Carbon dioxide/methanol conversion cycle based on cascade enzymatic reactions supported on superparamagnetic...

Area of Science:

• Biocatalysis
• Chemical Engineering
• Sustainable Chemistry

Background:

• Carbon dioxide conversion to valuable chemicals like methanol is crucial for sustainability.
• Enzymatic catalysis offers high selectivity but often requires enzyme stabilization.
• Immobilization techniques are key to enhancing enzyme stability and reusability.

Purpose of the Study:

• To develop and optimize an immobilized enzyme cascade for efficient carbon dioxide to methanol conversion.
• To investigate the performance of sequentially immobilized enzymes powered by a co-enzyme regeneration system.
• To assess the yield improvement of methanol production using a multi-enzyme system.

Main Methods:

• Sequential immobilization of alcohol dehydrogenase (ADH), formaldehyde dehydrogenase (FalDH), and formate dehydrogenase (FDH) onto magnetite nanoparticles.
• Integration of glutamate dehydrogenase (GDH) for nicotinamide adenine dinucleotide (NAD+/NADH) co-enzyme regeneration.
• Optimization of individual enzyme performance and cascade reaction under carbon dioxide pressure.

Main Results:

• Individual enzyme immobilization and reaction conditions were optimized.
• A stepwise enzymatic conversion yielded only 2.3% methanol per NADH.
• The cascade system with four immobilized enzymes achieved a 64-fold increase in methanol yield.
• Successful in situ regeneration of NADH was demonstrated.

Conclusions:

• Immobilized enzymes on magnetite nanoparticles provide a stable and efficient platform for CO2 to methanol conversion.
• The developed cascade system significantly enhances methanol yield compared to stepwise reactions.
• This approach demonstrates a viable strategy for industrial CO2 utilization via biocatalysis.