title: Dominance of endospore-forming bacteria on a Rotating Activated Bacillus Contactor biofilm for advanced wastewater treatment.
abstract: The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.
authors.affiliation: Department of Microbiology and Biotechnology, Daejeon University, Daejeon 300-716, Republic of Korea. psjj@dju.ac.kr
authors.forename: Seong Joo
authors.initials: SJ
authors.lastname: Park
authors.forename: Jerng Chang
authors.initials: JC
authors.lastname: Yoon
authors.forename: Kwang-Soo
authors.initials: KS
authors.lastname: Shin
authors.forename: Eung Ho
authors.initials: EH
authors.lastname: Kim
authors.forename: Soobin
authors.initials: S
authors.lastname: Yim
authors.forename: Yeon-Je
authors.initials: YJ
authors.lastname: Cho
authors.forename: Gi Moon
authors.initials: GM
authors.lastname: Sung
authors.forename: Dong-Geun
authors.initials: DG
authors.lastname: Lee
authors.forename: Seung Bum
authors.initials: SB
authors.lastname: Kim
authors.forename: Dong-Uk
authors.initials: DU
authors.lastname: Lee
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Woo
authors.forename: Ben
authors.initials: B
authors.lastname: Koopman
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development; D001407:Bacillus / Q000235:genetics / Q000254:growth & development*; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004725:Endospore-Forming Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D008969:Molecular Sequence Data; D010802:Phylogeny; D020560:Proteobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage