Encapsulation of lipases in aerogels

Pseudomonas cepacia (PC) lipase was encapsulated in silica and aluminosilicate gels made by different chemical processes. Some samples were dried by the supercritical method in CO2 to obtain aerogels, while other ones made by the same wet chemical procedure were dried by evaporation to produce xerogels. The biocatalysts which were obtained were compared in the esterification reaction of 1-octanol by lauric acid. In all cases, the aerogels performed better than the corresponding xerogels. This biocatalysis behavior is discussed in relationship with the textural and structural characteristics of the gels, studied by nitrogen sorption, 29Si NMR and 27Al NMR. It is proposed that supercritical drying avoids a simultaneous compression of the gel network and of the enzyme, hence improving the biocatalytic activity.