In Situ Encapsulation of Phosphotriesterases by a Mesoporous Hydrogen-Bonded Organic Framework Engenders Enhanced Activity and Stability

Enzymes employed in biocatalysis often face harsh operational environments that undermine their structural integrity and catalytic function. To mitigate this, enzyme immobilization within porous matrices has emerged as a promising stabilization strategy. A key challenge lies in balancing enzyme activity/accessibility with stability─a dilemma that may be addressed through in situ encapsulation of enzymes into mesoporous matrices. However, conventional synthesis of such mesoporous materials often involves specialized ligands and severe conditions, limiting their broad applicability for enzyme immobilization. In this work, phosphotriesterase (PTE), an organophosphorus hydrolase, was successfully encapsulated within a nontoxic mesoporous hydrogen-bonded organic framework (HOF) via an in situ assembly approach. The intrinsic mesoporous channels of the HOF structure facilitate efficient interaction between the immobilized enzymes and substrates, ensuring high accessibility to the enzyme's catalytic sites. Following immobilization, HOF-101 achieved an encapsulation efficiency of approximately 70% for PTE. The immobilized PTE exhibited a catalytic activity toward organophosphorus hydrolysis that was 1.60 times higher than that of the free enzyme, along with markedly enhanced acid resistance, thermal stability, and long-term stability.