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.