Abstract:

Glycyrrhiza residues were used as substrates to conduct solid-state fermentation with Trametes versicolor, followed by the extraction of flavonoids from fermented glycyrrhiza residues. The purpose of this study was to investigate the use of onefactor- at-a-time and orthogonal array design methods to optimize the fermentation of glycyrrhiza residues by Trametes versicolor for the extraction of flavonoids. Fermentation by T. versicolor could significantly improve the yield of flavonoids. Fermentation temperature, water content in materials and fermentation time exhibited obvious effects on the yield of flavonoids. The optimal conditions for the fermentation of glycyrrhiza residues were determined as follows: with addition of 0.2 g/L ammonium tartrate as nitrogen source and water content in materials of 55%, fermentation for 3 days at 28 ℃. Under these optimal fermentation conditions, the yield of flavonoids reached up to 1.18%, which exhibited 90.32% improvement compared to direct ethanol extraction.

Key words: glycyrrhiza residues, Trametes versicolor, fermentation, flavonoids, extraction