Optimization of Selective Lipase-Catalyzed Feruloylated Monoacylglycerols by Response Surface Methodology

Abstract

The use of solvent engineering to achieve selective enzymatic synthesis of feruloylated acylglycerols during the transesterification of ethyl ferulate with TAG was investigated. Novozym 435 catalyzed transesterification of ethyl ferulate and TAG resulted in a mixture of feruloylated monoacylglycerols (FMAG) and feruloylated diacylglycerols (FDAG). These feruloylated acylglycerols have recently received much attention because of their health benefits, antioxidant properties and UV absorption. However, FMAG in a pure form is more advantageous than the FMAG–FDAG mixture in exhibiting stabilizing, emulsifying and conditioning properties. Thus, it is significant to perform efficient selectivity in the synthetic process. In this present study, the effect of various solvent mixtures, including unitary, binary and ternary organic media selective enzymatic synthesis of feruloylated acylglycerols was investigated by response surface methodology. Selectivity towards FMAG substantially increased from 14.5% in the unitary solvent n-hexane to 94.2% in the binary mixtures of 2-methyl-2-butanol (2M2B) and toluene (1:1, v/v). The maximum conversion achieved was 75.4% in this binary mixture medium. Analysis of variance (ANOVA) showed that 99.6% of the observed variation was explained by the polynomial model. Lack of fit analysis indicated that the regress equation was adequate for predicting the degree of the selectivity.