Nocardioides caeni sp. nov., isolated from wastewater

Abstract

A Gram-positive, non-motile, rod- or coccoid-shaped bacterial strain, designated MN8(T), was isolated from sludge of domestic wastewater in Korea, and its taxonomic position was investigated by use of a polyphasic study. Strain MN8(T) grew optimally at pH 6.5-7.5 and 30 degrees C and in the presence of 0-0.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MN8(T) fell within the cluster comprising Nocardioides species, clustering with Nocardioides simplex KCTC 9106(T), Nocardioides aromaticivorans H-1(T), Nocardioides kongjuensis A2-4(T) and Nocardioides nitrophenolicus NSP41(T), with which it shared 98.4-99.0 % 16S rRNA gene sequence similarity. The chemotaxonomic properties of strain MN8(T) were consistent with those of the genus Nocardioides: the cell-wall peptidoglycan type was based on ll-2,6-diaminopimelic acid, the predominant menaquinone was MK-8(H(4)) and the major fatty acids were iso-C(16 : 0) and C(18 : 1)omega9c. The DNA G+C content was 71.5 mol%. Strain MN8(T) exhibited levels of DNA-DNA relatedness of 13-31 % to the type strains of phylogenetically related Nocardioides species and could be differentiated from these species based on differences in phenotypic characteristics. On the basis of the data presented, strain MN8(T) is considered to represent a novel species of the genus Nocardioides, for which the name Nocardioides caeni sp. nov. is proposed. The type strain is MN8(T) (=KCTC 19600(T)=CCUG 57506(T)).