Construction of β-galactosidase-inorganic hybrid nanoflowers through biomimetic mineralization for lactose degradation

Herein, β-galactosidase (β-Gal) was successfully encapsulated in Cu3(PO4)2-based hybrid nanoflowers through biomimetic mineralization to prepare immobilized enzyme β-Gal@Nanoflower. The catalytic activity of β-Gal was detected using o-nitrophenyl-β-D-galactopyranoside as the substrate. Compared with free β-Gal, β-Gal@Nanoflower possessed superior catalytic activity and stability, even in harsh conditions (e.g., high temperature, acidic or alkali environment and in the presence of metal ions). More importantly, β-Gal@Nanoflower exhibited favourable long-term storage stability and reusability, with catalytic activity remaining at 74.8% and 70.1% after being stored at 25 °C for 5 weeks or repeatedly used for 15 cycles. Finally, β-Gal@Nanoflower was successfully applied in the decomposition of lactose, with substrate conversion of 82.0% in the first cycle. Taken together, β-Gal@Nanoflower showed excellent catalytic activity, high stability and reusability, providing an effective platform to facilitate the application of immobilized β-Gal in the industrial production of lactose-free dairy products.