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

ABSTRACT

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 S2-17T. 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 C16  0, C17  1 ω8c, summed feature 3 (comprising C16  1 ω7c/C16  1 ω6c) and C18  1 ω9c were the major fatty acids. The cell wall of strain S2-17T 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 S2-17T formed a phyletic lineage within the genus Rhodococcus and was most closely related to Rhodococcus jostii DSM 44719T (99.2 % 16S rRNA gene sequence similarity). Average nucleotide identity and digital DNA-DNA hybridization values between strain S2-17T and R. jostii DSM 44719T were 82.6 and 26.5 %, respectively, indicating differences between the species. Based on its phenotypic, chemotaxonomic and molecular features, strain S2-17T represents a novel species of the genus Rhodococcus, for which the name Rhodococcus oxybenzonivorans sp. nov. is proposed. The type strain is S2-17T (=KACC 19281T=JCM 32046T).