الفهرس 
1-keratinolytic and keratinophilic fungiOnly 14 pages are availabe for public view
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Abstract
Keratinase have extensive applications in food, feed, pharmaceutical and medical industries. The present study deals with isolation, identification and production of Keratinase by certain thermophilic and fungi locally isolated from soil. The results obtained can be summarized as follows: 1- Forty seven samples of animal manures and thirty eight samples of floor dust were randomly collected from the vicinity of Ayatt City. Keratinophilic and thermophilic fungi were isolated. A total of 26 sp belonging to 15 genera and 23 sp belonging to 17 genera of keratinophilic and thermophilic fungi were identified, respectively. Out of 76 encounters of animal manures Thamnostylum piriforme was the most frequent (10.52 %) followed by Aspergillus brasiliensis = chrysosporium keratinophilum (7.89%) each. 78 encounters were isolated from floor dust. The most frequent was Arachniotus dankaliensis (10.25%) followed by Candida albicans (7.69%). 76 isolates of thermophilic fungi were isolated from animal manure. Aspergillus fumigatus is the most frequent (9.21%) followed by Aspergillus flavus var. columnaris (7.89%). 75 isolates were identified from floor dust. Again, Aspergillus fumigatus is the most frequent (9.33%). Aspergillus brasiliensis = A. carneus = A. flavus var. columnaris = Rasamsonia byssochlamydoides = chrysosporium zonatum (6.66%) each comes second. Keratinophilic and thermophilic fungi were identified.-Five wild isolates were screened for keratinase production, these are: Asergillus Carneus, Asergillus terrus, Malbranchea cinnamomea, Myceliophthora thermophila, and Thermomyces lanuginosus. Only three isolates were chosen as potent producers for keratinase enzyme; Malbranchea Cinamomea, Myceliophthera thermophila, and Thermomyces lanuginosus. All are true thermophiles. Keratinase production by the experimental fungi was optimized under Surface Culture (SC) conditions.A-The optimum pH for keratinase production was pH 5.6 for M. cinnamomea &M. thermophila and 5.2 for T. lanuginosus. B-Maximal production of keratinase was obtained at 40°C for t M. cinamomea and 45°C M. thermophila and T. lanuginosus. C-Maximal production of keratinase was obtained after 7 days of incubation with 1.0 ml (4.6 × 106 spores )of inoculum size for three experimental fungi. In the second part of the study, the effect of solid substrate culture (SSC) technique was investigated.The obtained results can be summarized as follows: The best substrate loadage was (3g/500ml conical flask) of razored chicken feather for three experimental fungi. B- Maximal production of keratinase was obtained after 9 days of incubation for M. cinnamomea & M. thermophila and 11 days for T. lanuginosus at 40°C for M. cinnamomea and at 45°C for M. thermophila and T. lanuginosus of incubation. C- Maximal activity of keratinase was obtained after 60 min. of reaction time for M. cinnamomea at 45°C of reaction temperature and 45& 60 min. of reaction time for M. thermophila and T. lanuginosus, respectively at 50°C. D- Maximal activity of keratinase was obtained at pH 8.0 for M. cinnamomea & M. thermophila and at pH 7.8 for T. lanuginosus, E- Purification of keratinase of the three potent fungi after Sephadex G-25, dialysis and Ion exchange chromatography on bentonite was also adopted. F- Some properties of purified keratinase from M. cinnamomea, M. thermophila and T. lanuginosus, were studied and the following results were obtained A-The optimum reaction temperature was 45°C for M. cinamomea and 50°C for both M. thermophila and T. lanuginosus, the enzyme was stable at a wide range of temperature (40-90 °C) for three experimental fungi. B-The optimum pH was (7.0) the enzyme was stable at a wide range of pH (3.0-8.0) for three experimental fungi.C-Alkaline metal ions Na+, in addition to divalent metal ion Ag2+,Cu2+,Ca2+,Co2+, Mg2+and Mn2+(5 mM & 10 mM); Stimulated the enzyme activity, while Hg2+ and Zn2+ completely inhibited the enzyme activity for three experimental fungi. D-Treatment of the enzyme with the chelating agent EDTA completely inhibited the enzyme activity, PMSF and ME also had partial inhibition effect on the enzyme activity, indicating that it is a metalloproteases. E- The effect of partially purified keratinase on dehairing baby hair, camel hair, goat hair, rabbit fur and sheep wool of three experimental fungi was studied, and 15 h was the best reaction time for each substrate for for M. cinnamomea & M.thermophila and (20) h for T. lanuginosus.Valine was the common essential amino acids in white Leghorn chicken feather hydrolysate of M. cinamomea & M.thermophila and lysine for T. lanuginosus. Glutamic was the most common non- essential amino acids for the three experimental fungi.