Bacillus pumilis F3-4 utilized feather as a sole source of carbon, nitrogen and sulfur. Supplementation of the feather medium with glucose or MgSO4 center dot 7H(2)O increased keratinolytic protease production (14.6-16.7 U/mg). The synthesis of keratinolytic protease was repressed by an exogenous nitrogen source. Keratinolytic protease was produced in the absence of feather (9.4 U/mg). Feather degradation resulted in sulfhydryl group formation (0.8-2.6 mu M). B. pumilis F3-4 effectively degraded chicken feather (75%), duck feather (81%) and feather meal (97%), whereas human nails, human hair and sheep wool under went less degradation (9-15%).