DOI: 10.1016/j.watres.2018.05.021
Scopus记录号: 2-s2.0-85052939557
论文题名: Impact of UVA pre-radiation on UVC disinfection performance: Inactivation, repair and mechanism study
作者: Xiao Y. ; Chu X.N. ; He M. ; Liu X.C. ; Hu J.Y.
刊名: Water research
ISSN: 18792448
出版年: 2018
卷: 141 起始页码: 279
结束页码: 288
语种: 英语
英文关键词: Disinfection
; Light emitting diode (LED)
; Mechanism
; Photo/dark repair
; Sequential ultraviolet (UV) radiation
Scopus关键词: DNA
; DNA directed DNA polymerase
; Escherichia coli protein
; pyrimidine dimer
; UmuD protein, E coli
; disinfection
; Escherichia coli
; metabolism
; procedures
; radiation response
; ultraviolet radiation
; water management
; water pollutant
; Disinfection
; DNA
; DNA-Directed DNA Polymerase
; Escherichia coli
; Escherichia coli Proteins
; Pyrimidine Dimers
; Ultraviolet Rays
; Water Pollutants
; Water Purification
英文摘要: Ultraviolet (UV) light emission diode (LED), which is mercury free and theoretically more energy efficient, has now become an alternative to conventional UV lamps in water disinfection industry. In this research, the disinfection performance of a novel sequential process, UVA365nm LED followed by UVC265nm LED (UVA-UVC), was evaluated. The results revealed that the responses of different bacterial strains to UVA-UVC varied. Coupled with appropriate dosages of UVC, a 20 min UVA pre-radiation provided higher inactivations (log inactivation) of E. coli ATCC 11229, 15597 and 700891 by 1.2, 1.4 and 1.2 times, respectively than the sum of inactivations by UVA alone and UVC alone. On the contrary, the inactivation of E. coli ATCC 25922, the most UVC sensitive strain, decreased from 3 log to 1.8 log after UVA pre-radiation. A 30 min UVA pre-radiation did not affect the photo repair capacity of the four strains (n = 23, p > 0.1), but their dark repair ability was significantly inhibited (n = 14, p < 0.05). Mechanism study was conducted for two representative strains, E. coli ATCC 15597 and 25922 to understand the observed effect. The hypothesis that UVA pre-radiation promoted the yield of reactive oxygen species (ROS) was rejected. ELISA results indicated that 18% more cyclobutane pyrimidine dimers (CPD) were formed in E. coli ATCC 15597 with UVA pre-radiation (n = 3, p < 0.01), however, the CPD levels of E. coli ATCC 25922 was the same with or without UVA pre-radiation (n = 3, p > 0.01). Considering the results of both dark repair and CPD formation, it was concluded that the increased UV sensitivity of E. coli 15597 was originated from the increased CPD. For E. coli ATCC 25922, the enhanced UV resistance was attributed to the strain's adoption of a survival strategy, translesion DNA synthesis (TLS), when triggered by UVA pre-radiation. The study on UmuD protein, which is a key protein during TLS, confirmed this hypothesis. Copyright © 2018 Elsevier Ltd. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/112675
Appears in Collections: 气候减缓与适应
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作者单位: Department of Civil and Environmental Engineering, National University of Singapore117576, Singapore
Recommended Citation:
Xiao Y.,Chu X.N.,He M.,et al. Impact of UVA pre-radiation on UVC disinfection performance: Inactivation, repair and mechanism study[J]. Water research,2018-01-01,141