Bacillus sp. CSK2 produced thermostable alkaline keratinase using agro-wastes: keratinolytic enzyme characterization
- PDF / 3,166,660 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 2 Downloads / 140 Views
RESEARCH ARTICLE
Open Access
Bacillus sp. CSK2 produced thermostable alkaline keratinase using agro-wastes: keratinolytic enzyme characterization Nonso E. Nnolim1,2 and Uchechukwu U. Nwodo1,2*
Abstract Background: Chicken feathers are the most abundant agro-wastes emanating from the poultry processing farms and present major concerns to environmentalists. Bioutilization of intractable feather wastes for the production of critical proteolytic enzymes is highly attractive from both ecological and biotechnological perspectives. Consequently, physicochemical conditions influencing keratinase production by Bacillus sp. CSK2 on chicken feathers formulation was optimized, and the keratinase was characterized. Results: The highest enzyme activity of 1539.09 ± 68.14 U/mL was obtained after 48 h of incubation with optimized conditions consisting of chicken feathers (7.5 g/L), maltose (2.0 g/L), initial fermentation pH (5.0), incubation temperature (30 °C), and agitation speed (200 rpm). The keratinase showed optimal catalytic efficiency at pH 8.0 and a temperature range of 60 °C – 80 °C. The keratinase thermostability was remarkable with a half-life of above 120 min at 70 °C. Keratinase catalytic efficiency was halted by ethylenediaminetetraacetic acid and 1,10-phenanthroline. However, keratinase activity was enhanced by 2-mercaptoethanol, dimethyl sulfoxide, tween-80, but was strongly inhibited by Al3+ and Fe3+. Upon treatment with laundry detergents, the following keratinase residual activities were achieved: 85.19 ± 1.33% (Sunlight), 90.33 ± 5.95% (Surf), 80.16 ± 2.99% (Omo), 99.49 ± 3.11% (Ariel), and 87.19 ± 0.26% (Maq). Conclusion: The remarkable stability of the keratinase with an admixture of organic solvents or laundry detergents portends the industrial and biotechnological significance of the biocatalyst. Keywords: Keratinase, Bacillus sp., Chicken feathers, Valorization, Thiol group, Laundry detergent
Background Keratinases (EC 3.4.21/24/99.11) are inducible proteolytic enzymes that mediate the bioconversion of insoluble keratinous protein into smaller organic molecules including functional peptides and amino acids [1]. The enzymes have been reported to disintegrate keratin either in synergy [2], or isolation [3] of sulfitolytic systems. Keratinases are mostly serine or metallo-class of protease, and are distinct * Correspondence: [email protected] 1 SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice 5700, South Africa 2 Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314, Alice 5700, South Africa
from classic proteases owing to their ability to degrade keratin which is the major structural constituent of avian feathers, hair, hooves, nails and horns. Keratinous biomass are generated in significant quantities from commercial slaughterhouses, and poultry and leather processing industries [4]. The recalcitrant tendency of keratinous residues poses disposal challenge which leads to a lo
Data Loading...
