title: Identification and comparison of aerobic and denitrifying polyphosphate-accumulating organisms.
abstract: Two laboratory-scale sequencing batch reactors (SBRs) were operated for enhanced biological phosphorus removal (EBPR) in alternating anaerobic-aerobic or alternating anaerobic-anoxic modes, respectively. Polyphosphate-accumulating organisms (PAOs) were enriched in the anaerobic-aerobic SBR and denitrifying PAOs (DPAOs) were enriched in the anaerobic-aerobic SBR. Fluorescence in situ hybridization (FISH) demonstrated that the well-known PAO, "Candidatus Accumulibacter phosphatis" was abundant in both SBRs, and post-FISH chemical staining with 4,6-diamidino-2-phenylindol (DAPI) confirmed that they accumulated polyphosphate. When the anaerobic-anoxic SBR enriched for DPAOs was converted to anaerobic-aerobic operation, aerobic uptake of phosphorus by the resident microbial community occurred immediately. However, when the anaerobic-aerobic SBR enriched for PAOs was exposed to one cycle with anoxic rather than aerobic conditions, a 5-h lag period elapsed before phosphorus uptake proceeded. This anoxic phosphorus-uptake lag phase was not observed in the subsequent anaerobic-aerobic cycle. These results demonstrate that the PAOs that dominated the anaerobic-aerobic SBR biomass were the same organisms as the DPAOs enriched under anaerobic-anoxic conditions.
authors.affiliation: Advanced Wastewater Management Centre, University of Queensland, St. Lucia, Brisbane 4072, Australia.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Zeng
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Saunders
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
authors.forename: Linda L
authors.initials: LL
authors.lastname: Blackall
authors.forename: Jürg
authors.initials: J
authors.lastname: Keller
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000378:metabolism; D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism* / Q000648:ultrastructure; D018533:Biomass; D001711:Biotransformation; D007700:Kinetics; D018613:Microscopy, Confocal / Q000379:methods; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011122:Polyphosphates / Q000378:metabolism*
chemical_list: D009566:Nitrates; D009573:Nitrites; D010710:Phosphates; D011122:Polyphosphates; D000641:Ammonia