Synthesis of amylase and protease by Aspergillus niger strain UO-1 was followed in media prepared with brewery (BW) and meat (MPW) wastewaters supplemented with different starch concentrations. The highest amylase (70.29 and 60.12 EU/mL) and protease (6.11 and 6.03 EU/mL) production were, respectively, obtained in the BW and MPW media supplemented with 40 g of starch/L of medium after 88 It of fermentation. In addition, the initial chemical oxygen demand (COD) in both wastes was reduced by more than 92%. High amylase and protease activities were found in the BW medium supplemented with casarninoacids, peptone or yeast extract, but ammonium nitrate and sodium nitrate were also good nitrogen sources for amylase production. The stabilities of amylase and protease were higher at 50 degrees C and pH 4.95 and at 53.4 degrees C and pH 3.87, respectively, but they were highly sensitive at temperatures of 70 degrees C or higher. (c) 2005 Elsevier Ltd. All rights reserved.