Efficient Acylation of Sugars and Oligosaccharides in Aqueous Environment Using Engineered Acyltransferases

Abstract

A major challenge for the enzymatic synthesis of sugar esters is the low solubility of sugars in anhydrous, often toxic, organic solvents. We overcame this limitation by using acyltransferases for efficient acetylation of sugars in water. Selective 6-Oacetylation of glucose, maltose, and maltotriose with conversions of up to 78% was achieved within 15 min using engineered acyltransferases (4 μM). Moreover, we identified EstA as a promiscuous acyltransferase preferentially acetylating sugars instead of hydrophobic acyl acceptors. This expands the applicability of promiscuous acyltransferases to sugar modifications and contributes to the understanding of how to adapt acyltransferases to hydrophilic substrates.