One-Step Biocatalytic Synthesis of Sustainable Surfactants Using Selective Amide Bond Formation

N-alkanoyl-N-methylglucamides (MEGAs) are non-toxic surfactants widely used in pharmaceutical and biochemical applications and hence more sustainable syntheses towards these compounds are highly desired. Here we present an aqueous, enzymatic synthesis route towards MEGAs and analogues using carboxylic acid reductase (CAR), which has been engineered to catalyse amide bond formation (CAR-A). Compared to lipase catalysed reactions, this biocatalyst is capable of selective amide bond formation between amino-polyols and fatty acids without the competing esterification reaction being observed. The wide substrate scope of CAR-A catalysed amidation was exemplified by the synthesis of 16 amides including several commercially relevant targets. The ATP co-factor could be recycled from cheap polyphosphate using a kinase. This work establishes acyl-phosphate mediated chemistry as a selective strategy for biocatalytic amide bond formation in the presence of competing alcohol functionalities.