A model for adaptation of microorganisms to nitrates

A simple variation of Monod kinetics is presented which describes extended lag phases observed in microbial cultivation. This variation of Monod kinet ics can be expressed in a compact exponential form and is used to explain t he adaptation of mixed cultures to adverse environmental conditions. The pe rformance of the Monod model and the proposed exponential model in predicti ng the behavior of a mixed culture exposed to high nitrate concentrations a re compared. A parameter for nitrate degradation is defined which is correl ated to changes in the maximum specific growth rate as the culture adapts t o increasing concentrations of nitrate.