Optimization of Keratinase Production for Feather Degradation by Bacillus subtilis

Background: The feather is an environmental pollutant that can be degraded by bacterial and fungal microorganisms. The keratin sheets constitute 90% of the feather mass. Due to the extremely rigid structure, keratin is insoluble and hard to degrade. Some microorganisms such as Bacillus spp. were reported to be able to degrade keratin by secretion of keratinase. Objectives: The aim of this study was the isolation of feather degrading Bacillus spp. from a poultry waste and the optimization of conditions for the highest enzyme activity and feather degradation. Materials and Methods: The microorganisms were isolated from the waste of a poultry in Miyaneh, Iran, and the Bacillus spp. were identified using morphological, physiological and biochemical tests. The Bacillus spp. cultured in a medium consisted of feather at pH 7.4 and 27 degrees C for seven days to identify the feather-degrading Bacillus spp. The biochemical tests were performed to determine the strain of the bacterium. The study was repeated under different pH and temperatures to find the optimum conditions for best enzyme activity. Results: The PCR approved the Bacillus genus of the isolates. The strain of Bacillus subtilis was identified using biochemical tests. 40 degrees C and pH 11 are the optimum condition for maximum keratinase enzyme activity. Conclusions: B. subtilis was found to be able to degrade the feather.