A Gram-stain-negative, facultatively aerobic bacterium, designated strain D1T, was isolated from soil in South Korea. Cells of strain D1T were non-motile rods with oxidase- and catalase-positive activities. Growth was observed at 15-40 °C (optimum, 30-37 °C), at pH 5.5-9.0 (optimum, pH 7.0-8.0) and in the presence of 0.0-5.0 % (w/v) NaCl (optimum, 0.0-1.0 %). The only respiratory quinone detected was menaquinone 7 (MK-7), and iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) were identified as the major fatty acids. Phosphatidylethanolamine was the major polar lipid, and two unidentified glycophospholipids and four unidentified lipids were also detected as minor polar lipids. Sphingolipids, a typical chemotaxonomic feature of the genus Sphingobacterium, were detected. The G+C content of the genomic DNA was 43.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain D1T formed a phyletic lineage with Sphingobacterium hotanense XH4T within the genus Sphingobacterium. Strain D1T was most closely related to S. hotanense XH4T (98.1 % 16S rRNA gene sequence similarity) and Sphingobacterium cellulitidis R-53603T (97.2 %), and the DNA-DNA relatedness level between strain D1T and the type strain of S. cellulitidis was 43.1±0.7 %. Based on the phenotypic, chemotaxonomic and molecular features, strain D1T clearly represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium humi sp. nov. is proposed. The type strain is D1T (=KACC 18595T=JCM 31225T).
Keywords: Bacteroidetes; Sphingobacterium humi; new taxa; species novel.