title: Bacterial community structure in cooling water and biofilm in an industrial recirculating cooling water system.
abstract: Microbial fouling is a serious problem in open recirculating cooling water systems. The bacterial communities that cause it have not been fully understood. In this study, we analyzed the community structure of free-living bacteria and particle-attached bacteria in cooling water, and bacteria in biofilm collected from the wall of the water reservoir in an industrial recirculating cooling water system by construction of a 16S rRNA gene clone library. Based on amplified ribosomal DNA restriction analysis, clones of all three libraries were clustered into 45 operational taxonomic units (OTUs). Thirteen OTUs displaying 91-96% sequence similarity to a type strain might be novel bacterial species. Noted differences in community structure were observed among the three libraries. The relative species richness of the free-living bacteria in cooling water was much lower than that of particle-attached bacteria and bacteria in biofilm. The majority of the free-living bacterial community (99.0%) was Betaproteobacteria. The predominant bacteria in the particle-attached bacterial community were Alphaproteobacteria (20.5%), Betaproteobacteria (27.8%) and Planctomycetes (42.0%), while those in the biofilm bacterial community were Alphaproteobacteria (47.9%), Betaproteobacteria (11.7%), Acidobacteria (13.1%) and Gemmatimonadetes (11.3%). To control microbial fouling in industrial recirculating cooling water systems, additional physiological and ecological studies of these species will be essential.
authors.affiliation: State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, China E-mail: pengfuli@nju.edu.cn.
authors.forename: Jinmei
authors.initials: J
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Huijie
authors.initials: H
authors.lastname: Xiao
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Meijuan
authors.initials: M
authors.lastname: Xie
authors.forename: Mengjia
authors.initials: M
authors.lastname: Sun
authors.forename: Chenglin
authors.initials: C
authors.lastname: Zhu
authors.forename: Pengfu
authors.initials: P
authors.lastname: Li
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D018441:Biofilms; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014871:Water Microbiology; D014872:Water Movements
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S