Streptosporangium becharense sp. nov., an actinobacterium isolated from desert soil.

Abstract

The taxonomic position of a novel actinobacterium, strain SG1T, isolated from a Saharan soil sample collected from Béni-Abbès, Béchar (south-west Algeria), was established by using a polyphasic approach. The micro-organism had morphological and chemical features that were consistent with its classification in the genus Streptosporangium. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose and glucose, but not madurose. The predominant menaquinones were MK-9(H2) and MK-9(H4). The polar lipid profile contained diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylhydroxymethylethanolamine, phosphatidylhydroxyethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The predominant cellular fatty acids were C17 : 1ω8c, iso-C16 : 0, 10-methyl C17 : 0, C18 : 1ω9c and C17 : 0. 16S rRNA gene sequence similarity analysis supported the classification of the isolate in the genus Streptosporangium and indicated that it was related most closely to 'Streptosporangium subfuscum' DSM 46724 (99.7 % similarity), Streptosporangium pseudovulgare DSM 43181T (98.7 %), Streptosporangium fragile DSM 43847T (98.6 %) and Streptosporangium sandarakinum DSM 45763T (98.5 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SG1T formed a cluster with its closest relative 'S. subfuscum' DSM 46724. However, DNA-DNA relatedness as well as physiological and chemotaxonomical analyses showed that strain SG1T could be differentiated from its closest phylogenetic relatives. Therefore, it is proposed that strain SG1T should be classified as representing a novel species in the genus Streptosporangium, for which the name Streptosporangiumbecharense sp. nov. is proposed. The type strain is SG1T (=DSM 46887T=CECT 8961T).