An investigation was carried out on enzyme production of an oxidant and SDS-stable alkaline protease secreted by Bacillus clausii I-52 using the submerged fermentation and its application as a detergent additive. Maximum enzyme activity was produced when cells were grown under the submerged fermentation conditions at 37 degrees C for 48 h with an aeration rate of 1.5 vvm and agitation rate of 700 rpm in a medium (pH 10.65) containing (w/v): soybean meal, 20; wheat flour, 10; liquid maltose, 25; K2HPO4, 4; Na2HPO4, 1; MgSO(4)(.)7H(2)O, 0.1; NaCl, 4; FeSO(4)(.)7H(2)O, 0.5; Na2CO3, 6. The alkaline protease produced was found to be highly compatible and stable against not only the commercial detergent components such as alpha-orephin sulfonate and zeolite but also the commercial detergent preparations. Wash performance analysis using EMPA test fabrics revealed that BCAP exhibited high efficiency for the removal of protein stains in the presence of commercial detergents as well as surfactants. These results suggest that the alkaline protease produced from B. clausii I-52 which showed high stability against detergents has significance for an industrial perspective, especially, detergent additive. (c) 2005 Elsevier Inc. All rights reserved.