Abstract: Optimization experiments showed that potato glucose medium was the optimal medium for sugar production by Thelephora ganbajun Zang, and using this medium, the mycelial yield and mycelial polysaccharide yield were 7.56 and 0.42 g/L, respectively. Plackett-Burman design and response surface methodology were used to optimize the ultrasonicassisted extraction of T. ganbajun Zang polysaccharides. Ultrasonic power, irradiation time and alcohol precipitation fold were found to be significant factors affecting the polysaccharide yield and their optimal levels were 400 W, 10 min and 3, respectively, which resulted in maximum polysaccharide yield of 6.98%. The results of in vitro antioxidant tests showed that the polysaccharides had a strong antioxidant capacity, and hydrolysis with enzymes (cellulase and snailase) or acid (sulfuric acid) could significantly enhance the antioxidant capacity of the polysaccharides. Monosaccharide composition analysis by stepwise acid hydrolysis combined with pre-column derivatization high performance liquid chromatography showed that the terminal residues of branches of the polysaccharides were composed of galactose as well as a small amount of mannose; galactose was mostly distributed on the outer side and at the end of the branches; glucose was the main monosaccharide component, and it was mainly distributed in the main chain and the inside of the branches; mannose was mainly distributed inside the branches. This study lays a theoretical foundation for the application of enzymatic hydrolysis and acid hydrolysis on polysaccharides and the exploitation and utilization of T. ganbajun Zang polysaccharides.

Key words: Thelephora ganbajun Zang, mycelial polysaccharide, extraction process, acid hydrolysis, enzymatic hydrolysis, antioxidant activity