【摘要】 以大肠杆菌为实验菌种 ,研究了壳聚糖的浓度、脱乙酰化度、分子量、及环境 p H值等因素对壳聚糖抗菌活性的影响 ,并初步探讨了壳聚糖的抗菌机理 .结果表明 :在研究范围内 ,随着浓度和脱乙酰化度的提高 ,抗菌活性增强 ;随分子量的增加 ,抗菌活性出现先增强而后略有减弱的趋势 ,转折点在 9.16× 10 4 前后 ;在 p H为 6.5左右 ,抗菌活性最优 .通过激光共焦显微镜对异硫氰酸荧光素 ( FITC)标记的壳聚糖齐聚物 ( Mw=80 0 0 )与大肠杆菌作用的观察 ,发现具有抗菌性的壳聚糖齐聚物进入到了细菌细胞的内部 .用扫描电镜观察分子量为 2 7.4× 10 4 的壳聚糖对大肠杆菌的作用 ,发现壳聚糖使菌体凹陷变形 ,并伴有自溶现象 .更多还原

【Abstract】 The effects of concentration, deacetylation degree, molecular weight and pH of medium on the antibacterial activity of chitosan against Esherichia Coli have been investigated. The results showed that the antibacterial activity of chitosan increased with increase in concentration and deacetylation degree and it first increased with increasing molecular weight, reached a maximum at M w=9.16×10.4 and pH=6.5 and then decreased with further increase in molecular weight. The effects of chitosan on the E.Coli was studied morphologically by confocal laser scanning microscopy and SEM with the results that the E.Coli cells were deformed and autolysed in contact with chitosan samples.更多还原