活性污泥微生物解壳聚糖松江菌中菌胶团形成相关大型基因簇的鉴定和分析  

Identification and analysis of a large gene cluster involved in floc formation of activated sludge bacterium Mitsuaria chitosanitabida

作　　者：王晶 高娜[1,2] 刘双元 戴景程 刘亚琦[1,2] 邱东茹 WANG Jing;GAO Na;LIU Shuang-Yuan;DAI Jing-Cheng;LIU Ya-Qi;QIU Dong-Ru(Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]中国科学院水生生物研究所,湖北武汉430072 [2]中国科学院大学,北京100049

出　　处：《微生物学通报》2019年第8期1946-1953,共8页Microbiology China

基　　金：中国科学院重点部署项目(KFZD-SW-219-3-2)~~

摘　　要：【背景】活性污泥法已广泛应用于城市污水和工业废水的处理,微生物菌胶团的形成在污泥通过重力沉淀实现泥水分离和污泥回用的过程中起着重要作用。从西安北石桥污水处理厂活性污泥中分离到一株菌胶团形成菌XHY-A6,经鉴定为解壳聚糖松江菌(Mitsuaria chitosanitabida)。【目的】旨在揭示该株解壳聚糖松江菌菌胶团形成相关的基因及其菌胶团形成机制。【方法】结合分子遗传学,包括转座子插入突变技术和遗传互补分析以及基因组学方法分析与菌胶团形成相关的基因和基因簇。【结果】通过转座子插入突变技术获得了两株菌胶团形成缺陷的突变株,转座子插入位点在糖基转移酶(称为gt3)和多糖链长决定蛋白(wzz)基因内,且这两个基因位于一个与菌胶团形成相关的大型基因簇内,该基因簇内还包括与胞外多糖生物合成和分泌相关的基因、epsB2-prsK-psrR-prsT基因以及一个编码PEP-CTERM蛋白A的基因,遗传互补分析证明gt3基因、wzz基因及其下游wzc基因在菌胶团形成过程中是必需的。【结论】松江菌中菌胶团形成和调控机制极可能与活性污泥优势菌动胶菌(Zoogloea)非常相似,即由胞外多糖和PEP-CTERM家族胞外蛋白质共同介导。从武汉二郎庙、汤逊湖和深圳南山污水处理厂活性污泥中分离纯化出松江菌,这些松江菌属细菌可以用于富含几丁质和壳聚糖的市政污水和虾蟹类食品加工废水的净化和资源化利用。[Background] The activated sludge(AS) process has been widely applied for municipal sewage and industrial wastewater treatment. The microbial floc formation is very important in gravitational sludge-effluent separation and sludge recycling. A floc-forming strain of Mitsuaria chitosanitabida XHY-A6,has been isolated from the sludge sample of Beishiqiao Sewage Treatment Plant, Xi’an.[Objective] We intended to analyze the genes and reveal the mechanism underlying the floc-forming phenotype of Mitsuaria chitosanitabida XHY-A6 strain.[Methods] Molecular genetics, including the mariner transposon mutagenesis and genetic complementation, and genomics approaches were utilized for analyzing the genes and gene cluster required for floc formation.[Results] Two floc-formation deficient mutants have been isolated and the transposon insertional sites successfully mapped to the sequenced and annotated genome of Mitsuaria chitosanitabida XHY-A6. The glycosyltransferase(termed gt3) and polysaccharide chain length determinant protein(wzz) genes are located within a large gene cluster comprising the genes for extracellular polysaccharide biosynthesis and secretion, eps B2-prs K-prs R-prs T genes, a PEP-CTERM gene and other genes.The requirement of gt3 gene, wzz gene and wzc gene for floc-formation were further confirmed by genetic complementation.[Conclusion] Our results demonstrate that bacterial floc formation mediated by both exopolysaccharides and PEP-CTERM proteins might be well-conserved between Zoogloea resiniphila and Mitsuaria chitosanitabida. The chitosan-degrading capability of Mitusaria strains could be utilized for treating the seafood processing and other chitin-containing sewage and wastewater.

关 键 词：解壳聚糖松江菌 活性污泥 菌胶团形成 胞外多聚物 基因簇分析 

分 类 号：X703[环境科学与工程—环境工程] X172