A novel carotenoid-producing bacterium, Paenibacillus roseopurpureus sp. nov., isolated from Korean marine mud.

A novel bacterial strain, designated MBLB1832, was isolated from marine mud in Uljin, Republic of Korea. The strain was Gram-stain-positive, endospore-forming, and exhibited rod-shaped morphology. It grew at temperatures ranging from 10 to 45 °C (optimum 30 °C), at pH 6.0-9.0 (optimum 7.0), and in the presence of 0-2% NaCl (optimum 0%). Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain MBLB1832 is closely related to Paenibacillus allorhizoplanae JJ-42, with 98.3% similarity. The predominant fatty acids were anteiso-C and iso-C, and menaquinone-7 was identified as major isoprenoid quinone. Strain MBLB1832 contained meso-diaminopimelic acid within the cell wall peptidoglycan. Polar lipid profiling indicated the presence of diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine as the major lipids. The genome of strain MBLB1832 is 5.8 Mb in size with a G + C content of 46.9%. Average nucleotide identity, average amino acid identity, and DNA-DNA hybridization values confirmed that this strain is distinct from previously described species. Genome analysis revealed the presence of a complete C carotenoid biosynthetic pathway, including genes encoding farnesyl diphosphate synthase, diapophytoene synthase, several diapophytoene desaturases, and distinct carotenoid glycosyltransferases and acyltransferases. Notably, the carotenoid pigments produced by the strain imparted a pink color, consistent with the coloration of its cell pellets. Based on these polyphasic taxonomic data, strain MBLB1832 is proposed as a novel species of the genus Paenibacillus, for which the name Paenibacillus roseopurpureus sp. nov. is suggested (type strain MBLB1832 = KCTC 43262 = JCM 34221).