Structural characterization, antioxidant and hypolipidemic activity of Grifola frondosa polysaccharides in novel submerged cultivation

Rice bran and wheat bran are high-yield but low-utilization agricultural by-products in China. Rice and wheat brans were used as substrates of fermentation by Grifola frondosa JSULY2020 strains. Two novel intracellular polysaccharides (GFP-W1 and GFP-W2) and one exopolysaccharides (EP-X1) were obtained following purification. GFP-W1 (Mw 9.161 × 105 Da), GFP-W2 (Mw 2.733 × 107 Da), and EP-X1 (Mw 2.564 × 104 Da) were composed of arabinose, fucose, xylose, mannose, glucose and galactose. GFP-W1 and GFP-W2 comprised mainly glucose, while EP-X1 was mainly arabinose. All three polysaccharides exhibited remarkable antioxidant activity and hypolipidemic ability. This study demonstrates that rice and wheat brans are feasible fermentation substrates for the production of polysaccharides from G. frondosa, and these polysaccharides could be a promising ingredient for health-beneficial functional foods.