Effect of ultrasonic treatment on the molecular weight of carboxymethylated chitin-glucan complex from Aspergillus niger

Different factors affecting the efficiency of the ultrasonic depolymerizati on of the high-molecular-weight carboxymethylated chitin-glucan prepared fr om the fungal mycelium of Aspergillus niger have been investigated. The inf luence of the following parameters was examined: concentration of the chiti n-glucan complex, duration of ultrasonic irradiation, reaction temperature and volume of the ultrasonicated solution. The optimized conditions for the efficient ultrasonic depolymerization include: polysaccharide concentratio n - 0.2 mg ml(-1); volume of the sonicated solution - 25 ml; duration of th e sonication - 10 min; and constant cooling of the sonicated sample in an i ce-water bath. (C) 1999 Elsevier Science B.V. All rights reserved.