Deposition and disinfection of Escherichia coli O157:H7 on naturally occurring photoactive materials in a parallel plate chamber.
Deposition and disinfection of Escherichia coli O157:H7 on naturally occurring photoactive materials in a parallel plate chamber.
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DOI：
10.1039/c3em00527e
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发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Walker SL
中科院分区：
文献类型：
--
作者：
Taylor AA;Chowdhury I;Gong AS;Cwiertny DM;Walker SL
溶解的有机物与氧化铁结合，已被证明在紫外线和可见光下通过产生活性氧（ROS）促进光化学消毒。然而，由于这些自由基的寿命极短，消毒效率受到活性氧成功转运到细菌表面的限制。本研究旨在定量研究三种具有不同ROS生成电位的收集器表面[裸石英、赤铁矿（α-Fe2O3）包覆石英和苏万尼河腐植酸（SRHA）]，以及细胞外聚合物（EPS）（完全或部分包覆）和溶液化学（离子强度，IS）对细菌与ROS生成底物之间相互作用的影响。除了少数例外，平行板（PP）流室中的细菌沉积研究显示细胞与IS的粘附性增加。此外，收集器表面与细胞之间的相互作用可以用静电力来解释，带负电荷的SRHA减少了细菌的沉积，带正电荷的α-Fe2O3显著增强了细菌的沉积。在EPS含量充足的情况下，沉积也有所增加，这表明EPS能够促进水生环境中细胞和表面之间的相互作用。在模拟光的辅助消毒研究中，在所有IS条件下，当与α-Fe2O3结合时，观察到完全包被EPS的细胞的生存能力下降。基于我们之前的研究，发现EPS不抑制对细菌的羟基自由基活性，我们提出EPS可能因此通过促进细胞附着在产生ROS的表面上，从而促进消毒，因为在靠近活性底物（例如SRHA和α-Fe2O3）的地方，ROS浓度较高。我们对细胞与光活性底物相互作用的机制和控制因素的研究结果为离子强度在光化学消毒过程中的作用提供了见解。
Dissolved organic matter in combination with iron oxides has been shown to facilitate photochemical disinfection through the production of reactive oxygen species (ROS) under UV and visible light. However, due to the extremely short lifetime of these radicals, the disinfection effciency is limited by the successful transport of ROS to bacterial surfaces. This study was designed to quantitatively investigate three collector surfaces with various potentials to produce ROS [bare quartz, hematite (α-Fe2O3) coated quartz, and Suwannee River humic acid (SRHA)] and the effects of extracellular polymeric substance (EPS) (full or partial coating) and solution chemistry (ionic strength, IS) on the interactions between bacteria and the ROS-producing substrates. With few exceptions, bacterial deposition studies in a parallel plate (PP) flow chamber have revealed increasing cell adhesion with IS. Furthermore, interactions between collector surfaces and cells can be explained by electrostatic forces, with negatively charged SRHA reducing and positively charged α-Fe2O3 enhancing bacterial deposition significantly. Increased deposition was also observed with full EPS content, indicating the ability of EPS to facilitate interaction between cells and surfaces in the aquatic environment. In complementary disinfection studies conducted with simulated light, viability loss was observed for cells fully coated with EPS when attached to α-Fe2O3 under all IS conditions. Based upon our prior study in which EPS was found to not inhibit hydroxyl radical activity toward bacteria, we proposed that EPS might therefore promote disinfection by facilitating cell attachment to ROS-producing surfaces where higher concentrations of ROS are expected at closer proximities to reactive substrates (e.g., SRHA and α-Fe2O3). Our findings on the mechanism and controlling factors of cell interactions with photoactive substrates provide insight as to the role of ionic strength in photochemical disinfection processes.
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影响因子：
12.8
作者：
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通讯作者：
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影响因子：
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作者：
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作者：
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DOI：
10.1016/0927-7757(95)03349-1
发表时间：
1996-02-20
影响因子：
5.2
作者：
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3
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