Enzyme-modified amphiphilic polymer nanoparticles as high-performance Pickering interface biocatalysts

Abstract

Pickering biphasic biocatalysts have risen in popularity in enzymatic engineering. Herein, monodispersed amphiphilic nanoparticles are synthesized by surfactant-free emulsion copolymerization, and then decorated by Candida Antarctica Lipase B (CALB) through EDC/NHS crosslinking. Using the CALB-loaded nanoparticles as a stabilizer, a highly stable o/w Pickering emulsion gel with a dispersed phase volume ratio of 75% is proposed. Such shear-independent static biocatalysis occurs on CALB-loaded nanoparticles at the two-phase interface of the emulsion, and the catalytic process is completed within 1 hour. The specific activity of the enzyme was significantly enhanced by up to 57.2 times compared to free CALB. The emulsion morphology and biocatalytic effect are rigorously illustrated as the enzyme loading content increases. Impressively, after each single biocatalysis, the immobilized CALB particles can be reused by centrifuging, dispersing, and re-emulsifying to form the Pickering emulsion gel again. After 10 reaction cycles, the CALB-loaded particles retained 90% relative activity compared to their original activity, demonstrating remarkable recyclability. Our work serves as a paradigm for Pickering biphasic catalysis with gradient-content enzyme molecular surface-modified nanoparticles, and the Pickering gel system could be used for sustainable applications of biphasic enzyme catalysis.