Study on Abiotic Factors Effects on Antibacterial Activities of Chitosan

The effects of abiotic factors such as acid solvent、metal ion、ion strength and pH on the antibacterial activitiesof chitosan were investigated by using two kinds of typical pathogens: Escherichia coli and Staphylococcus aureus as testmicroorganisms. The results showed that organic acids with low carbon number are better solvents for chitosan than those inorganicacid. pH6.0 was optimum to the antibacterial activity of chitosan oweing to the chelating capacity of chitosan toward metal ions.The addition of Zn2+ ions inhibited the antibacterial activity of chitosan the most, while the addition of Mg2+ ions inhibited theantibacterial activity of chitosan the least. The antibacterial activity of chitosan increased with ionic strength.