A Review on the Prospective Applications of Fungal Keratinases

Keratin is the most abundant insoluble protein in the epithelial cells of vertebrates and represents the major constituents of skin, hair, feathers, wool, and nails. It is among the hardest-to-degrade animal protein, the major component in poultry feathers. Keratinases are exciting proteolytic enzymes that display the capability to degrade the insoluble protein keratin, recalcitrance to common proteolytic enzymes like pepsin, trypsin, and papain. Keratinases are versatile enzymes gaining momentum in the field of Biotechnology with potential applications. As the keratin is too hard to degrade, substrates like hair, hoof, horn, feather nail etc. can be treated effectively with keratinases, which is considered as the remarkable application of the enzyme. The poultry feather degradation using keratinase improve the nutritional value of feather meal and can be applied for the production of rare amino acids like proline, cysteine, serine, and methionine. The potential use of these enzymes have been associated with cosmetic industry and acne treatment. The other applications of keratinase include the production of biofuel, detergent, films, coatings, glues and pesticidal toxins, degumming of silk, scale removal from wool fibre, degradation of prions etc. Keratinases are mainly produced by different microorganisms like fungi and bacteria which are considered as biodegradable, eco-friendly enzymes without any harmful effects like that of the chemical counterparts. As the separation of bacterial keratinase is a cost intensive process compared to fungal keratinase, the review is focussed on isolation, purification and prospective applications of fungal keratinase.