Nocardioides kongjuensis sp. nov., an N-acylhomoserine lactone-degrading bacterium.

A Gram-positive, rod- or coccoid-shaped and N-hexanoyl-l-homoserine lactone-degrading bacterial strain, A2-4(T), was isolated from a soil in Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain A2-4(T) grew optimally at pH 7.0-8.0 and 30 degrees C without NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain A2-4(T) is most closely related to members of the genus Nocardioides. Strain A2-4(T) possessed chemotaxonomic properties indicative of members of the genus Nocardioides; the cell-wall peptidoglycan type was based on ll-diaminopimelic acid, MK-8(H(4)) was the predominant menaquinone and iso-C(16 : 0) was the predominant fatty acid. The DNA G+C content was 72.1 mol%. The 16S rRNA gene sequence of strain A2-4(T) was 98.3-99.1 % similar to those of the type strains of Nocardioides simplex, Nocardioides aromaticivorans and Nocardioides nitrophenolicus and 93.8-96.3 % similar to those of the type strains of other Nocardioides species. Strain A2-4(T) could be distinguished from the three phylogenetic relatives, N. nitrophenolicus, N. aromaticivorans and N. simplex, by DNA-DNA relatedness (25-42 %) and by differences in some phenotypic characteristics. On the basis of the phenotypic, phylogenetic and genetic data, the strain represents a novel species of the genus Nocardioides, for which the name Nocardioides kongjuensis sp. nov. is proposed. The type strain is A2-4(T) (=KCTC 19054(T)=JCM 12609(T)).