Abstract

A Gram-negative, motile, rod-shaped, non-spore-forming bacterial strain, designated as Ko03T, was isolated from microbial granules, and was characterized, using a polyphasic approach, in order to determine its taxonomic position. The isolate was positive for catalase and oxidase, but negative for gelatinase and β-galactosidase. Phylogenetic analyses using the 16S rRNA gene sequence showed that the strain formed a monophyletic branch towards the periphery of the evoluionary radiation occupied by the genus Comamonas, its closest neighbors being Comamonas koreensis KCTC 12005T (95.9% sequence similarity), Comamonas nitrativorans DSM 13191T (95.7%), and Comamonas odontotermitis LMG 23579T (95.7%). Strain Ko03T had a genomic DNA G+C content of 68.4 mol% and the predominant respiratory quinone was Q-8. The major fatty acids were C16:1 ω7c (44.7%), C16:0 (28.1%), C18:1 (16.1%), and C10:0 3-OH (3.5%). These chemotaxonomic results supported the affiliation of strain Ko03T to the genus Comamonas. However, low 16S rRNA gene sequence similarity values and distinguishing phenotypic characteristics allowed genotypic and phenotypic differentiation of strain Ko03T from recognized Comamonas species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Ko03T represents a novel species of the genus Comamonas, for which the name Comamonas granuli sp. nov. is proposed. The type strain is Ko03T (= KCTC 12199T= NBRC 101663T).

• Keywords: betaproteobacteria; polyphasic taxonomy; Comamonas granuli; 16S rRNA gene