Maribacter cobaltidurans sp. nov., a heavy-metal-tolerant bacterium isolated from deep-sea sediment

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated B1^T, was isolated from deep-sea sediment collected from the South Atlantic Ocean. Cells of strain B1^T grew in medium containing 0.5-6.0 % (w/v) NaCl (optimum 1.0-2.0 %), at pH 5.5-7.5 (optimum pH 7.0) and at 15-37 °C (optimum 30 °C). Aesculin, starch and Tweens 20, 40 and 60 were hydrolysed. The strain was able to grow in medium containing a high concentration of Co²⁺ (10 mM). The 16S rRNA gene sequence of strain B1^T shared high similarity with respect to Maribacter orientalis DSM 16471^T (97.7 %), and exhibited less than 97.0 % sequence similarity with the type strains of other species with validly published names. Phylogenetic analyses revealed that strain B1^T fell within the cluster comprising Maribacter species and formed an independent lineage. The average nucleotide identity and in silico DNA-DNA hybridization values between strain B1^T and M. orientalis DSM 16471^T were 72.0 % and 17.6 %, respectively. Strain B1^T contained menaquinone 6 (MK-6) as the sole isoprenoid quinone and iso-C17 : 0 3-OH, iso-C15 : 0 and iso-C15 : 1 G as the predominant cellular fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The DNA G+C content was 39.7 mol%. According to the phylogenetic, chemotaxonomic and phenotypic data, B1^T represents a novel species of the genus Maribacter, for which the name Maribacter cobaltidurans sp. nov. is proposed. The type strain is B1^T (=CGMCC 1.15508^T=KCTC 52882^T=MCCC 1K03318^T).