title: Comparative genomics analyses on EPS biosynthesis genes required for floc formation of Zoogloea resiniphila and other activated sludge bacteria.
abstract: Activated sludge (AS) process has been widely utilized for municipal sewage and industrial wastewater treatment. Zoolgoea and its related floc-forming bacteria are required for formation of AS flocs which is the key to gravitational effluent-and-sludge separation and AS recycling. However, little is known about the genetics, biochemistry and physiology of Zoogloea and its related bacteria. This report deals with the comparative genomic analyses on two Zoogloea resiniphila draft genomes and the closely related proteobacterial species commonly found in AS. In particular, the metabolic processes involved in removal of organic matters, nitrogen and phosphorus were analyzed. Furthermore, it is revealed that a large gene cluster, encoding eight glycosyltransferases and other proteins involved in biosynthesis and export of extracellular polysaccharides (EPS), was required for floc formation. One of the two asparagine synthase paralogues, associated with this EPS biosynthesis gene cluster, was required for floc formation in Zoogloea. Similar EPS biosynthesis gene cluster(s) were identified in the genome of other AS proteobacteria including polyphosphate-accumulating Candidatus Accumulibacter phosphatis (CAP) and nitrifying Nitrosopira and Nitrosomonas bacteria, but the gene composition varies interspecifically and intraspecifically. Our results indicate that floc formation of desired AS bacteria, including CAP strains, facilitate their recruitment into AS and gradual enrichment via repeated AS settling and recycling processes.
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Weixing
authors.initials: W
authors.lastname: An
authors.affiliation: School of Life Sciences, Xiamen University, Xiamen 361005, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Guo
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Song
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Na
authors.initials: N
authors.lastname: Gao
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; Institute of Deep-sea Science and Technology, Chinese Academy of Sciences, Sanya 572000, China.
authors.forename: Shijie
authors.initials: S
authors.lastname: Bai
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Dai
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Hehong
authors.initials: H
authors.lastname: Wei
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Dianzhen
authors.initials: D
authors.lastname: Yu
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Xia
authors.affiliation: Institute for Genetics and Development, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Institute for Genetics and Development, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Qi
authors.affiliation: School of Life Sciences and Technology, Hubei Engineering University, Xiaogan 43200, China.
authors.forename: Chunyuan
authors.initials: C
authors.lastname: Tian
authors.affiliation: Institute for Genetics and Development, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Haofeng
authors.initials: H
authors.lastname: Chen
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors.forename: Zhenbin
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong. Electronic address: zhangt@hku.hk.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address: qiu@ihb.ac.cn.
authors.forename: Dongru
authors.initials: D
authors.lastname: Qiu
mesh_terms: D001419:Bacteria; D005427:Flocculation; D023281:Genomics; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid; D015045:Zoogloea
chemical_list: D012722:Sewage
keywords: Activated sludge; Asparagine synthases; Floc formation; Genome; Zoogloea