Key factors controlling the enzyme catalyzed alcoholysis of vegetable oils

Abstract

The alcoholysis of vegetable oils is the reaction involved in the synthesis of products of high interest for different industrial sectors, such as biodiesel and nutraceuticals employed in functional nutrition, cosmetics, pharmacy and biomedicine. The enzyme‐catalyzed alcoholysis of oils requires the contact of the two immiscible precursor reagents (oil and short alcohol) with the biocatalyst [1]. Immobilized lipases are the most convenient type of biocatalyst used. In these systems, the reaction can be affected by diffusional limitations of reagents and products through the matrix pores. This fact can be especially important in solvent free systems. Also, the alcoholysis reaction can be carried out in presence and absence of an organic solvent to facilitate the mutual contact of substrates. The yields of the process usually depend on lipase preparation, type of nucleophile and solvent and composition of the reaction mixture. The objective of this investigation has been to develop a robust and highly active biocatalyst, and the optimization of enzymatic alcoholysis process of Camelina oil. The results comprise construction of seven different immobilized lipase derivatives of commercial Novozym® 435, and the identification of the most important reaction limitations. Lipase microenvironment in the biocatalyst preparation can be chemically modified. In this work the commercial biocatalysts was modified to obtain a more hydrophobic enzyme surface with TNBS, a hydrophobic and crosslinked enzyme surface with Glutaraldehyde, EDA modification to change anionic groups of the enzyme by cationic groups, treatment with ionic polymers to generate a very hydrophobic shell around the enzyme molecules, among others. The results permitted to identify optimal operation conditions and a biocatalyst characterized by an increased operational activity and stability in the alcoholysis of Camelina oil.