Increasing demands to the quality of drinking water necessitate the search for environmentally friendly and effective methods of its disinfection and purification. The purpose of this work was to study the disinfecting activity of chitosan (ChTS) obtained from natural polymer chitine in relation to E. coli and C. albicans depending on the physicochemical parameters of medium. It has been established that the degree of inactivation of E. coli culture does not depend on the type of ChTS used in this study: high-molecular ChTS₁ (molecular weight (Mw) = 100–300 kDa) and low-molecular ChTS₂ (Mw = 50–60 kDa) with the deacetylation degree of 95 and 75–85%, respectively. In the case of C. albicans, high-molecular weight ChTS with deacetylation degree of 95% is a more effective disinfecting agent. The highest degree of C. albicans inactivation by using ChTS₁ is achieved in a weak acid medium (pH 5.0), while at pH 8.5 the disinfecting effect is negligible. For the first time, a significant contribution of the process of flocculation of microorganisms by chitosan to the total effect of water disinfection has been shown that is especially pronounced at relatively short contact periods (< 1 h) of the culture with chitosan. It is shown that the presence of impurities of an organic and inorganic nature in water reduces both the disinfecting and flocculating effects of polysaccharide in relation to the microbiological objects. It is, probably, associated with the competing activity of these impurities on the interaction of ChTS molecules with microorganisms. The attained results confirm that C. albicans is a more reliable test object of disinfection processes as compared to E. coli that is of practical importance.

中文翻译：

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理化参数对壳聚糖水消毒过程的影响

对饮用水质量的要求不断提高，因此必须寻求一种环境友好，有效的消毒和净化方法。这项工作的目的是研究根据介质的理化参数，从天然聚合物壳聚糖中获得的壳聚糖（ChTS）对大肠杆菌和白色念珠菌的消毒活性。现已确定，大肠杆菌培养物的失活程度不取决于本研究中使用的ChTS的类型：高分子ChTS ₁（分子量（Mw）= 100–300 kDa）和低分子ChTS ₂（Mw = 50–60 kDa），脱乙酰度分别为95％和75–85％。就白色念珠菌而言，具有95％脱乙酰度的高分子量ChTS​​是更有效的消毒剂。通过使用ChTS ₁最高程度的白色念珠菌灭活在弱酸性介质（pH 5.0）中达到的效果，而在pH 8.5时的消毒效果可忽略不计。首次显示，壳聚糖对微生物的絮凝过程对水消毒的总体效果有重要贡献，这在培养物与壳聚糖接触时间相对较短（<1小时）时尤为明显。已经表明，水中有机和无机性质的杂质的存在降低了多糖相对于微生物对象的消毒和絮凝作用。这可能与这些杂质对ChTS分子与微生物相互作用的竞争活性有关。获得的结果证实白色念珠菌与具有实际重要性的大肠杆菌相比，它是消毒过程中更可靠的测试对象。