Replacing the lactose used in the commercial preparation of lipase from Candida rugosa by dextrans with different molecular weight, several preparations with enhanced activities in esterification of (R,S)-ibuprofen in organic medium were obtained. The presence of carbohydrates modifies the microenvironment of the enzyme and maintains the hydration of the biocatalyst. We can modulate the hydrophilic/hydrophobic balance on the surface of the biocatalyst creating non covalent enzyme-dextran complexes.