Nocardioides eburneus sp. nov., isolated from commercial soil

A novel bacterial strain, designated DS6^T, was isolated from the commercial soil for biofertilization and characterized as a novel species within the Actinomycetota phylum. The morphological and biochemical analysis revealed that strain DS6^T is a Gram-positive, rod-shaped bacterium with pili, forming ivory colonies on R2A agar after 3 days of incubation at 25 °C. The strain shows a broad growth pH range of 4-9, with an optimum pH of 8, and can tolerate temperatures between 20 and 45 °C, optimally growing at 37 °C. Salinity tolerance ranges from 0% to 5%, with optimal growth occurring at 0-1%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain DS6^T is closely related to Nocardioides marinus KCCM 4231^T (96.4%), Nocardioides panaciterrulae KCTC 19471^T (96.3%), Nocardioides gansuensis KCTC 49117^T (96.3%) and Nocardioides ginkgobilobae KCTC 39594^T (96.2%). Biochemical tests showed that the strain is oxidase negative and catalase positive. The major fatty acids were C_16 : 0 iso (26.85%) and C_18 : 0 10-methyl (15.9%). The major respiratory quinone was MK-8 (H4) and the strain contained ll-2,6-diaminopimelic acid as the cell-wall diamino acid. The major polar lipids consist of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phospholipids, phosphatidylinositolmannosides and unknown lipids. The DNA G+C mol% of genomic DNA is 71.3. Based on its distinct phylogenetic, phenotypic and biochemical characteristics, strain DS6^T is proposed to represent a novel species of the genus Nocardioides, for which the name Nocardioides eburneus sp. nov. is proposed. The type strain is DS6^T (KEMB 22008^T=KCTC 59264^T=JCM 37205^T).