Vreelandella arctica sp. nov. and Vreelandella indica sp. nov., isolated from the Arctic Ocean and the Southwest Indian Ocean sediment.

Abstract

Four Gram-stain-negative bacterial strains which can metabolize alkanes and polycyclic aromatic hydrocarbons were isolated. Strains R06ZXJ2^T and R09ZXJ6 were isolated from sediments collected in the Arctic Ocean. Strains DY715-9^T and DY716-13-1 were isolated from surface sediment samples collected by the deep-sea TV grab in the southwestern Indian Ocean. Phylogenomic analyses based on 16S rRNA gene sequences, average nt identity (ANI) and digital DNA-DNA hybridization (dDDH) revealed that the strains formed two distinct lineages within the genus Vreelandella. Their closest relative was Vreelandella maris QX-1^T, with ANI values of 94.35% (R06ZXJ2^T) and 95.54% (DY715-9^T) and dDDH values of 57.00% and 61.80%, respectively. The pairwise ANI (95.47%) and dDDH (60.70%) between the two novel strains further supported their status as separate species. Phenotypic and chemotaxonomic analyses distinguished them from known Vreelandella species through differences in colony morphology, hydrocarbon degradation profiles and polar lipid compositions. The strains grew optimally at 28 °C and pH 7.0 and can degrade alkanes and polycyclic aromatic hydrocarbons. Based on these results, we propose two novel species: Vreelandella arctica sp. nov. (type strain R06ZXJ2^T=MCCC 1A08467^T=KCTC 92631^T) and Vreelandella indica sp. nov. (type strain DY715-9^T=MCCC 1A12469^T=KCTC 92628^T).