title: Occurrence of ammonia-oxidizing Archaea in activated sludges of a laboratory scale reactor and two wastewater treatment plants.
abstract: OBJECTIVE
  Characterization of the ammonia-oxidizing archaea (AOA) community in activated sludge from a nitrogen removal bioreactor and wastewater treatment plants (WWTPs).
  
  
  RESULTS
  Three primer sets specific for ammonia mono-oxygenase alpha-subunit (amoA) were used to construct clone libraries for activated sludge sample from a nitrogen removal bioreactor. One primer set resulted in strong nonspecific PCR products. The other two clone libraries retrieved both shared and unique AOA amoA sequences. One primer set was chosen to study the AOA communities of activated sludge samples from Shatin and Stanley WWTPs. In total, 18 AOA amoA sequences were recovered and compared to the previous reported sequences. A phylogenetic analysis indicated that sequences found in this study fell into three clusters.
  
  
  CONCLUSIONS
  Different primers resulted in varied AOA communities from the same sample. The AOA found from Hong Kong WWTPs were closely similar to those from sediment and soil, but distinct from those from activated sludge in other places. A comparison of clone libraries between Shatin WWTP and bioreactor indicated the AOA community significantly shifted only after 30-day enrichment.
  
  
  CONCLUSIONS
  This study confirmed the occurrence of AOA in a laboratory scale nitrogen removal bioreactor and Hong Kong WWTPs treating saline or freshwater wastewater. AOA communities found in this study were significantly different from those found in other places. To retrieve diverse AOA communities from environmental samples, a combination of different primers for the amoA gene is needed.
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Hong Kong SAR, China. zhangt@hkucc.hku.hk
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.forename: T
authors.initials: T
authors.lastname: Jin
authors.forename: Q
authors.initials: Q
authors.lastname: Yan
authors.forename: M
authors.initials: M
authors.lastname: Shao
authors.forename: G
authors.initials: G
authors.lastname: Wells
authors.forename: C
authors.initials: C
authors.lastname: Criddle
authors.forename: H H
authors.initials: HH
authors.lastname: P Fang
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification*; D019843:Archaeal Proteins / Q000235:genetics; D019149:Bioreactors / Q000382:microbiology*; D017931:DNA Primers; D019641:DNA, Archaeal / Q000032:analysis; D014644:Genetic Variation; D006723:Hong Kong; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D014871:Water Microbiology
chemical_list: D019843:Archaeal Proteins; D017931:DNA Primers; D019641:DNA, Archaeal; D012722:Sewage; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase