alpha-Amylase fermentation with soluble starch as the limiting substrate was performed by Bacillus amyloliquefaciens. We investigated the influence, of the presence of alpha-amylase, on the hydrolysis of different starch concentrations. Both the initial and average rates for the hydrolysis of starch under different initial conditions were compared and calculated. The time for the completion of starch hydrolysis was also obtained. Effects of kinetic factors, such as pH of 5.5, 6.3, 7.0 and temperature of 30 degrees C and 37 degrees C, on the performance of alpha-amylase fermentation were studied. The influence of the dynamic variables, such as agitation speed and aeration rate, on this fermentation were also evaluated and are discussed. The variations of cell mass, alpha-amylase activity, and reducing sugar with regard to the step changes of aeration rates during a batch fermentation are also discussed. The optimal conditions of these variables have been determined.