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

Abstract

A Gram-reaction-positive, non-motile, non-spore-forming, aerobic rod, designated BXN5-15T, was isolated from the soil of a ginseng field on Baekdu Mountain in China. Strain BXN5-15T grew optimally at 30 °C and pH 6.0–7.0 in the absence of NaCl on R2A agar. Strain BXN5-15T displayed β-glucosidase activity, which allowed it to transform ginsenoside Rb1 (one of the dominant active components of ginseng) via Rd to minor ginsenoside F2. On the basis of 16S rRNA gene sequence analysis, strain BXN5-15T was shown to belong to the genus Solirubrobacter. The closest phylogenetic relatives were Solirubrobacter soli Gsoil 355T (98.4 % 16S rRNA gene sequence similarity) and Solirubrobacter pauli B33D1T (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(H4). The major fatty acids (>10 %) were C18 : 1ω9c, iso-C16 : 0 and C18 : 3ω6,9,12c. The G+C content of the genomic DNA was 70.6 mol%. DNA−DNA relatedness between strain BXN5-15T and S. soli KCTC 12628T was 23.3 %. On the basis of genotypic, phenotypic and chemotaxonomic data, strain BXN5-15T represents a novel species within the genus Solirubrobacter, for which the name Solirubrobacter ginsenosidimutans sp. nov. is proposed. The type strain is BXN5-15T ( = KACC 20671T  = LMG 24459T).