Biological Characteristics and Domestication of Dichomitus squalens and the Antioxidant Activity of Its Cultivated Fruiting Bodies

Single-factor and orthogonal experiments were conducted to investigate the biological characteristics of <i>Dichomitus squalens</i> strains isolated from wild fruiting bodies collected in Tekes County, Xinjiang Uygur Autonomous Region. Building upon the optimal mycelial culture conditions identified, domestication cultivation studies were performed, including experiments to induce fruiting body formation. Liquid strains were inoculated into substrates to monitor developmental stages from primordia formation to mature fruiting bodies, with macroscopic characteristics recorded throughout the cultivation process. Crude polysaccharides were extracted from the cultivated fruiting bodies using the water extraction and ethanol precipitation method. The scavenging rates of these polysaccharides against hydroxyl radicals (OH^-) and superoxide anion radicals (O₂^-) were measured to evaluate their in vitro antioxidant activity. Results demonstrated that the optimal growth conditions for <i>D. squalens</i> were as follows: sucrose as the preferred carbon source, yeast extract powder as the optimal nitrogen source, a pH of 5.0, and a temperature of 30 °C. Among these factors, pH exerted the most significant influence on the mycelial growth rate, followed by nitrogen source, carbon source, and temperature. Mature fruiting bodies developed approximately 57 days after inoculation with liquid strains. The crude polysaccharide extraction yield from the cultivated fruiting bodies reached 7.07%, with a total polysaccharide content of 24.69% in the extract. The crude polysaccharides exhibited potent radical scavenging activity: at a concentration of 5.0 mg/mL, the hydroxyl radical scavenging rate was 56.74%, while the superoxide anion radical scavenging rate reached 78.3%. These findings indicate that <i>D. squalens</i> possesses significant antioxidant potential.