Studies On Effective Extraction Of Chicken Feather Keratin And Its Applications In Controlling Drug Release Materials

Population and economic growth worldwide has caused an enormous increase in waste production. To minimize this problem, alternative waste solutions are being studied, such as the recycling of abandoned biopolymers and the substitution of conventional synthetic polymer materials with biopolymers. Feather, hair, wool, nails and so on, the most abundant keratinous biomass worldwide, are a valuable and renewable protein source. However, they are currently an important waste product in the poultry industry, causing an environmentally difficult disposal problem as they are not efficiently extracted and applied. The aim of this paper was to determine a simple and effective method of reutilize keratins from disused chicken feathers.Firstly, on the basis of introducing the research progress of abandoned biopolymers, the extracted methods of keratins and their applications in all aspects of life were reviewed. Then, we summarized the problems of extraction and application of keratins currently.Secondly, we reported a simple method to reutilize disused feathers. Some treatment conditions, such as temperature, time, pH value and dosages of the reagents, had a significant influence on the yield and the molecular weight of the extracted keratin. Therefore, all of these factors were investigated. And the optimal processes and conditions for extracting up to 90% of the keratins from feathers were given. Meanwhile, the extracted feather keratin was characterized using FT-IR Spectroscopy, Circular Dichroism (CD), MALDI–TOF MS, Scanning electron microscopy (SEM), TG measurement, Elemental Analysis and Amino Acid Analysis. It is concluded that the molecular weight of the feather keratins extracted in this paper was 20.460 kDa, it contains scores of cysteine residues (14-15%). And a keratin chain was about 67nm. Based on the results of FT-IR and CD, it is considered that the secondary structure of feather keratin mainly consisted of theβ–sheet conformation. During the extraction procedure, theβ–sheet conformation was partly destroyed, and the keratin chains had a random coil conformation. Thirdly, the reduced keratins could be re-oxidized easily in air, In order to prevent aggregation of the extracted keratins, carboxy compounds, such as glycin and chloroactic acid, were used to modify the extracted keratins. It was found that the extracted keratins did not re-aggregate when carbonyl compounds were introduced to cysteine residues of keratins. This meant that completely soluble keratin was obtained. The obtained reversible water-soluble derivatives may be applied in many fields, such as cosmetics, iatrical and officinal materials, and biodegradable materials.In finally, the films based on the extracted keratin were easily prepared. They showed good mechanical properties. Furthermore, the feather keratin films were used to load and release drugs. The resultant feather keratin films were pH-responsive and showed controllable drug-release behavior. In summary, we found a kind of new cheaper materials for preparation of films. It could be attractive candidates for applications in the biomedical field. Meanwhile, we found a simple method to reutilize disused feathers.