Lentisphaera marina sp. nov., and emended description of the genus Lentisphaera

Two Gram-stain-negative, non-motile, non-pigmented cocci, designated IMCC11369(T) and IMCC11389, were isolated from surface seawater of the East Sea of Korea by high-throughput cultivation based on dilution to extinction. Strains IMCC11369(T) and IMCC11389 shared 99.9 % 16S rRNA gene sequence similarity and >86.3 % DNA-DNA relatedness, which suggested that they belong to the same genomic species. The isolates were most closely related to Lentisphaera araneosa HTCC2155(T) (99.0 % 16S rRNA gene sequence similarity). Phylogenetic analysis revealed that the isolates formed a robust cluster with L. araneosa HTCC2155(T). DNA-DNA relatedness values, however, showed that the isolates were distantly related to L. araneosa HTCC2155(T) (2.0-18.6 %), which suggested that they represent a separate genomic species in the genus Lentisphaera. The two isolates were phenotypically differentiated from their closest relative by several characteristics, including degradation of macromolecules and carbon source utilization. The DNA G+C content was 44.5-45.2 mol% and the predominant cellular fatty acids were C14 : 0, C16 : 1ω9c and C16 : 0. Strain IMCC11369(T) contained MK-7 as the respiratory quinone and phosphatidylethanolamine and an unknown lipid as the major polar lipids. On the basis of data obtained in this study, a novel species is proposed to accommodate the isolates, Lentisphaera marina sp. nov. The type strain is IMCC11369(T) ( = KCTC 23780(T) = NBRC 108776(T)).