Nocardioides caeni sp. nov., isolated from wastewater

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 °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(H₄) and the major fatty acids were iso-C_16:0 and C_18:1ω9c. 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).