title: Quantification and comparison of ammonia-oxidizing bacterial communities in MBRs treating various types of wastewater.
abstract: The community structure and abundance of ammonia-oxidizing bacteria (AOB) in membrane bioreactors (MBRs) constructed to treat different types of wastewater were analyzed by PCR-DGGE, cloning of 16S rRNA fragments and quantitative real-time PCR techniques. DGGE analysis revealed that the diversity of the ammonia-oxidizing bacterial communities was similar among the four reactors. Additionally, variation in influents had no significant effect on the distribution of the AOB communities. Sequencing analysis of screened clones revealed a wide variety of nitrifying organisms and denitrifying bacteria, which suggests that there may be multiple modes of nitrification and denitrification in MBRs. Real-time PCR revealed that the AOB comprised less than 0.1% of the total bacteria in all MBRs. The free ammonia content of the influent was well correlated with the AOB cell numbers. Taken together, these data suggest that higher NH(4)(+)-N content favors the growth of ammonia oxidizers in MBRs.
authors.affiliation: School of Environmental Science and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Baosheng
authors.initials: B
authors.lastname: Sun
authors.forename: Min
authors.initials: M
authors.lastname: Ji
authors.forename: Huina
authors.initials: H
authors.lastname: Liu
authors.forename: Xianhua
authors.initials: X
authors.lastname: Liu
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D004587:Electrophoresis, Agar Gel; D018628:Gene Dosage / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014865:Waste Disposal, Fluid / Q000295:instrumentation*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D012336:RNA, Ribosomal, 16S; D000641:Ammonia