Hierarchically Structured CA@ZIF-8 Biohybrids for Carbon Dioxide Mineralization

Area of Science:

• Biocatalysis
• Materials Science
• Chemical Engineering

Background:

• Carbonic anhydrase (CA) is a key enzyme for CO2 mineralization.
• Immobilization of CA enhances stability but can impede catalytic efficiency due to diffusion resistance.
• Zeolitic imidazolate framework-8 (ZIF-8) is a promising material for enzyme immobilization.

Purpose of the Study:

• To develop novel CA@ZIF-8 biohybrids using poly-L-glutamic acid (PLGA) as a structure regulator.
• To investigate the effect of PLGA on the morphology and catalytic performance of CA@ZIF-8.
• To enhance CO2 mineralization efficiency and biocatalyst stability.

Main Methods:

• Synthesis of CA@ZIF-8 biohybrids with varying amounts of PLGA.
• Characterization of biohybrid morphology and surface area using techniques like SEM.
• Evaluation of catalytic activity for CO2 mineralization and reusability.

Main Results:

• PLGA introduction altered ZIF-8 crystallization, transforming morphology from dodecahedron to 3D lamellar nano-flowers.
• Increased PLGA content led to higher CA loading and significantly elevated catalytic activity.
• CO2 conversion rate nearly doubled, and CaCO3 yield reached 5.6 mg mgcat-1.
• The biohybrids maintained over 80% of initial activity after 8 cycles.

Conclusions:

• PLGA effectively regulates the structure of CA@ZIF-8 biohybrids, enhancing surface area and catalytic performance.
• The developed biohybrids offer improved efficiency and stability for CO2 mineralization.
• This approach presents a promising strategy for efficient carbon capture and utilization using immobilized enzymes.