壳聚糖的抗菌活性研究

以大肠杆菌和金黄色葡萄球菌为实验菌,研究壳聚糖的抗菌活性.结果表明:分子量大的壳聚糖对大肠杆菌和金黄色葡萄球菌都有较强的抑菌作用.梯度稀释结果显示,两种壳聚糖的MIC均为:0.05%抑制大肠杆菌,0.025%抑制金黄色葡萄球菌.研究壳聚搪的抑菌机理时发现,当壳聚糖形成纳米粒子时其抑菌能力丧失,推测抑菌作用可能与壳聚糖上氨基的质子,化有密切关系.壳聚糖抑菌可能是因为壳聚糖上的氨基(NH2 )与细菌细胞壁中带负电荷的磷壁酸或脂多糖结合,并螯合Mg2 、Ca2 等阳离子,从而改变细胞壁的通透性,起到押菌作用.     

Antibacterial activity of chitosan against Aeromonas hydrophila

The effect of chitosan on growth and production of haemolysin by Aeromonas hydrophila was investigated as well as the effects of temperature, pH, salts and irradiation on the antibacterial activity of chitosan. It was found that chitosan affected growth and haemolysin production of A. hydrophila in varying degrees compared to the control. Growth and haemolysin production were clearly suppressed at 0.04% of chitosan. Suppression was more effective at pH 6.0 than at pH 7.0. The bactericidal effects of chitosan increased with increasing temperature and decreasing pH. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Sodium ions at concentrations of 10 and 25 mM also reduced chitosan's activity. Irradiation of chitosan at 150 kGy under dry condition was effective in slightly increasing its activity.     

苎麻织物的壳聚糖抗菌整理

采用天然抗菌整理剂壳聚糖对苎麻织物进行抗菌整理,经试验得到优化工艺条件:壳聚糖浓度6%、多元羧酸浓度6%、催化剂浓度4%、焙烘条件160℃×3.5 min.整理后苎麻织物的抗菌性能明显改善,经20次洗涤后,仍具有良好的耐洗性.     

Antibacterial activity of N-alkylated disaccharide chitosan derivatives

Antibacterial activity of the water-soluble N-alkylated disaccharide chitosan derivatives against Escherichia coli and Staphylococcus aureus was investigated. It was found that the antibacterial activity of chitosan derivatives was affected by the degree of substitution (DS) with disaccharide and the kind of disaccharide present in the molecule. Regardless the kind of disaccharide linked to the chitosan molecule, a DS of 30-40%, in general, exhibited the most pronounced antibacterial activity against both test organisms. E. coli and S. aureus were most susceptible to cellobiose chitosan derivative DS 30-40% and maltose chitosan derivative DS 30-40%, respectively, among the various chitosan derivatives examined. Although the disaccharide chitosan derivatives showed less antibacterial activity than the native chitosan at pH 6.0, the derivatives exhibited a higher activity than native chitosan at pH 7.0. Antibacterial activity of the chitosan derivatives (DS 30-40%) against E. coli increased as the pH increased from 5.0 and reached a maximum around the pH of 7.0-7.5. The effect of pH on the antibacterial activity of chitosan derivatives against S. aureus was not as pronounced as that observed with E. coli. Population reduction of E. coli or S. aureus in nutrient broth increased markedly upon increasing the concentration of chitosan derivatives from 0 to 500 ppm. No marked increase in population reduction was noted with further increase in the concentration of chitosan derivatives even up to 2000 ppm.     

溶菌酶与壳聚糖复配液抑菌作用的研究

本实验以溶菌酶和壳聚糖联合使用以增强对三种模型菌(大肠杆菌(E.coli)、金黄色葡萄球菌(St.aureus)及白色念珠菌(C.albicans))的抑菌效果。首先采用抑菌圈法考察不同浓度醋酸溶液对不同浓度壳聚糖溶液抑菌效果的影响,其次通过对倍稀释法测定壳聚糖溶液和溶菌酶溶液的最小抑菌浓度(MIC),并采用定量法确定复配液的配比,最后通过酶标法监测加入复配抑菌剂后三种模型菌的生长曲线。结果表明,1%的醋酸溶液与壳聚糖的协同抑菌效果最好;壳聚糖溶液对三种模型菌的最小抑菌浓度均为0.1562mg/m L,溶菌酶溶液对大肠杆菌、金黄色葡萄球菌和白色念珠菌的最小抑菌浓度分别为0.625mg/mL、1.25mg/mL和1.25mg/mL,而复合液对三种模型菌的抑制作用优于单独使用溶菌酶或壳聚糖;复配液对大肠杆菌和金黄色葡萄球菌的抑制作用主要表现在对数生长期,而加入材料后白色念珠菌由延迟期直接进入稳定期内。     

Antibacterial activity of shrimp chitosan against Escherichia coli

The effects of cell age, reaction temperature, pH value, and salts on the inhibitory activity of shrimp chitosan (98% deacetylated) against Escherichia coli were investigated. The age of a bacterial culture affected its susceptibility to chitosan, with cells in the late exponential phase being most sensitive to chitosan. Higher temperature (25 and 37 degrees C) and acidic pH increased the bactericidal effects of chitosan. Sodium ions (100 mM Na+) might complex with chitosan and accordingly reduce chitosan's activity against E. coli. Divalent cations at concentrations of 10 and 25 mM reduced the antibacterial activity of chitosan, in the order of Ba2+ > Ca2+ > Mg2+. Chitosan also caused leakage of glucose and lactate dehydrogenase from E. coli cells. These data support the hypothesis that the mechanism of chitosan antibacterial action involves a cross-linkage between the polycations of chitosan and the anions on the bacterial surface that changes the membrane permeability.     

棉家纺织物的壳聚糖抗菌整理

阐述了使壳聚糖产生抗菌性的三种工艺及将脱乙酰甲壳素季铵盐化的三种方法和抑菌机理，将季铵盐化的壳聚糖和BTCA混合整理在棉织物上，测试了壳聚糖整理对织物白度、撕破强力、抗菌性、尺寸稳定性和色牢度的影响。结果表明，壳聚糖整理后织物的抑菌率达90％，且耐水洗，尺寸稳定性良好。     

棉织物的壳聚糖双胍盐酸盐抗菌整理

采用壳聚糖双胍盐酸盐整理纯棉织物,通过单因素试验得到抗菌整理的较佳工艺条件.对经抗菌整理织物的白度、强力以及免烫性能等测试结果表明,在1%的壳聚糖双胍盐酸盐抗菌整理液中加入6%BTCA,于pH值8～9,170 ℃焙烘3 min的条件下,整理织物的抗菌性能优良,且免烫性和耐洗性良好,洗涤20次后抑菌率仍达95%以上.     

壳聚糖衍生物及其纳米粒的抗菌性能研究

利用壳聚糖、壳聚糖衍生物及相应纳米粒对织物进行抗菌整理，研究整理织物的抗菌作用。结果显示，纳米材料整理后的织物对金黄色葡萄球菌、大肠杆菌的抑菌作用最强，经壳聚糖衍生物整理的织物抑菌性能大于壳聚糖；试验研究使用不同交联剂对抑菌性能的影响的结果表明，柠檬酸和酒石酸混和交联剂整理的织物抗菌效果强于单一柠檬酸交联剂。     

壳聚糖和黄芩甙对毛织物的抗菌整理

以壳聚糖和中草药黄芩甙提取物为整理剂对纯毛织物进行抗菌整理,采用浸轧法,利用单因素的分析方法,对不同质量浓度抗菌剂、不同焙烘温度、不同焙烘时间进行实验,并对整理后织物的抑菌性能进行测试分析,结果表明:整理后的织物对大肠杆菌、金黄色葡萄球菌、枯草杆菌抗菌效果较好,抗菌率在92%以上,水洗20次后金黄色葡萄球菌抗菌率仍在80%以上,并基本保留织物原有风格及服用性能.抗菌整理对白度和透气性影响不大.实验确定了最佳抗菌剂质量浓度为20～25 g/L,最佳焙烘温度为110℃.     

棉针织物纳米银/壳聚糖抗菌整理

采用纳米银/壳聚糖复合抗菌整理对棉针织物进行抗菌加工。结果表明,优化的抗菌整理工艺为:先进行纳米银抗菌整理,纳米银60μg/L,黏合剂PDA 10 g/L,分散剂LA 20 g/L,渗透剂T 6 g/L,50℃浸渍处理20 min;随后进行壳聚糖整理,其用量为20 g/L。采用纳米银和壳聚糖复合抗菌整理,降低了纳米银的流失,抑制了织物色变,提高了耐洗性,抗菌整理织物经50次水洗后仍能保持较好的抗菌效果。     

壳聚糖改性及其在抗菌方面的应用

以脱乙酰度为85%的壳聚糖(CTS)为原料,在其氨基上引入自制的环氧丙基十二烷基二甲基氯化铵,生成的N-羟丙基十二烷基二甲基氯化铵壳聚糖(HDCC)水溶性良好。将HDCC与N-羟甲基丙烯酰胺(NMA)交联得最终产物O-甲基丙烯酰胺-N-羟丙基十二烷基二甲基氯化铵壳聚糖（NMA-HDCC）,其可与纤维素纤维以共价键结合。抗菌实验研究表明,经壳聚糖、HDCC、NMA-HDCC处理后的棉织物对大肠杆菌的抑菌率都达到95%以上,带有长链烷基的HDCC抑菌率接近100%。水洗30次之后,经过壳聚糖和壳聚糖季铵盐处理后的棉织物抗菌效果甚微,而NMA-HDCC处理后的棉织物抗菌性仍在85%以上。以抗菌耐久性为依据,得出NMA-HDCC对纯棉织物的最佳整理工艺为：整理剂质量浓度2 g/L,焙烘温度140 ℃,焙烘时间5 min     

壳聚糖/Ag+复合抗菌剂整理莫代尔织物

为提高Modal织物的抗菌性能,本文采用有机和无机复合的方式,制备了新型壳聚糖/ Ag+复合抗菌整理剂,并将其用于Modal织物的抗菌整理。先用单因素实验探讨两种抗菌剂单独整理Modal织物时的适用浓度范围。再用正交实验优化复合抗菌整理工艺条件,结果表明：复合抗菌剂抗菌效果明显优于单独采用壳聚糖或银离子的抗菌效果。经0.8g/L的壳聚糖、0.8mg/L的Ag+在PH为6.5的条件下整理后,Modal织物的抗菌率可达93%以上,洗涤50次以后抗菌率没有明显下降,对断裂强力和白度的损伤较小,Modal织物的抗皱性能还有所提高。     

棉织物的壳聚糖季铵盐抗菌整理

采用缩水甘油三甲基氯化铵(GTMAC)与壳聚糖反应,合成了壳聚糖季铵盐HACC,并将其用于棉织物抗菌整理。通过单因素试验和正交试验,对壳聚糖季铵盐抗菌整理工艺进行优化,并在优化工艺条件下对比壳聚糖季铵盐与壳聚糖的抗菌性。试验结果表明,在柠檬酸4.0%,HACC 1.0 g/L,三乙醇胺0.2%,次亚磷酸钠(SHP)与酸的摩尔分数比为1∶1,浴比1∶50,60℃浸渍30 min,80℃预烘5 min,165℃焙烘1 min的条件下,整理后棉织物对大肠埃希菌的抗菌整理效果最佳,对金黄葡萄球菌也有一定的抗菌效果,而且抗皱效果也得到提高。     

纯棉牛仔布的壳聚糖季铵盐抗菌整理

以3-氯-2-羟丙基三甲基氯化铵(CTA)为改性剂,在碱性条件下制备水溶性壳聚糖季铵盐(HTCC);并应用于纯棉牛仔布的抗菌整理,讨论了整理工艺对纯棉牛仔布抗菌性能的影响.结果表明,HTCC整理纯棉牛仔布的最佳工艺条件为:HTCC3％,柠檬酸6％,次亚磷酸钠4％,60℃浸渍30 min,80℃预烘5 min,160 ℃焙烘3 min.整理后,纯棉牛仔布抑菌效果可达90％以上.     

壳聚糖食品保鲜膜抗菌性及其应用的研究进展

壳聚糖由于其良好的功能特性,近年来作为天然保鲜包装材料在各类食品的包装中已有大量的应用。该文章在对壳聚糖食品薄膜材料的抗菌机理总结的基础上,对近年来壳聚糖薄膜在食品的研究及应用现状进行了综述,并对壳聚糖食品薄膜的未来发展趋势进行了展望。     

Antibacterial activity of chitosans and chitosan oligomers with different molecular weights

Antibacterial activities of six chitosans and six chitosan oligomers with different molecular weights (Mws) were examined against four gram-negative (Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Vibrio parahaemolyticus) and seven gram-positive bacteria (Listeria monocytogenes, Bacillus megaterium, B. cereus, Staphylococcus aureus, Lactobacillus plantarum, L. brevis, and L. bulgaricus). Chitosans showed higher antibacterial activities than chitosan oligomers and markedly inhibited growth of most bacteria tested although inhibitory effects differed with Mws of chitosan and the particular bacterium. Chitosan generally showed stronger bactericidal effects with gram-positive bacteria than gram-negative bacteria in the presence of 0.1% chitosan. The minimum inhibitory concentration (MIC) of chitosans ranged from 0.05% to >0.1% depending on the bacteria and Mws of chitosan. As a chitosan solvent, 1% acetic acid was effective in inhibiting the growth of most of the bacteria tested except for lactic acid bacteria that were more effectively suppressed with 1% lactic or formic acids. Antibacterial activity of chitosan was inversely affected by pH (pH 4.5-5.9 range tested), with higher activity at lower pH value.     

TG酶催化丝胶和壳聚糖对羊毛织物的抗菌整理

为了提高羊毛织物的抗菌性能,以处理后羊毛织物的增重率为考核指标,采用谷氨酰胺转胺酶(TG酶)催化丝胶、壳聚糖和羊毛的接枝反应,对羊毛织物进行整理。利用X-射线光电子能谱、扫描电子显微镜(SEM)和热重分析对比织物整理前后的变化,结果表明丝胶和壳聚糖与羊毛发生接枝反应。整理后羊毛织物对金黄色葡萄球菌和大肠杆菌的抑菌率都大于99%,断裂强力提高,白度有所下降。经20次水洗后,对金黄色葡萄球菌和大肠杆菌抑菌率分别为86.8%和83.9%,说明具有很好的抗菌性能。     

氧化石墨烯-壳聚糖改性丙纶非织造布抗菌性能研究

为提高丙纶非织造布的抗菌性能,拓展丙纶非织造布的应用范围,将氧化石墨烯、壳聚糖应用于丙纶非织造布.利用静电吸附作用,通过层层自组装将壳聚糖分子与氧化石墨烯分子整理到丙纶非织造布的表面,然后对改性丙纶非织造布进行红外光谱、染色深度、抗菌性能及拉伸性能测试.结果 表明:壳聚糖与氧化石墨烯能在丙纶非织造布表面进行有效的自组装整理;抗菌测试数据表明,经过8次自组装改性整理的丙纶非织造布具有优异的抗菌性能,且抗菌水洗稳定性良好;自组装改性整理后的丙纶非织造布的断裂强力也略有提升.     

Antibacterial activity and mechanism of action of chlorogenic acid

In this study, the antibacterial activity and mechanism of action of chlorogenic acid against bacteria were assessed. The data from minimum inhibitory concentration (MIC) values showed that chlorogenic acid effectively inhibited the growth of all tested bacterial pathogens, and the MIC values were ranging from 20 to 80 μg/mL. An investigation into action mode of chlorogenic acid against the pathogen indicated that chlorogenic acid significantly increased the outer and plasma membrane permeability, resulting in the loss of the barrier function, even inducing slight leakage of nucleotide. The leakage of cytoplasmic contents was also observed by electron micrographs. These results supported our hypothesis that chlorogenic acid bound to the outer membrane, disrupted the membrane, exhausted the intracellular potential, and released cytoplasm macromolecules, which led to cell death.