Continuous enzymatic biodiesel production from coconut oil in two-stage packed-bed reactor incorporating an extracting column to remove glycerol formed as by-product

The transesterification of coconut oil with ethanol catalyzed by Burkholderia cepacia lipase immobilized on polysiloxane–polyvinyl alcohol was performed in a continuous flow. The experimental design consisted of a two-stage packed-bed reactor incorporating a column with cationic resin (Lewatit GF 202) to remove the glycerol formed as by-product and the reactor performance was quantified for three different flow rates corresponding to space-times from 10 to 14 h. The influence of space-time on the ethyl ester (FAEE) concentrations, yields and productivities was determined. The reactor operation was demonstrated for space-time of 14 h attaining FAEE concentrations of 58.5 ± 0.87 wt%, FAEE yields of 97.3 ± 1.9 % and productivities of 41.6  ± 1.0 mgester gmedium−1 h−1. Biodiesel purified samples showed average kinematic viscosity values of 5.5 ± 0.3 mm2 s−1 that meet the criteria established by the American National Standard ASTM (D6751). The immobilized lipase was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t1/2) around 1540 h. The continuous packed-bed reactor connected in series with simultaneous glycerol removal has a great potential to attain high level of transesterification yields, raising biodiesel productivity.