The temperature and pH optima, and the temperature and pH stability, of crude and purified enzymes of the cellulase complex of the cellulolytic ascomycete fungus Neurospora crassa were investigated. The effects of some non-ionic surfactants and fatty acids on the production/release of enzymes of the cellulase complex were also examined. For the different enzymes of the complex, activity maxima occurred between pH 4·0 and 7·0, with pH 5·0 being close to optimal for stability of all. Temperature optima for activity ranged between 45 and 65 °C, with the stability optimum between 45 and 50 °C. The presence of C18 fatty acids and surfactants resulted in increased production of both endoglucanase and exoglucanase in the medium. Oleic acid was the most effective fatty acid tested, and Tween 80 the most effective surfactant. Oleic acid had no detectable effect on production of β-glucosidase, and Tween 80 actually reduced its production.
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