Carotenoid-Producing Paracoccus aurantius sp. nov., Isolated from the West Coast of Dokdo Island, Republic of Korea.

In this study, a novel species within the genus Paracoccus was isolated from the coastal soil of Dokdo (Seodo) Island and investigated. We elucidated the novel species, designated MBLB3053(T), through genomic analysis of novel functional microbial resources. Cells were gram-negative, non-motile, and coccoid, and the colony was light orange in color. Phylogenetic analysis based on the 16S rRNA gene showed that strain MBLB3053(T) was related to the genus Paracoccus, with 98.5% similarity to Paracoccus aestuariivivens. Comparative genome analysis also revealed the strain to be a novel species of the genus Paracoccus by average nucleotide identity and in silico DNA-DNA hybridization values. Through secondary metabolite analysis, terpene biosynthetic gene clusters associated with carotenoid biosynthesis were found in strain MBLB3053(T). Using high-performance liquid chromatography, strain MBLB3053(T) was confirmed to produce carotenoids, including all-trans-astaxanthin, by comparison to the standard compound. Notably, the isolate was also confirmed to produce carotenoids that other closely related species did not produce. Based on this comprehensive polyphasic taxonomy, strain MBLB3053(T) represents a novel species within the genus Paracoccus, for which the name Paracoccus aurantius sp. nov is proposed. The type strain was MBL3053(T) (=KCTC 8269(T) =JCM 36634(T)). These findings support the research and resource value of this novel species, which was isolated from the Dokdo environmental microbiome.