title: Long-term effects of engineered nanoparticles on enzyme activity and functional bacteria in wastewater treatment plants.
abstract: The pervasive use of engineered nanoparticles (NPs) in a wide range of fields raises concerns about their potential environmental impacts. Previous studies confirmed that some NPs had already entered wastewater treatment plants (WWTPs). Wastewater nutrient removal depends on the metabolisms of activated sludge bacteria and their related key enzymes. Therefore, this study compared the possible influences of Al2O3, SiO2, TiO2, and ZnO NPs on the key enzymes activities and microbial community structures involved in wastewater treatment facilities. It was found that long-term exposure to these NPs significantly affected the microbial communities and changed the relative abundances of key functional bacteria, such as ammonia-oxidizing bacteria. Also, the gene expressions and catalytic activities of essential enzymes, such as ammonia monooxygenase, nitrite oxidoreductase, nitrate reductase, and nitrite reductase, were decreased, which finally resulted in a lower efficiency of biological nitrogen removal.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: yinguangchen@tongji.edu.cn.
authors.forename: Xiong
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: yinguangchen@tongji.edu.cn.
authors.forename: Haining
authors.initials: H
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: yinguangchen@tongji.edu.cn.
authors.forename: Yinglong
authors.initials: Y
authors.lastname: Su
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: yinguangchen@tongji.edu.cn.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China E-mail: yinguangchen@tongji.edu.cn.
authors.forename: Yinguang
authors.initials: Y
authors.lastname: Chen
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D053758:Nanoparticles / Q000009:adverse effects* / Q000737:chemistry; D009584:Nitrogen / Q000032:analysis; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013997:Time Factors; D064091:Waste Disposal Facilities; D062065:Wastewater / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D009584:Nitrogen; D012722:Sewage; D062065:Wastewater