Combined Effects of Chitosan and Potassium Acetate on Growth Inhibition of Escherichia coli

Abstract

The antibacterial action of chitosan combined with potassium acetate against Escherichia coli IFO 3301 (E. coli) was investigated. The growth of E. coli was more inhibited with chitosan at a higher concentration and more than 3.0mg/l of chitosan suppressed sufficiently its growth at 30°C-incubation for 48h. The antibacterial action of chitosan was more promoted by potassium acetate than any other reagents. Chitosan combined with potassium acetate inhibited the bacterial growth during incubation at various temperatures (20-40°C). The cell-surface hydrophobicity increased by combining chitosan with potassium acetate. Leakage of the UV-absorbing substances from the cells was enhanced in the presence of chitosan and potassium acetate. Furthermore, combined use of chitosan and potassium acetate strongly inhibited respiratory activity. Lastly, glycerol restored the respiratory activity of the injured cells, suggesting reduction in glycerol metabolism in E. coli cells would be one of the combined effects of chitosan and potassium acetate.