Microbial production and industrial applications of keratinases: an overview

Massive production of keratinaceous byproducts in the form of agricultural and industrial wastes throughout the world necessitates its justified utilization. Chemical treatment of keratin waste is proclaimed as an eco-destructive approach by various researchers since it generates secondary pollutants. Microbial degradation of keratin waste is an emerging and eco-friendly approach and offers dual benefits, i.e., treatment of recalcitrant pollutant (keratin) and procurement of a commercially important enzyme (keratinase). This review summarizes the potential utility of some bacterial and fungal species for the production of keratinase using a variety of keratinaceous wastes as growth substrates. The application of microbial keratinases in waste management; animal feed, detergent, and fertilizer manufacturing; and leather, cosmetic, and pharmaceutical industries is also abridged in this review.