Systematic Approach to In-Depth Understanding of Photoelectrocatalytic Bacterial Inactivation Mechanisms by Tracking the Decomposed Building Blocks
Systematic Approach to In-Depth Understanding of Photoelectrocatalytic Bacterial Inactivation Mechanisms by Tracking the Decomposed Building Blocks
复制标题
通过跟踪分解的构件来深入了解光电催化细菌灭活机制的系统方法
DOI：
10.1021/es502471h
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发表时间：
2014-08-19
影响因子：
11.4
通讯作者：
An, Taicheng
中科院分区：
文献类型：
--
作者：
Sun, Hongwei;Li, Guiying;An, Taicheng
开发了一种系统的方法来深入了解使用光电催化（PEC）过程与大肠杆菌K-12作为模式微生物的细菌细胞灭活过程中所涉及的机制。发现细菌细胞被灭活并分解，主要是由于来自光生H2 O2的攻击。细胞外活性氧（ROS），如H2 O2，可以渗透到细菌细胞内，引起细胞内ROS水平的显著升高，这将超过细菌保护酶如超氧化物歧化酶和过氧化氢酶的抗氧化能力。在PEC失活过程中，由于ROS的攻击，这两种酶的活性均降低。然后观察到细菌细胞壁损伤，包括细胞膜完整性丧失和渗透性增加，随后细胞包膜分解（通过扫描电子显微镜图像证明）。细菌的一个基本组成部分，蛋白质，也被发现由于ROS的攻击而受到氧化损伤。在长时间的PEC失活过程中，细胞质和生物分子（蛋白质和核酸等细菌结构单元）的泄漏很明显。泄漏的细胞质物质和细胞碎片可以进一步降解，并最终矿化与延长PEC处理。
A systematic approach was developed to understand, in-depth, the mechanisms involved during the inactivation of bacterial cells using photoelectrocatalytic (PEC) processes with Escherichia coli K-12 as the model microorganism. The bacterial cells were found to be inactivated and decomposed primarily due to attack from photogenerated H2O2. Extracellular reactive oxygen species (ROSs), such as H2O2, may penetrate into the bacterial cell and cause dramatically elevated intracellular ROSs levels, which would overwhelm the antioxidative capacity of bacterial protective enzymes such as superoxide dismutase and catalase. The activities of these two enzymes were found to decrease due to the ROSs attacks during PEC inactivation. Bacterial cell wall damage was then observed, including loss of cell membrane integrity and increased permeability, followed by the decomposition of cell envelope (demonstrated by scanning electronic microscope images). One of the bacterial building blocks, protein, was found to be oxidatively damaged due to the ROSs attacks, as well. Leakage of cytoplasm and biomolecules (bacterial building blocks such as proteins and nucleic acids) were evident during prolonged PEC inactivation process. The leaked cytoplasmic substances and cell debris could be further degraded and, ultimately, mineralized with prolonged PEC treatment.