Document Type : Research Paper
Department of Natural and Microbial Products, National Research Centre, Dokki, Cairo, Egypt.
Department of Microbial Chemistry, National Research Centre, Dokki, Cairo, Egypt.
Nine Aspergillus and three of Trichoderma strains were grown on wheat bran (WB) medium under solid state fermentation (SSF) for amylase production. Aspergillus oryzae LS1 produced the highest level of the enzyme. The thermal stability profile of its crude enzyme revealed the half-life time of more than 2 h at 50 and 60ºC. The enzyme production was affected by strain type, incubation periods, level of moisture content and carbon source supplementation. Maximum enzyme production of about 14249 IU/g WB was obtained under optimum conditions with an incubation period of 120 h, an initial moisture content of 54.5% and in the presence of sucrose (1 g/100g WB) at 30ºC. Of substrates tested, soluble starch was the best one hydrolyzed by the crude enzyme. Corn starch, dextrin and potato starch were also hydrolyzed to a lesser extent. The enzyme exhibited maximum activity at 55ºC. Moreover, the enzyme was also able to hydrolyze wheat flour under optimized conditions with efficiency of 89%.