Immobilization of porcine pancreatic lipase on activated carbon by adsorption and covalent bonding and its application in the synthesis of butyl butyrate

Abstract

Porcine pancreatic lipase (PPL) extract have been immobilized on activated carbon (ACT) and functionalized activated carbon (FCT). The effects of immobilization solution pH, addition of surfactant Triton X-100, and pH and temperature in the catalytic properties of the biocatalyst were evaluated. The functionalization led to an increase in the point of zero charge (5.13–6.11), reduction in the oxygenated groups (2.15 meq.g−1 to 1.99 meq.g−1) and a specific surface area (1028 m2. g−1 to 132 m2. g−1). The optimum immobilization pH was 5.0, resulting in the PPL extract loading of 71.80 mg/g (ACT) and 55.2 mg/g (FCT). A better hydrolytic activity (239.6 U/g) was observed for ACT to 0.6 mM Triton-X concentration, while FCT exhibited higher activity (208.63 U/g) in the absence of surfactant. For the PPL extract immobilized on ACT, the activity at pH 8.0 was 240.95 U/g, while a greater activity was observed at pH 7.0 for the PPL extract immobilized on FCT (221.94 U/g). The temperature of 35 °C led the highest activity values. The esterification yield of butyl butyrate was 82 % and 66 % for the PPL extract immobilized on ACT and FCT, respectively. Both biocatalysts showed residual esterification yield greater than 86 % after five cycles of use.