Gholamreza Goudarzi - Amirkabir University of Technology
Fatemeh Dadashian - Department of Textile Engineering, Amirkabir University of Technology, Tehran, Iran
Alireza Vatanara - Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran,
Zargham Sepehrizadeh - Department of Biotechnology and Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran

It is highly economical to extract keratin from the waste chicken feathers due to their high keratin content, plentiful availability, and sustainable resources. Various methods of keratin extraction have been reported in the last few decades. In addition, sodium sulfide (Na۲S) treatment has received more attention due to its simplicity and ability to produce on an industrial scale. Although several studies have been conducted on improving keratin extraction yield through Na۲S treatment, there need to be more systematic studies to evaluate and optimize the effect of different extraction parameters and their interactions to maximize extraction efficiency. In this research, the response surface method (RSM) established on the central composite practical design (CCPD) was employed satisfactorily to understand the influence of experimental parameters and their interactions to determine the optimal conditions for keratin extraction. Na۲S concentration, extraction time, and extraction temperature were chosen as the most critical parameters for investigation. Experimentally, the extraction yield of ۹۴±۰.۵% was obtained under the RSM-optimized conditions (i.e. ۸۰ °C, ۶.۳ hr., and ۳۲.۰ g l-۱ Na۲S concentration), which is in close agreement with the model-predicted value (۹۵%). The optimized keratin extraction yield in this study is relatively high. Physicochemical properties of the extracted powder were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results revealed that the extracted material contains both β-keratins and α-keratins, which have great potential for advanced healthcare and medical applications.

Chicken feather, Keratin, Sodium Sulfide treatment, Response Surface Methodology