Improvement of Baicalein and Wogonin Yields from Scutellaria baicalensis Georgi Roots Fermented by a Novel Endophytic Fungus Capable of Producing Cellulase and β-Glucosidase

Baicalein and wogonin, two health-promoting flavonoid aglycones in Scutellaria baicalensis Georgi roots, have better bioactivity and bioavailability than their glycoside precursors (baicalin and wogonoside). The search for novel microorganisms for the fermentation of S. baicalensis roots to improve the yields of baicalein and wogonin is of great interest in the food and nutraceutical industries. In this study, a novel endophytic fungus ( Penicillium rubens ) capable of producing cellulase (0.82 ± 0.12 U/mL) and β-glucosidase (4.55 ± 0.97 U/mL) was used to ferment S. baicalensis roots to obtain high yields of baicalein and wogonin. Semi-solid-state fermentation with homogeneous fungal cultures was found to be the appropriate strategy. Under the optimal fermentation parameters (temperature 30 °C, inoculation dose of fungal cultures 4 mL/g, and time 60 h), the yields of baicalein and wogonin (46.95 ± 4.98 mg/g DW and 31.41 ± 9.36 mg/g DW) from S. baicalensis roots were tremendously increased by 16.13-fold and 15.47-fold over control, respectively. Results of industrial enzyme bioprocessing and scanning electron microscope indicated that the remarkable increase in aglycone product yields could be due to the synergistic effects of cellulase and β-glucosidase produced by P. rubens on cell wall hydrolysis and glycoside deglycosylation. In addition, extracts of S. baicalensis roots fermented by P. rubens showed a significant increase in antioxidant and antimicrobial activities. Overall, the semi-solid-state fermentation of S. baicalensis roots using the novel P. rubens was an effective strategy that could yield high quantities of baicalein and wogonin, which had promising potential in the food and nutraceutical industries. Graphical Abstract