Schoenen D, Kolch A
Hygiene-Institut, Universität Bonn.
Zentralbl Hyg Umweltmed. 1992 Mar;192(6):565-70.
Interest in the disinfection of drinking water by UV rays has been growing in recent years. Since the beginning of the 40's it has been known that, by means of certain repair mechanism, microorganisms are able to restore lesions on DNA. These processes are more or less clarified. However there is no secure knowledge about the degree of possible repair. Photoreactivation induced by light of 350-600 nm is one of these repair mechanisms. Thus the effect of light exposure on disinfection results with E. coli after UV disinfection was examined. E. coli ATCC 11229 were cultivated, washed, suspended and irradiated by means of UV rays from a mercury low-pressure lamp. After UV disinfection, the bacterial suspension was illuminated by fluorescent light. The degree of photoreactivation could be influenced by illumination intensity. The speed of reactivation decreased with the distance of the probes to the illumination source and increased with the period of time of illumination. After a 4 log reduction of the colony count (10(6)/ml-10(2)/ml) through UV rays, the reduction rate could be decreased to only 1 log (10(5)/ml) after UV disinfection and illumination. In probes kept in darkness for the same period there was no change in the count of reproductive bacteria. It seems to be necessary to take photoreactivation into consideration with the UV disinfection of drinking water.
近年来，人们对紫外线消毒饮用水的兴趣与日俱增。自40年代初以来，人们就知道，微生物能够通过某些修复机制修复DNA损伤。这些过程或多或少已得到阐明。然而，对于可能的修复程度尚无确切了解。350 - 600纳米光诱导的光复活是这些修复机制之一。因此，研究了紫外线消毒后光照对大肠杆菌消毒效果的影响。培养、洗涤、悬浮大肠杆菌ATCC 11229，并通过汞低压灯发出的紫外线进行照射。紫外线消毒后，用荧光灯照射细菌悬液。光复活程度会受到光照强度的影响。复活速度随着探头与光照源距离的增加而降低，随着光照时间的延长而增加。通过紫外线使菌落数减少4个对数单位（从10⁶/ml降至10²/ml）后，经过紫外线消毒和光照，减少率可降至仅1个对数单位（10⁵/ml）。在相同时间段内置于黑暗中的探头中，繁殖细菌数量没有变化。在饮用水紫外线消毒中考虑光复活似乎是必要的。
