الفهرس 
Growth and keratinase activity of some fungal speciesOnly 14 pages are availabe for public view
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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 .