An alkaline cellulase from Bacillus sp. HSH-810 was purified 8.7-fold with a 30% yield and a specific activity of 71 U mg(-1) protein. It was optimally active at pH 10 and 50 degrees C and was stable from pH 6 to 10 with more than 60% activity remaining after heating at 60 degrees C for 60 min. The molecular mass of cellulase was 80 kDa. It was inhibited by 50% by Fe3+ (1 mM) and Mn2+ (0.1 mM) but was relatively insensitive to Hg2+ and Pb2+ at 1 mM.