title: Chronic impact of sulfamethoxazole on the metabolic activity and composition of enriched nitrifying microbial culture.
abstract: This study investigated the chronic impact of sulfamethoxazole (SMX) on activated sludge sustaining an enriched nitrifying biomass. For this purpose, a laboratory scale fill and draw reactor was operated with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia at a sludge age of 15 days. Additionally, the biomass was exposed to a daily SMX dose of 50 mg/L once the reactor reached steady-state conditions. The reactor performance and microbial composition were monitored for 37 days with conventional parameters and molecular techniques based on the gene for ammonia monooxygenase subunit A (amoA) and the prokaryotic 16S rRNA gene. Denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene cloning analyses suggested a microbial community change concurrent with the addition of SMX. Specifically, quantitative polymerase chain reaction analyses (qPCR/RT-qPCR) revealed a significant reduction in the levels and activity of ammonia oxidizing bacteria (AOB). However, the acclimation period ended with high amoA mRNA levels and improved nitrification efficiency. Partial degradation of SMX by heterotrophic bacteria was also observed.
authors.affiliation: Istanbul Technical University, Faculty of Civil Engineering, Environmental Engineering Department, 34469 Maslak, Istanbul, Turkey; CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France. Electronic address: tugce.katipoglu@gmail.com.
authors.forename: Tugce
authors.initials: T
authors.lastname: Katipoglu-Yazan
authors.affiliation: CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France; Université de Lorraine, LCPME, UMR 7564, 15 Avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France. Electronic address: christophe.merlin@univ-lorraine.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Merlin
authors.affiliation: Laboratoire Réactions et Génie des Procédés (UMR 7274 CNRS) Université de Lorraine, 1 rue Grandville, BP 20451, 54001 Nancy Cedex, France. Electronic address: marie-noelle.pons@univ-lorraine.fr.
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Pons
authors.affiliation: Istanbul Technical University, Faculty of Civil Engineering, Environmental Engineering Department, 34469 Maslak, Istanbul, Turkey. Electronic address: ubay@itu.edu.tr.
authors.forename: Emine
authors.initials: E
authors.lastname: Ubay-Cokgor
authors.affiliation: Istanbul Technical University, Faculty of Civil Engineering, Environmental Engineering Department, 34469 Maslak, Istanbul, Turkey; ENVIS Energy and Environmental Systems R&D Ltd, ITU Arı Teknokent, Arı 1 Building No.16, Maslak 34469, Turkey. Electronic address: orhon@itu.edu.tr.
authors.forename: Derin
authors.initials: D
authors.lastname: Orhon
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D058465:Nitrification; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012722:Sewage / Q000382:microbiology; D013420:Sulfamethoxazole / Q000378:metabolism*
chemical_list: D012336:RNA, Ribosomal, 16S; D012722:Sewage; D000641:Ammonia; D013420:Sulfamethoxazole
keywords: Community molecular analyses; Enriched nitrifying culture; Gene activity; Nitrification; Sulfamethoxazole