Maribellus mangrovi sp. nov., an iron-reducing bacterium isolated from mangrove sediment

A novel facultatively anaerobic and Gram-stain-negative bacterium, designated FJH33^T, was isolated from mangrove sediment sampled in Zhangzhou, PR China. Cells of strain FJH33^T were rod-shaped or slightly curved-shaped, with widths of 0.3-0.5 µm and lengths of 1.0-3.0 µm. Optimum growth of strain FJH33^T occurred in the presence of 3 % NaCl (w/v), at 33 °C and at pH 7.0. Oxidase activity was negative, while catalase activity was positive. Its iron-reducing ability was determined. Based on 16S rRNA gene sequence similarity, strain FJH33^T was most closely related to Maribellus luteus XSD2^T (95.1 %), followed by Maribellus sediminis Y2-1-60^T (95.0 %) and Maribellus maritimus 5E3^T (94.9 %). Genome analysis of strains FJH33^T and M. luteus XSD2^T revealed low genome relatedness, with an average nucleotide identity value of 73.8% and a digital DNA-DNA hybridization value of 19.0%. Phylogenetic trees built from 16S rRNA genes and genome sequences showed that strain FJH33^T represents a relatively independent phylogenetic lineage within the genus Maribellus. The major cellular fatty acids (≥10 %) were iso-C_15 : 0 and C_18 : 1  ω9c. The sole respiratory quinone was MK-7. The polar lipids consisted of phosphatidylethanolamine, diphosphatidylcholine, diphosphatidyglycerol and one unidentified lipid. The DNA G+C content was 41.4 mol%. Based on the integrated results of phylogenetic, physiological, biochemical and chemotaxonomic characterizations, we propose that strain FJH33^T represents a novel species of the genus Maribellus, for which the name Maribellus mangrovi sp. nov. is proposed. The type strain is FJH33^T (=KCTC 102210^T=MCCC 1H01459^T).