Diversity of cultivable β-glycosidase-producing micro-organisms isolated from the soil of a ginseng field and their ginsenosides-hydrolysing activity

This research aimed to explore the diversity of cultivable beta-glycosidase-producing micro-organisms in ginseng field soil. Fifty-three strains showing beta-glucosidase activity were isolated from a ginseng field, using a newly designed Esculin-R2A agar. All the isolated strains belonged to the genus Agrobacterium, Arthrobacter, Burkholderia, Dyella, Edaphobacter, Luteibacter, Mucilaginibacter, Paenibacillus, Phenylobacterium, Pseudomonas, Sphingomonas and Streptomyces. The main beta-glucosidase-producing micro-organisms in the ginseng field soil were Sphingomonas, Burkholderia, Luteibacter and Streptomyces, while concentrations of Agrobacterium, Arthrobacter, Paenibacillus and Pseudomonas were relatively low. Of these micro-organisms, the strain GS 09 could hydrolyse major ginsenosides Rb1, Rb2 and Rc to the active metabolite compound K. The strain GS 09 belonged to the genus Sphingomonas, and its 16S rRNA gene sequence showed 100% similarities with that of Sphingomonas asaccharolytica.