title: Population dynamics of ammonia-oxidizing bacteria in an aerated submerged biofilm reactor for micropolluted raw water pretreatment.
abstract: Population dynamics of ammonia-oxidizing bacteria (AOB) in a full-scale aerated submerged biofilm reactor for micropolluted raw water pretreatment was investigated using molecular techniques for a period of 1 year. The ammonia monooxygenase (amoA) gene fragments were amplified from DNA and RNA extracts of biofilm samples. Denaturing gradient gel electrophoresis (DGGE) profile based on the amoA messenger RNA approach exhibited a more variable pattern of temporal dynamics of AOB communities than the DNA-derived approach during the study. Phylogenetic analysis of excised DGGE bands revealed three AOB groups affiliated with the Nitrosomonas oligotropha lineage, Nitrosomonas communis lineage, and an unknown Nitrosomonas group. The population size of betaproteobacterial AOB, quantified with 16S ribosomal RNA gene real-time polymerase chain reaction assay, ranged from 6.63 x 10(5) to 2.67 x 10(9) cells per gram of dry biofilm and corresponded to 0.23-1.8% of the total bacterial fraction. Quantitative results of amoA gene of the three specific AOB groups revealed changes in competitive dominance between AOB of the N. oligotropha lineage and N. communis lineage. Water temperature is shown to have major influence on AOB population size in the reactor by the statistic analysis, and a positive correlation between AOB cell numbers and ammonia removal efficiency is suggested (r = 0.628, P < 0.05).
authors.affiliation: Key Laboratory of Microbial Metabolism (Shanghai Jiaotong University), Ministry of Education, School of Life Science and Biotechnology, Shanghai Jiaotong University, Shanghai, China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Qin
authors.forename: Xiao-Wen
authors.initials: XW
authors.lastname: Zhang
authors.forename: Hong-Qiang
authors.initials: HQ
authors.lastname: Ren
authors.forename: Dao-Tang
authors.initials: DT
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
mesh_terms: D000641:Ammonia / Q000032:analysis*; D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis; D008969:Molecular Sequence Data; D009606:Nitrosomonas / Q000235:genetics / Q000254:growth & development*; D010084:Oxidation-Reduction; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011157:Population Dynamics; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012621:Seasons; D013696:Temperature; D014877:Water Pollution, Chemical; D018508:Water Purification
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012333:RNA, Messenger; D000641:Ammonia