Secretory expression in Bacillus subtilis, purification, and characterization of a persistent protein-degrading enzyme from Nocardiopsis sp. TOA-1

Keratinase from Nocardiopsis sp. TOA-1 (NAPase) holds significant potential for industrial and medical applications. Here, we developed a heterologous secretory expression system for NAPase in Bacillus subtilis. The recombinant enzyme exhibited catalytic properties comparable to the native enzyme, demonstrating its suitability for further protein engineering. This work provides a foundation for enhancing NAPase activity and stability, expediting its biotechnological applications.