Unravelling kinetic and microbial responses of enriched nitrifying sludge under long-term exposure of cephalexin and sulfadiazine.

Wang, B; Ni, B-J; Yuan, Z; Guo, J

Unravelling kinetic and microbial responses of enriched nitrifying sludge under long-term exposure of cephalexin and sulfadiazine.

Wang, B Ni, B-J Yuan, Z Guo, J

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Publisher:: PERGAMON-ELSEVIER SCIENCE LTD
Publication Type:: Journal Article
Citation:: Water research, 2020, 173
Issue Date:: 2020-04

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Field	Value	Language
dc.contributor.author	Wang, B
dc.contributor.author	Ni, B-J
dc.contributor.author	Yuan, Z
dc.contributor.author	Guo, J
dc.date.accessioned	2021-02-04T04:07:35Z
dc.date.available	2020-02-04
dc.date.available	2021-02-04T04:07:35Z
dc.date.issued	2020-04
dc.identifier.citation	Water research, 2020, 173
dc.identifier.issn	0043-1354
dc.identifier.issn	1879-2448
dc.identifier.uri	http://hdl.handle.net/10453/145819
dc.description.abstract	Wastewater treatment plants (WWTPs) have been identified as one of the reservoirs of antibiotics. Although nitrifying bacteria have been reported to be capable of degrading various antibiotics, there are very few studies investigating long-term effects of antibiotics on kinetic and microbial responses of nitrifying bacteria. In this study, cephalexin (CFX) and sulfadiazine (SDZ) were selected to assess chronic impacts on nitrifying sludge with stepwise increasing concentrations in two independent bioreactors. The results showed that CFX and SDZ at an initial concentration of 100 μg/L could be efficiently removed by enriched nitrifying sludge, as evidenced by removal efficiencies of more than 88% and 85%, respectively. Ammonia-oxidizing bacteria (AOB) made a major contribution to the biodegradation of CFX and SDZ via cometabolism, compared to limited contributions from heterotrophic bacteria and nitrite-oxidizing bacteria. Chronic exposure to CFX (≥30 μg/L) could stimulate ammonium oxidation activity in terms of a significant enhancement of ammonium oxidation rate (p < 0.01). In contrast, the ammonium oxidation activity was inhibited due to exposure to 30 μg/L SDZ (p < 0.01), then it recovered after long-term adaption under exposure to 50 and 100 μg/L SDZ. In addition, 16S rRNA gene amplicon sequencing revealed that the relative abundance of AOB decreased distinctly from 23.8% to 28.8% in the control phase (without CFX or SDZ) to 14.2% and 10.8% under exposure to 100 μg/L CFX and SDZ, respectively. However, the expression level of amoA gene was up-regulated to overcome this adverse impact and maintain a stable and efficient removal of both ammonium and antibiotics. The findings in this study shed a light on chronic effects of antibiotic exposure on kinetic and microbial responses of enriched nitrifying sludge in WWTPs.
dc.format	Print-Electronic
dc.language	eng
dc.publisher	PERGAMON-ELSEVIER SCIENCE LTD
dc.relation.ispartof	Water research
dc.relation.isbasedon	10.1016/j.watres.2020.115592
dc.rights	info:eu-repo/semantics/restrictedAccess
dc.subject.classification	Environmental Engineering
dc.subject.mesh	Ammonia
dc.subject.mesh	Cephalexin
dc.subject.mesh	Sulfadiazine
dc.subject.mesh	RNA, Ribosomal, 16S
dc.subject.mesh	Bioreactors
dc.subject.mesh	Sewage
dc.subject.mesh	Oxidation-Reduction
dc.subject.mesh	Nitrification
dc.subject.mesh	Ammonia
dc.subject.mesh	Cephalexin
dc.subject.mesh	Sulfadiazine
dc.subject.mesh	RNA, Ribosomal, 16S
dc.subject.mesh	Bioreactors
dc.subject.mesh	Sewage
dc.subject.mesh	Oxidation-Reduction
dc.subject.mesh	Nitrification
dc.subject.mesh	Ammonia
dc.subject.mesh	Bioreactors
dc.subject.mesh	Cephalexin
dc.subject.mesh	Nitrification
dc.subject.mesh	Oxidation-Reduction
dc.subject.mesh	RNA, Ribosomal, 16S
dc.subject.mesh	Sewage
dc.subject.mesh	Sulfadiazine
dc.title	Unravelling kinetic and microbial responses of enriched nitrifying sludge under long-term exposure of cephalexin and sulfadiazine.
dc.type	Journal Article
utslib.citation.volume	173
utslib.location.activity	England
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Strength - CTWW - Centre for Technology in Water and Wastewater Treatment
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	/University of Technology Sydney
utslib.copyright.status	closed_access	*
pubs.consider-herdc	false
dc.date.updated	2021-02-04T04:07:25Z
pubs.publication-status	Published
pubs.volume	173

Abstract:

Wastewater treatment plants (WWTPs) have been identified as one of the reservoirs of antibiotics. Although nitrifying bacteria have been reported to be capable of degrading various antibiotics, there are very few studies investigating long-term effects of antibiotics on kinetic and microbial responses of nitrifying bacteria. In this study, cephalexin (CFX) and sulfadiazine (SDZ) were selected to assess chronic impacts on nitrifying sludge with stepwise increasing concentrations in two independent bioreactors. The results showed that CFX and SDZ at an initial concentration of 100 μg/L could be efficiently removed by enriched nitrifying sludge, as evidenced by removal efficiencies of more than 88% and 85%, respectively. Ammonia-oxidizing bacteria (AOB) made a major contribution to the biodegradation of CFX and SDZ via cometabolism, compared to limited contributions from heterotrophic bacteria and nitrite-oxidizing bacteria. Chronic exposure to CFX (≥30 μg/L) could stimulate ammonium oxidation activity in terms of a significant enhancement of ammonium oxidation rate (p < 0.01). In contrast, the ammonium oxidation activity was inhibited due to exposure to 30 μg/L SDZ (p < 0.01), then it recovered after long-term adaption under exposure to 50 and 100 μg/L SDZ. In addition, 16S rRNA gene amplicon sequencing revealed that the relative abundance of AOB decreased distinctly from 23.8% to 28.8% in the control phase (without CFX or SDZ) to 14.2% and 10.8% under exposure to 100 μg/L CFX and SDZ, respectively. However, the expression level of amoA gene was up-regulated to overcome this adverse impact and maintain a stable and efficient removal of both ammonium and antibiotics. The findings in this study shed a light on chronic effects of antibiotic exposure on kinetic and microbial responses of enriched nitrifying sludge in WWTPs.

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http://hdl.handle.net/10453/145819