Synthesis of Biosurfactants: Enzymatic Esterification of Diglycerol and Oleic Acid. 1. Kinetic Modeling

The growing application of environmentally friendly products raised in the last few years has increased the interest in biodegradable nonionic surfactant products. As an example of these, polyglycerol fatty acid esters have a wide field of application in many industries as additives of cosmetics, food, photography, inks, etc. Also, the huge range of possible raw materials for these products increases cited interest. The esterification of diglycerol with oleic acid using an enzyme (NOVOZYM-435) as catalyst was studied in this work. Several experiments were carried out at different temperatures, catalyst concentrations, and acid/alcohol molar ratios. A pseudo-second-order kinetic model, including Langmuir adsorption factors for the acid, was developed. The results show that this proposed kinetic model reproduces the experimental data with a maximum 10% error.