Bacillus sp. L21 was isolated from the by-products of a leather factory (located in Izmir, Turkey) working under extreme alkaline conditions. Its phenotypic and genotypic identifications were completed, and determined as a potential alkaline protease producer. After screening various elements. carbon and nitrogen sources, soybean meal, maltose50, tween80 and the initial pH conditions were chosen as main factors to be used in the experimental design and response surface methodology (RSM) for the optimization of a low cost enzyme producing media for potential use on an industrial scale. The optimized values obtained by the statistical analysis showed that soybean meal at 3.0 g/l, maltose50 between the ranges of 30 and 40 0, tween80 at 0.35 g/l and an initial pH of 8.0 gives maximum protease activity. (c) 2005 Elsevier Ltd. All rights reserved.