Robust biocatalyst for the green continuous flow synthesis of esters from biomass-derived furfuryl alcohol and C8–C18 carboxylic acids

Abstract

A sustainable method suitable for industrial-scale continuous flow synthesis of esters from biomass-derived furfuryl alcohol (FA) and C₈–C₁₈ carboxylic acids was developed. Under optimized reaction conditions, lipase from Aspergillus oryzae immobilized on an octyl-silane MgO·SiO₂ material demonstrated high activity. A conversion of 88.7–90.2% for FA with 100% selectivity to esters using a FA : fatty acid molar ratio of 1 : 3 and cyclohexane as the solvent at 25 °C in 45 min was achieved in a batch system. The biocatalyst retained its high activity for at least 10 consecutive reaction cycles. Successful upgradation from a batch to continuous flow reactor led to an increased FA conversion of up to 96.8%, with a reagent flow rate of 0.070 mL min⁻¹ and a residence time of 10.5 minutes. The biocatalyst maintained excellent performance for 30 h. The developed method, considered within the framework of green chemistry metrics, ensures a balance between the high activity, stability, recyclability, and biodegradability of the catalyst. This work proposes as a generic approach to green chemistry dedicated to support the biocatalytic continuous flow synthesis of value-added chemicals.