Liu_2026_J.Biotechnol__

This study proposes an innovative immobilized lipase construction strategy to address the low activity and poor stability limitations of current biocatalysts for flavor ester synthesis. L-histidine-based ionic liquid (IL) is covalently grafted onto the surface of magnetic covalent organic framework (COF) via Schiff base reaction, and porcine pancreatic lipase (PPL) is further covalently immobilized on the composite carrier through amide bond coupling. The resulting Fe3O@COF-IL-PPL shows 1.6-fold higher catalytic activity and 2.3-fold better thermal stability than free PPL, and 32% higher activity retention after cycles than PPL immobilized on IL-free COF carrier. Its optimal reaction pH and temperature are 7.5 and 50 degreesC respectively, maintaining 86% of initial activity at 60 degreesC and 76% activity after 6h incubation at 50 degreesC. Under n-hexane reaction system, the isoamyl acetate yield reaches 87.4% under optimal conditions, and the biocatalyst retains 71.4% activity after 10 consecutive isoamyl acetate synthesis cycles. Although the additional preparation steps and higher cost of the support need to be considered for industrial applications, the improved catalytic performance of Fe(3)O(4)@COF-IL-PPL verified the effectiveness of IL surface modification strategy, and the system can be further extended to solvent-free systems to verify its broader applicability.