Starch is a high yield feedstock for ethanol production, but its hydrolysis is required to produce ethanol by fermentation. Starch was traditionally hydrolyzed by acids, but the specificity of the enzymes, their inherent mild reaction conditions and the absence of secondary reactions have made the amylases to be the catalysts generally used for this process. α-amylase obtained from thermoresistant bacteria like Bacillus licheniformis or from engineered strains of Escherichia coli or Bacillus subtilis is used during the first step of hydrolysis of starch suspensions.. For amylases to attack starch, these suspensions should be brought to high temperatures (90–110 °C) for the breakdown of starch kernels. Apar and Özbek (2004) provides information about the effects of operating conditions on the enzymatic hydrolysis of corn starch using commercial α-amylase. In last years, the possibility of hydrolyzing starch at low temperatures for achieving energy savings is being investigated (Robertson et al., 2006). The product of this first step, called liquefaction, is a starch solution containing dextrines and small amounts of glucose. The liquefied starch is subject to saccharification at lower temperatures (60–70 °C) through glucoamylase obtained generally fromAspergillus niger or Rhizopus species ( Pandey et al., 2000 and Shigechi et al., 2004).