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S. HAYASHIDA and K. OHTA Kyokai No. 7, maintained on slopes of koji extract agar medium, was inoculated into 100ml of basal synthetic medium3) in a 250 ml flask. After 40 hr-incubation at 30•Ž under anaerobic culture conditions,3) about 1 ml of yast culture was again transferred to 100 ml of fresh basal synthetic medium and further incubated for 40 hr at 30•Ž.

Mutation experiments were performed to decrease the protease productivity of Aspergillus awamori var. kawachi using ultraviolet light and TV-methyl-TV'-nitro-TV-nitrosoguanidine. The selected mutant HF-15 showed reductions in protease productivity of 93%, 84% and 50% in solid wheat bran culture, shaking MediumB and wheat bran cultures, respectively, as compared with the parent. Protease-less mutant HF-15 failed to produce a-mannosidase, and iV-acetyl-/?-Dglucosaminidase productivity decreased by 35%. Mutant HF-15 specifically produced a high amount of raw starch-adsorbable and raw starch-digestive glucoamylase similar to GAI under all tested cultural conditions. Onthe contrary, high protease-producing mutant HF-10 produced a glucoamylase with very limited adsorption and digestion capacity on raw corn starch, and lower hydrolysis toward gelatinized potato starch and glycogen that was similar to GAV.

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Strain YH-50 from a thermophilic fungus isolated from compost heaps produced the highest amount of thermostable xylanase among 1 80 isolates tested. This xylanase-producing strain YH-50 was identified as Talaromyces byssochlamydoides Stolk & Samson by taxonomical characteristics. Whenit was cultivated in solid wheat bran mediumcontaining xylan as an additive carbon source, the maximalamount of thermostable xylanase was produced after 3 days at 50°C. This culture filtrate hydrolyzed 90%ofxylan as xylose, and the sugars formed were xylose, arabinose, glucose and galactose. The optimal pH and temperature were 5.5 and 70°C, respectively. The enzyme was quite stable after heating at 65°C for 5 min and retained 55% of original activity after heating at 95°C for 5 min. Wehave been considered that thermophilic fungi are useful for the production of industrial enzyme because of the rapid growth and prevention of comtamination. Enzymes responsible for the decomposition of plant materials, i.e., xellulase,1* /?-glucosidase,2)3)