Study On Strain Screening And Optimization Of Culture Conditions In Cordyceps Militaris

Cordyceps militaris is a substitute of the Cordyceps sinensis. Because of the decreasing natural resources, the researches about its cultivation and application are taken into account at home and abroad.The cultivation Cordyceps M. fruit body and mycelium of liquid fermentation could be applied in food and medicinal diet safely, so it has huge market demand.The agricultural structure has been adjusted and the agricultural economic benefit has been raised through the Cordyceps M. cultivation.In this study, the artificial culture of Cordyceps M. fruit body is discussed.4 good strains are selected and its optimal condition of fruit body growth isobtained:the optimal temperature is 22℃, water content of the medium is 60%, range of pH is 5-7.The illumination intensity of fruit body differentiation should above 150 lx, the best illumination intensity is 500 lx and there is no undesirable impact in fruit body growth if the illumination intensity is over 3000 lx.The results of the liquid fermentation medium optimization and the active ingredient determination showed that the biomass increases 28.6% if the sucrose is carbon source, the exopolysaccharide increases 240% if the sucrose is corn starch and the intracellular polysaccharides increases 589.6% if the sucrose is bran. While if the nitrogen source is peptone, the biomass is 4.98 mg/mL,higher than normal's. If it is yeast extract, the exopolysaccharide increases 48.8%. If it is bran, the intracellular polysaccharides increases 296.4%. The optimal inorganic salt is ZnSO4+KH2PO4, the biomass,exopolysaccharide and the intracellular polysaccharide increase 18.5%,2.1%,176.8%, respectively. This study provides theoretical basis for improving the specific component content.The study of Cordyceps M. infected the silkworm showed that the 4th strain has the better infection ability. The silkworm roasted 2-4 h in the oven and injection method is more vulnerable to infection. Considering the nutrient component and medicinal value of silkworm, if baking would lose the nutrients of silkworm is still a question needing further study and discussion.This study artifical cultured Cordyceps M., infected silkworm and compared products in different fermentation. Analyzing the results and its reasons, the theoretical basis and practical basis were supplied to regulate and improve the Cordyceps M. fermentation and industrialization of artificial cultivation.