Optimization of Liquid Culture Method and Antioxidant Activity Analysis of Ntracellular Polysaccharides for 2 Wild Auricularia Strains

This research investigates the optimal liquid fermentation incubation conditions and the antioxidant activity of intracellular polysaccharides in the mycelium of 2 wild Auricularia strains. In this study, 2 wild Auricularia strains were used as test strains, the liquid fermentation culture technique was used to develop single factor tests and orthogonal tests to screen the best liquid fermentation method and simultaneously to determine the in vitro antioxidant activity of its intracellular polysaccharide. The findings revealed that the optimized fermentation conditions were as follows: glucose(2.0%), peptone(0.3%), KH₂PO₄(0.1%), potato 20.0% and initial pH 7.0. After 6 days of incubation under the above conditions, the dry weight of wild Jingjiang′s black fungus mycelium was 1.04 g/150 mL, and the semi-scavenging rates of hydroxyl radical, superoxide anion radical and DPPH radical were 0.67, 0.43 and 0.40 mg, respectively. After 10 days of incubation, the dry weight of wild Auricularia polytricha mycelium was 1.26 g/150 mL, and the semi-scavenging rates of hydroxyl radical, superoxide anion radical and DPPH radical were 0.75, 0.42 mg/ mL and 0.39 mg/ mL, respectively. Optimized fermentation conditions could increase the mycelia biomass of the 2 wild Auricularia species, and the intracellular polysaccharides of the tested mycelia had certain antioxidant activity.