Valorization of keratin based waste

Chandrakant R. Holkar, Saransh S. Jain, Ananda J. Jadhav, Dipak V. Pinjari

Research output: Contribution to journalArticlepeer-review


Keratin is considered a major animal product. It can be obtained from the sources such as animal feathers, hair, hoof, and nails. Such keratinous materials have high protein content, consisting of at least 17 amino acids which can be used for purposes such as nutrition in animal feed or fertilizers. However, these materials are hardly digestible because of the highly-structured di-sulphide linked polypeptides which must be cleaved before utilization. Degradation of keratin waste can therefore provide an inexpensive source of digestible protein and amino acids. Methods known to degrade keratin include hydrolysis under pressure while using steam, enzymatic hydrolysis or chemical hydrolysis with e.g. base, acid or other reactive agent such as ozone, hydrogen peroxide etc. Current paper is a review of the recent trends in the valorization of the keratinous substances, namely wool, feather and hair. In this review, various upcoming and established techniques to utilize these wastes are studied and their methods, advantages and disadvantages are compiled. A near-complete degradation is deemed possible using certain methods as in the cases of the ionic liquids, the reduction using thiols and tertiary-phosphines, the High Density Steam Flash Explosion, and the enzymatic keratinolysis. The cost and time required however, may make them infeasible. Thus, the optimum method may be chosen based on their product, its value, cost of the process and the time required for its completion.
Original languageEnglish
Pages (from-to)85-98
JournalProcess Safety and Environmental Protection
Publication statusPublished - Sept 2017


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