In order to develop a novel variety of shiitake (Lentinula edodes), the progenies obtained by mass mating among the cultivated and wild strains with relatively high content of eritadenine, hypocholesterolemic substance, were subjected to a cultivation test on a saw-dust medium. As a result of the cultivation for screening, strain H44 was selected on the basis of eritadenine content and yield of fruit bodies. In addition, we found that eritadenine content is notably affected by temperature during the growth of fruit bodies, and then we developed a method for the cultivation of eritadenine-enriched shiitake with a five-fold content of eritadenine as compared with that of the normal shiitake. The hypocholesterolemic effect of the eritadenine-enriched shiitake thus obtained was investigated in relation to its influence on lipid metabolisms in rats. Dietary supplementation with eritadenine-enriched shiitake powder (473mg/100g) significantly decreased plasma total cholesterol in a dosedependent manner, where the minimum effective dose was found to be 0.05% in the basal diet. Rats were fed for 2 weeks on the basal diet containing 0.2% shiitake powders with different contents of eritadenine, (0, 107, 194, and 473mg/100g of shiitake powder) to clarify the relationship between eritadenine content and some parameters in lipid metabolism, which are affected by eritadenine. There were significant correlations between eritadenine content and SAM : SAH ratio, PC:PE ratio, or fatty acid composition, i.e., 20:4n-6/18:2n-6 ratio of PC in the liver, in addition to the plasma cholesterol concentration. Dietary supplementation with eritadenine-enriched shiitake powder (473 mg/100g) decreased the plasma total cholesterol and (VLDL+LDL)-cholesterol when rats were fed a diet containing 1% cholesterol, whereas shiitake powder of normal eritadenine content (107mg/100g) did not decrease the plasma cholesterol concentration. Abbreviations: HDL, high density lipoprotein; HPLC, high-performance liquid chromatography; LDL, low density lipoprotein; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PL, phospholipid; SAH, S-adenosylhomocysteine; SAM, Sadenosylmethione; TG, triglyceride; TLC, thin-layer chromatography; VLDL, very low density lipoprotein.
Fuscoporia obliqua is a parasite on birches such as the white birch (Betula platyphylla), which is classified into white rot fungi. The sclerotium of F. obliqua is called Charga in Russian, whose extract with boiling water has several kinds of physiological activities, inhibition of HIV-1 protease, antitumor activity and hypoglycemic effects on plasma glucose. We examined several nutritional requirements of liquid culture to obtain much mycelia of F. obliqua. The optimum initial pH of liquid culture was 4.5 and the mycelia had an ability to grow in the pH range from 3.0 to 6.5. Trehalose was better for the mycelial growth than the other nine kinds of carbon sources and yielded the most mycelia with 3.0% concentration. Organic nitrogen sources were more effective than inorganic ones in nine kinds of materials. The most mycelia were obtained with yeast extract, whose optimum concentration was 0.6%. In this study, the fundamental conditions for the mass culture of F. obliqua mycelia were established.
This study presents the cultivation of Pleurotus ostreatus using charcoal made from used paper. On crushed charcoal rice bran medium in a bottle, the yield of fruit bodies was greater than that on the Sugi sawdust rice bran medium. Moisture content of the medium had a greater influence on the yield of fruit bodies, the mycelial growth and days after fruiting induction than the carbonization temperatures or the charcoal size. These results suggest that charcoal made from used paper can be used for the cultivation substrate of P. ostreatus. In the cultivation using a solid charcoal, mycelia were accumulated into the medium. It was shown that cultivation with solid charcoal was possible, though the yield of fruit bodies was less than that in the sawdust medium.
The effects of water content in substrate on the degree of maturity and yields of fruiting body of Sugi sawdust bed were investigated using shiitake fungus. Effects of lignin addition to the medium on the yield of fruiting body were also examined. The colonization period was longer in Sugi sawdust bed than in Konara sawdust bed. In Sugi sawdust bed, however, the period decreased with the increase in water content. The brinell hardness on the surface of Konara sawdust bed increased with the increase in incubation period. On the other hand, the hardness on the surface of Sugi sawdust bed gradually increased up to 40 days of incubation, whereas it gradually decreased thereafter. The results obtained suggest that brinell hardness can be used as an indicator for evaluating the maturity degree of sawdust bed. The lignin addition to the sugi sawdust bed remarkably promoted the yields of shiitake fruiting body, although little yield of fruiting body was obtained in Sugi sawdust bed without lignin addition. These results suggest that certain compounds derived from degraded lignin are involved in shiitake fruiting body formation.
The cultivation of the edible mushroom, Pholiota adiposa in the Sugi (Cryptomeriajaponica) saw dust-based substrate containing Sugi saw dust, cotton hull, corncob meal and rice bran (Sccr) was investigated. The optimal temperature range for mycelial growth of P. adiposa wild strains was 20℃-30℃ and the optimal temperature was around 26℃. Growth did not occur at 40℃, and all but one strain named Oninome-B died after 5 days. The optimal initial pH value of the cultivation medium was around 6.5 and various initial pH values converged to 3.5-5.5 after cultivation. The C/N ratio and pH value of the Sugi saw dust-based substrate (Sccr) were suitable for mycelial growth and fruit body formation of P. adiposa. Adding cotton hull and corn-cob meal were effective to improve the water balance, decrease the C/N ratio and increase the pH value respectively. Packing 500g of the Sugi saw dustbased substrate (Sccr) into the Nameko bottle (800 ml), cultivating at 22.5℃ under dark conditions for about 10 weeks, germinating at 14℃ with over 95% RH and under around 700 Lux, a yield of over 150g of fruit bodies was attained by flushing twice. Although less than the Buna (Fagus crenata) saw dust-based substrate, the Sugi saw dust-based substrate is considered to be available for cultivating P. adiposa due to its low cost.