不同脱乙酰度和分子质量的壳聚糖的抑菌性能

通过壳聚糖的抑茵实验和几种壳聚糖最低抑茵浓度的测定，比较了相同脱乙酰度不同分子质量以及分子质量相近但脱乙酰度不同的壳聚糖对金黄色葡萄球菌、枯草杆菌、大肠杆菌和假单胞菌的抑茵性能．结果表明：脱乙酰度相同、分子质量为400～800ku的壳聚糖，其抑茵能力随分子质量的增加而增强；而分子质量相近（均在430ku左右）、脱乙酰度不同（分别为68．4％，75．3％，83．6％和93．7％）的壳聚糖对上述4种细菌的抑茵能力差别不大；在pH值为5．5～6．0左右的条件下，壳聚糖具有最强的抑茵能力；实验条件下的壳聚糖对4种细菌都有较强的抑制作用，总体看来，壳聚糖对金黄色葡萄球菌的抑制作用最强，而对大肠杆菌的抑制作用相对较弱；实验条件下的壳聚糖对上述4种细菌的抑制作用普遍比苯甲酸钠强．

Antibacterial Activities of Chitosans with Different Degrees of Deacetylation and Molecular Masses

Chitosans with different Degrees of Deacetylation (DDs) or different Molecular Masses (MMs) were prepared. The antibacterial activities of the prepared chitosans against Staphylococcus aureus ( S. aureus) , Escherichia coli (E. coli) , Bacillus subtilis (B. subtilis) and Pseudomonas fluorescens (P. fluorescens) were then determined and compared by measuring the MIC ( Minimum Inhibitory Concentration). Results indicate that the antibacterial activities of chitosans with the same DD increase with their MMs ranging from 400 to 800ku, that chitosans with different DDs (68.4%, 75.3%, 83.6% and 93.7%) but approximate MM ( about 430 ku) possess almost the same antibacterial activity, that chitosan has the highest antibacterial activity at the pH value of about 5.5 to 6. 0, that the growth of S. aureus can be easily inhibited by chitosan, while E. coli is the bacterium that is most difficult to inhibit in the experiment, and that, generally, all tested chitosans have strong antibacterial activity against the four bacteria, which is higher than that of sodium benzoate (C7H5O2Na).