Polysaccharides extraction from submerged-cultured mycelium of Grifola frondosa

Alkaline (NaOH) hydrolysis and aqueous extraction method were comparatively studied in polysaccharides extraction from mycelia of Grifola frondosa obtained with submerged-culture. The results show that the polysaccharide content and the total extract rate from alkaline extraction method were obviously higher than those from the aqueous extraction method. The conditions of alkaline extraction were further optimized by the orthogonal matrix method, and the results reveal that the optimum extraction conditions were as follows: ratio of alkaline volume to mycelium weight was 15 (mL/g), alkaline concentration was 1.0 mol/L, hydrolysis temperature was 70°C, and hydrolysis time was 1.5 hour. With the optimized condition, the polysaccharide extraction rate reached 11.18 ± 0.37 %. The mycelial polysaccharide obtained with alkaline hydrolysis method was fractionated by the DEAE column chromatography. Four G. frondosa polysaccharide (GFPS) fractions were isolated in the polysaccharide sample with GFPS-1 as the main component.