Genomic and Physiological Characterization of Metabacillus flavus sp. nov., a Novel Carotenoid-Producing Bacilli Isolated from Korean Marine Mud.

The newly isolated strain KIGAM252 T was found to be facultatively anaerobic, Gram-stain-positive, spore-forming, and rod-shaped. They grew at 10-45 °C, pH 6.0-10.0, and were able to tolerate up to 6% NaCl in the growth medium. Phylogenetic analysis indicated that the KIGAM252 T strain was related to the genus Metabacillus . The cell membrane fatty acid composition of strain KIGAM252 T included C 15:0 anteiso and C 15:0 iso (25.6%) as the major fatty acids, and menaquinone 7 was the predominant isoprenoid quinone. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The size of the whole genome was 4.30 Mbp, and the G + C content of the DNA was 43.8%. Average nucleotide and amino acid identity and in silico DNA-DNA hybridization values were below the species delineation threshold. Pan-genomic analysis revealed that 15.8% of all genes present in strain KIGAM252 T was unique to the strain. The analysis of the secondary biosynthetic pathway predicted the carotenoid synthetic gene cluster in the strain KIGAM252 T . Based on these current polyphasic taxonomic data, strain KIGAM252 T represents a novel species of the genus Metabacillus that produces carotenoids, for which we propose the name Metabacillus flavus sp. nov. The type of strain was KIGAM252 T (=KCTC 43261 T = JCM 34406 T ).