Sphingobacterium cavernae sp. nov., a novel bacterium isolated from soil sampled at Tiandong Cave

A Gram-stain-negative, non-motile and rod-shaped bacterium, designated strain 5.0403-2 T , was isolated from a cave soil sample collected from Tiandong Cave, Guizhou Province, south-west PR China. Cells showed positive oxidase and catalase reactions. The predominant isoprenoid quinone was MK-7. The major fatty acids were identified as iso-C 15 : 0 , summed feature 3 (C 16 : 1  ω7 c and/or C 16 : 1  ω6 c ), iso-C 17 : 0 3OH and summed feature 9 (iso-C 17 : 1  ω9 c or C 16 : 0 10-methyl). The cellular polar lipids contained phosphatidylethanolamine, one unidentified phospholipid, three unidentified phosphoglycolipids and four unidentified lipids. The genomic DNA G+C content was 36.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 5.0403-2 T should be assigned to the genus Sphingobacterium . Results of 16S rRNA gene sequence similarity analysis showed that strain 5.0403-2 T was most similar to Sphingobacterium bovisgrunnientis KCTC 52685 T (98.7 %), Sphingobacterium composti KCTC 12578 T (98.0 %) and Sphingobacterium alimentarium DSM 22362 T (97.3 %) and less than 95.0 % similar to other species of the genus Sphingobacterium . The average nucleotide identity values between strain 5.0403-2 T and S. bovisgrunnientis KCTC 52685 T , S. composti KCTC 12578 T and S. alimentarium DSM 22362 T were 94.2, 82.3 and 77.2 % respectively. The digitalDNA–DNA hybridization values between strain 5.0403-2 T and S. bovisgrunnientis KCTC 52685 T , S. composti KCTC 12578 T and S. alimentarium DSM 22362 T were 68.4, 25.6 and 20.7 %. These results indicated that the isolate represented a novel genomic species. The polyphasic taxonomic characteristics indicated that strain 5.0304-2 T represents a novel species of the genus Sphingobacterium , for which the name Sphingobacterium cavernae sp. nov. (type strain 5.0403–2 T =KCTC 62981 T =CCTCC AB 2019257 T ) is proposed.