Lipase-catalyzed acidolysis of tripalmitin with capric acid in organic solvent medium: Analysis of the effect of experimental conditions through factorial design and analysis of multiple responses

The acidolysis of tripalmitin with capric acid catalyzed by an immobilized form of a 1,3-positionally selective lipase (Rhizomucor miehei) showed to be effective for the synthesis of structured lipids of the MLL and MLM type. The effects that reaction parameters such as substrate molar ratio (N), biocatalyst load (E), and reaction temperature (T) have on selected responses variables (i.e. total conversion of tripalmitin, selectivity and yield of the desired structured lipid, hydrolysis yield, and acyl migration importance), were evaluated by use of an experimental factorial design of three factors and three levels with two central points and with a confidence level of 95%. The range of each parameter was selected as follows: N = 3-9, E = 5-15 wt%, T = 50-70 °C. The statistical analysis of results was addressed by use of both simple linear models and more complicated quadratic models using specific commercial software. The results obtained showed that a proper selection of reaction conditions is needed in order to maximize not only the yield of the desired structured lipid, but also to minimize the generation of hydrolysis and acyl migration by-products.