title: Evaluation of autotrophic growth of ammonia-oxidizers associated with granular activated carbon used for drinking water purification by DNA-stable isotope probing.
abstract: Nitrification is an important biological function of granular activated carbon (GAC) used in advanced drinking water purification processes. Newly discovered ammonia-oxidizing archaea (AOA) have challenged the traditional understanding of ammonia oxidation, which considered ammonia-oxidizing bacteria (AOB) as the sole ammonia-oxidizers. Previous studies demonstrated the predominance of AOA on GAC, but the contributions of AOA and AOB to ammonia oxidation remain unclear. In the present study, DNA-stable isotope probing (DNA-SIP) was used to investigate the autotrophic growth of AOA and AOB associated with GAC at two different ammonium concentrations (0.14 mg N/L and 1.4 mg N/L). GAC samples collected from three full-scale drinking water purification plants in Tokyo, Japan, had different abundance of AOA and AOB. These samples were fed continuously with ammonium and (13)C-bicarbonate for 14 days. The DNA-SIP analysis demonstrated that only AOA assimilated (13)C-bicarbonate at low ammonium concentration, whereas AOA and AOB exhibited autotrophic growth at high ammonium concentration. This indicates that a lower ammonium concentration is preferable for AOA growth. Since AOA could not grow without ammonium, their autotrophic growth was coupled with ammonia oxidation. Overall, our results point towards an important role of AOA in nitrification in GAC filters treating low concentration of ammonium.
authors.affiliation: Department of Urban Engineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo 113-8656, Japan. Electronic address: niujia@env.t.u-tokyo.ac.jp.
authors.forename: Jia
authors.initials: J
authors.lastname: Niu
authors.forename: Ikuro
authors.initials: I
authors.lastname: Kasuga
authors.forename: Futoshi
authors.initials: F
authors.lastname: Kurisu
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Furumai
authors.forename: Takaaki
authors.initials: T
authors.lastname: Shigeeda
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000235:genetics / Q000254:growth & development*; D052818:Autotrophic Processes; D001419:Bacteria / Q000235:genetics / Q000254:growth & development*; D044822:Biodiversity; D002247:Carbon Isotopes; D002606:Charcoal; D060766:Drinking Water; D059013:Microbial Consortia / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D058465:Nitrification; D010084:Oxidation-Reduction; D010802:Phylogeny; D014041:Tokyo; D018508:Water Purification / Q000379:methods*
chemical_list: D002247:Carbon Isotopes; D060766:Drinking Water; D002606:Charcoal; D000641:Ammonia
keywords: AOA; AOB; Advanced drinking water purification; Ammonia-oxidizing archaea; Ammonia-oxidizing bacteria; DNA-SIP; DNA-stable isotope probing; GAC; Granular activated carbon; OTU; Operational Taxonomic Unit; PCR; Q-PCR; T-RFLP; ammonia-oxidizing archaea; ammonia-oxidizing bacteria; granular activated carbon; polymerase chain reaction; quantitative-polymerase chain reaction; terminal-restriction fragment length polymorphism