The aim of this research study was to develop hydrogels samples for using in potential biomedical applications. Hydrogels consisting of different volumes of keratin, polyvinyl alcohol (PVA), Polyvinylpyrrolidone (PVP), and starch. The keratin is derived from the chicken was the primary material on the hydrogels due to attractively for the potential wound healing application. The hydrogel samples were made by using the freeze‑thawing method, and they were examined using the Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), porosity amusement, swelling ratio and keratin release kinetic models that analyzed using (zero-order, first-order Higuchi and Korsmeyer-Peppas models). These results were indicated that feather keratin could use with formulated hydrogels suitably for controlled keratin release studies .

Biopolymers based on plant and animal proteins are interesting alternatives in the development of films with future prospects as food packaging. Considering that in recent years there has been an increasing interest in the valorization of agro-industrial residues and by-products and that the blending of polymers can lead to materials with improved properties, in this work, keratin-rich feather fibers and gliadins were blended at different ratios in order to develop sustainable and biodegradable films. Control gliadin G100, feather F100 films and their blends at 3:1 (G75F25) , 2:2 (G50F50) and 1:3 (G25F75) ratios were successfully developed through thermoprocessing. The physical properties were differentiated as a function of the concentration of both polymeric matrices. Although gliadins showed higher hydrophilicity confirmed by its highest swelling degree, films with high gliadin ratios exhibited lower water permeability values at low and medium relative humidities. On the other hand, the feathers displayed the highest Young´s modulus values and provided oxygen barrier to the blends, principally at the highest relative humidity. In conclusion, the blend of these protein-based polymers at different ratio resulted on interesting composites whose physical properties could be adjusted.

Abstract: There are a large number of cross-linked chemical bonds such as tight disulfide bonds, hydrogen bonds,and salt bonds in keratin, which makes it difficult to break the structural stability of the protein using conventional methods. The degradation of feather waste using keratinases produced by microorganisms has the advantage of being efficient and environmentally friendly. In this study, 23 strains capable of producing transparent circles were obtained via preliminary screening with skim milk as the sole carbon and nitrogen source, and 9 strains capable of degrading feathers were obtained via rescreening with feathers as the sole carbon and nitrogen source. Finally, through the determination of enzyme activity, the strain CY-A with a high ability to degrade feathers was obtained. The strain was identified as Bacillus tequilensis via morphological observation, physiological and biochemical identification, and 16 S rRNA molecular biology. The keratinase gene (bta) of Bacillus tequila was cloned, and its full-length gene sequence was 1110 bp, containing an open reading frame of 1089, encoding 369 amino acids (GeneBank accession number OR733336). The physicochemical properties, secondary structure, and tertiary structure of the recombinant protein were analyzed using bioinformatics tools such as ProtParm, SOPMA, MEGA, and SWISS-MODELS. It was found that the relative molecular mass was 37.953 kD and that the isoelectric point was 8.48. The protein was a hydrophilic protein. The keratinase bta gene was ligated to the expression vector pET28a(+) using T4 ligase, and the recombination expression plasmid pET28-bta was constructed and transformed into E. coli BL21(DE3) to obtain recombinant engineered bacteria. The expressed keratinase was purified using a Ni2+ affinity chromatography column to obtain recombinant bta keratinase bta with a molecular weight of 37.953 kD. The identification and characterization of this keratinase gene provides some theoretical basis for the further enhancement of keratinase activity by means of genetic engineering.

Aquaculture is growing rapidly as a food-producing sector and in recent years, fishmeal prices have climbed by more than twofold on a global scale. This review of previous studies was performed to contribute to the extant literature on the aquaculture sector to aid cost reduction of aquafeeds by identifying substitute protein that can replace fishmeal. The review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) using the SCOPUS and WOS (Web of Science), DOAJ (Directory of Open Access Journals), Academia, and Pubmed Central databases with the following search terms: “fishmeal,” “alternative protein source” and “aquafeeds.” This resulted in 5,331 articles from the SCOPUS and WOS databases. Finally, the titles and abstracts of the articles were screened, giving a total of 162 articles that were used in the study; another 58 articles came from open databases. Results have shown that 100% replacement of fishmeal with blood meal did not affect the growth of fish as well as 75% to 100% combination of poultry-by-product (PBM), feather meal (FEM), and blood meal (BM). Moreover, a 10% replacement of fishmeal using seaweed (Gracilaria arcuata) has no adverse effect on feed efficiency and growth performance of tilapia, a 50% replacement of fishmeal using black soldier fly (Hermetia illucens), and 25% replacement using soybean (Glycine max) also showed better results for fish growth. With that, this review shows that alternative protein can be a great alternative to the aquaculture sector in reducing the cost of aquafeeds since alternative proteins are much cheaper than the usual fishmeal.