title: The microbial community analysis of a 5-stage BNR process with step feed system.
abstract: The microbial communities of 5-stage BNR activated sludge samples were analyzed using fluorescence in-situ hybridization (FISH) and 16S rDNA characterization. The total cell numbers of each reactor were from 2.36 x 10(9) cells/ml to 2.83 x 10(9) cells/ml. From 56.5% to 62.0% of total DAPI cell counts were hybridized to the most bacterial specific probe EUB 338. Among them, beta-proteobacteria were most dominant in each tank. The number of phosphate accumulating organisms (PAOs) was almost 50% of the total cell number in anoxic-1 tank, and these results indicate that this process has a high content of denitrifying phosphorus accumulating organisms (dPAOs). In contrast with FISH, 16S rDNA analysis showed that dominant groups were the Cytophaga-Flavobacterium group and high G+C% gram-positive bacteria, which were determined as PAOs in anoxic-1 tank. The beta subclass Proteobacteria did not accumulate a large amount of polyphosphate. The overall results indicate that high G+C% gram-positive bacteria and the Cytophaga-Flavobacterium group might play a key role as dPAOs in this process.
authors.affiliation: Graduate School of Biotechnology, Korea University, 1 Anam-dong, Seoul 136-701, Korea.
authors.forename: H W
authors.initials: HW
authors.lastname: Lee
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.forename: J O
authors.initials: JO
authors.lastname: Lee
authors.forename: H G
authors.initials: HG
authors.lastname: Kim
authors.forename: J B
authors.initials: JB
authors.lastname: Park
authors.forename: E
authors.initials: E
authors.lastname: Choi
authors.forename: Y K
authors.initials: YK
authors.lastname: Park
mesh_terms: D019149:Bioreactors; D003589:Cytophaga / Q000302:isolation & purification / Q000502:physiology*; D004269:DNA, Bacterial / Q000032:analysis; D041965:Flavobacteriaceae / Q000302:isolation & purification / Q000502:physiology*; D017404:In Situ Hybridization, Fluorescence; D010710:Phosphates / Q000378:metabolism*; D011157:Population Dynamics; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D010710:Phosphates