Salinactinospora qingdaonensis gen. nov., sp. nov., a halophilic actinomycete isolated from a salt pond

Abstract

A novel halophilic, filamentous, actinomycete strain, designated CXB832T, was isolated from a salt pond in Qingdao, China. Optimal growth occurred at 37 °C, pH 7.0–8.0 and 9–12 % (w/v) NaCl. Strain CXB832T formed pale yellow to deep yellow branched substrate mycelium without fragmentation. Abundant white aerial mycelium differentiated into long chains of spores and the spores were rod-shaped with smooth surfaces. Strain CXB832T contained meso-diaminopimelic acid as the diagnostic diamino acid of the cell-wall peptidoglycan, and glucose and xylose as the major whole-cell sugars. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipids, glycolipid and unidentified lipids. MK-10(H8), MK-9(H8), MK-10(H2) and MK-10(H6) were the predominant menaquinones. The major fatty acids were i-C16 : 0 (30.71 %), ai-C17 : 0 (13.31 %) and C16 : 0 (11.28 %). The G+C content of the DNA was 60.1 mol%. Comparative analysis of 16S rRNA gene sequences showed that the novel strain was most closely related to genera within the family Nocardiopsaceae , but formed a separate lineage. The highest sequence similarities were to Nocardiopsis arabia DSM 45083T (95.4 %) and Haloactinospora alba DSM 45015T (94.9 %). On the basis of phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain CXB832T represents a new genus and novel species in the family Nocardiopsaceae , for which the name Salinactinospora qingdaonensis gen. nov., sp. nov. is proposed. The type strain of the type species is CXB832T ( = DSM 45442T = LMG 25567T).