Caenibacterium thermophilum gen. nov., sp. nov., isolated from a thermophilic aerobic digester of municipal sludge

摘要

A bacterial strain, N2-680T (=DSM 15264T=LMG 21760T), isolated from a thermophilic aerobicdigester of municipal sludge, was characterized with respect to its morphology, physiology and taxonomy. Phenotypically, the isolate was a Gram-negative rod with a polar flagellum,catalase- and oxidase-positive, containing cytoplasmic inclusions of poly-b-hydroxybutyrate and had an optimal growth temperature of about 47 6C. Strain N2-680T was unable to reduce nitrate and could use organic acids, amino acids and carbohydrates as single carbon sources. Chemotaxonomic analysis revealed that ubiquinone 8 was the major respiratory quinone of thisorganism and that phosphatidylethanolamine and phosphatidylglycerol were the major polarlipids. At 50 6C, the major components in fatty acid methyl ester analysis were C16 : 0 and cyclo-C17 : 0. The highest 16S rDNA sequence identity of isolate N2-680T was to Leptothrix mobilis and Ideonella dechloratans (95?7%) and to Rubrivivax gelatinosus and Aquabacterium commune(95?6 %). 16S rDNA sequence similarities to species of two related thermophilic genera,Caldimonas manganoxidans and Tepidimonas ignava, were lower (93?6 and 94?7 %). On the basis of phylogenetic analyses and physiological and chemotaxonomic characteristics, it is proposed thatisolate N2-680T represents a new genus and species, for which the name Caenibacteriumthermophilum gen. nov., sp. nov. is proposed