Microbacterium flavum sp. nov. and Microbacterium lacus sp. nov., isolated from marine environments.

Abstract

Strains YM18-098^T and A5E-52^T were both Gram-positive, aerobic, irregular rod-shaped bacteria, with lysine and ornithine as the diagnostic diamino acids of their peptidoglycans, respectively. The acyl type of the peptidoglycan in both cases was N-glycolyl. The major menaquinones were MK-11, -12 and -13. Mycolic acids were not detected. The G+C content of the DNA was 69–70 mol%. Comparative 16S rRNA studies revealed that the isolates belonged to the genus Microbacterium, that YM18-098^T was closely related to the species Microbacterium lacticum and Microbacterium schleiferi, and that A5E-52^T was closely related to the species Microbacterium aurum, Microbacterium aoyamense, Microbacterium deminutum and Microbacterium pumilum. DNA-DNA relatedness analysis showed that the isolated strains represented two separate genomic species. Based on both phenotypic and genotypic data, the following new species of the genus Microbacterium are proposed: Microbacterium flavum sp. nov. and Microbacterium lacus sp. nov., with the type strains YM18-098^T (= MBIC08278^T, DSM 18909^T) and A5E-52^T (= MBIC08279^T, DSM 18910^T), respectively.