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 B1T, was isolated from deep-sea sediment collected from the South Atlantic Ocean. Cells of strain B1T 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 B1T shared high similarity with respect to Maribacter orientalis DSM 16471T (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 B1T 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 B1T and M. orientalis DSM 16471T were 72.0 % and 17.6 %, respectively. Strain B1T 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, B1T represents a novel species of the genus Maribacter, for which the name Maribacter cobaltidurans sp. nov. is proposed. The type strain is B1T (=CGMCC 1.15508T=KCTC 52882T=MCCC 1K03318T).