Concentrated cellulase fraction was analyzed by 12% gel SDS-PAGE to determine the molecular weight. Concentrated cellulase fractions were loaded to 12% gel SDS-PAGE (containing 1% CMC) for zymogram analysis. Then, SDS was removed by soaking the gel in wash buffer (containing 30 mM sodium phosphate buffer and 40% isopropanol (pH 7.2)) for 1 h. The gel was soaked in equilibrated buffer (containing 30 mM sodium phosphate buffer (pH 7.2)) for 1 h, and transferred into renaturing buffer (containing 30 mM sodium phosphate buffer, 5 mM β-mercaptoethanol and 1 mM EDTA (pH 7.2)) at 4°C overnight.