Extraction of mycelial polysaccharides from submerged-cultured cordyceps militaris (a caterpillar fungus)

Cordyceps militaris, a kind of caterpillar fungus, has therapeutic effects including immunoregulative, anticancer, antibacterial and antifungal effects. Aqueous extraction and alkaline (NaOH) hydrolysis method were comparatively studied in polysaccharides extraction from submerged-cultured C. militaris mycelia. The results indicate that the polysaccharide content and the total extract rate from alkaline extraction method were obviously higher than those from the aqueous extraction method. The extraction process parameters of alkaline extraction were further optimized using response surface methodology (RSM), and a mathematical model was then developed to show the effect of each extraction condition and their interactions on the polysaccharide extraction. The model predicted the optimum alkaline concentration was 1.6 mol/L, extraction temperature 56.7 □, extraction time 1.94, and the extraction rate was 11.57%. Furthermore, verification of the calculated optimum of the model was done with a condition representing this maximum point and obtaining a extraction rate of 11.12 %. The good correlation between predicted and measured values of these experiments justifies the validity of the response model and the existence of an optimum point.