Lipase-catalyzed synthesis of secondary glucose esters under continuous flow conditions

Chemical methods for the synthesis of sugar esters require the use of high temperatures in the presence of alkaline catalysts resulting in undesirable by-products and low regiosselectivity. Sugar-based fatty acid esters are non-ionic, biodegradable, odorless, non-irritating, non-toxic surfactants widely used pharmaceuticals, cosmetics, detergents, and food industry. Here in we report our results on enzymatic esterification of protected glucose (glucose ketal) with several fatty acids using the immobilized lipase from Rhizomucor miehei under batch and continuous flow conditions, to afford new glucose derivatives with potential surfactant properties. The results presented here shows that high conversions can be obtained in short reaction time. Practical application: The research of new non-toxic, environmentally friendly and biodegradable surfactants to replace chemicals has increased along with the development of green chemistry. Nonionic biosurfactants, such as sugar fatty acid esters, may be obtained by enzymatic synthesis, a simple manufacturing method for application in several areas, including food, cosmetic, detergent, and pharmaceutical industry. In this work we have described the uncommon esterification of a steric hindered secondary hydroxyl group on glucose ketal leading to new glucose derivatives with potential application as surfactants.