Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs13568-017-0524-9/MediaObjects/13568_2017_524_Fig1_HTML.gif)
Optimization of a the concentration of total protopanaxadiol (PPD)-type ginsenosides in ginseng root extract as substrates; b the concentration of the β-glycosidase from Dictyoglomus turgidum (DT-bgl) as an enzyme for 20(S)-protopanaxadiol (APPD) production; and c the time-course reactions for the production of APPD from PPD-type ginsenosides in ginseng root extract by DT-bgl alone under the optimal conditions. Data represent the means of three experiments and error bars represent the standard deviation