100 ml salt solution, containing 0.02 g MgSO47H2O, 0.03 g K2HPO4, 0.04 g KH2PO4, 0.02 g CaCl2, and 5 g chopped feather fragments, in 500 ml flasks was autoclaved at 114 C for 15 min. The flasks were then inoculated with 1 % (v/v) of an overnight culture of B.subtilis S1–4 and incubated 37 C for 72 h with shaking. A clarified supernatant was obtained by filtration through four layers of gauze and centrifugation at 15,5009g for 10 min. The supernatant was used for antioxidative activity assay by the ferric reducing ability of plasma (FRAP) method described below.