Biotransformation of saponins (such as ginseng saponins)
Techniques Dong-Shan An Uses:
Isolation, identification and taxonomic characteriation of bacteria
Cloning and characterization of bacterial glycosidase hydrolases
Biotransformation of ginsenosides using recombinant glycoside hydrolases
Dong-Shan An's Problem Solving Skills:
Development of ginsenoside-hydrolyzing glycoside hydrolases
Mass production of rare ginsenosides using recombinant enzymes
Dong-Shan An's Problem Solving Experience:
I have isolated more than 15 novel bacterial strains which convert major ginsenosides into rare ginsenosides from soil of ginseng farms during my Ph. D. course. Then I have isolated, purified and characterized the ginsenoside-hydrolyzing glycoside hydrolases from these isolates and their ginsenoside specificities and ginsenoside-hydrolyzing activities were investigated.
Among them, I have succeeded in cloning of two types of β-D-glucosidases (Bgl3054 and Bgl3082), and two types of α-L-arabinofuranosidases (Araf3054 and Araf3082) from the two bacterial strains, Rhodanobacter sp. Gsoil 3054 and Terrabacter sp. Gsoil3082 , respectively. Using these four recombinant enzymes, I can produce almost every ginsenoside metabolite from the PPD type ginsenosides, such as, gypenoside XVII and gypenoside LXXV from Rb1, C-O and C-Y from Rb2, C-Mx1 and C-Mx from Rb3, C-Mc1 and C-Mc from Rc, F2 and C-K from Rb1, Rb2, Rc and Rd, respectively.