Ultrasonic depolymerization of the chitin–glucan complex from Aspergillus niger and antimutagenic activity of its product

Sonication was effective for the depolymerization of carboxymethylated chitin–glucan complex (CM–CG) isolated from the cell wall of Aspergillus niger. After 10 min of sonication and subsequent gel filtration, two samples (CM–CGI and CM–CGII) with significantly distinct molecular weights ( 660 kDa and 19 kDa, respectively) and different nitrogen contents (3.02 and 1.69%) were obtained. CM–CGII with lower Mw was also effective against cyclophosphamide mutagenicity by oral administration in mice.