SYNTHESIS OF ETHYL ESTERS BY COMBI-LIPASES HAVING DIFFERENT SPECIFICITIES UNDER CONTINUOUS RUN

The transesterification of palm kernel oil with ethanol by simultaneous action of lipases from different microbial sources was assessed aiming at producing biodiesel with residual levels of monoacylglycerol (MG) and diacylglycerol (DG) within the limits required by standard regulations for biofuel. For this purpose, nonspecific and 1,3 specific lipases (Burkholderia cepacia – LBC and Thermomyces lanuginosus – LTL, respectively) were immobilized on silica-hydroxyethylcellulose hybrid support (SiO2-HEC) and the assays were carried out in two-stage packed-bed reactor under different molar ratios oil-to-alcohol (1:12, 1:10 and 1:8) and space-times (16 and 14 h). The best performance was achieved at space-time 16 h and molar ratio of 1:8 attained productivities of about 30 mmolester gcat-1 h-1. The biodiesel exhibited alkyl ester contents > 98%, MG contents  0.7% (wt), absence of DG and kinematic viscosity of 4.22 ± 0.25 mm2 s-1 that meet the criteria established by both Brazilian (ANP 45/2014) and European EN 14214 legislations.