Characterization of Sulfitobacter sediminivivens sp. nov., A Novel Halotolerant, Nitrogen-Assimilating Bacterium from Tidal Flat Sediment.

A novel halotolerant bacterial strain, designated MF3-043, was isolated from marine sediment collected at the Gunsan tidal flat, South Korea. The strain was characterized as a Gram-negative, aerobic, non-motile, oval-shaped rod bacterium that exhibited catalase and oxidase-positive activities. Colonies were circular, convex, and cream-white in color. The strain was able to grow at temperatures ranging from 4 to 30 °C (optimum, 25 °C), within a pH range of 6.0-9.0 (optimum, pH 7.0), and in the presence of 1-8% (w/v) NaCl (optimum, 2%). Phylogenetic analysis based on 16S rRNA gene sequences revealed the highest sequence similarity to Sulfitobacter mediterraneus KCTC 32188 (97.8%), Sulfitobacter marinus SW-265 (97.7%), Roseobacter fucihabitans B14 (97.6%), Sulfitobacter noctilucae NB-68 (97.4%), and Sulfitobacter indolifex HEL-45 (97.4%), confirming its affiliation with the genus Sulfitobacter. The genomic DNA G + C content was 56.5%. Ubiquinone-10 (Q-10) was the predominant respiratory quinone, and summed feature 8 (Cω7c) was the major fatty acid. Polar lipids included phosphatidylglycerol (PG), phosphatidylcholine (PC), diphosphatidylglycerol (DPG), one aminolipid, one phospholipid, and several unidentified lipids. The genome sequencing and digital DNA-DNA hybridization (dDDH) analyses further supported its distinction from closely related species. Based on a polyphasic taxonomic approach, strain MF3-043 is proposed as a novel species of the genus Sulfitobacter, named Sulfitobacter sediminivivens sp. nov. The type strain is MF3-043 (= KCTC 8706 = TBRC 19386).