Nocardiopsis mwathae sp. nov., isolated from the haloalkaline Lake Elmenteita in the African Rift Valley

During a screening for novel and biotechnologically useful bacteria in haloalkaline lakes, strain No.156ᵀ was isolated from a sediment sample from lake Elmenteita in the African Rift Valley and studied by a polyphasic taxonomic approach. The strain was observed to form yellow aerial and substrate mycelia; optimal growth was found to be at 30–35 °C in salt concentrations of 6–9 % (w/v) and at pH 7–9. The DNA G+C content of the novel strain was 71 mol%. Analysis of 16S rRNA sequences indicated that the isolate belongs to the genus Nocardiopsis with sequence similarities below 98 % to the type strains of all other representatives of the genus. Mycolic acids were not detected in whole cell methanolysates. The peptidoglycan was found to contain meso-diaminopimelic acid as the diamino acid with no diagnostic sugars. The main polar lipids were identified as phosphatidylmethylethanolamine, phosphatidylcholine, phosphatidylglycerol and phosphatidylinositol but no diphosphatidylglycerol. The predominant menaquinones were MK-11(H₈), MK-11(H₆), MK-10(H₈) and MK-10(H₆). Cellular fatty acids were found to consist of saturated and monounsaturated iso- and anteiso-branched acids with 16–18 C-length, tuberculostearic acid (Me18:0), and straight-chain saturated (16:0, 18:0) acids. These characteristics match those of the genus Nocardiopsis. Based on 16S rRNA gene sequence analysis and phenotypic characteristics, a novel species with the name Nocardiopsis mwathae is proposed. The type strain is No.156ᵀ (=DSM 46659ᵀ = CECT 8552ᵀ). The INSDC accession number for the 16S rRNA gene sequence of strain No.156ᵀ is KF976731.