PURPOSE: To prepare a novel chitosanase having excellent chitosan-decomposing ability, highly stable against metals, etc., and useful for preparing chitosan oligosaccharide by culturing a specific microorganism having an ability to produce the novel chitosanase and subsequently collecting the produced novel chitosanase.
CONSTITUTION: A microorganism (e.g. Bacillus sp.PI-7S, FERM 9843) having an ability to produce the novel chitosanase is cultured in a medium and the produced novel chitosanase is collected. The chitosanase has substrate specificities having a good chitosan-decomposing ability and not having a carboxymethylcellulose-decomposing ability and further has the following characteristics: the optimal pH: 3.8-6.8; stable pH: 3.3-7.4; molecular weight measured by a SDS-polyacrylamide gel electrophoresis method: 25000±3000; inhibiting substances: Ag+, Hg+ and p-chlorobenzoic acid mercuric salt and inhibiting substances are relatively few.
TSUKUDA KOJI
SEINO HARUYOSHI
