Porphyrobacter donghaensis sp. nov., isolated from sea water of the East Sea in Korea

Abstract

Two Gram-negative, motile, non-spore-forming, bacteriochlorophyll a-containing slightly halophilic strains, SW-132T and SW-158, were isolated from sea water of the East Sea in Korea, and subjected to a polyphasic taxonomic study. The two isolates were characterized chemotaxonomically as having Q-10 as the predominant respiratory lipoquinone and major amounts of unsaturated fatty acids C18:1ω7c and C17:1ω6c. The DNA G+C contents of the two strains were in the range 66.8-65.9 mol%. The 16S rRNA gene sequences of strains SW-132T and SW-158 were 99.9 % (1 nt difference) similar and their mean level of DNA-DNA relatedness was 86 %. The 16S rRNA gene sequence analysis showed that strains SW-132T and SW-158 are phylogenetically closely related to Porphyrobacter species and Erythromicrobium ramosum. Similarities between the 16S rRNA gene sequences of strains SW-132T and SW-158 and the type strains of Porphyrobacter species and E. ramosum ranged from 97.8 to 99.0 %. DNA-DNA relatedness data indicated that strains SW-132T and SW-158 are members of a genomic species that is separate from the four Porphyrobacter species. On the basis of phenotypic and phylogenetic data and genetic distinctiveness, strains SW-132T (=KCTC 12229T = DSM 16220T) and SW-158 (= KCTC 12230) are classified as a novel Porphyrobacter species, for which the name Porphyrobacter donghaensis sp. nov. is proposed.