Nocardiopsis algeriensis sp. nov., an alkalitolerant actinomycete isolated from Saharan soil.

ABSTRACT

An alkalitolerant actinomycete strain, designated B32(T), was isolated from a Saharan soil sample collected from Adrar province (South of Algeria), and then investigated using a polyphasic taxonomic approach. The strain was observed to produce short chains of spores on the dichotomous branched aerial mycelium and formed a fragmented substrate mycelium. The optimum NaCl concentration for growth was found to be 0-5 % (w/v) and the optimum growth temperature and pH were found to be 25-35 °C and 7.0-10.0 °C, respectively. The diagnostic diamino acid in the cell-wall peptidoglycan was identified as meso-diaminopimelic acid. The predominant menaquinones of strain B32(T) were identified as MK-10 (H4) and MK-11 (H4). The major fatty acids were found to be iso-C160 and anteiso-C150. The diagnostic phospholipids detected were phosphatidylcholine, phosphatidylmethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The chemotaxonomic properties of strain B32(T) are consistent with those shared by members of the genus Nocardiopsis. 16S rRNA gene sequence analysis indicated that strain B32(T) is most closely related to Nocardiopsis alba DSM 43377(T) (98.7 %), Nocardiopsis lucentensis DSM 44048(T) (98.6 %), Nocardiopsis aegyptia DSM 44442(T) (98.6 %), Nocardiopsis sinuspersici HM6(T) (98.6 %) and Nocardiopsis arvandica HM7(T) (98.5 %). However, the DNA-DNA relatedness values between strain B32(T) and the closely related type strains were 17.9, 14.6, 31.1, 27.1 and 14.1 %, respectively. Based on the combined genotypic and phenotypic evidence, it is proposed that strain B32(T) should be classified as representative of a novel species, for which the name Nocardiopsis algeriensis sp. nov. is proposed. The type strain is B32(T) (=DSM 45462(T) = CECT 8712(T)).