An unusual pattern of product inhibition: Batch acetic acid fermentation

The limited tolerance of microorganisms to their metabolic products results in inhibited growth and product formation. The relationship between the specific growth rate, mu , and the concentration of an inhibitory product has been described by a number of mathematical models. In most cases, mu was found to be inversely proportional to the product concentration and invariably the rate of substrate utilization followed the same pattern. In this communication, the authors report a rather unusual case in which the formation rate of a product, acetic acid, increased with a decreasing growth rate of the microorganism, Acetobacter aceti .