Star Polyelectrolyte Coacervates Enable Adaptive and Robust Enzyme Immobilization for Efficient Biocatalysis

Enzyme immobilization in solid porous supports often suffers from a trade-off among enzyme loading, mass transport, catalytic activity, and operational stability. Here, we report a liquid-like immobilization platform based on star polyelectrolyte coacervates (SPECs) formed by simple mixing of oppositely charged star polyelectrolytes. The multivalent star topology organizes the coacervate into a compact yet dynamically adaptive network, enabling enzyme loading efficiencies exceeding 97% and order-of-magnitude enhancements in apparent catalytic rates. Moreover, SPEC exhibits topology-enabled ion exclusion that suppresses ion penetration even under high-salinity conditions, thereby stabilizing both the coacervate structure and embedded enzymes. As a result, SPEC maintains high catalytic activity under salinity, pH, temperature, and organic solvent perturbations and supports sustained continuous-flow biocatalysis. The platform is broadly applicable to diverse enzymes, including lipases from multiple biological sources, alkaline phosphatase, and trypsin, thereby establishing SPEC as a general and scalable immobilization strategy for efficient and practical biocatalysis.