title: Analysis of ammonia-oxidizing bacteria dominating in lab-scale bioreactors with high ammonium bicarbonate loading.
abstract: The ammonia-oxidizing bacterial community (AOB) was investigated in two types of laboratory-scale bioreactors performing partial oxidation of ammonia to nitrite or nitrate at high (80 mM) to extremely high (428 mM) concentrations of ammonium bicarbonate. At all conditions, the dominant AOB was affiliated to the Nitrosomonas europaea lineage as was determined by fluorescence in situ hybridization and polymerase chain reaction in combination with denaturing gradient gel electrophoresis. Molecular analysis of the mixed populations, based on the 16S rRNA and cbbL genes, demonstrated the presence of two different phylotypes of Nitrosomonas, while microbiological analysis produced a single phylotype, represented by three different morphotypes. One of the most striking features of the AOB populations encountered in the bioreactors was the domination of highly aggregated obligate microaerophilic Nitrosomonas, with unusual cellular and colony morphology, commonly observed in nitrifying bioreactors but rarely investigated by cultural methods. The latter is probably not an adaptation to stressful conditions created by high ammonia or nitrite concentrations, but oxygen seems to be a stressful factor in these bioreactors.
authors.affiliation: Department of Water Technology and Environmental Engineering, Institute of Chemical Technology, Prague, Czech Republic. dana.vejmelkova@vscht.cz
authors.forename: Dana
authors.initials: D
authors.lastname: Vejmelkova
authors.forename: Dimitry Y
authors.initials: DY
authors.lastname: Sorokin
authors.forename: Ben
authors.initials: B
authors.lastname: Abbas
authors.forename: Olga L
authors.initials: OL
authors.lastname: Kovaleva
authors.forename: Robbert
authors.initials: R
authors.lastname: Kleerebezem
authors.forename: Marlies J
authors.initials: MJ
authors.lastname: Kampschreur
authors.forename: Gerard
authors.initials: G
authors.lastname: Muyzer
authors.forename: Mark C M
authors.initials: MC
authors.lastname: van Loosdrecht
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D001639:Bicarbonates / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D058448:Biota; D016000:Cluster Analysis; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009606:Nitrosomonas / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D001639:Bicarbonates; D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D009566:Nitrates; D009573:Nitrites; D012336:RNA, Ribosomal, 16S; C027043:ammonium bicarbonate; D000641:Ammonia