A NEW METHOD TO DETERMINE THE A(W) RANGE IN WHICH IMMOBILIZED LIPASESDISPLAY OPTIMUM ACTIVITY IN ORGANIC MEDIA

We describe a qualitative method to predict the pre-equilibration a(w) system value in which, covalent immobilized lipase B from Candida ant arctica to sepharose and silica, displayed best synthetic activity. Th e methodology is based in the analysis of the water adsorption isother ms of the biocatalyst in air and in the organic solvent. The biocataly st is active at pre-equilibration a(w) values higher than the divergen ce point between both isotherms. In addition, native and immobilized l ipase display highest activity if the biocatalyst is pre-equilibrated at a(w) = P point. For preparative purposes, the validity of the metho d was proved in the esterification of racemic 2-(4'-isobutyl phenyl) p ropionic acid with l-propanol in isooctane at long reaction time.