Effect of gamma irradiation treatment on keratinase production of bacillus licheniformis strains

ABSTRACT

The biochemical changes of the two tested bacterial strains, namely Bacillus licheniformis CF-26, B. licheniformis PWD-28 were studied when were induced by gamma irradiation for the production of keratinase and the utilization of feathers. Chicken feather is an environmental waste of keratinaceous origin. It is obtained annually in huge amounts poor given its degradability and is not efficiently utilized especially in developing countries. In order to improve the production of the keratilytic enzyme using this waste, the gamma rays were employed and variations among the tested bacteria were obtained. Two efficient local bacterial strains [B. licheniformis CF-26 and B. licheniformis PWD-28] were used. The obtained data for gamma irradiation revealed a decrease in the survival probability of the tested bacterial strains. Data also showed that the bacterial cells of the two tested bacterial strains grown in nutrient broth were more sensitive to gamma irradiation than those grown on nutrient agar slant. Some prototrophic and auxotrophic mutants of B. licheniformis PWD-28 significantly increased keratinase activity in all fermentation periods with that of their parent strains. A significant reduction in enzymatic activity was observed for some prototrophic and auxotrophic mutants of B. licheniformis F-26. The results obtained showed a dose-response for mutation frequency, mutagenecity ratio and a relative increase in mutagenecity ratio of gamma irradiation