Esawy Mona A., Combet-Blanc Yannick. (2006). Immobilization of Bacillus licheniformis 5A1 milk-clotting enzyme and characterization of its enzyme properties. World Journal of Microbiology and Biotechnology, 22 (3), p. 197-200. ISSN 0959-3993.
Titre du document
Immobilization of Bacillus licheniformis 5A1 milk-clotting enzyme and characterization of its enzyme properties
World Journal of Microbiology and Biotechnology, 2006,
22 (3), p. 197-200 ISSN 0959-3993
Milk-clotting enzyme from Bacillus licheniformis 5A1 was immobilized on Amberlite IR-120 by ionic binding. Almost all the enzyme activity was retained on the support. The immobilized milk-clotting enzyme was repeatedly used to produce cheese in a batch reactor. The production of cheese was repeated 5 times with no loss of activity. The specific activity calculated on a bound-protein basis was slightly higher than that of free enzyme. The free and immobilized enzyme were highly tolerant to repeated freezing and thawing. The optimum temperature for milk-clotting activity was 70 degrees C with the free enzyme whereas, it was ranged from 70 to 80 degrees C with the immobilized milk-clotting enzyme. The activation energy (E-A) of the immobilized milk-clotting enzyme was lower than the free enzyme (E-A = 1.59 and 1.99 Kcal mol(-1) respectively). The immobilized milk-clotting enzyme exhibited great thermal stability. The milk-clotting optimum pH was 7.0 for both free and immobilized enzyme. The Michaelis constant K-m of the immobilized milk-clotting enzyme was slightly lower than the free enzyme.
