title: Antibacterial activity of chitosans and chitosan oligomers with different molecular weights.
abstract: Antibacterial activities of six chitosans and six chitosan oligomers with different molecular weights (Mws) were examined against four gram-negative (Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Vibrio parahaemolyticus) and seven gram-positive bacteria (Listeria monocytogenes, Bacillus megaterium, B. cereus, Staphylococcus aureus, Lactobacillus plantarum, L. brevis, and L. bulgaricus). Chitosans showed higher antibacterial activities than chitosan oligomers and markedly inhibited growth of most bacteria tested although inhibitory effects differed with Mws of chitosan and the particular bacterium. Chitosan generally showed stronger bactericidal effects with gram-positive bacteria than gram-negative bacteria in the presence of 0.1% chitosan. The minimum inhibitory concentration (MIC) of chitosans ranged from 0.05% to >0.1% depending on the bacteria and Mws of chitosan. As a chitosan solvent, 1% acetic acid was effective in inhibiting the growth of most of the bacteria tested except for lactic acid bacteria that were more effectively suppressed with 1% lactic or formic acids. Antibacterial activity of chitosan was inversely affected by pH (pH 4.5-5.9 range tested), with higher activity at lower pH value.
authors.affiliation: Department of Food Science and Technology, Catholic University of Daegu, Hayang, South Korea. hkno@cuth.cataegu.ac.kr
authors.forename: Hong Kyoon
authors.initials: HK
authors.lastname: No
authors.forename: Na Young
authors.initials: NY
authors.lastname: Park
authors.forename: Shin Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Samuel P
authors.initials: SP
authors.lastname: Meyers
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002686:Chitin / Q000031:analogs & derivatives / Q000494:pharmacology*; D048271:Chitosan; D004305:Dose-Response Relationship, Drug; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight
chemical_list: D000900:Anti-Bacterial Agents; D002686:Chitin; D048271:Chitosan