Feathers are discarded in large quantities at industrial poultry-processing plants as a waste by-product leading to environmental pollution. Because of the insoluble nature of keratin and its resistance to enzymatic digestion by animal, plant and many known microbial proteases, use of feathers as a source of value-added products has been very limited. Most feather wastes however is land filled or burned, which involves expenses and cause environmental problems. Traditional methods such as steam and pressure and strong alkali or acid usually used in processing feathers required significant...