Fig 1.
The chemical structural formula of ginsenosides.
Glc, β-D-glucopyranosyl; arap, α-L-arabinopyranosyl; xyl, β-D-xylopyranosyl; araf, α-L-arabinofuranosyl; rha, α-L-rhamncpyranosyl; Gyp, gypenoside; C, compound.
Fig 2.
Screening of strains biotransformed GE into CK.
A: Geniposide was hydrolyzed to genipin by β-glucosidase; B: Colonies on the plate without glucosidase activity (a), colonies with a blue circle had a higher β-glucosidase activity (b); C: Comparison the ability of strains to biotransform GE into CK. Values are means ± SD of three replications; D: HPLC profiles of ginsenosides in ginsenosides standard, GE, and GE fermented with JE0512.
Fig 3.
UPLC-Q-TOF-MS analysis of the fermented sample of JE0512.
A: Total ion current chromatograms of CK standard; B: Total ion current chromatograms of JE0512 fermentation sample; C: Mass spectrum of CK standard; D: Mass spectrogram of JE0512 fermentation sample; E: The chemical structural formula of CK.
Fig 4.
Identification of strain JE0512.
A: Colony morphology of the isolate JE0512 grown at 25°C on PDA. B: Phylogenetic analysis of the related species of the strain JE0512 using the neighbor-joining approach. The scale bars represent 0.002 substitutions per site. The tree was constructed using a neighbor-joining method with bootstrap values of 1000 replications.
Fig 5.
Optimization of main SSF process parameters for maximum CK content and β-glucosidase activity.
A: Effect of the solid-state fermentation substrate (20 g); B: Effect of inoculation volume (%); C: Effect of the amount of ginseng extracts (g); D: Effect of fermentation period (d). Values are shown as means ± SD of three replications. A one-way ANOVA was used to assess the statistical significance of the differences in expression levels. Different letters (a-e) indicate significant differences between each other (P < 0.05).
Table 1.
The changes in ginsenosides content under different fermentation methods.