Pseudobacter ginsenosidimutans gen. nov., sp. nov., isolated from ginseng cultivating soil

Abstract

A Gram-stain-negative, pseudo-rod, non-spore-forming, oxidase- and catalase-positive, strictly aerobic bacterium, designated Gsoil 221T, was isolated from soil of a ginseng field and subjected to a taxonomic analysis using a polyphasic approach. Strain Gsoil 221T grew at 10-37 °C and at pH 5.0-8.0 on R2A medium. Strain Gsoil 221T possessed β-glucosidase activity, which was responsible for its ability to transform ginsenosides Rb1 and Rc (two dominant active components of ginseng) to ginsenoside F2. Phylogenetic study based on the 16S rRNA gene sequence positioned strain Gsoil 221T in a distinct lineage in the family Chitinophagaceae, sharing less than 94.4 % 16S rRNA gene sequence similarity with all taxa with validly published names. The strain showed the highest sequence similarities with members of the genera Parasegetibacter,Flavitalea,Niastella and Terrimonas. Strain Gsoil 221T contained MK-7 as predominant quinone, and iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G as major fatty acids. The DNA G+C content was 47.1 mol%. Strain Gsoil 221T could be distinguished from the other members of the family Chitinophagaceae by a number of chemotaxonomic and phenotypic characteristics. The major polar lipids of strain Gsoil 221T were diphosphatidylglycerol, phosphatidylethanolamine and one unidentified polar lipid. Based on these combined data, strain Gsoil 221T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Pseudobacter ginsenosidimutans gen. nov., sp. nov. is proposed. The type strain of the type species is Gsoil 221T (=KACC 14278T=DSM 18116T).