壳寡糖对大肠杆菌抑菌活性研究

分析壳寡糖对大肠杆菌抑菌效果的影响因素.采用摇瓶法和ELISA板法对不同浓度的壳寡糖进行抑菌试验;比较不同pH、不同脱乙酰度的壳寡糖对大肠杆菌抑菌效果的差异;比较不同聚合度的单一聚合度壳寡糖抑菌效果的差异.壳寡糖浓度大于5 mg/mL时抑菌效果与同浓度苯甲酸钠相近;pH为4时,0.156 mg/mL的壳寡糖溶液抑菌活性即能超过90%;pH为7时,5 mg/mL的壳寡糖才能达到90%抑菌活性.脱乙酰度为95%时,5 mg/mL的壳寡糖溶液抑菌活性能超过97%;脱乙酰度为45%时,40 mg/mL的壳寡糖溶液抑菌活性仅有56%;聚合度大于4的单一聚合度壳寡糖40 mg/mL时抑菌活性能达到99%.结果表明:提高壳寡糖溶液浓度、降低pH、提高脱乙酰度,能提高壳寡糖的抑菌活性,单一聚合度壳寡糖聚合度越高,对大肠杆菌的抑制作用越强.此外,采用ELISA板的方法进行实验,即节省试药又方便快捷.

Antibacterial activity of chitosan oligosaccharide on Escherichia coli

In order to observe the effects of the antibacterial activity of chitosan oligosaccharide ( COS ) on Escherichia coli, shake-flask method and ELISA-plate method were performed under the environments of different concentrations, different pH, different degree of deacetylation ( DD) and different polymerization degree of monomers. Results revealed that its inhibitory effect was similar to that of the same concentration of sodium benzoate when the concentration ≥5 mg/mL. When pH was 4, the antibacterial activity of 0. 156 mg/mL COS solution was over 90%. While pH was 7, the concentration of COS solution was 5 mg/mL. When DD was 95%, 5 mg/mL COS solution had antibacterial activity>97%. while DD was 45%, 40 mg/mL COS solution had antibacterial activity about 56%. When degree of polymerization was more than 4 , the antibacterial activity of 40 mg/mL COS solution could reach 90%. These results showed that antibacterial activity on E. coli increased with the increasing of concentration, DD, polymerization degree of monomer and the decreasing of pH. In addition, the ELISA-plate method had advantages of processing sample easily, fast analysis and saving reagents.