Antibacterial activity of chitin, chitosan and its oligomers prepared from shrimp shell waste

Abstract

The antimicrobial activities of chito-oligosaccharides against four Gram-positive and seven Gram-negative bacteria were compared to chitosan and chitin with an emphasis on the effects of biopolymer molecular weight (Mv) and degree of deacetylation (DD). Chitin was isolated from shrimp (. Parapenaeus longirostris) shell waste by sequential chemical treatments. Chitosan and its oligomers N-acetyl chito-oligosaccharides and chito-oligosaccharides were prepared by deacetylation and chemical hydrolysis, respectively. Chitin exhibited a bacteriostatic effect on Gram-negative bacteria, . Escherichia coli ATCC 25922, . Vibrio cholerae, . Shigella dysenteriae, and . Bacteroides fragilis. Chitosan exhibited a bacteriostatic effect on all bacteria tested, except . Salmonella typhimurium. The oligomers exhibited a bactericidal effect on all bacteria tested. © 2012 Elsevier Ltd.