De‐hairing activity of extracellular proteases produced by keratinolytic bacteria

The depilatory activity of keratinolytic bacteria was investigated. Three keratinolytic bacteria isolated from feather waste were tested for their ability to grow in mineral medium containing bovine hair as sole carbon, nitrogen and energy source. The strains kr2, kr6 and kr10 grew well on bovine hair, producing proteolytic activity as judged by assay with azokeratin as substrate. The proteolytic enzymes from all three strains showed similar pH and temperature optima. Strain kr2 showed mainly serine-type protease activity, whereas kr6 and kr10 enzymes showed metalloprotease characteristics. The culture supernatants were used as crude enzyme preparations for depilatory studies on bovine pelts. All three strains were efficacious in promoting de-hairing. Microscopic analysis revealed that the epidermis was completely removed and the absence of hair in follicles was observed. Proteases of keratinolytic bacteria were efficient in promoting depilation of bovine pelts. Enzymatic de-hairing represents a suitable alternative to the conventional tannery process, with the benefit of avoiding environmental pollution. Copyright © 2003 Society of Chemical Industry