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Appl Environ Microbiol. 1984 March; 47(3): 560-565
Copyright © 1984, American Society for Microbiology. All Rights Reserved.
Department of Biology, Nuclear Research Center "Demokritos," Aghia Paraskevi, Attiki, Greece
ABSTRACT
A mutant of Alternaria alternata excreted enhanced levels of carboxymethylcellulase and particularly ß-glucosidase when grown in cellulose liquid media. Both enzymes were purified two- to four-fold by ammonium sulfate precipitation and gel filtration, and the kinetic data showed Km values of 16.64 mg/ml of culture fluid for carboxymethylcellulase and 0.14 mM p-nitrophenyl-ß-D-glucoside and 0.81 mM cellobiose for ß-glucosidase at pH 5. Carboxymethylcellulase and extracellular ß-glucosidase functioned optimally at pH 5 to 6 and 4.5 to 5 and at temperatures of 55 to 60 and 70 to 75°C, respectively. Both temperature optima and thermostability of ß-glucosidase were among the highest ever reported for the same enzyme excreted from cellulase and ß-glucosidase hyperproducing microorganisms.
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