Microbacterium kyungheense sp. nov. and Microbacterium jejuense sp. nov., isolated from salty soil

Two novel strains, THG-C26^T and THG-C31^T, were characterized using a polyphasic approach to determine their taxonomic positions. These two isolates were aerobic, Gram-stain-positive, non-motile, non-spore-forming and rod-shaped. 16S rRNA gene sequences and phenotypic features including chemotaxonomic characteristics indicated that the two isolates clearly represented members of the genus Microbacterium. The quinone systems of strains THG-C26^T and THG-C31^T contained MK-12/MK-13 as major menaquinones. The diamino acid in cell-wall hydrolysates of the two strains was ornithine. The major fatty acids were iso-C_{16: 0}, anteiso-C_{15: 0} and anteiso-C_{17: 0}. The polyamine pattern had spermidine as the predominant component. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and unidentified glycolipids. Phenotypic characteristics supported the affiliation of strains THG-C26^T and THG-C31^T to the genus Microbacterium. Chemotaxonomic data and DNA-DNA relatedness values allowed differentiation of these strains from other species of the genus Microbacterium with validly published names. Strains THG-C26^T and THG-C31^T showed highest 16S rRNA gene sequence similarities with Microbacterium resistens DMMZ 1710^T (98.5 %) and Microbacterium trichothecenolyticum IFO 15077^T (98.8 %), respectively, and the 16S rRNA gene sequence similarity between them was 99.0 %. DNA-DNA hybridization values between the novel isolates and strains of other species of the genus Microbacterium with validly published names were 4-25 %. Therefore, strains THG-C26^T and THG-C31^T are considered to represent two novel species of the genus Microbacterium, for which the names Microbacterium kyungheense sp. nov. [type strain THG-C26^T (= KACC 17124^T = JCM 18735^T)] and Microbacterium jejuense sp. nov. [type strain THG-C31^T (= KACC 17123^T = JCM 18734^T)] are proposed.