Antimicrobial activity of native chitosan, degraded chitosan, and O-carboxymethylated chitosan.

The antimicrobial activity of native chitosan was compared to that of lipase-degraded chitosan. The effects of O-carboxymethylated (O-CM) substitution on native (molecular weight, 120; degree of deacetylation, 84.71%) and lipase-degraded chitosans were also investigated. The antimicrobial activity of native chitosan was more extensive than that of lipase-degraded chitosan; however, lipase-degraded chitosan was still highly effective and more water-soluble. O-CM chitosan derived from degraded chitosan was more effective than O-CM chitosan derived from native chitosan. O-CM substitution enhanced lipase-degraded chitosan's antimicrobial activity without reducing its solubility.