Production, structure, and bioactivity of polysaccharide isolated from Tremella fuciformis XY

Tremella fuciformis polysaccharide (TFP) is an important bioactive substance in Tremella, that contributes to its use as medicine and food. In this study, a novel fungus Tremella fuciformis XY was isolated and introduced to produce macromolecule polysaccharides (TFPB). The fermentation conditions were optimized and results demonstrates that the initial pH, optimal temperature and liquid volume were 6.0, 26 °C and 80 mL in a 500 mL flask, respectively. The maximum yield of TFPB was 9.05 ± 0.05 g/L, which is 59.05% higher than the basic yield (5.69 ± 0.02 g/L). The TFPB, purified by DEAE column, had a molecular weight (Mw) of 1.14 × 10³ kDa and consisted mainly of mannose, glucuronic acid, glucose, galactose, xylose, and rhamnose at a molar ratio of 3.5:1.2:2:1.6:1.4:3. The structure of TFPB was preliminarily investigated by methylation analysis, infrared spectroscopy, and nuclear magnetic resonance analysis. The main linkage types were identified as 1,4-xylp, 1,4-manp, 1-xylp, 1-manp, 1,4-glcp, and 1,3,4-galp. Moreover, the antioxidant assays showed that TFPB could scavenge reactive oxygen species and hydroxyl radicals.