Chitosan-alginate beads as encapsulating agents for Yarrowia lipolytica lipase: Morphological, physico-chemical and kinetic characteristics

Extracellular lipase from Yarrowia lipolytica was immobilized by ionotropic gelation with alginate and chitosan as encapsulating agents. Photomicrographs revealed a collapsed and heterogeneous surface of these microcapsules due to freeze-drying process. The optimum reaction temperature for the microencapsulated lipase (40 degrees C) was higher than for free lipase (35 degrees C) as well as the optimum pH (8.0 and 7.5, respectively). The study of the reaction kinetics showed that a higher maximum reaction rate (V-max) (221.1 U/mg) for the free lipase in comparison to the immobilized form (175.3 U/mg). A protective effect of the microcapsule was detected in the storage of the enzyme at room temperature, as after 75 days 35% of activity was maintained for the microcapsules, while no activity remained after 15 days with the free enzyme. Lower values for inactivation constant (k(d)) and increase in half-life for immobilized lipase showed that lipase microencapsulation favored the thermostability of this enzyme. (C) 2019 Elsevier B.V. All rights reserved.