Biotransformation of the total flavonoid extract of epimedium into icaritin by two thermostable glycosidases from Dictyoglomus thermophilum DSM3960

The thermostable GH78 family α-L-rhamnosidase DthRha from Dictyoglomus thermophilum DSM3960 was found to have the ability to remove the α-L-rhamnose moiety that was directly linked to the aglycone by an α-1-rhamnosidic bond at the C-3 position of epimedium flavonoids. It exhibited high specific activity on p-nitrophenyl-α-L-rhamnopyranoside (pNPR) (281.06 U/mg), followed by epimedin C (30.42 U/mg), icariin (9.74 U/mg), baohuoside I (1.02 U/mg)...