title: Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems.
abstract: Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTPs) is lacking. In this study, stable-isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridization (FISH) to identify previously unrecognized active denitrifying phylotypes in a full-scale WWTP with biological N and P removal. Acknowledging that different denitrifiers will have specific carbon source preferences, a fully (13)C-labelled complex substrate was used for SIP incubations, under nitrite-reducing conditions, in order to maximize the capture of the potentially metabolically diverse denitrifiers likely present. Members of the Rhodoferax, Dechloromonas, Sulfuritalea, Haliangium and Thermomonas were represented in the 16S rRNA gene clone libraries from DNA enriched in (13)C, with FISH probes optimized here for their in situ characterization. FISH and MAR confirmed that they were all active denitrifiers in the community. The combined approach of SIP and MAR-FISH represents an excellent approach for identifying and characterizing an un-described diversity of active denitrifiers in full-scale systems.
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Simon Jon
authors.initials: SJ
authors.lastname: McIlroy
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Anna
authors.initials: A
authors.lastname: Starnawska
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Piotr
authors.initials: P
authors.lastname: Starnawski
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Aaron Marc
authors.initials: AM
authors.lastname: Saunders
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Marta
authors.initials: M
authors.lastname: Nierychlo
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Per Halkjaer
authors.initials: PH
authors.lastname: Nielsen
authors.affiliation: Department of Biotechnology, Chemistry and Environmental Engineering, Center for Microbial Communities, Aalborg University, Aalborg, Denmark.
authors.forename: Jeppe Lund
authors.initials: JL
authors.lastname: Nielsen
mesh_terms: D001345:Autoradiography; D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000737:chemistry; D002247:Carbon Isotopes / Q000737:chemistry; D042621:Comamonadaceae / Q000235:genetics* / Q000378:metabolism; D058440:Denitrification / Q000235:genetics*; D015723:Gene Library; D017404:In Situ Hybridization, Fluorescence; D009573:Nitrites / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D002247:Carbon Isotopes; D009573:Nitrites; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D002244:Carbon; D009584:Nitrogen