Bacillus sp. KK01, which was isolated from soil, produced beta-mannanase about 2 U ml(-1) in culture medium. By DEAE-ion exchange column chromatography, four enzyme components F1, F2, F3, and F4 were separated. All components showed maximum activity at pH 7.1. F1 showed maximum activity at 60 degrees C, which was 5-10 degrees C higher than those of the rest. The Sour components Fl, F2, F3, and F4 hydrolyzed copra mannan to the extent of 23-31%; yielded mannobiose, mannotriose, and mannotetraose as hydrolysis products; and also hydrolyzed locust bean gum to the extent of 19-22%, giving similar products.