G_Fe3O4/Ag supporting Candida rugosa lipase for the “green” synthesis of pomegranate seed oil derived liquid wax esters

Abstract

Wax esters were obtained through hydrolysis/esterification of pomegranate seed oil (PSO) with cetyl alcohol in the presence of Candida rugosa lipase (CRL) immobilized on G_Fe3O4/Ag@OA (oleic acid-coated magnetic nano-hybrid) catalyst. Lipase was immobilized successfully on the as-produced nanoparticles with an efficiency, depending on the operating conditions, up to ∼94%. The immobilized CRL shows very high activity on the respect of the free counterpart, which can be attributed to the lipase conformational structure modification related to interfacial activation. The immobilized lipase was used for the wax esters synthesis from PSO in a solvent-free system. A conversion of ∼83% was observed after 12 h alcohol/FFA molar ratio 1:1, it increases up to ∼95% with an alcohol/FFA molar ratio of 2:1. After the first three cycles of use, no significant reduction of the lipase activity was observed. Analyses of wax esters properties compared with jojoba oil evidence the feasibility of the produced wax ester for different applications. Iodine number of ∼209 (gI2/100 g oil) was obtained indicating a high degree of anti-oxidant and moisturizing properties.