PRODUCTION OF EXTRACELLULAR ENZYMES BY TRICHODERMA REESEI M-7 ON MIXTURES OF LACTOSE AND GLUCOSE AT DIFFERENT TEMPERATURES.
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Publication date: 2002-03-31
Pol. J. Food Nutr. Sci. 2002;52(1):23-29
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ABSTRACT
Continuous cultivation of Trichoderma reesei M-7 mutant was performed at different temperatures (26, 30 and 34°C) with 1% lactose or glucose alone or a total of 1% mixtures of both sugars at different ratio. The secretion of individual enzymes was affected by the ratio of cellulase inducer (lactose) to the repressor (glucose). The ratio of enzyme secretions was additionally modified by the temperature of cultivations. An insignificant increase of nonspecific activity of cellulases (FPU) and significant increase of aryl-b-glucosidase activity were observed at 26 °C with lactose/ glucose ratio of 3:1 and 1:1. However, when cultivated both at 30 or 34°C, the cellulolytic activities (FPU) increased significantly in the presence of 1 % glucose alone. The activity of xylanases increased significantly (about 8-fold) with lactose/glucose ratio of 1: 1 at 30°C. The increased synthesis of lytic enzymes ( proteases, b-1,3-glucanases ) correlated with increased glucose concentration in the feeding medium and this effect potentiated at 34°C of cultivation.