Maximized lipase-catalysed production of a monoester of ferulic acid derivatives and ethylene glycol: a key step toward intrinsically antioxidant biosourced polymers

Ferulic acid, a powerful antioxidant, is found in agricultural by-products. Valorising this phenolic acid through the production of intrinsically antioxidant and original biopolymers is clearly of great interest. This study focuses on the enzymatic production of the monoester of dihydroferulic acid, a ferulic acid derivative, and ethylene glycol, the intermediary molecule in the pathway towards an original monomer. The performance of the acid and ethyl ester as acyl donors was compared in two different media: one using 2-methyl-2-butanol as a solvent and another based on a solvent-free approach. In organic solvent, the molar excess of ethylene glycol resulted in yields up to 74% and 71% of ethylene glycol hydroferulate, for the ester and acid, respectively. More interestingly, the solvent-free approach combined with the addition of 10% v/v of water and ethyl ester as the substrate led to a maximum yield of 99% of monoester with full lipase activity retention at 55 °C even after numerous cyclings.