Cellulase binding assay on POSWOI-pretreated Avicel. 2.5 mg of Avicel was mixed with 10 μg of POSWOI at 50°C for 48 h. The mixture was then incubated at 90°C for 10 min to inactivate the POSWOI and rinsed with sodium acetate buffer to remove the POSWOI. The Avicel was then incubated with 0.08 FPU cellulases at 4°C for 2 h with rotation. The amount of cellulase bound on the POSWOI-pretreated Avicel was calculated by subtracting the quantity of cellulases in the supernatant from the total cellulases added in the reaction. The cellulases bound on the sodium acetate buffer-pretreated Avicel were used as a control. Each reaction was performed in triplicate, and the data points and error bars indicate the means ± standard deviations.