The fungus Schizophyllum commune (NBRC6504) exhibited high protease activity and an optimal pH of acidic-neutral. The mycelia of S. commune grew vigorously in kelp stock and ground kelp containing high carbohydrate levels. The medium showing the highest concentration of total free amino acids was ground kelp and dried bonito (1:1) (fermented at 20% concentration for 8 weeks). In addition, the sample exhibited high concentrations of aspartic and glutamic acids upon fermentation. Therefore, using fungal fermentation, we were able to produce seasoning materials using kelp and dried bonito by-products typically discarded as industrial waste.

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An extracellular protease in Isaria cicadae extracted from a liquid culture with wheat bran was purified and characterized. This mushroom showed two morphologies on agar plates: mycelia with and without conidia. High enzyme activity was detected in the culture filtrate extract of the mycelia with conidia. The enzyme was purified 13-fold with a yield of 33% using CM-Sepharose column chromatography. Electrophoretic analysis of the purified enzyme showed a single band. The molecular mass of the enzyme was 30.6 kDa by SDS-PAGE and 31 kDa by gel filtration. The N-terminal amino acid sequence of the protease was AFTTQPGAVW. The optimum temperature and pH were 55℃ and 9.0, respectively. The enzyme was stable in the pH range 4 to 7. The Km value for the hydrolysis of casein was 0.48mg/mL. The enzyme activity was strongly inhibited by phenylmethylsulfonyl fluoride. From the results, it is suggested that the enzyme is a serine protease.

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The purpose of this study was to evaluate the safety of Grifola gargal fruit body. Items for the safety assessment test were toxicity and mutagenicity. In 30-day and 100-day subchronic toxicity studies of G. gargal fruit body dry powder (GFD), all animals gained weight No changes attributable to GFD treatment in these subchronic toxicity studies were observed in overall condition or hematological parameters. No adverse effects or mortality were observed during these toxicity test periods. Additionally, the mutagenicity of the extracts from GFD was evaluated by a preincubation method using a modified Ames test. There was no mutagenicity of GFD extract (up to 5,000μg/plate) towards the two tested strains (TA98 and TA100), with or without metabolic activation (S9). These findings suggest that the fruit body of G. gargal was not toxic under these measurement conditions.

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We aimed to produce high concentrations of heme iron by Schizophyllum commune NBRC6504 fermentation of powdered dark red flesh of dried bonito, characterized by its high heme iron content. Iron concentrations in products fermented for nine week by S. commune were analyzed by atomic absorption spectrophotometry. We found that the concentrations of non-heme and heme iron in the fermented products were significantly higher than those in the materials. High concentrations of iron were recovered from the powdered material by the fermentation ability of S. commune. This is the first report detailing that high concentrations of heme iron are able to be obtained from powdered dark red flesh of dried bonito by basidiomycete fermentation.

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