A novel actinomycete, strain HBU206404T, belonging to the genus Actinokineospora, was isolated from the lakeside soil of Baiyangdian, in China. Cells grew at 9-37 °C (optimum temperature, 28 °C) and pH 6-9 (optimum, pH 7). Meso-diaminopimelic acid was the diagnostic diamino acid of the cell-wall peptidoglycan, and sugars present in whole-cell hydrolysates were arabinose, mannose, glucose and galactose. The predominant menaquinone was MK-9(H4). The predominant cellular fatty acids (> 5%) of the strain HBU206404T were iso-C16:0 (21.5%), iso-C15:0 (20.3%), C16:1ω7c/C16:1ω6c and/or C16:1ω6c/C16:1ω7c (15.0%), iso-C17:0 (8.6%), C16:0 (7.0%) and C17:1ω8c (6.9%). The major polar lipids of the strain HBU206404T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, six unknown aminolipids, two unknown aminolipids and an unidentified lipid. The 16S rRNA gene sequence analysis indicated that the strain HBU206404T was most closely related to Actinokineospora alba KCTC 19294T (99.58%), but whole-genome comparisons, using average nucleotide identity (ANI) value (91.77%) and digital DNA-DNA hybridization (dDDH) value (60%), confirmed low genome relatedness. Nitrogen metabolism pathway was found in the genome of strain HBU206404T which haboured nitrate reductase and nitrite reductase. Other phenotypic characteristics, such as ability to hydrolyze substances, enzyme activity, acid production from carbon source, etc., could also distinguish strain HBU206404T from Actinokineospora alba KCTC 19294T. On the basis of genetic and phenotypic evidence, strain HBU206404T represents a novel species of the genus Actinokineospora, for which the name Actinokineospora xionganensis sp. nov. is proposed. The type strain is HBU206404T (= MCCC 1K04412T = KCTC 49404T).
Keywords: Actinomycetes; Baiyangdian; Lakeside soil; New species of Actinokineospora.