Rhodococcus oxybenzonivorans sp. nov., a benzophenone-3-degrading bacterium, isolated from stream sediment

A Gram-stain-positive, facultative aerobic, oxidase-negative, catalase-positive, non-sporulating, and non-motile bacterium, which degraded benzophenone-3, was isolated from stream sediment collected in the Republic of Korea and designated as strain S2-17^T. Cells of this strain were rod-shaped during the early growth phase but became coccoid after the late exponential growth phase. Bacterial growth was observed at 15-37 °C (optimum, 25-30 °C) and pH 6.0-9.5 (optimum, pH 7.5-8.5) and in the presence of 0-9.0 % (w/v) NaCl (optimum, 0-1.0 %). Menaquinone-8 (H₂) was the sole isoprenoid quinone, and C_16 : 0, C_17 : 1  ω8c, summed feature 3 (comprising C_16 : 1  ω7c/C_16 : 1  ω6c) and C_18 : 1  ω9c were the major fatty acids. The cell wall of strain S2-17^T contained meso-diaminopimelic acid, and arabinose, galactose and mycolic acid were found in whole-cell hydrolysates, suggesting a chemotype IV cell wall. The G+C content of the genome was 65.6 mol%. Phylogenetic analyses revealed that strain S2-17^T formed a phyletic lineage within the genus Rhodococcus and was most closely related to Rhodococcus jostii DSM 44719^T (99.2 % 16S rRNA gene sequence similarity). Average nucleotide identity and digital DNA-DNA hybridization values between strain S2-17^T and R. jostii DSM 44719^T were 82.6 and 26.5 %, respectively, indicating differences between the species. Based on its phenotypic, chemotaxonomic and molecular features, strain S2-17^T represents a novel species of the genus Rhodococcus, for which the name Rhodococcus oxybenzonivorans sp. nov. is proposed. The type strain is S2-17^T (=KACC 19281^T=JCM 32046^T).