Encapsulation of Fe3O4 and Lipase in a Squarate Metal–Organic Framework for Nonaqueous Catalysis

Enzyme immobilization in metal–organic frameworks (MOFs) has emerged as a promising strategy to enhance the stability and reusability of biocatalysts. However, maintaining high enzymatic activity, especially in nonaqueous media, remains a challenge. Herein, we report a facile one-pot in situ encapsulation strategy to coincorporate Fe3O4 nanoparticles and lipase within the cavities of NKMOF-101. The synthesized Fe3O4/lip@NKMOF-101-Ni composite was thoroughly characterized, which confirmed the successful encapsulation of both components. The incorporated Fe3O4 nanoparticles not only endowed the biocomposite with magnetic susceptibility for facile separation but also surprisingly acted as an activity enhancer. In the esterification reaction conducted in a nonaqueous system, the Fe3O4/lip@NKMOF-101-Ni composite demonstrated significantly enhanced catalytic activity, achieving an approximately 6-fold increase compared to free lipase. Furthermore, the magnetic biocomposite exhibited excellent operational stability, retaining over 80% of its original activity after five consecutive uses and could be efficiently recycled. This work presents a novel and effective approach for constructing robust and highly active enzyme-MOF composites for advanced applications in nonaqueous biocatalysis.