3.5. Proteases. The quest for novel proteases and their
formulations for industries like detergents, animal feed, and
breweries is observed from several decades. Most of the
proteases reported from Streptomyces spp. are alkali-tolerant,
and some of themare salt tolerant and belong to genera other
than the genus Streptomyces [21]. Proteases fromNocardiopsis
spp. are employed as detergents additives [22] and for the
depilation of hides and skins in the leather industry.
Dehairing of goat skin by proteases from Streptomyces
sp. makes the process economically and environmentally
feasible [23]. Keratin-rich wastes like feathers, hair, nails,
and horn are waste products of agroindustrial processes.
Keratinolytic Streptomyces spp. capable of degrading keratin
at temperatures higher than 50∘C are reported [24]. Some
Streptomyces hydrolyze keratin by pronases as seen for Streptomyces
griseus [24]. Proteases fromother sources are used in
conjunction with enzymes from actinomycetes for recovery
of antioxidants from shellfish waste. Protease production
was also carried by growing Microbispora sp. on the shellfish
waste [25]. End products of protein hydrolysis rich in amino
acids and peptides serve as a low cost animal feed.