Abstract

A Gram-negative, non-motile, non-spore-forming, small, orange, rod-shaped bacterium was isolated from soil in South Korea and characterized to determine its taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequence examination revealed that strain PB323T belongs to the family Sphingomonadaceae. The highest degree of sequence similarity was found with Sphingomonas kaistensis PB56T (98.9%), followed by Sphingomonas astaxanthinifaciens TDMA-17T (98.3%). Chemotaxonomic characteristics (the G+C content of the genomic DNA 69.0 mol%, Q-10 quinone system, C18:1ω7c/ω9t/ω12t, C16:1ω7c/C15:0 iso 2OH, C17:1ω6c, and C16:0 as the major fatty acids) corroborated assignment of strain PB323T to the genus Sphingomonas. Results of physiological and biochemical tests clearly demonstrate that strain PB323T represents a distinct species and support its affiliation with the genus Sphingomonas. Based on these data, PB323T (=KCTC 12341T =JCM 16603T =KEMB 9004-003T) should be classified as a type strain of a novel species, for which the name Sphingomonas humi sp. nov. is proposed.

• Keywords: taxonomy; 16S rRNA gene; S. humi