Micromonospora caldifontis sp. nov., isolated from hot spring soil.

A single spore forming actinomycete, designated strain HSS6-8, was isolated from a sample of hot spring soil. The strain had the chemotaxonomic properties consistent with its classification in the genus Micromonospora. The strain was found to have meso-diaminopimelic acid in the cell-wall peptidoglycan. The acyl type of the cell-wall muramic acid was glycolyl. The reducing sugars in the cell hydrolysates were glucose, arabinose, xylose, ribose, mannose, galactose and rhamnose. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphoglycolipid. The major menaquinones were MK-10(H6) and MK-10(H4). The major cellular fatty acids were iso-C16 : 0, anteiso-C17 : 0, C17 : 0 and anteiso-C15 : 0. The G+C content of the genomic DNA was 70.5 mol%. 16S rRNA gene sequence analysis revealed that strain HSS6-8 was closely related to Micromonospora nigra DSM 43818 (98.2 %), Micromonospora eburnea DSM 44814 (98.2 %) and Micromonospora spongicola S3-1 (98.1 %). The physiological and DNA-DNA hybridization data allowed the differentiation of strain HSS6-8 from its related species. Thus, the strain represents a novel species of the genus Micromonospora, for which the name Micromonospora caldifontis sp. nov. is proposed. The type strain is HSS6-8 (=TBRC 8927=JCM 17126).