Frequent analytical/experimental problems in lipase-mediated synthesis in Solvent Free Systems and how to avoid them

MARÍA LAURA FORESTI; MARÍA LUJÁN FERREIRA

ANALYTICAL AND BIOANALYTICAL CHEMISTRY

Año: 2005 vol. 381 p. 1408 - 1425

1618-2642

Compared with chemical catalysis, enzymatic catalysis is a relatively new topic. Experimental work envolving lipases deserves careful attention and accurate procedures still need to be implemented. A rapid but careful look at published data, immediately demonstrates that experiments performed in similar conditions with similar reagents have led to very different results. The aim of this work is to point out the importance of accurate and systematic procedures in order to ensure the reproducibility of experimental data. We strongly believe that different results found by different labs are due to problems detected in the procedures used. Quantification through UV/Visible methods of the immobilisation efficiency of lipase on several supports, and sampling methods in order to obtained correct enzymatic activity values are specially analysed. After a brief review section aiming to demonstrate the high discrepancies found in literature, original data from Candida rugosa lipase adsorption on polypropylene powder and its use in the solvent-free synthesis of ethyl oleate are introduced in order to exemplify the difficulties found in these kind of systems. Several procedures described in literature are assayed and the accuracy of the results obtained is carefully analysed. The aim of the whole analysis performed is that it would be useful for any powdered solid used as support of a lipase in a solvent free system (SFS) for any synthesis reaction, especially for those involving a volatile reagent. In the whole contribution special emphasis is taken on how catalytic reaction results using enzymes (free and immobilised) are reported, in order to allow comparison among published data, something usually difficult since very different units are used and often complementary data are not included. Compared with chemical catalysis, enzymatic catalysis is a relatively new topic. Experimental work envolving lipases deserves careful attention and accurate procedures still need to be implemented. A rapid but careful look at published data, immediately demonstrates that experiments performed in similar conditions with similar reagents have led to very different results. The aim of this work is to point out the importance of accurate and systematic procedures in order to ensure the reproducibility of experimental data. We strongly believe that different results found by different labs are due to problems detected in the procedures used. Quantification through UV/Visible methods of the immobilisation efficiency of lipase on several supports, and sampling methods in order to obtained correct enzymatic activity values are specially analysed. After a brief review section aiming to demonstrate the high discrepancies found in literature, original data from Candida rugosa lipase adsorption on polypropylene powder and its use in the solvent-free synthesis of ethyl oleate are introduced in order to exemplify the difficulties found in these kind of systems. Several procedures described in literature are assayed and the accuracy of the results obtained is carefully analysed. The aim of the whole analysis performed is that it would be useful for any powdered solid used as support of a lipase in a solvent free system (SFS) for any synthesis reaction, especially for those involving a volatile reagent. In the whole contribution special emphasis is taken on how catalytic reaction results using enzymes (free and immobilised) are reported, in order to allow comparison among published data, something usually difficult since very different units are used and often complementary data are not included.