Extraction of Keratin from Poultry Feathers with Choline Chloride-Oxalic Acid Deep Eutectic Solvent

A great amount of poultry feathers wastes are produced every year in the world, leading to the discard of keratin resources and causing environmental pollution. The recycling of poultry feathers keratin is of great significance to the protection of environment and utilization of resource. In this work, poultry feathers were dissolved in a dissolution system composed of deep eutectic solvent (choline chloride (ChCl) and oxalic acid (OA) mixed in a certain molar ratio) and deionized water. After dissolution, dialysis, and filtration, the water soluble and insoluble extraction fractions were obtained and separated. The effects of dissolution system composition, dissolution temperature, and dissolution time on the dissolution of poultry feathers and keratin extraction were evaluated. Under the dissolution conditions of ChCl/OA=1:2, mwater=30 wt%, 80 °C×6 h, the dissolution rate of poultry feathers reached more than 90 %, and the total extraction yield was nearly 30 %. The results of SEM, FTIR, Raman spectra, and XRD data showed that the secondary structure of poultry feathers’ macromolecules changed obviously during the process of dissolution and extraction. The results of TGA and DTG showed that insoluble extraction fraction had better thermal stability than soluble extraction fraction.