b-glucosidase activity was assayed in a reaction mixture consisting of 25 mL of enzyme solution, 25 mL of 10mMp-nitrophenylb-D-glucopyranoside (pNPG) in 0.05 M sodium citrate buffer (pH4.8) at 50 C for 10 min. After the incubation, 0.1 mL of a 0.4 M Na2CO3 solution was added. After the color developed (indicating release of p-nitrophenol), absorbance was measured at 405 nm. For all these dosages, one unit of activity is the amount of enzyme required to release 1 mmol p-nitrophenol per min under the conditions of the assay. Total protein was measured by the Bradford method using bovine serum albumin (BSA) as a standard.