Pedobacter kyungheensis sp. nov., with ginsenoside converting activity

Abstract

The Gram-negative, aerobic, non-motile, non-spore forming, and rod-shaped bacterium designated as THG-T17(T) was isolated from the soil of a ginseng field of Pocheon in Korea, and its taxonomic position was investigated by using a polyphasic approach. The growth of strain THG-T17(T) occurred at 4-40°C and pH 4.0-9.0 with 1-2% (w/v) NaCl on nutrient agar. Strain THG-T17(T) displayed β-glucosidase activity that was responsible for its ability to transform ginsenoside Rb(1) (one of the dominant ginsenosides of ginseng) to compound F2 via gypenoside XVII. On the basis of 16S rRNA gene sequence similarity, strain THG-T17(T) was shown to belong to the genus Pedobacter and was related to Pedobacter soli 15-51(T) (98.8%), Pedobacter sandarakinus DS-27(T) (98.0%) and Pedobacter terrae DS-57(T) (98.1%). The G+C content of the genomic DNA was 42.4 mol%. The DNA-DNA relatedness values between strain THG-T17(T) and its phylogenetically closest neighbors were below 14%. Phenotypic and chemotaxonomic data, especially analysis of cellular fatty acid, supported the affiliation of strain THG-T17(T) to the genus Pedobacter. The results of genotyping and biochemical tests showed strain THG-T17(T) to be differentiated genotypically and phenotypically from the recognized species of the genus Pedobacter. Therefore, the novel isolate represents a novel species, for which the name Pedobacter kyungheensis sp. nov. is proposed, with the type strain THG-T17(T) (=KACC 16221(T) = LMG 26577(T)).