Novosphingobium ginsenosidimutans sp nov., with the Ability to Convert Ginsenoside

Abstract

A Gram-negative, strictly aerobic, non-motile, non-spore-forming, and rod-shaped bacterial strain designated FW-6(T) was isolated from a freshwater sample and its taxonomic position was investigated by using a polyphasic approach. Strain FW-6(T) grew optimally at 10-42 degrees C and at pH 7.0 on nutrient and R2A agar. Strain FW-6(T) displayed beta-glucosidase activity, that was responsible for its ability to transform ginsenoside Rb-1 (one of the dominant active components of ginseng) to Rd. On the basis of 16S rRNA gene sequence similarity, strain FW-6(T) was shown to belong to the family Sphingomonadaceae and was related to Novosphingobium aromaticivorans DSM 12444(T) (98.1% sequence similarity) and N. subterraneum IFO 16086(T) (98.0%). The G+C content of the genomic DNA was 64.4%. The major menaquinone was Q-10 and the major fatty acids were summed feature 7 (comprising C-18:1 omega 9c/omega 12t/omega 7c), summed feature 4 (comprising C-16:1 omega 7c/iso-C-15:0 2OH), C-16:0, and C-14:0 2OH. DNA and chemotaxonomic data supported the affiliation of strain FW-6(T) to the genus Novosphingobium. Strain FW-6(T) could be differentiated genotypically and phenotypically from the recognized species of the genus Novosphingobium. The isolate that has ginsenoside converting ability therefore represents a novel species, for which the name Novosphingobium ginsenosidimutans sp. nov. is proposed, with the type strain FW-6(T) (= KACC 16615(T) = JCM 18202(T)).