Microbacterium salsuginis sp. nov., a halotolerant actinobacterium with antimicrobial activity

A novel Gram-staining-positive actinobacterium with antimicrobial activity, designated CFH 90308 T , was isolated from the sediment of a salt lake in Yuncheng, Shanxi, south-western China. The isolate exhibited the highest 16S rRNA gene sequence similarities to Microbacterium yannicii G72 T , Microbacterium hominis NBRC 15708 T and Microbacterium xylanilyticum S3-E T (98.5, 98.4 and 98.2 %, respectively), and formed a separate clade with M. xylanilyticum S3-E T in phylogenetic trees. The strain grew at 15–40 ºC, pH 6.0–8.0 and could tolerate NaCl up to a concentration of 15 % (w/v). The whole genome of strain CFH 90308 T consisted of 4.33 Mbp and the DNA G+C content was 69.6 mol%. The acyl type of the peptidoglycan was glycolyl and the whole-cell sugars were galactose and mannose. The cell-wall peptidoglycan mainly contained alanine, glycine and lysine. The menaquinones of strain CFH 90308 T were MK-12, MK-13 and MK-11. Strain CFH 90308 T contained anteiso-C 15:0 , anteiso-C 17:0 , iso-C 16:0 and iso-C 15:0 as the predominant fatty acids. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between CFH 90308 T and the other species of the genus Microbacterium were found to be low (ANIb <81.3 %, dDDH <25.6 %). The secondary metabolite produced by strain CFH 90308 T showed antibacterial activities against Bacillus subtilis , Pseudomonas syringae , Aeromonas hydrophila and methicillin-resistant Staphylococcus aureus . Based on genotypic, phenotypic and chemotaxonomic results, the isolate is considered to represent a novel species of the genus Microbacterium , for which the name Microbacterium salsuginis sp. nov . is proposed. The type strain is CFH 90308 T (=DSM 105964 T =KCTC 49052 T ).