Nocardioides daeguensis sp nov., a nitrate-reducing bacterium isolated from activated sludge of an industrial wastewater treatment plant

Abstract

A Gram-reaction-positive, rod-shaped, non-spore-forming bacterium (strain 2C1-5(T)) was isolated from activated sludge of an industrial wastewater treatment plant in Daegu, South Korea. Its taxonomic position was investigated by using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity, the closest phylogenetic relatives were the type strains of Nocardioides nitrophenolicus (98.6 % similarity), N. kongjuensis (98.5 %), N. caeni (98.4 %), N. simplex (98.3%), N. aromaticivorans (98.1%) and N. ginsengisoli (97.5 %); the phylogenetic distance from other species with validly published names within the genus Nocardioides was greater than 3%. Strain 2C1-5(T) was characterized chemotaxonomically as having LL-2, 6-diaminopimelic acid in the cell-wall peptidoglycan, MK-8(H-4) as the predominant menaquinone and iso-C-16:0, C-16:0 and C-17:1 omega 6c as the major fatty acids. The G+C content of the genomic DNA was 74.9 mol%. These chemotaxonomic properties and phenotypic characteristics supported the affiliation of strain 2C1-5(T) to the genus Nocardioides. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain 2C1-5(T) from existing species with validly published names. Therefore, strain 2C1-5(T) represents a novel species of the genus Nocardioides, for which the name Nocardioides daeguensis sp. nov. is proposed, with the type strain 2C1-5(T) (=JCM 17460(T)=KCTC 19799(T)).