Evaluation of different commercial hydrophobic supports for the immobilization of lipases: tuning their stability, activity and specificity
Five different commercial supports (Lifetech™ ECR1061M (styrene/methacrylic polymer), Lifetech™ ECR8804M (octadecyl methacrylate), Lifetech™ ECR8806M (octadecyl methacylate), Lifetech™ ECR1090M (styrene) and Lifetech™ ECR1030M (DVB/methacrylic polymer)) were compared to octyl agarose in their performance in the immobilization of four different lipases (from Rhizomucor miehie (RML), from Thermomyces lanuginosus (TLL) and the forms A and B from Candida antarctica, (CALA and CALB)) and of the phospholipase Lecitase Ultra™ (LU). The new enzymatic derivatives were evaluated and compared with the commercial biocatalyst (Novozym 435 (CALB), Lipozyme RM IM and Lipozyme TL IM). Textural properties, loading capacity, enzyme stability under different conditions, and activity versus different substrates were analyzed. Although all of the supports reversibly immobilized lipases via interfacial activation of lipases versus the hydrophobic surface of the support, some of them permitted a significant improvement in the final biocatalyst compared to the reference support or the commercial preparations. Enzyme specificity depended strongly on the used support (e.g., the new ones gave almost null activity versus p-nitrophenyl butyrate). However, there is not a universal optimal support; the “best” support depends on the enzyme, the parameter studied and the substrate utilized. Nevertheless, under the conditions utilized, the preparations showed a very good performance in a diversity of reactions and permitted their reuse (both the biocatalyst and the supports after eliminating the enzyme by washing the enzyme with triton X-100). These supports will permit enlarging the library of immobilized lipase biocatalyst, being supports useful for aqueous or organic medium.