CO₂-responsive Pickering emulsions stabilized by soft protein particles for interfacial biocatalysis

Area of Science:

• Biocatalysis and green chemistry
• Colloid and interface science
• Sustainable chemical processes

Background:

• Pickering emulsions offer a platform for biphasic enzymatic catalysis.
• Challenges exist in enzyme stability, product separation, and stabilizer recovery.
• Developing green and efficient strategies is crucial for industrial applications.

Purpose of the Study:

• To develop a sustainable biocatalysis system using a CO2/N2-responsive Pickering emulsion.
• To utilize sodium caseinate (NaCas) as a natural, scalable stabilizer for oil-in-water emulsions.
• To demonstrate efficient enzyme catalysis, product separation, and recycling.

Main Methods:

• Fabrication of a CO2/N2-responsive Pickering emulsion stabilized solely by sodium caseinate.
• Utilizing the emulsion for biphasic enzymatic catalysis.
• Implementing CO2/N2 bubbling for demulsification, separation, and recycling of enzyme and NaCas.

Main Results:

• The NaCas-stabilized emulsion showed higher reaction efficiency than conventional systems.
• Enzymes were effectively transferred and enriched at the oil-water interface.
• Facile demulsification, separation, and recycling were achieved over 30 cycles with >90% enzyme activity retention.

Conclusions:

• A robust and sustainable CO2/N2-responsive Pickering emulsion system was developed using natural sodium caseinate.
• This system facilitates efficient enzymatic catalysis, product separation, and recycling, outperforming previous methods.
• The protein-based emulsion holds significant promise for green chemical conversions in various industries.