A lipase/poly (ionic liquid)-styrene microspheres/PVA composite hydrogel for esterification application

Enzymes are particularly attractive as biocatalysts for the green synthesis of chemicals and pharmaceuticals. However, the traditional enzyme purification and separation process is complex and inefficient, which limits the wide application of enzyme catalysis. In this paper, an efficient strategy for enzyme purification and immobilization in one step is proposed. A novel poly (ionic liquid)-styrene microsphere is prepared by molecular design and synthesis for adsorbing and purifying high activity lipase from fermentation broth directly. By optimizing the surface morphologies and charge of the microspheres, the enzyme loading is significantly improved. In order to further stabilize the catalytic environment of lipase, the resulting lipase/poly (ionic liquid)-styrene microspheres are immobilized in physical crosslinking hydrogel to obtain a complex lipase catalytic system, which can be prepared into various shapes according to the requirements of catalytic environment. In the actual catalytic reaction process, this complex lipase catalytic system exhibits excellent catalytic activity (6314.69 ± 21.27 U mg^-1) and good harsh environment tolerance compared with the lipase fermentation broth (1672.87 ± 36.68 U mg^-1). Under the condition of cyclic catalysis, the complex lipase catalytic system shows the outstanding reusability (After 8 cycles the enzymatic activity is still higher than that of the lipase fermentation broth) and is easily separated from the products.