the present invention relates to a naturally occuring , isolated and characterized microorganism producing hydrolase enzyme , specifically , chitosanase ; chitosanase isolated thereof ; the nucleic acid sequence of the portion of the gene encoding this chitosanase ; complete amino acid sequence of this chitosanase ; hybrid plasmids containing the related gene ; host microorganisms transformed with the plasmids ; recombinant microorganisms overexpressing the enzyme ; and to enzymatic treatment of chitosan with the aforementioned enzyme resulting in molecular weight decrease , viscosity decrease and increase of solubility of chitosan in water .