Pure silica nanoparticles for liposome/lipase system encapsulation: Application in biodiesel production

In this work we report the synthesis of organic–inorganic solid with spherical morphology where enzyme, as active compounds, is encapsulated. The organic phase of nanospheres is composed of l-α-phosphatidylcholine, as liposome, and lipase from Rhizomucor miehei, as enzyme. The organic phase is covered with porous inorganic silica shell that could stabilize the internal liposomal phase and, consequently, isolate and protect the bioactive molecules. The liposome and silica amount used during the immobilization procedure have been optimized in order to obtain active and stable heterogeneous biocatalyst. Hybrid-nanospheres containing the enzyme were used to catalyze the transesterification reaction of triolein with methanol to methyl esters, typical biodiesel mixture compounds. The encapsulated enzyme retains its activity after 5 reaction cycles. The total productivity of the best catalyst obtained is higher than that of the free enzyme.