Abstract
Microbial keratinases’ versatility in the beneficiation of keratinous waste biomass into high-value products prompts their application in diverse spheres hence, advancing green technology and the bioeconomy. Consequently, a feather-degrading Chryseobacterium aquifrigidense FANN1 (NCBI: MW169027) was used to produce keratinase, and its biochemical properties were determined. The optimization of physicochemical parameters and analysis of the free amino acid constituents of the feather hydrolysate were also carried out. FANN1 showed a maximum keratinase yield of 1,664.55 ± 42.43 U/mL after 72 h, at optimal process conditions that included initial medium pH, incubation temperature, inoculum size, and chicken feather concentration of 8, 30°C, 4% (v/v), and 15 (g/L), respectively. Analysis of degradation product showed 50.32% and 23.25% as the protein value and total free amino acids, respectively, with a relatively high abundance of arginine (2.25%) and serine (2.03%). FANN1 keratinase was optimally active at pH 8.0 and relatively moderate to high temperature (40–50°C). EDTA and 1,10-phenanthroline inhibited the keratinase activity, and that suggests a metallo-keratinase. The enzyme showed remarkable stability in the presence of chemical agents, with residual activity 141 ± 10.38%, 98 ± 0.43%, 111 ± 1.73%, 124 ± 0.87%, 104 ± 3.89%, 107 ± 7.79%, and 112 ± 0.86% against DTT, H2O2, DMSO, acetonitrile, triton X-100, tween-80, and SDS, respectively. The residual activity of FANN1 keratinase was enhanced by Sunlight (129%), Ariel (116%), MAQ (151%), and Surf (143%) compared to the control after 60 min preincubation. Likewise, the enzyme was remarkably stable in the presence Fe3+ (120 ± 5.06%), Ca2+ (100 ± 10.33%), Na+ (122 ± 2.95%), Al3+ (106 ± 10.33%); while Co2+ (68 ± 8.22%) and Fe2+ (51 ± 8.43%) elicited the most repressive effect on keratinase activity. The findings suggest that C. aquifrigidense FANN1 is a potential candidate for keratinous wastes bio-recycling, and the associated keratinase has a good prospect for application in detergent formulation.
Highlights
In recent years, investment increase in the agro-industrial sector is evident for food security sustenance for the teeming population
The inoculum size evaluation indicated that keratinase activity increased in a stepwise manner from 667.27 ± 15.42 U/mL, 716.36 ± 10.28 U/mL, 724.55 ± 16.71 U/mL to 782.72 ± 26.99 U/mL following the increase in bacterial cell concentrations from 1 to 4% (v/v), respectively (Figure 1B)
The influence of incubation temperature was investigated, and the results showed that the keratinase production was maximum (793.64 ± 8.99 U/mL) at 30°C (Figure 1C)
Summary
Investment increase in the agro-industrial sector is evident for food security sustenance for the teeming population. The vast tons of agro-wastes generated from this economic sector have been a global concern due to their associated environmental challenges (Falade, 2021). Non-food agro-waste residues with sturdy characteristics have become a burden to society and the environment. The need for sustainable beneficiation and management approach for these renewable resources. The poultry industry is a significant player as per contribution to the substantial agro-waste biomass generated. Most of the wastes from the poultry processing farms are keratinous. The abundance of keratin in chicken feathers impairs the natural degradability of the biomass in the environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
