Sonication of chitin–glucan, preparation of water-soluble fractions and characterization by HPLC

A water-insoluble chitin–glucan complex, isolated from the mycelium of Aspergillus niger, was swollen in various aqueous media and treated subsequently by high-energy sonication. The concentration of the resulting water-soluble polysaccharide fractions was dependent on the swelling medium, the amount of the chitin–glucan complex in the suspension, and on the time of sonication. The yields of water-soluble chitin–glucan were within the range 13.6 to 24.4% relative to the mass of the original chitin–glucan. The nitrogen content obtained for the samples of water-soluble chitin–glucan indicated a higher content of chitin (3.45% of nitrogen in high-molecular fraction) than in the original water-insoluble chitin–glucan sample (1.8%). The distribution of the molecular weights of the water-soluble fractions prepared was determined by high-performance liquid chromatography.