Saxeibacter lacteus gen. nov., sp. nov., an actinobacterium isolated from rock

A Gram-positive, cream-coloured, non-motile, rod-shaped actinomycete, designated DLS-10T, was isolated from a rock collected on the peak of Darangshi Oreum (a small mountain 300 m above sea level) in Jeju, Republic of Korea. The temperature and pH ranges for growth were 4-37 degrees C and pH 5.1-9.1. The organism grew at NaCl concentrations up to 3 % and had the following chemotaxonomic characteristics: meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan, the polar lipids included diphosphatidylglycerol, phosphatidylmethylethanolamine and two unknown phospholipids, the major menaquinone was MK-8(H4) and the major fatty acids were anteiso-C15 : 0, C16 : 0, iso-C16 : 0 and anteiso-C17 : 0. The DNA G+C content was 74.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the organism was related to members of the family Nakamurellaceae in the suborder Frankineae. The most closely related described organisms were the type strains of Humicoccus flavidus (97.1 % sequence similarity) and Nakamurella multipartita (95.2 %). On the basis of the morphological, cultural, physiological, chemotaxonomic and phylogenetic evidence presented here, the organism represents a novel genus and species of the family Nakamurellaceae, for which the name Saxeibacter lacteus gen. nov., sp. nov. is proposed. The type strain of Saxeibacter lacteus is DLS-10T (=KCTC 19285T =DSM 19367T).