الفهرس | Only 14 pages are availabe for public view |
Abstract Keratinases are a group of proteolytic enzymes that able to hydrolyze insoluble keratins into peptides and amino acids, further metabolized as a carbon and nitrogen source . The keratinolytic enzymes are used for unhairing and in tanning industry, leather processing as components of various detergents and manufacture of pharmaceutical chemicals. Therefore the aim of this study was to screen microorganisms with high ability to degrade the keratinous wastes, especially chicken feathers and to exploit for the application of keratinases in waste resources. This investigation included search for productive fungal species, screening and selection for the efficient fungi. Nutritional and environmental factors influencing the production of keratinase enzyme were studied. A potent local fungal isolates were identified as Aspergillus niger, A. flavus, A. fumigatus, A. parasiticus, Penicillium chrysogenum, Alternaria alternata, and Fusarium verticilliodes. Using additional carbon and nitrogen sources were found to promote keratinases productivity. Among different keratin containing wastes, chicken, duck, goose, turkey and pigeon feathers were the most degradable keratinous wastes by A. flavus, A. fumigatus and Alternaria alternata.. during the course of investigation, keratinase production and degradation of keratinous wastes positively and significantly correlated. The incubation periods for keratinase production were 15 and 20 days. Therefore, keratinous wastes can be biologically degraded by either isolated fungi or their keratinases into useful products. Cultivation conditions are essential in successful production of an enzyme, and optimization of parameters such as pH, temperature and media composition are important in developing the cultivation process. The optimum temperature and pH for keratinase production from fungal isolates depend on the type of microorganisms and the condition of production. Key words: Keratin, Keratinous wastes, Enzyme production, degradation, Optimization , Keratinophilic fungi . |