title: Responses of community structure of amoA-encoding archaea and ammonia-oxidizing bacteria in ammonia biofilter with rockwool mixtures to the gradual increases in ammonium and nitrate.
abstract: OBJECTIVE
  To investigate community shifts of amoA-encoding archaea (AEA) and ammonia-oxidizing bacteria (AOB) in biofilter under nitrogen accumulation process.
  
  
  RESULTS
  A laboratory-scale rockwool biofilter with an irrigated water circulation system was operated for 436 days with ammonia loading rates of 49-63 NH(3) g m(-3) day(-1). The AEA and AOB communities were investigated by denaturing gradient gel electrophoresis, sequencing and real-time PCR analysis based on amoA genes. The results indicated that changes in abundance and community compositions occurred in a different manner between archaeal and bacterial amoA during the operation. However, both microbial community structures mainly varied when free ammonia (FA) concentrations in circulation water were increasing, which caused a temporal decline in reactor performance. Dominant amoA sequences after this transition were related to Thaumarchaeotal Group I.1b, Nitrosomonas europaea lineages and one subcluster within Nitrosospira sp. cluster 3, for archaea and bacteria, respectively.
  
  
  CONCLUSIONS
  The specific FA in circulation water seems to be the important factor, which relates to the AOB and AEA community shifts in the biofilter besides ammonium and pH.
  
  
  CONCLUSIONS
  One of the key factors for regulating AEA and AOB communities was proposed that is useful for optimizing biofiltration technology.
authors.affiliation: Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan. tomokoya@affrc. go.jp
authors.forename: T
authors.initials: T
authors.lastname: Yasuda
authors.forename: M
authors.initials: M
authors.lastname: Waki
authors.forename: K
authors.initials: K
authors.lastname: Kuroda
authors.forename: D
authors.initials: D
authors.lastname: Hanajima
authors.forename: Y
authors.initials: Y
authors.lastname: Fukumoto
authors.forename: T
authors.initials: T
authors.lastname: Yamagishi
authors.forename: Y
authors.initials: Y
authors.lastname: Suwa
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000393:Air Pollutants / Q000378:metabolism*; D000641:Ammonia / Q000378:metabolism*; D001105:Archaea / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D019149:Bioreactors; D058645:Denaturing Gradient Gel Electrophoresis; D058440:Denitrification; D005374:Filtration; D059013:Microbial Consortia; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry; D009587:Nitrogen Isotopes / Q000737:chemistry; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D000644:Quaternary Ammonium Compounds; D060888:Real-Time Polymerase Chain Reaction; D014867:Water / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D009566:Nitrates; D009587:Nitrogen Isotopes; D000644:Quaternary Ammonium Compounds; D014867:Water; D000641:Ammonia; D010088:Oxidoreductases; C045582:ammonia monooxygenase; D009584:Nitrogen