pH-Tunable gliadin-chitosan-lipase ternary complexes enabling efficient interfacial synthesis of phytosterol ester

Area of Science:

• Biomaterials Science
• Enzyme Engineering
• Sustainable Chemistry

Background:

• Nature uses scaffold proteins for enzyme control and catalysis.
• Mimicking this with food-grade materials is difficult.
• Lipase immobilization is key for efficient biocatalysis.

Purpose of the Study:

• To create a pH-tunable, food-grade scaffold for lipase immobilization.
• To develop a Pickering interfacial biocatalysis (PIB) system using the scaffold.
• To enhance lipase activity, stability, and yield in lipid synthesis.

Main Methods:

• Self-assembly of gliadin-chitosan matrix with lipase AYS.
• Formation of a stable gliadin-chitosan-lipase (GCL) complex via hydrogen bonding and hydrophobic interactions.
• Utilizing GCL particles as stabilizers in a Pickering interfacial biocatalysis system at pH 7.
• Application in sterol ester synthesis via interesterification of flaxseed oil.

Main Results:

• GCL complex formed with high binding affinity (∆G_binding = -331.7 kJ·mol⁻¹).
• PIB system achieved 81.4% yield in sterol ester synthesis within 6 hours.
• Enzymatic conversion rate was nearly three times higher than free lipase (31.8%).
• System retained 73.4% activity after five cycles and showed broad oil compatibility.

Conclusions:

• The gliadin-chitosan scaffold effectively immobilizes lipase in an active conformation.
• The developed PIB system offers a sustainable and scalable platform for functional lipid production.
• This work provides a blueprint for next-generation biomacromolecular enzyme carriers.