Enzymatic hydrolysis of chitosan-dialdehyde cellulose hydrogels

A new cellulose-based hydrogel was prepared by grafting chitosan onto cellulose. The material was obtained by partial oxidation of cellulose hydrogel by NaIO4, followed by the Schiff base formation with chitosan and subsequent reduction for stabilization. The chitosan-dialdehyde cellulose hydrogel showed high chemical stability under the pH ranged from 4.5 to 9.5. The enzymatic hydrolysis of three grades of chitosan-dialdehyde cellulose hydrogel with different chitosan content was examined by solutions containing cellulase and beta-glucosidase with and without chitosanase. The glucose released ratio of the chitosan-dialdehyde cellulose hydrogels was 38-62% lower than that of original cellulose hydrogel without chitosanase. When chitosanase was added to the system, the hydrolysis was enhanced significantly, reaching 65-85% of that for the pure cellulose. The hydrolysis rate in chitosan-dialdehyde cellulose hydrogels was slower with an increase in the chitosan content. This behavior can be interpreted in terms of the differences in the mode of chitosan grafting on to cellulose due to the difference in population of aldehyde groups. (C) 2010 Elsevier Ltd. All rights reserved.