Microwave-assisted biocatalysis: A pathway to efficient and sustainable chemical synthesis

Microwave (MW)-assisted biocatalysis emerged as a highly attractive route for green chemical synthesis. This review discusses how MW can combine its rapid and selective dielectric heating with specificity, efficiency, and mild conditions of enzymatic catalysis to accelerate enzyme kinetics, reduce energy consumption, and enable process intensification in MW-assisted enzymatic processes. Emphasis is placed on the fundamental mechanisms of MW irradiation interactions with enzymatic and chemical systems, including dipolar rotation and ionic conduction, dielectric parameters, and penetration depth, which govern temperature distribution and reaction performance. Strength and weakness-consideration brings about issues such as hotspots, absorption depending on the solvent used, enzyme stability, and finally scale-up challenges. MW hybrid heating (MHH), which combines MW with other heating sources, such as conventional conduction or ultrasound, is proposed to address these limitations and improve thermal uniformity and selectivity. Examines the key process variables influencing MW-assisted biocatalysis, including solvent polarity, hydration state, molar ratio, catalyst loading, immobilization strategies, and reactor configuration, in both batch and continuous modes. Various enzymatic reactions demonstrate the advantages of MW-assisted biocatalysis, including shorter reaction times, higher yields, and greater operational stability. Furthermore, the use of immobilized enzymes under MW or MHH conditions is crucial for enhancing process robustness, reusability, and control. Finally, the limitations of scaling up processes using MW and MHH for industrial applications are discussed, and future research directions are outlined, focusing on expanding the enzymatic repertoire, improving kinetic and thermodynamic models, optimizing and developing processes and reactors, and further integrating green solvents to promote sustainable biocatalysis.