title: Bacterial diversity in activated sludge from a consecutively aerated submerged membrane bioreactor treating domestic wastewater.
abstract: The bacterial diversity of activated sludge from submerged membrane bioreactor (SMBR) was investigated. A 16S rDNA clone library was generated, and 150 clones were screened using restriction fragment length polymorphism (RFLP). Of the screened clones, almost full-length 16S rDNA sequences of 64 clones were sequenced. Phylogenetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequences from NCBI for identification purposes. The 90.6% of the clones were affiliated with the two phyla Bacteroidetes (50%) and Proteobacteria (40%), and beta-, gamma-, and delta-Proteobacteria accounted for 7.8%, 28.1%, and 4.7%, respectively. Minor portions were affiliated with the Actinobacteria and Firmicutes (both 3.1%). Only 6 out of 64 16S rDNA sequences exhibited similarities of more than 97% to classified bacterial species, which indicated that a substantial fraction of the clone sequences were derived from unknown taxa. Rarefaction analysis of operational taxonomic units (OTUs) clusters demonstrated that 150 clones screened were still insufficient to describe the whole bacterial diversity. Measurement of water quality parameter demonstrated that performance of the SMBR maintained high level, and the SMBR system remained stable during this study.
authors.affiliation: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. dutilapia@126.com
authors.forename: Cheng
authors.initials: C
authors.lastname: Du
authors.forename: Zhenbin
authors.initials: Z
authors.lastname: Wu
authors.forename: Enrong
authors.initials: E
authors.lastname: Xiao
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Zhou
authors.forename: Shuiping
authors.initials: S
authors.lastname: Cheng
authors.forename: Wei
authors.initials: W
authors.lastname: Liang
authors.forename: Feng
authors.initials: F
authors.lastname: He
mesh_terms: D000388:Air; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D041963:Bacteroidetes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D019149:Bioreactors; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D015723:Gene Library; D007101:Immersion; D008567:Membranes, Artificial; D008969:Molecular Sequence Data; D020560:Proteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D008567:Membranes, Artificial; D012722:Sewage