Kinetics and mechanisms of depolymerization of alginate and chitosan in aqueous solution.

The kinetics and mechanisms of depolymerization of aqueous chitosan and alginate solutions at elevated temperatures have been investigated. Chitosan salts of different degree of acetylation (FA), type of counterions (-glutamate, -chloride) and degree of purity were studied. One commercially available highly purified sodium alginate sample with high content of guluronic acid (G) was also studied.

Biospecific fractionation of chitosan.

We have previously reported that, although a fully de-N-acetylated chitosan does not bind to hen egg white lysozyme, chitosans with a low fraction of N-acetylated units (FA) bind biospecifically to lysozyme with an affinity strongly dependent upon pH and ionic strength and without concomitant cleavage of glycosidic linkages. In this study, we report on the fractionation of a low FA chitosan with low molecular weight by biospecific adsorption of the chitosan molecules containing N-acetyl groups to immobilized lysozyme. Hen egg white lysozyme was immobilized to CNBr-activated Sepharose 4B, and a chitosan with a fraction of N-acetylated units of 0.