Sphingobacterium ginsenosidimutans sp. nov., a bacterium with ginsenoside-converting activity isolated from the soil of a ginseng field

[摘要] A Gram-staining-negative, aerobic, non-motile, non-spore-forming, and rod-shaped bacterium designated THG 07T was isolated from the soil of a ginseng field of Pocheon in South Korea, and its taxonomic position was investigated by using a polyphasic study. Strain THG 07T grew optimally at 25−30°C and at pH 6.5−7.0 and in the absence of NaCl on nutrient agar. Strain THG-T17T displayed β-glucosidase activity that was responsible for its ability to transform ginsenoside Rb1 (one of the dominant ginsenosides of ginseng) to compound C-K. On the basis of 16S rRNA gene sequence similarity, strain THG 07T was shown to belong to the family Sphingobacteriaceae and was related to Sphingobacterium canadense CR11T (98.7%), S. cladoniae No.6T (98.1%), S. detergens 6.2ST (98.0%), S. multivorum IAM14316T (97.9%), S. siyangense SY1T (97.8%) and S. thalpophilum DSM11723T (96.9%). The G+C content of the genomic DNA was 40.6 mol%. The major menaquinone, MK-7, and major fatty acids, iso-C15:0 and C16:1 ω7c and/or ω6c, supported the affiliation of strain THG 07T to the genus Sphingobacterium. The DNA-DNA relatedness values between strain THG 07T and its closest phylogenetic neighbors were below 26.9%. The results of physiological and biochemical tests enabled strain THG 07T to be differentiated phenotypically from the recognized species of the genus Sphingobacterium. Therefore the isolate represents a novel species, for which the name Sphingobacterium ginsenosidimutans sp. nov. is proposed, with the type strain THG 07T (=KACC 14526T=JCM 16722T).

[学科分类] 微生物学和免疫学

[关键词] compound K;polyphasic taxonomy;Sphingobacterium ginsenosidimutans;16S rRNA gene