In order to improve the extraction rate and activity of Sanghuangporus sanghuang polysaccharide,the fermentation process of fermented S. sanghuang polysaccharide (SSP-F) was optimized,and its structure was characterized and antioxidant activities were evaluated.The fermentation conditions were optimized based on single factors and response surface experiments using Linqing S. sanghuang as the research material,Saccharomyces cerevisiae as the fermentation strain,and the extraction rate of SSP-F as the response value.The structure was characterized by high-performance anion exchange chromatography-pulsed amperometric detection,Fourier transform infrared spectroscopy,scanning electron microscopy,and X-diffraction.Furthermore,the radical-scavenging activities of SSP-F were investigated.The results showed the optimal fermentation conditions were as follows:fermentation time 30.3 h,inoculum amount 9.3%,pH 7.0. Under the optimal conditions,the rate of SSP-F was 3.30%,which was 41.03% higher than that of water extracted S. sanghuang polysaccharide (SSP-W) (2.34%). Both SSP-W and SSP-F had the pyran ring as their basic backbone,and both of them were composed of four monosaccharides,including fucose,glucosamine,glucose,mannose,but their molar ratios were significantly different.In addition,the hydroxyl radical-scavenging rate,reducing power,and ABTS+ radical-scavenging rate of SSP-F were higher than those of SSP-W. The results would provide a scientific basis for the rational development and deep processing of S. sanghuang resources.

Sanghuangporus sanghuang polysaccharide;Saccharomyces cerevisiae;process optimization;structural characterization, antioxidant activity