Abstract
In sawdust-based cultivation of edible mushrooms, it was determined that the types and composition ratios of substrates and nutrients in the sawdust-based medium have effects on the yield and quality of fruiting bodies. In particular, it was shown that industrial waste and underutilized biomass resources can be utilized as medium materials in sawdust-based cultivation. By mixing sawdust and soybean waste, which is discarded in large quantities in the manufacturing of processed soybean foods, with rice bran or wheat bran, the yield of fruiting bodies increased compared to rice bran or wheat bran alone. It is presumed that the complementary action of the nutritional environment in the sawdust-based medium was a factor. A similar attempt to cultivate Hiratake (Pleurotus ostreatus) on sawdust-based bed medium containing bean paste waste nutrient, produced in the manufacturing of processed azuki bean products, was not successful. However, the fruiting body yield increased by replacing the soft wood sawdust as the substrate of the medium with the azuki bean paste waste. In the cultivation of Enokitake (Flammulina velutipes), the content of the free amino acids alanine and glycine increased, which affected the components of fruiting bodies, allowing the cultivation of mushrooms with strong sweetness. This indicated that azuki bean paste waste is useful as a substrate. Yamabushitake (Hericium erinaceus) is a mushroom that can be grown on a wide selection of substrates in sawdust-based cultivation. Thus, I examined the applicability of the cultivation waste of several edible mushrooms for the cultivation of Yamabushitake. The cultivation waste of Shiitake (Lentinula edodes), Maitake (Grifola frondosa), Nameko (Pholiota microspora), and Bunashimeji (Hypsizygus marmoreus) could be used in place of beech sawdust. The fruiting body yields when cultivated with the above substrates were higher than that with beech sawdust. It was also found that the increase in yield was further promoted by composting the culture waste. It was found that the contents of free glucose, low-molecular a-glucan, and low-molecular b-glucan were increased in the cultivation medium containing the cultivation waste. Therefore, I investigated the effect of adding a polysaccharide-degrading enzyme instead of the cultivation waste at the time of medium preparation on fruiting body yield in cultivated Yamabushitake. Based on these results, a new cultivation method using a polysaccharide-degrading enzyme was described. As another example of an underutilized biomass, abandoned bamboo groves have become a social problem. Thus, to aid in the development of novel applications, I examined the use of bamboo as a material in the sawdust-based cultivation of Hiratake and showed that the yield on fresh bamboo sawdust was equal to or greater than that on hardwood sawdust. It was observed that the fruiting body yield was increased by composting bamboo sawdust, indicating that bamboo sawdust is applicable as a substrate for Hiratake sawdust-based cultivation.
