Production of alkaline protease by a new Bacillus subtilis isolate for use as a bating enzyme in leather treatment

Bacillus subtilis, isolated from tannery waste, produced an alkaline protease at optimal activity when grown in a casein/gelatine medium in a stirred tank fermenter at 37 degrees C with the dissolved oxygen tension at 40% air saturation. Optimum protease activity (223 U ml(-1)) was at pH 8.5 and was stable for 1 h up to 45 degrees C but at 60 degrees C lost 80% activity. Use of the crude protease as a bating agent for producing high quality leather is indicated. Tensile strength, bursting strength, tear strength and elongation at break of prepared leather were increased with increasing amounts of protease used for bating.