Bacillus ehimensis EAG1 (IFO15659) produced and secreted chitosanase in the presence of exogenous chitosan. The chitosanase was purified from the culture filtrate of the bacterium to apparent homogeneity in SDS-polyacrylamide gel electrophoresis. The purified enzyme had a molecular weight of approximately 31,000, A 1.9-kbp DNA fragment containing the chitosanase gene was cloned and the complete nucleotide sequence was determined. The sequence was found to contain a single open reading frame encoding a protein of 302 amino acids. The deduced amino acid sequence showed significant homology with the chitosanase from Bacillus circulans MH-K1.