Effect of the presence of surfactant and ionic liquids on the esterification of oleic acid catalyzed by immobilized lipase

Abstract

Ionic liquids (ILs) and surfactants are widely used in order to increase the catalytic efficiency of lipases. In this sense, the present study aimed to evaluate the potential of different ionic liquids (C₄MIM.Ac, C₄MIM.HSO₄, C₄MIM.TF₂N, C₄MIM.BF₄, C₁₂MIM.I, and C12MIM.Cl), Aliquat 336 and di-2-ethylhexyl sodium sulfosuccinate (AOT) as adjuvants in the esterification of oleic acid with different alcohols catalyzed by Novozyme 435. First of all, it evaluates the effect of alkyl chain length of the alcohol and the positioning of the hydroxyl group. The selection of additives, made with isopropyl alcohol, pointed AOT and C4MIM.Ac as adjuvants effective on the potential of esterification of the enzyme (an increase of 35% in the potential of esterification). Using methanol, ethanol and 3-methyl-1-butanol, the C₄MIM.Ac was proven not to be efficient, while the AOT shows adjuvant effect in the esterification of oleic acid with methanol (increasing in catalytic efficiency of enzyme in 21%).

Key words: Esterification, di-2-ethylhexyl sodium sulfosuccinate (AOT), Ionic Liquids, Novozyme 435.