Study on Obtaining Keratin Extracts from Leather Industry By-Products

Keratin is a biopolymer with numerous functional properties for the production of biomaterials with applications such as: additives for cosmetics, biostimulator for growth and nutrition in agriculture, ecological treatments in reconstruction and protection of leather and furs, as alternative to pollutant chemical compounds. In most of the applications, in either large or niche industries, keratin is used as gels, films, nano- or micro-particles. This study presents the possibilities of using thermal and enzymatic processes of leather industry by-products to obtain keratin extracts. Keratin extracts were characterized by chemical and instrumental analyses: gravimetric, volumetric, potentiometry, Polyacrylamide Gel Electrophoresis, Infrared Spectroscopy, High-Performance Liquid Chromatography, Dynamic Light Scattering. Analytical investigation has shown that the keratin extracts obtained as polydispersions with 5% dry matter have 14% total nitrogen and contain 50% small and medium sized particles (10-500 nm range), such as free amino acids and oligopeptides and 50% larger sized particles (500-5560 nm ranges) such as polypeptides. The IR spectrum of keratin extract is similar to the IR spectrum of collagen from leather.