The effect of trehalose on the heat tolerance of Lentinula edodes vegetative raycelia was examined. After heat stress (39℃, 48 h), initial mycelial growth was observed on 5 % trehalose medium 7 days after inoculation. However, mycelia cultured on PDA medium did not revive until 10 days after inoculation. The trehalose content of the mycelia increased in parallel with that of the culture medium. Moreover, the intracellular trehalose levels in the vegetative mycelia were effectively increased by soaking in trehalose solution. The trehalose content increased with soaking period and reached a maximum of approximately 300 mg/g dry mycelia after soaking in 1.0 M trehalose solution for 3 days. Scanning electron microscopy revealed that the mycelia that had grown on trehalose-supplemented medium after incubation at 39℃ for 48 h were more dense and expanded than those grown without trehalose. These results indicate that trehalose functions to protect vegetative mycelia of L. edodes against heat treatment.

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In order to test the fruiting body production of Panellus serotinus, we prepared various sawdust-rice bran media in which the size of sawdust particle of Fagus crenata (0.25-1.0mm and 1.0-2.0mm in diameter), sawdust-to-rice bran ratio (10:1 to 10:3), and moisture contents (55-70%) were varied. It was determined that optimal temperature for fruiting of P. serotinus was at 10℃ when the spawn running was performed for 90 days at 23℃. High moisture content and high rice bran content of the media tended to increase the number of watery fruiting bodies. It appeared that the medium composed with small sawdust particle, 10:3 of sawdust-to-rice bran ratio, and 65% of moisture content was suitable for the cultivation of this mushroom. The CO_2 content and the air ratio against the medium volume in the plastic bag at 90 days of the mycelium incubation (the timing of fruiting treatment) was 3.1-3.3% and 34-46%, respectively.

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Aroma components produced by Laetiporus sulphureus, an alcohol fermentable mushroom, was examined. Laetiporus sulphureus produced peach-like aroma in the malt extract medium during mycelial cultivation. The aroma components were extracted from culture filtrate by steam distillation and organic solvent extraction, and the components were analyzed by gas chromatography and mass spectrometry. The extract contained about twenty components. The four major compounds were ydecalactone, y-octalactone, non-identified compound B (m/z:41, 55, 111, 132) and γ-dodecen-6-lactone, and their contents were 46.33%, 7.58%, 4.08% and 1.98%, respectively.

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Effects of mineral salts, vitamins, nucleic acid relating substances and phytohormones on the vegetative growth of Sparassis crispa were investigated using a synthetic liquid medium. The vegetative mycelium did not grow in the absence of KH_2PO_4 and MgSO_4. The mycelial yield was decreased by omission of ZnSO_4, FeSO_4, CuSO_4, CaCl_2 and MnSO_4. The vegetative mycelium did not grow in the absence of thiamine, but each of the other vitamins, nucleic acid relating substance in the liquid medium did not show any special effect on vegetative growth. Adding of phytohormones into the basal medium decreased the mycelial yield.

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