Purification and characterization of chitosanases from Trichosporon sp

Five kinds of chitosanases, termed Al-1, A2-1, A2-2, B1, and B2, were isolated from the culture filtrate of Trichosporon sp. by ammonium sulfate precipitation and column chromatographies on DEAE Bio-Gel Agarose, TSK-GEL DEAE-3SW, and HiLoad 26/60 Superdex 200, and their enzymatic properties were investigated. The molecular masses of the purified chitosanases were estimated to be above 120 kDa by gel-filtration. A1-1, A2-1, B1, and B2 showed similar tendencies in pH optimum, heat stability, and the time courses of their reactions toward chitosans with different degrees of N-acetylation, and had activities reward glycol chitin and colloidal chitin. A2-2, however, was more thermostable than the other four chitosanases; it showed weak activity toward the chitosan hexamer, but none toward glycol and colloidal chitins.