Solirubrobacter ginsenosidimutans sp. nov., isolated from soil of a ginseng field

A Gram-reaction-positive, non-motile, non-spore-forming, aerobic rod, designated BXN5-15(T), was isolated from the soil of a ginseng field on Baekdu Mountain in China. Strain BXN5-15(T) grew optimally at 30 °C and pH 6.0-7.0 in the absence of NaCl on R2A agar. Strain BXN5-15(T) displayed β-glucosidase activity, which allowed it to transform ginsenoside Rb(1) (one of the dominant active components of ginseng) via Rd to minor ginsenoside F(2). On the basis of 16S rRNA gene sequence analysis, strain BXN5-15(T) was shown to belong to the genus Solirubrobacter. The closest phylogenetic relatives were Solirubrobacter soli Gsoil 355(T) (98.4 % 16S rRNA gene sequence similarity) and Solirubrobacter pauli B33D1(T) (96.4 %). Lower sequence similarities (<96.0 %) were found with all of the other recognized members of the order Solirubrobacterales. The predominant quinone was MK-7(H(4)). The major fatty acids (>10 %) were C(18 : 1)ω9c, iso-C(16 : 0) and C(18 : 3)ω6,9,12c. The G+C content of the genomic DNA was 70.6 mol%. DNA-DNA relatedness between strain BXN5-15(T) and S. soli KCTC 12628(T) was 23.3 %. On the basis of genotypic, phenotypic and chemotaxonomic data, strain BXN5-15(T) represents a novel species within the genus Solirubrobacter, for which the name Solirubrobacter ginsenosidimutans sp. nov. is proposed. The type strain is BXN5-15(T) ( = KACC 20671(T) = LMG 24459(T)).