Nocardiopsis oceanisediminis sp. nov., a Marine-Derived Actinobacterium Isolated from Sediment

Strain CNT-189^Τ, previously isolated from marine sediment and identified as an androsamide producer, was taxonomically characterized in this study. Strain CNT-189^Τ is a Gram-stain-positive, non-motile, pale yellow-pigmented, aerobic actinomycete. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CNT-189^Τ belonged to the genus Nocardiopsis and was most closely related to Nocardiopsis potens DSM 45234^Τ (99.6% similarity). Whole-genome sequencing revealed a DNA G + C content of 74.1% and genome size of 7.12 Mbp. Average nucleotide identity (92.8-95.1%) and digital DNA-DNA hybridization values (45.9-55.4%) between strain CNT-189^Τ and related species were below the species delineation thresholds, supporting its classification as a novel species. The major respiratory quinone was menaquinone-10 (MK-10) and the predominant cellular fatty acids were C_18:1 ω9c (25.0%), C_16:0 (13.5%), and anteiso-C_15:0 (12.7%). Major polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylmonomethylethanolamine, phosphatidylinositol mannoside, and monomannosyl diglyceride. Whole-cell hydrolysates contained meso-diaminopimelic acid, glycine, and no diagnostic sugars. Based on phylogenetic and phenotypic evidence, strain CNT-189^T is considered to represent a novel species of the genus Nocardiopsis, for which the name Nocardiopsis oceanisediminis sp. nov. is proposed. The type strain is CNT-189^Τ (= KACC 22136^Τ = NBRC 114760^Τ).