Self-Assembled Immobilization and Metal-Polyphenol Network Encapsulation of β-Galactosidase on T4 Phage for Enhanced Biocatalytic Performance

Enzymes, key catalysts in biochemical reactions, are prone to denaturation under harsh conditions, leading to reduced stability and higher costs. Enzyme immobilization, using carriers like magnetic nanoparticles, metal–organic frameworks, and viruses, is a common solution. T4 bacteriophage, a virulent E. coli phage containing 155 Hoc and 870 Soc proteins, offers a cost-effective and highly stable platform for enzyme immobilization. In this study, Soc-β-galactosidase (Soc-β-gal) was immobilized on the surface of T4 bacteriophage via affinity fixation and further encapsulated with a metal-polyphenol network (MPN) coating. Comparative analysis of the biochemical properties revealed that the immobilized enzyme, β-gal T4, retained over 85% activity after 6 h at 50 °C, while free Soc-β-gal retained only 40.63%. Moreover, β-gal T4@TA-Ti demonstrated superior stability, retaining 92.88% of its activity after 6 h of UV exposure, compared to 10.21% for β-gal T4 and 7.23% for Soc-β-gal. The MPN coating also enhanced resistance to proteolytic degradation, with β-gal T4@TA-Ti retaining 9.48% of its activity after exposure to proteinase K, in contrast to 4.62% for β-gal T4. Overall, these results demonstrate that enzyme immobilization significantly enhances stability, while the MPN coating further improves resistance to extreme pH, ultraviolet radiation, and other environmental stressors, highlighting the potential of this approach for biocatalytic applications.