Extraction of soluble keratin from poultry feathers and its properties

Protein-compound keratin is one of the most durable bio-based materials. More than 90% of poultry feathers consist of hard proteins in the keratin structure. It is interesting to evaluate these animal wastes due to their recyclable properties. The main purpose of this study is to recover keratin from poultry waste feathers and examine its structural properties. Feathers collected from slaughterhouses in the Al-Anbar-Iraq region were used in the research. Keratin extraction was carried out from washed and oven-dried feathers using sodium bisulfite, sodium dodecyl sulfate and urea. Physical/chemical characterizations of the extracted keratin were performed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray Spectroscopy (EDS) and X-ray diffractometry (XRD) analyses. FTIR, SEM, EDS and XRD analyzes confirmed the structural form of the sulfated fibrous protein of the obtained keratin model. While FTIR analysis determined the peptide bond (O=C-NH) structure between the carboxyl groups of amino acids, Amide I, Amide II, Amide III parts were detected in the keratin content. In SEM analysis, it was determined that the keratin surface had a morphologically very porous form. EDS and SEM analyzes revealed that the amounts of the elements, which are the structural components of keratin, were different in the intermediate, dorsal and ventral layers and filament parts. XRD results showed that the extracted keratin had a semi-crystalline structure. EDS and SEM analyzes revealed that the amounts of the elements, which are the structural components of keratin, were different in the intermediate, dorsal and ventral layers and filament parts. XRD results showed that the extracted keratin had two types, α and β, and a semi-crystalline structure. It is thought that this study will contribute to studies on bringing animal waste, which poses a risk to the environment, into a circular economy by using abundant and easily accessible feathers as raw materials to obtain keratin.