). The liberation of p-nitrophenol was measured at 400 nm and its yield was determined using a standard curve of p-nitrophenol (1-10 μg mL-1) prepared in sodium carbonate-bicarbonate buffer