Filter paper cellulase (FPase) activity was assayed by incubating the 125 mL of enzyme solution with 250 mL of sodium citrate buffer (50 mM, pH 4.8) with filter paper (Whatman no. 1, 0.25 mm pore size, 1.5 cm diameter]). The mixture was incubated at 50 C for 60 min. Then, 200 mL of enzyme solution (supernatant) was added to 200 mL of DNA reagent and boiled at 100 C for 5 min. Reducing sugar was determined by the dinitrosalicylic acid (DNS) method[16]. One international unit of FPase activity is the amount of enzyme that forms 1 mmol of glucose (reducing sugars as glucose) per minute during the hydrolysis reaction. All presented data are average of three independent experiments.