Microbacterium halotolerans sp. nov., isolated from a saline soil in the west of China

Abstract

A Gram-positive short rod isolated from a saline soil in China was characterized using a polyphasic approach. This actinobacterium grew over a wide salinity range [0-15% NaCl, 0-20% KCl and 0-30% MgCl2.6H2O (w/v); optimum concentrations for growth were 5% NaCl, 5-10% KCl, 10% MgCl2.6H2O]. The optimum growth temperature and pH were 28-30°C and 7.0-8.0, respectively. Chemotaxonomic features (peptidoglycan-type B2β with glycolyl residues; major menaquinones MK-10 and MK-11; predominating iso- and anteiso-branched cellular fatty acids; DNA G+C content 66.5 mol%) placed this organism within the genus Microbacterium. 16S rRNA gene sequence analysis confirmed this classification of the strain, but showed that it was distinct from its nearest neighbours. It formed a separate branch with type strains of the genus Microbacterium, and also shared low sequence similarity with them (<96%). Based on phenotypic and molecular taxonomic results, it is proposed that the unknown isolate should be classified as a novel species in the genus Microbacterium, for which the name Microbacterium halotolerans sp. nov. is proposed. The type strain is YIM 70130T (=KCTC 19017T=CIP 108071T).