Mitochondrial DNA (mtDNA) restriction fragment length polymorphisms (RFLPs) in 32 Naematoloma sublateritium wild strains collected from 11 different prefectures of Japan were assayed to examine the genetic variability in the natural population. Each of the 32 wild strains produced its own unique mtDNA RFLP pattern by digestion with EcoRI and EcoRV. Based on the sum of the restriction fragments, the estimated molecular size of N. sublateritium mtDNAs ranged from 53.4 to 84.4kb (average, 69.3kb). Distance values, which were calculated between all pairs of mtDNA phenotypes, were larger than those of Lentinula edodes, Pleurotus ostreatus and Pholiota nameko from Japan, suggesting that high mtDNA variability is maintained in the natural population of N. sublateritium of Japan. A dendrogram based on mtDNA RFLPs suggests that there is little or no correlation between geographical distribution and mtDNA phenotype.

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Production of useful phenolic compounds from plant biomass was studied using Schizophyllum commune. In softwood (akamatsu; Pinus densiflora) powder culture, vanillin and vanillic acid were detected after autoclaving and their amounts increased by the action of S. commune. The amounts of phenolic compounds released from hardwood (buna; Fagus crenata) powder culture were about one-tenth of those from softwood powder culture. In rice straw powder culture, only syringic acid was formed during incubation but at a low level. Using rice bran as the substrate, large quantities of ferulic and p-coumaric acids were released most likely through the action of corresponding esterases produced by S. commune. Based on these results, characteristic phenolic products to the substrate were obtained by fermentation of plant biomass using S. commune, which appears to have any specificity in substrate metabolism.

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Grifola gargal Singer is naturally found only in limited areas of Chile and Argentina in South America. It is an edible mushroom with a characteristic almond flavor. The aim of this study was to select suitable strains of G. gargal for commercial mushroom production, among 13 strains (IWADE-GG000 to GG012) previously collected in Chile, by comparing their fruit body formation using beech (Fagus crenata) wood meal medium. Five strains (GG007, GG006, GG008, GG010 and GG000) showed greater mycelial growth rate than other strains and formed normal colonies on agar medium. Of these, three strains (GG010, GG006 and GG000) also grew faster in beech wood meal medium and formed fruit bodies. GG010 and GG006 were found to be the most suitable strains for cultivation in beech wood meal medium based on their yield, shape and mushroom color. This is the first report on cultivation of G. gargal in sawdust medium for commercial mushroom production.

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Reutilization of waste substrate of Pholiota nameko and Flammulina velutipes for sawdust based cultivation of Hericium erinaceum was investigated. When waste substrate of P. nameko was used as a substitution of beech sawdust, as the substitution ratio of waste substrate increased, the yield of fruit body of H. erinaceum significantly increased. The yield of fruit body on aging waste substrate of P. nameko at 25℃ for a week significantly increased and that on aging waste substrate for four weeks decreased compared with that on the fresh waste substrate. When waste substrate of F. velutipes was used as a substitution of beech sawdust, as the substitution ratio of waste substrate increased, the yield of fruit body of H. erinaceum significantly decreased and showed the least at 100% substitution. The yield of fruit body on aging waste substrate of F. velutipes for three weeks compared with that on the fresh waste substrate significantly increased and showed 85% yield of beech sawdust substrate. These suggested that waste substrate of P. nameko would be useful as a substrate for sawdust based cultivation of H. erinaceum and that of F. velutipes would be useful, when it was aged for more than 3 weeks.

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