Enzyme-catalyzed production of emollient cetostearyl stearate using different immobilized commercial lipases under vacuum system

This work reports the enzymatic esterification of stearic acid and cetostearyl alcohol for the production of cetostearyl stearate, a widely employed substance in the cosmetic and hygiene personal industry as emollient, as it assists in the consistency of beauty products and provides a soft feeling on the skin. The development of this work presents important results for the scientific literature since just a few references on this subject are available. For the maximization of the enzyme-catalyzed process, two immobilized commercial lipases were tested, NS 88011 and Novozym 435, and a study of reaction conditions was carried out, taking into account the catalyst concentration, enzyme catalyst type, reaction time, vacuum influence, process temperature, substrates molar ratio and agitation. Through the experimental design, the optimum reaction condition was determined as 75 °C, 1:1.5 acid to alcohol molar ratio, 600 mmHg vacuum and 760 rpm agitation. For such condition, high conversion values (99%) were obtained. The quality of the final product was characterized by the acidity index (0.6 mg KOH g−1), iodine index (0% of iodine absorbed/g of sample), hydroxyl index (17.06 mg KOH.g−1), saponification index (133.68 mg KOH g−1) and color analysis.