Estimation of Cellulase activity
Cellulase activity was assayed using dinitrosalicylic acid
(DNS) reagent (Miller 1959) [17] by estimation of reducing
sugars released from CMC solubilized in 0.05 M phosphate
buffer at pH 8 (Bailey et al., 1992) [4]. The culture broth was
centrifuged at 14000×g for 10 min at 4 °C and the clear
supernatant served as crude enzyme source. Crude enzyme
was added to 0.5 ml of 1% CMC in 0.05 M phosphate buffer
and incubated at 50 °C for 30 min. After incubation, reaction
was stopped by the addition of 1.5ml of DNS reagent and
boiled at 100 °C in water bath for 10 min. Sugars liberated
were determined by measuring absorbance at 540 nm.
Cellulase production was estimated by using glucose
calibration curve (Shoham et al., 1999) [22]. One unit (U) of