Mucilaginibacter ginsenosidivorans sp. nov., Isolated from Soil of Ginseng Field

A Gram-reaction-negative, aerobic, nonmotile, nonspore-forming, and rod-shaped bacterial strain designated Gsoil 3017^T was isolated from soil of ginseng field and investigated by phenotypic and phylogenetic analyses. Strain Gsoil 3017^T grew at 10-37 °C (optimal growth at 30 °C) and at pH 5.5-8.0 (optimal growth at pH 7) on R2A and nutrient agar without additional NaCl as a supplement. Strain Gsoil 3017^T possessed β-glucosidase activity, which was responsible for its ability to transform ginsenosides Rb₁, Rc, and Rd (the three dominant active components of ginseng) to F₂ and C-K, respectively. Based on 16S rRNA gene phylogeny, the novel strain represents a new branch within the genus Mucilaginibacter family Sphingobacteriaceae, and clusters with Mucilaginibacter frigoritolerans FT22^T (95.6%) and Mucilaginibacter gotjawali SA3-7^T (95.6%). The G+C content of the genomic DNA was 48.7%. The predominant respiratory quinone was MK-7, and the major fatty acids were iso-C_15:0, iso-C_17:0 3-OH, and summed feature 3 (comprising C_16:1 ω6c and/or C_16:1 ω7c). The major polar lipid was phosphatidylethanolamine. Strain Gsoil 3017^T could be differentiated genotypically and phenotypically from other type strains of the genus Mucilaginibacter. The isolate therefore represents a novel species, for which the name Mucilaginibacter ginsenosidivorans sp. nov. is proposed, with the type strain Gsoil 3017^T (=KACC 14954^T = JCM 17081^T).