title: Subcellular mechanism of Escherichia coli inactivation during electrochemical disinfection with boron-doped diamond anode: A comparative study of three electrolytes.
abstract: Although the identification of effective oxidant species has been extensively studied, yet the subcellular mechanism of bacterial inactivation has never been clearly elucidated in electrochemical disinfection processes. In this study, subcellular mechanism of Escherichia coli inactivation during electrochemical disinfection was revealed in terms of comprehensive factors such as cell morphology, total organic components, K(+) leakage, membrane permeability, lipid peroxidation, membrane potential, membrane proteins, intracellular enzyme, cellular ATP level and DNA. The electrolysis was conducted with boron-doped diamond anode in three electrolytes including chloride, sulfate and phosphate. Results demonstrated that cell inactivation was mainly attributed to damage to the intracellular enzymatic systems in chloride solution. In sulfate solution, certain essential membrane proteins like the K(+) ion transport systems were eliminated. Thus, the pronounced K(+) leakage from cytosol resulted in gradual collapse of the membrane potential, which would hinder the subcellular localization of cell division-related proteins as well as ATP synthesis and thereby lead to the bacterial inactivation. Remarkable lipid peroxidation was observed, while the intracellular damage was negligible. In phosphate solution, the cells sequentially underwent overall destruction as a whole cell with no captured intermediate state, during which the organic components of the cells were mostly subjected to mineralization. This study provided a thorough insight into the bacterial inactivation mechanism on the subcellular level.
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
authors.forename: Yujiao
authors.initials: Y
authors.lastname: Long
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China. Electronic address: nijinren@iee.pku.edu.cn.
authors.forename: Jinren
authors.initials: J
authors.lastname: Ni
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
authors.forename: Zuhui
authors.initials: Z
authors.lastname: Wang
mesh_terms: D001895:Boron / Q000737:chemistry / Q000633:toxicity*; D018130:Diamond / Q000737:chemistry*; D004203:Disinfection; D055664:Electrochemical Techniques; D004566:Electrodes; D004573:Electrolytes; D004926:Escherichia coli / Q000187:drug effects*
chemical_list: D004573:Electrolytes; D018130:Diamond; D001895:Boron
keywords: Bacterial inactivation; Cell damage; Intracellular enzyme; Membrane potential; Membrane protein; Subcellular mechanism