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vol.17 número4-7A simplified kinetic model for the side reactions occurring during the enzymatic synthesis of ampicillinEvaluation of inorganic matrixes as supports for immobilization of microbial lipase índice de autoresíndice de assuntospesquisa de artigos
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Brazilian Journal of Chemical Engineering

versão impressa ISSN 0104-6632versão On-line ISSN 1678-4383


CALSAVARA, L.P.V.; MORAES, F.F.  e  ZANIN, G.M.. Thermal stability and energy of deactivation of free and immobilized cellobiase. Braz. J. Chem. Eng. [online]. 2000, vol.17, n.4-7, pp.841-848. ISSN 0104-6632.

Commercial cellobiase has been immobilized in controlled pore silica particles by covalent binding with the silane-glutaraldehyde method with protein and activity yields of 67% and 13.7%, respectively. Thermal stability of the free and immobilized enzyme (IE) was determined with 0.2% w/v cellobiose solution, pH 4.8, temperatures from 40 to 70°C for free enzyme and 40 to 75°C for IE. Free cellobiase maintained its activity practically constant for 240 min at temperatures up to 55°C. The IE has shown higher stability retaining its activity in the same test up to 60° C. Half-lives for free enzyme were 14.1, 2.1 and 0.17 h at 60, 65 and 70°C, respectively, whereas the IE at the same temperatures had half-lives of 245, 21.3 and 2.9 h. The energy of thermal deactivation was 80.6 kcal/mol for the free enzyme and 85.2 kcal/mol for the IE, confirming stabilization by immobilization.

Palavras-chave : Thermal stability; immobilized enzyme; cellobiase; cellobiose.

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