Keratinases: emerging trends in production and applications as novel multifunctional biocatalysts

Abstract

Keratinases are proteolytic enzymes capable of degrading rigid and insoluble keratinous proteins present in skin and appendages. They are produced in the keratinous substrates such as feather, hair, wool, nail, horn and hoof by microorganisms. They are mostly serine proteases, although there are very few reports about metallokeratinases. Keratinases are active over wide range of conditions, and are useful in biorecycling of keratin wastes into feed and fertilizers. They also have potential applications in leather, cosmetic, textile, biomedical and detergent industries. The promising applications of keratinases also extend to energy generation and green synthesis of nanoparticles. Owing to their ubiquitous biotechnological applications, techniques such as immobilization, optimization strategies, protein engineering and DNA recombinant technology have been used to improve their activities and stabilities thereby widening the scope for commercialization. This review chronicles recent trends in the production and multi-functional applications of keratinases.