The effect of dissolved organic matter (DOM) on bacterial regrowth in water after disinfection using ultraviolet (UV) light emitting diodes (UV) is still unclear. Herein, the regrowth and responses of and were investigated after being exposed to UV at combined wavelengths (265 and 280 nm) in a phosphate-buffered saline consisting of Suwannee River natural organic matter (SRNOM) and Suwannee River fulvic acid (SRFA). Low-molecular-weight (MW) organic compounds, which may form into intermediary photoproducts, and indicate bacterial repair metabolism, were characterized through non-target screening using orbitrap mass spectrometry. This study demonstrates the ability of the UV-inactivated cells to regrow. After UV exposure, a considerable upregulation of A was observed in two strains. With increasing the incubation time, the expression levels of A in increased, which may be attributed to the dark repair mechanism. Coexisting anionic DOM affects both the disinfection and bacterial regrowth processes. The time required for bacterial regrowth after UV exposure reflects the time needed for the individual cells to reactivate, and it differs in the presence or absence of DOM. In the presence of DOM, the cells were less damaged and required less time to grow. The UV exposure results in the occurrence of low-MW organic compounds, including carnitine or acryl-carnitine with -acetylmuramic acid, which are associated with bacterial repair metabolism. Overall, the results of this study expand the understanding of the effects of water matrices on bacterial health risks. This can aid in the development of more effective strategies for water disinfection.

中文翻译：

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溶解有机物对紫外线消毒后细菌再生和反应的影响

使用紫外线 (UV) 发光二极管 (UV) 消毒后，溶解有机物 (DOM) 对水中细菌再生的影响仍不清楚。在此，在由苏万尼河天然有机物 (SRNOM) 和苏万尼河黄腐酸 (SRFA) 组成的磷酸盐缓冲盐水中暴露于组合波长（265 和 280 nm）的紫外线后，研究了 和 的再生和响应。低分子量（MW）有机化合物可能形成中间光产物，并表明细菌修复代谢，通过使用轨道阱质谱法进行非目标筛选进行了表征。这项研究证明了紫外线灭活细胞的再生能力。紫外线照射后，在两个菌株中观察到 A 的显着上调。随着孵育时间的增加，A的表达水平增加，这可能归因于暗修复机制。共存的阴离子 DOM 会影响消毒和细菌再生过程。紫外线照射后细菌重新生长所需的时间反映了单个细胞重新激活所需的时间，并且在 DOM 存在或不存在的情况下有所不同。在 DOM 存在的情况下，细胞受到的损伤较小，生长所需的时间也较短。紫外线照射会导致低分子量有机化合物的出现，包括肉碱或丙烯酰肉碱与乙酰胞壁酸，它们与细菌修复代谢有关。总体而言，这项研究的结果扩大了人们对水基质对细菌健康风险影响的理解。这有助于制定更有效的水消毒策略。