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vol.17 issue4-7Influence of substrate partition coefficient on the performance of lipase catalyzed synthesis of citronellyl acetate by alcoholysisCharacterization of free and immobilized invertase regarding activity and energy of activation author indexsubject indexarticles search
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Brazilian Journal of Chemical Engineering

Print version ISSN 0104-6632On-line version ISSN 1678-4383

Abstract

BASSETTI, F.J.; BERGAMASCO, R.; MORAES, F.F.  and  ZANIN, G.M.. Thermal stability and deactivation energy of free and immobilized invertase. Braz. J. Chem. Eng. [online]. 2000, vol.17, n.4-7, pp.867-872. ISSN 0104-6632.  http://dx.doi.org/10.1590/S0104-66322000000400050.

The thermal stability and the energy of deactivation of free invertase and the immobilized enzyme (IE) was measured at temperatures in the range of 35 to 65°C for the hydrolysis of a 5% w/v sucrose solution. The free enzyme at pH 5.0 is stable up to 50°C for a period of 4 h. Invertase immobilized in controlled pore silica by the silane-glutaraldehyde covalent method is stable up to 55ºC, in pH 4.5 for the same period. For higher temperatures the enzyme deactivation follows the exponential decay model and half-lives are 0.53, 1.80, and 13.9 h for free invertase, at 65, 60, and 55ºC, respectively. For the IE half-lives are 0.48, 1.83, and 20.9 h, at 65, 60, and 55ºC, respectively. The IE is more stable than the free invertase; the energy of deactivation being 83.1 kcal/mol for the IE and 72.0 kcal/mol for the free enzyme.

Keywords : invertase; thermal stability; immobilized invertase; sucrose; energy of deactivation.

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