Cellulase activity was determined based on Miller (1959). The reaction mixture consisted 0.5 mL of 1% carboxymethyl cellulose (CMC) as substrate in 1 mL phosphate buffer (0.1 M, pH 6.8) with 0.5 mL tissue homogenate. The reaction mixture was incubated at 37 °C for 1 h. The reaction was stopped by adding 3 mL of DNS reagent and the mixture was kept in boiling water bath for 10 min. The reaction mixture was diluted with distilled water and absorbance was recorded at 574 nm. One unit of cellulase activity was defined as number of molecules of glucose released from cellulose mg−1 protein min−1 at 37 °C.