Isothermal calorimetry and microbial growth: beyond modeling

A phenomenological approach, based on the simple consideration of the cell duplication mechanism, is suggested to describe the microbial growth monitored through isothermal calorimetry. Correlation of the calorimetric trace with the cell microbial population can be assessed. The method permits to obtain directly the generation time trend tau(t) in all the phases of the growth process discriminating the influence of the peculiar experimental setup and focusing on the factors that are intrinsic to the microorganism. This type of elaboration offers a reference point in order to compare results from different laboratories for similar systems and for further kinetic and energetic exploitation of the microbial system. The paper reports the case of Lactobacillus helveticus as an experimental evidence.