Optimization of Liquid Fermentation Medium for Production of Inonotus sanghuang (Higher Basidiomycetes) Mycelia and Evaluation of their Mycochemical Contents and Antioxidant Activities.

Inonotus sanghuang, an authentic "Sanghuang" mushroom used in traditional Chinese medicine, is known to possess important pharmacological activities. In this study, we aimed to optimize the liquid fermentation medium for I. sanghuang mycelial production and to determine the effects of two-stage cultivation (shake and static) on the yield of total flavonoids, total phenolics, and polysaccharides, as well as the antioxidant activities of I. sanghuang mycelial extracts (ISME). Under an optimized medium composition (38.96 g/L of corn flour, 4.15 g/L of yeast extract, 20.55 g/L of bran and pH 6.39), the predicted and experimental optimal mycelial biomasses were 17.60 g/L and 18.33±0.86 g/L, respectively. The results of two-stage cultivation showed that contents of total flavonoids and total phenolics in mycelia increased by 37.92% and 77.27%, respectively. However, irregular polysaccharide contents were noted throughout the experimental period. Antioxidant assays showed that ISME possessed good free-radical scavenging activity, which is mainly contributed by polyphenolic-type metabolites.