Application of recombinant hyperthermostable keratinase for degradation of chicken feather waste

Keratinase can degrade the complex protein structure, especially keratin from feathers resulting in short peptides and amino acids. Nowadays, the use of keratinase to degrade feathers in industry is worldwide because degradation products improve the value of feather waste for animal feed. Geoglobus acetivorans has specific gene (GacK) that can produce hyperthermostable keratinase enzyme. Thus, this research aimed to study the application of recombinant intracellular keratinase expressed in E. coli BL21 (DE3) to degrade poultry feather waste from the industry. The feather wastes were treated with the recombinant enzyme under harsh conditions of pH, temperature, EDTA and surfactants. The GacK enzyme was found to have keratinase activity, thermostability, EDTA and nonionic surfactant tolerance. GacK exhibited a potential stability at pH 9 after 1 h of feather degradation. With chicken feathers as substrate, GacK showed the highest specific activity of 481.63 ± 0.075 U/mg, the Km values of 1.38 ± 0.19 mg/ml, and the Vmax values of 505.46 ± 16.36 U/mg. Here, for the first time, it has been demonstrated that this recombinant hyperthermostable GacK, keratinase can efficiently degrade chicken feather waste from the industry. The findings of this investigation could be useful to the poultry industry in terms of proper chicken feather waste handling.