Study On Cultivating Of Agaricus Blazei Murill With Old Stems Of Asparagus

The main aim of this paper is to study the cultivating technology of mushroom Agaricus blazei Murill (ABM) using old stems of asparagus as main substrate, and analyze the polysaccharide content and antioxidant activity of ABM fruit bodies. Shanxi Province currently owns the nation's largest production base of asparagus. After harvest season, there are nearly one million tons of the old stems which can not be used except for rotten naturally and burning directly. It causes a tremendous waste of resources. Therefore, cultivating ABM with old stems of asparagus can, on the one hand, enhance the value-added agricultural products and build ecological cycle of agricultural economic structure, in line with the trend of modern agriculture; on the other hand, can fill gaps in cultivation of rare edible fungus in Shanxi Province and promote the development of mushroom cultivation technology in this region.Firstly, stock culture mediums of ABM were screened and optimized, and different spawn mediums were compared; and then, different compost formulas corresponded to old stems of asparagus+auxiliary materials (such as cottonseed hull, corn cob, dried cow dung and wood chips) were designed. Two strains of ABM (i.e.BJ and AJ) were cultivated with these composts, maize straw compost served as the control. These composts were processed by outdoor composting and indoor second treatment, and then, were inoculated. After spawnrunning and casing, mushrooms were grown and harvested. Dried fruit bodies of ABM were used to determine the polysaccharides content and antioxidant activity. In this experiment, dilute alkali extraction process was used to extract the polysaccharide from ABM fruit bodies, and phenol-sulfuric acid method was used to determine the polysaccharide content. Four complementary assays (i.e.reducing power, radical scavenging capacity, inhibition of lipid peroxidation and chelating ability for ferrous ions) were used to screen the antioxidant activity of extracts. The main results of this work were following: The most suitable medium for strains AJ and BJ was bran agar medium. The best spawn medium was wheat grain medium. The optimal medium and culture condition of AJ inoculum were:bran 150g, sugar 50g, agar 20g, calcium carbonate 0.2g, potassium dihydrogen phosphate 0.2g, distilled water 1000mL, pH 7.0, temperature 24℃. The optimal medium and culture conditions of BJ inoculum were:bran 150g, soluble starch 25g, agar20g, magnesium sulfate 0.2g, potassium dihydrogen phosphate 0.2g, distilled water 1000mL, pH 6.0, temperature 26℃The mushroom yield of strain BJ was 35.4% higher than that of strain AJ. No significant differences were found in mushroom yields between asparagus old stem compost and corn stalk compost. Addition of appropriate amounts of cottonseed hull or dried cow dung increased the mushroom yield significantly higher as compared with wood chips and corn cobs. These results manifested that the asparagus old stem was suitable for cultivating ABM, and cottonseed hull and dried cow dung were more helpful to increase the yield than wood chips and corn cobs.No significant differences were found in the polysaccharide contents of the fruit bodies between two strains, but the antioxidant activity of BJ was significantly higher than that of AJ. The antioxidant activity fruit bodies cultivated on old stems of asparagus compost was significantly stronger than that on maize straw compost. But the polysaccharide content of fruiting bodies cultivated on maize straw compost was significantly higher. Among four auxiliary materials, cottonseed hull and corn cob were favorable to the synthesis of polysaccharide, and cottonseed hull was more conducive to fruit bodies antioxidant activity than other materials.