Current Understanding of Feather Keratin and Keratinase and Their Applications in Biotechnology.

The food industry generates substantial keratin waste, particularly chicken feathers, which are rich in amino acids and essential nutrients. However, the insolubility of keratin presents a significant challenge to its conversion. Keratinase, an enzyme produced by certain fungi and bacteria, offers a promising solution by degrading feather keratin into amino acids and soluble proteins. Among these, bacterial keratinase is notable for its superior stability and activity, although its production remains constrained, necessitating continued research to identify efficient microbial strains. Keratin-derived hydrolyzates, recognized for their biological and immunological properties, have garnered significant research interest. This review examines the structural characteristics of chicken feather keratin, its resistance to conventional proteases, and advances in keratinase production and purification techniques. Additionally, the keratin degradation mechanism and the adoption of environmentally friendly technologies for managing feather waste are explored. Finally, the review highlights the potential applications of keratinase across diverse industries, including animal feed and cosmetics.