N,N,N-三甲基壳聚糖的制备、表征及其抑菌性能研究

Synthesis, Characteristic and Antibacterial Activity of N,N,N-trimethyl Chitosan

对高分子质量的壳聚糖进行分子修饰,所得水溶性N,N,N-三甲基壳聚糖(TMC)采用红外光谱(IR)、核磁共振氢谱(1HNMR)和凝胶渗透色谱(GPC)进行表征和分析。研究TMC对大肠杆菌、沙门氏菌、金黄色葡萄球菌和枯草芽孢杆菌的抑菌性能,以未修饰的壳聚糖为对照。结果表明:TMC对大肠杆菌、沙门氏菌、金黄色葡萄球菌和枯草芽孢杆菌的最低抑菌浓度(MIC)分别为0.250、0.250、0.250、0.125mg/mL,均明显低于壳聚糖。研究4种供试菌最小抑菌浓度时TMC对细菌致死时间的影响,结果显示:TMC在2h内对4种供试菌均达到99.99%的致死率。通过透射电镜(TEM)观察,TMC能够快速、有效地破坏细胞壁(膜)的完整性或使细胞壁(膜)趋于溶解,从而导致细胞死亡。

N,N,N-trimethyl chitosan （TMC） was synthesized by using high molecular Chitosan as starting material and characterized by FTIR, 1H NMR and GPC. The antibacterial activity of TMC and Chitosan against Escherichia coli, Salmonella cholerae-suis, Staphylococcus aureu and Bacillus subtilis were further investigated by assay of the minimum inhibitory concentration （MIC）. Results showed that TMC could inhibit the growth of various bacteria tested. Its MIC values were 0.250 mg/mL, 0.250 mg/mL, 0.250 mg/mL and 0.125 mg/mL to Escherichia coli, Salmonella cholerae-suis, Staphylococcus aureu and Bacillus subtilis, respectively. The time effect on the TMC against four bacteria tested was also studied. Result demonstrated that TMC could almost totally kill those bacteria tested at the minimum inhibitory concentration in 2 hours, and the lethality was up to 99.99% . Furthernore, comparing TEM images of Bacillus subtilis in the presence with absence of TMC, TMC can damage microbial walls/membranes efficiently, resulting in cell lysis.