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%. DNADNA relatedness between strain BXN5-15T 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 (5KACC 20671 ^T 5LMG 24459 ^T).