Subcritical water hydrolysis of poultry feathers for amino acids production.

This study assessed the subcritical water hydrolysis (SWH) of poultry feathers to recover amino acids. Experiments were conducted in a semi-continuous flow-through subcritical reactor (110 mL), which was operated over a range of temperatures (210–250 °C) and water flow rates (5–15 mL min–1), combined through a 22 central composite design, at constant feed (10 g) and pressure (15 MPa). The results demonstrated that non-essential and essential amino acids were obtained from SWH of poultry feathers. The highest hydrolysis temperature resulted in the highest concentrations of valine, methionine, tryptophan, phenylalanine, isoleucine, leucine, and lysine. Otherwise, threonine, histidine, and arginine were obtained more effectively at lower temperatures. The response surface methodology was adopted to identify the best conditions for amino acid production, and it was possible to identify the ranges of temperatures and water flow rates to be used to recover specific amino acids. This study allowed concluding that SWH is a promising eco-friendly technology to recover amino acids from protein-rich wastes. [Display omitted] • Subcritical water hydrolysis (SWH) was used to obtain amino acids from poultry feathers. • Hydrolysis temperature and water flow rate were investigated. • The highest amino acid yield was 2.7 ± 0.2 g L−1 at 250 °C and 5 mL min−1. • Alanine, proline, and tryptophan were the main amino acids recovered. • SWH is a chemical-free alternative to produce amino acids from poultry feathers. [ABSTRACT FROM AUTHOR]