Rapid Fabrication of Biocomposites by Encapsulating Enzymes into Zn-MOF-74 via a Mild Water-Based Approach

Area of Science:

• Materials Science
• Green Chemistry
• Biotechnology

Background:

• Metal-organic frameworks (MOFs) offer tunable properties for various applications.
• Enzyme immobilization is crucial for enhancing enzyme stability and reusability.
• Developing sustainable and efficient methods for MOF synthesis and enzyme encapsulation is essential.

Purpose of the Study:

• To develop a rapid, green synthesis of zinc-based MOF-74 (Zn-MOF-74).
• To investigate the encapsulation of enzymes, catalase (CAT) and α-chymotrypsin (CHT), within Zn-MOF-74.
• To evaluate the stability, biocatalytic activity, and size-selectivity of encapsulated enzymes.

Main Methods:

• Rapid synthesis of Zn-MOF-74 using a mild, water-based system at room temperature.
• Encapsulation of CAT and CHT enzymes into Zn-MOF-74 crystals.
• Characterization using electron microscopy and powder X-ray diffraction.
• Assessing enzyme activity and stability under denaturing and proteolytic conditions.

Main Results:

• Zn-MOF-74 was synthesized in 10 minutes, showcasing green chemistry principles.
• Encapsulated CAT (CAT@Zn-MOF-74) maintained significant catalytic activity in hydrogen peroxide decomposition, even under harsh conditions.
• CAT@Zn-MOF-74 exhibited superior bioactivity compared to composites using zeolitic imidazolate framework 90 (ZIF-90).
• Encapsulated CHT (CHT@Zn-MOF-74) demonstrated hydrolysis of a larger substrate, where ZIF-90 encapsulation was ineffective due to pore size limitations.

Conclusions:

• A rapid and eco-friendly method for synthesizing Zn-MOF-74 is established.
• Enzyme encapsulation in Zn-MOF-74 enhances stability and catalytic performance.
• Zn-MOF-74's unique structure facilitates size-selective enzyme activity, with broad applicability for industrial enzyme applications.