Ramlibacter ginsenosidimutans sp. nov., with ginsenoside-converting activity

Abstract

A novel β-proteobacterium, designated BXN5-27T, was isolated from soil of a ginseng field of Baekdu Mountain in China, and was characterized using a polyphasic approach. The strain was Gram-staining-negative, aerobic, motile, non-spore-forming, and rod shaped. Strain BXN5-27T exhibited β-glucosidase activity that was responsible for its ability to transform ginsenoside Rb1 (one of the dominant active components of ginseng) to compound Rd. Phylogenetic analysis based on 16S rRNA gene sequences showed that this strain belonged to the family Comamonadaceae; it was most closely related to Ramlibacter henchirensis TMB834T and Ramlibacter tataouinensis TTB310T (96.4% and 96.3% similarity, respectively). The G+C content of the genomic DNA was 68.1%. The major menaquinone was Q-8. The major fatty acids were C16:0, summed feature 4 (comprising C16:1 ω7c and/or iso-C15:0 2OH), and C17:0 cyclo. Genomic and chemotaxonomic data supported the affiliation of strain BXN5-27T to the genus Ramlibacter. However, physiological and biochemical tests differentiated it phenotypically from the other established species of Ramlibacter. Therefore, the isolate represents a novel species, for which the name Ramlibacter ginsenosidimutans sp. nov. is proposed, with the type strain being BXN5-27T (= DSM 23480T = LMG 24525T = KCTC 22276T).