Stable metal-organic frameworks containing single-molecule traps for enzyme encapsulation.

Area of Science:

• Materials Science
• Biotechnology
• Chemical Engineering

Background:

• Enzymatic catalysis is vital for chemical manufacturing but limited by enzyme instability and poor reusability.
• Developing robust enzyme immobilization strategies is crucial for industrial applications.

Purpose of the Study:

• To engineer stable metal-organic frameworks (MOFs) with ultra-large mesoporous cages for single-molecule enzyme encapsulation (SEE).
• To evaluate the impact of SEE on enzyme loading, recyclability, catalytic efficiency, and operational stability.

Main Methods:

• Synthesis of stable MOFs with ultra-large mesoporous cages (e.g., PCN-333(Al)).
• Encapsulation of three different enzymes within the MOF cages as single-molecule traps (SMTs).
• Characterization of immobilized enzyme performance (Km, catalytic efficiency) and stability under harsh conditions.

Main Results:

• PCN-333(Al) achieved record-high enzyme loadings and recyclability due to its high concentration of mesoporous cages.
• Enzymes undergoing SEE exhibited lower Km values than free enzymes.
• Immobilized enzymes demonstrated superior performance and stability compared to free enzymes under harsh conditions, preventing aggregation and denaturation.

Conclusions:

• Single-enzyme encapsulation within stable, ultra-large mesoporous MOFs significantly enhances enzyme operational stability and reusability.
• This SEE strategy offers a promising approach for advancing enzymatic catalysis in industrial applications.
• PCN-333's properties make it suitable for encapsulating various nanoscale functional moieties beyond enzymes.