Analysis of the kinetics of alpha-amylase production in a batch and a fed-batch culture of Bacillus subtilis made it possible to derive a kinetic model of the process describing mutual interactions between growth and production. The specific growth rate is limited by the concentration of both corn-steep liquor and starch. Higher concentrations of reducing sugars in the medium also inhibit growth. The overall production of alpha-amylase is a result of an equilibrium between the rate of enzyme production and its degradation due to the effect of environment. The actual specific production rate is directly proportional to the specific growth rate (characterizing the physiological state of the culture) and is inhibited by higher concentrations of corn-steep liquor in the medium.