Natural shellac nanoparticles embedded porous chitosan microgel as a stability-enhanced Pickering interfacial biocatalyst.

Enzyme-driven processes in green industries demand biocatalytic systems that harmonize efficiency, safety, and sustainability. Pickering interfacial biocatalysis (PIB) achieves impressive catalytic efficiency via emulsion-driven reactions, yet its potential is limited by unstable or harmful hydrophobic regulation. Herein, we present a novel synthesis strategy for biomaterials-based particles for PIB with high stability and sustainability through the immobilization of lipases within chitosan microgels enveloped by natural shellac nanoparticles (SNPs). The chitosan matrix establishes a confined microenvironment for lipase stabilization, while the SNPs provide hydrophobic regulation and physical barriers, enhancing Pickering emulsion stability and mitigating droplet coalescence. This system demonstrates high catalytic performance for hexyl hexanoate synthesis, achieving an 11-fold activity enhancement over free lipase in biphasic systems, alongside robust thermal/pH stability and reusability (95.10 % residual activity after 8 recycles and 69.25 % after 16 recycles). The high catalysis efficiency arises from huge interfacial surface area and accelerated interphase mass transfer endowed by Pickering emulsion. Physically embedded natural hydrophobic particles further provide this system with steady hydrophobic regulation and anti-coalescence properties. Crucially, given by the high biocompatibility of all components, this PIB system shows high promise in various applications, including food-grade enzymatic processing, cosmetics, and drug delivery areas.