Deacetylation of chitin obtained from black tiger
shrimp carapace under atmosphere yielded chitosans exhibiting
highest antimicrobial activity, due to higher % DD
chitosan, whereas chitosans obtained under nitrogen atmosphere
showed the least inhibition against all test microorganisms.
Degree of deacetylation exhibited significant effect on
the antimicrobial activity of chitosan as well as its MW.
Chitosan hydrolyzed by chemical reaction can improve antifungal
activity greatly against C. albicans as the MW decreases,
but had antibacterial activity that decreased with
the MW. However, hydrolyzed chitosan prepared by using
lysozyme did not show siginificant effect on the molecular
weight. The native chitosan and the hydrolyzed chitosan
were equally inhibitory against pathogenic E. coli, but the
degraded ones were not effective on S. aureus and C.
albicans at a concentration of 1250 ppm, the highest concentration
tested. This is maybe caused by performing the
antimicrobial assay of the chitosan in a buffer system, which
may limit the solubility of chitosan.