Dynamics of the diversity and structure of the overall and nitrifying microbial community in activated sludge along gradient copper exposures.
Diversity and composition of the microbial community, especially the nitrifiers, are essential to the treatment efficiency of wastewater in activated sludge systems. Heavy metals commonly present in the wastewater influent such as Cu can alter the community structure of nitrifiers and lower their activity. However, the dynamics of microbial community along a gradient of metal exposure have largely been unexplored, partially due to the limitations in traditional molecular methods. This study explored the dynamics regarding the diversity and community structures of overall and nitrifying microbial communities in activated sludge under intermittent Cu gradient loadings using Illumina sequencing. We created a new local nitrifying bacterial database for sequence BLAST searches. High Cu loadings (>10.9 mg/L) impoverished microbial diversity and altered the microbial community. Overall, Proteobacteria was the predominant phylum in the activated sludge system, in which Zoogloea, Thauera, and Dechloromonas (genera within the Rhodocyclaceae family of the Beta-proteobacteria class) were the dominant genera in the presence of Cu. The abundance of unclassified bacteria at the phylum level increased substantially with increasing Cu loadings. Nitrosomonas and Nitrospira were the predominant nitrifiers. The nitrifying bacterial community changed through increasing abundance and shifting to Cu-tolerant species to reduce the toxic effects of Cu. Our local nitrifying bacterial database helped to improve the resolution of bacterial identification. Our results provide insights into the dynamics of microbial community in response to various metal concentrations in activated sludge systems and improve our understanding regarding the effect of metals on wastewater treatment efficiency.
School of Environmental Science and Engineering, Tianjin University, Weijin Road 92, Tianjin, 300072, People's Republic of China.|School of Traffic and Environment, Shenzhen Institute of Information Technology, Longxiang Road 2188, Shenzhen, 518172, People's Republic of China.
Fan
F
Ouyang
School of Environmental Science and Engineering, Tianjin University, Weijin Road 92, Tianjin, 300072, People's Republic of China.|State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin Universty, Weijin Road 92, Tianjin, 300072, People's Republic of China.
Min
M
Ji
School of Environmental Science and Engineering, Tianjin University, Weijin Road 92, Tianjin, 300072, People's Republic of China. zhaihy@tju.edu.cn.
Hongyan
H
Zhai
Department of Environmental Health, Harvard T.H. Chan School of Public Health, 401 Park Drive, Landmark Center West 415, Boston, MA, 02215, USA.
Zhao
Z
Dong
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, People's Republic of China.
Lin
L
Ye
D001483:Base Sequence; D044822:Biodiversity; D019149:Bioreactors / Q000382:microbiology; D003300:Copper / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D064307:Microbiota / Q000235:genetics*; D058465:Nitrification; D009606:Nitrosomonas / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D020560:Proteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D003300:Copper
Activated sludge; Cu toxicity; Illumina sequencing; Microbial community; Nitrifying bacteria