The physical factors such as pH and incubation temperature were found to be effective on keratinase activity (10). To determine the optimum pH for highest enzyme activity, B. subtilis was cultured in a mineral medium with sterile feather at different pH. B. subtilis had the highest enzyme activity at pH 11 at the sixth day of incubation. Bacillus spp. usually show optimum keratinase production at temperatures ranging from 30 to 50°C (2, 21, 22). In this study, the enzyme production was studied over a broad range of temperature (20 – 45°C) and optimum temperature was determined for B. subtilis at 40°C at the sixth day of incubation. The results showed that B. subtilis can be used as a potential candidate for degradation of feather. The optimum condition for keratinase activity was determined at pH 11 and 40ºC.