Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

A Review: Valorization of Keratinous Materials



The aim of the present work was to discuss the current state-of-the-art in the methods of utilization of keratinous materials. Various approaches were discussed—thermal, physical, chemical and biological.


Keratinous wastes can be used as the feedstock, however processing is required to valorize the waste. Among the processing methods, several hydrolytic technologies can be mentioned: hydrothermal methods, enzymatic hydrolysis, bioconversion. Chemical hydrolysis requires the step of neutralization and some nutritive amino acids are lost. Among hydrothermal methods which require high temperature and pressure conditions, acidic hydrolysis assures more complete degradation of keratin than basic. The obtained product can be used as low-quality livestock feed. Another method to obtain solubilized keratin is degradation by lime. More advantageous are enzymatic and bioconversion methods which assure milder conditions and preserve nutritional properties of the produced meal.


The hydrolyzate can be used as the source of amino acids and peptides in the production of feeds and fertilizers.

This is a preview of subscription content, log in to check access.


  1. 1.

    Daroit, D.J., Correa, P.F., Brandelli, A.: Keratinolytic potential of a novel Bacillus sp. P45 isolated from the Amazon basin fish Piaractus mesopotamicus. Int. Biodet. Biodegr. 63, 358–363 (2009)

  2. 2.

    Vesela, M., Friedrich, J.: Amino acid and soluble protein cocktail from waste keratin hydrolysed by a fungal keratinase of Paecilomyces marquandii. Biotechnol. Bioprocess Eng. 14, 84–90 (2009)

  3. 3.

    Moreira, F.G., de Souza, C.G.M., Costa, M.A.F., Reis, S., Peralta, R.M.: Degradation of keratinous materials by the plant pathogenic fungus Myrothecium verrucaria. Mycopathologia 163, 153–160 (2007)

  4. 4.

    Onifade, A.A., Al-Sane, N.A., Al-Musallam, A.A., Al-Zarban, S.: A review: potentials for biotechnological applications of keratin-degrading microorganisms and their enzymes for nutritional improvement of feathers and other keratins as livestock feed resources. Bioresource Technol 66, 1–11 (1998)

  5. 5.

    Choi, J.M., Nelson, P.V.: Developing a slow-release nitrogen fertilizer from organic sources. 2. Using poultry feathers. J. Am. Soc. Horticul. Sci 121, 634–638 (1996)

  6. 6.

    Collins, S.N., Cope, B.C., Hopegood, L., Latham, R.J., Linford, R.G., Reilly, J.D.: Stiffness as a function of moisture content in natural materials: characterisation of hoof horn samples. J. Mater. Sci. 33, 5185–5191 (1998)

  7. 7.

    Grazziotin, A., Pimentel, F.A., de Jong, E.V., Brandelli, A.: Nutritional improvement of feather protein by treatment with microbial keratinase. Anim. Feed Sci. Tech. 126, 135–144 (2006)

  8. 8.

    McLean, C.M., Koller, C.E., Rodger, J.C., MacFarlance, G.R.: Mammalian hair as an accumulative bioindicator of metal bioavailability in Australian terrestrial environments. Sci. Total Environ. 407, 3588–3596 (2009)

  9. 9.

    Kurbanoglu, E.B.: Enhancement of citric acid production with ram horn hydrolysate by Aspergillus niger. Biores. Technol. 92, 97–101 (2004)

  10. 10.

    Suzuki, Y., Tsujimoto, Y., Matsui, H., Watanabe, K.: Decomposition of extremely hard-to-degrade animal proteins by thermophilic bacteria. J. Biosci. Bioeng. 102, 73–81 (2006)

  11. 11.

    Coward-Kelly, G., Chang, V.S., Agbogbo, F.K., Holtzapple, M.T.: Lime treatment of keratinous materials for the generation of highly digestible animal feed: 1 Chicken feathers. Bioresource Technol 97, 1337–1343 (2006)

  12. 12.

    Tsuboi, Y., Kimoto, N., Kabeshita, M., Itaya, A.: Pulsed laser deposition of collagen and keratin. J. Photoch. Photob. C 145, 209–214 (2001)

  13. 13.

    Tanabe, T., Okitsu, N., Yamauchi, Y.: Fabrication and characterization of chemically crosslinked keratin films. Mat. Sci. Eng. C 24, 441–446 (2004)

  14. 14.

    Yamauchi, K., Yamauchi, A., Kusunoki, T., Kohda, A., Konishi, Y.: Preparation of stable aqueous solution of keratins, and physiochemical and biodegradational properties of films. J. Biomed. Mater. Res. 31, 439–444 (1996)

  15. 15.

    Dalev, P., Neitchev, V.: Reactivity of alkaline proteinase to keratin and collagen containing substances. Appl. Biochem. Biotechnol. 27, 131–138 (1991)

  16. 16.

    Gupta, R., Ramnani, P.: Microbial keratinases and their prospective applications: an overview. Appl. Microbiol. Biotechnol. 70, 21–33 (2006)

  17. 17.

    Kida, K., Morimura, S., Noda, J.: Enzymatic hydrolysis of the horn and hoof of cow and buffalo. J. Ferment. Bioeng. 80, 478–484 (1995)

  18. 18.

    Coward-Kelly, G., Agbogbo, F.K., Holtzapple, M.T.: Lime treatment of keratinous materials for the generation of highly digestible animal feed: 2. Animal hair. Biores. Technol. 97, 1344–1352 (2006)

  19. 19.

    Bertsch, A., Coello, N.: A biotechnological process for treatment and recycling poultry feathers as a feed ingredient. Biores. Technol. 96, 1703–1708 (2005)

  20. 20.

    Kumar, C.G., Takagi, H.: Microbial alkaline proteases: from a bioindustrial viewpoint. Biotechnol. Adv. 17, 561–594 (1999)

  21. 21.

    Balint, B., Bagi, Z., Toth, A., Rakhely, G., Perei, K., Kovacs, K.L.: Utilization of keratin-containing biowaste to produce biohydrogen. Appl. Microbiol. Biotechnol. 69, 404–410 (2005)

  22. 22.

    El-Refai, H.A., AbdelNaby, M.A., Gaballa, A., El-Araby, M.H., Abdel-Fattah, A.F.: Improvement of the newly isolated Bacillus pumilus FH9 keratinolytic activity. Proc. Biochem. 40, 2325–2332 (2005)

  23. 23.

    Anwar, A., Saleemuddin, M.: Alkaline proteases: a review. Biores. Technol. 64, 175–183 (1998)

  24. 24.

    Kurbanoglu, E.B., Kurbanoglu, N.I.: Production of citric acid from ram horn hydrolysate by Aspergillus niger. Proc. Biochem. 38, 1421–1424 (2003)

  25. 25.

    Kurbanoglu, E.B., Kurbanoglu, N.I.: Utilization for lactic acid production with a new acid hydrolysis of ram horn waste. FEMS Microbiol. Lett. 225, 29–34 (2003)

  26. 26.

    Kurbanoglu, E.B., Kurbanoglu, N.I.: Utilization as peptone for glycerol production of ram horn waste with a new process. Energ. Convers. Manag. 45, 225–234 (2004)

  27. 27.

    Kurbanoglu, E.B.: Enhancement of glycerol production with ram horn hydrolysate by yeast. Energ. Convers. Manage. 44, 2125–2133 (2003)

  28. 28.

    Kurbanoglu, E.B., Algur, O.F.: The influence of ram horn hydrolyzate on the crop yield of the mushroom Agaricus bisporus. Sci. Hortic. 94, 351–357 (2002)

  29. 29.

    Kurbanoglu, E.B., Kurbanoglu, N.I.: A new process for the utilization as peptone of Ram Horn waste. J. Biosci. Bioeng. 94, 202–206 (2002)

  30. 30.

    Kurbanoglu, E.B., Algur, O.F.: Single-cell protein production from ram horn hydrolysate by bacteria. Biores. Technol. 85, 125–129 (2002)

  31. 31.

    Barrena, R., Pagans, E., Artola, A., Vazquez, F., Sanchez, A.: Co-composting of hair waste from the tanning industry with de-inking and municipal wastewater sludges. Biodegradation 18, 257–268 (2007)

  32. 32.

    Endres, L., Mercier, H.: Amino acid uptake and profile in bromeliads with different habits cultivated in vitro. Plant Physiol. Biochem. 41, 181–187 (2003)

  33. 33.

    Cahill, T.M., Anderson, D.W., Elbert, R.A., Perley, B.P., Johnson, D.R.: Elemental profiles in feather samples from a mercury-contaminated lake in Central California. Arch. Environ. Contam. Toxicol. 35, 75–81 (1998)

  34. 34.

    Poole, A.J., Church, J.S., Mickey, G.: Huson environmentally sustainable fibers from regenerated protein. Biomacromolecules 10, 1–8 (2009)

  35. 35.

    Daroit, D.J., Correa, P.F., Brandelli, A.: Keratinolytic potential of a novel Bacillus sp. P45 isolated from the Amazon basin fish Piaractus mesopotamicus. Int. Biodet. Biodegr. 63, 358–363 (2009)

Download references


The work was supported by Polish Ministry of Science and Higher Education—project nr N N204 019135, NR05-0008-06/2009, NR05-0014-10/2010.

Author information

Correspondence to Katarzyna Chojnacka.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Chojnacka, K., Górecka, H., Michalak, I. et al. A Review: Valorization of Keratinous Materials. Waste Biomass Valor 2, 317–321 (2011).

Download citation


  • Keratinous materials
  • Utilization
  • Livestock feed
  • Fertilizers
  • Valorization
  • Keratinous materials