Enzymatic Transesterification of Coconut Oil Using Chitosan-Immobilized Lipase Produced by Fluidized-Bed System

This work demonstrated the, catalytic performance of Cercospora kikichii lipase immobilized onto chitosan acetate microparticles activated with different cross-linking agents and dried using a fluidized-bed system. The activating agent affected the lipase activity, and the highest immobilizing yield was achieved by the chitosan microparticles activated with 1.5% glutaraldehyde (93.7%) followed by activation with metaperiodate (78.9%) and epichlorohydrin (70.6%). The immobilized biocatalysts produced showed low moisture content and water activity, namely, 3.5% and 0.12, respectively; and high stability under storage conditions maintaining 77.7% of its initial activity after 6 months at 5 degrees C. The industrial applicability of the biocatalyst was assessed in the transesterification of coconut oil (Cocos nueifera oil) using ethanol as an acylant agent. The viscosity value for the coconut oil (29 mm(2).s(-1)) sharply decreased to 3.2 mm(2)-s(-1), upon the progress of transesterification reaction. This represents a final product containing high ester content (97.9%) and low levels of acylglycerides (0.7%). The stability of chitosan-immobilized lipase was also estimated, under successive batch runs, and after five reuse cycles the ester content remained above 96.5%. Therefore, the immobilization process developed and the immobilized derivative produced could represent an alternative route both for protein engineering (specially for enzyme stability) as for biodiesel production employing lipases.