水中细菌的低温等离子体灭活效果

Low temperature plasma-induced inactivation effect on bacteria in aqueous solution

目的评价低温等离子体灭活水中细菌的效果,探讨等离子体效应对革兰阴性菌和革兰阳性菌的灭活机制。方法观察低温等离子体与水中初始浓度为(9.60±1.23)×106 cfu/ml的大肠杆菌和初始浓度为(5.71±3.14)×107 cfu/ml的金黄色葡萄球菌分别反应10、30、60、120 s后的灭活效果,采用透射电镜(TEM)对细菌超微结构的变化进行分析。结果大肠杆菌在灭菌30 s时灭活率达6.98 log,金黄色葡萄球菌在灭菌10 s时灭活率达7.76 log,水中大肠杆菌和金黄色葡萄球菌全部被灭活。大肠杆菌(革兰阴性菌)出现细胞变形和胞质整体不均匀;而金黄色葡萄球菌(革兰阳性菌)则出现体积膨胀和核心消失,菌体近似空壳。结论低温等离子体在短时间内对水中大肠杆菌和金黄色葡萄球菌具有明显灭活作用。

Objective To assess the inactivation effect on bacteria in water, and explore the inactivation mechanisms of the gram-negative bacteria and gram-positive bacteria by low-temperature plasma. Methods The inactivation effect on （9.60± 1.23）×10^6 cfu/ml of E.coli and （5.71±3.14）×10^7 cfu/ml of Staphylococcus aureus by low-temperature plasma was observed, and their uhrastructure variation was analyzed by TEM. Results The E.coli in water were obviously inactivated after a 30 s discharge time,and the inactivation rate reached up to 6.98 log,while the S.aureus were inactivated after a short discharge time of 10 s with a higher inactivation ratio of 7.76 log. The E.coli and S.aureus in water were inactivated thoroughly. The TEM results showed that the cell shape of E.coli was changed and the cytoplasm appeared to be nonuniform, while the expansion of cells volume,the disappear of cell core and the empty shell of cell shape were found during the inactivation of S.aureus. Conclusion Low-temperature plasma can rapidly inactivate E.coli and S.aureus in water.