[Theoretical analysis of potential variations of "Escherichia coli" K12 cultures in presence of an electron carrier (author's transl)].

Oxygen consumption and reductive hydrogenation of lipoic acid, linked to the exponential growth of Escherichia coli in a "minimal" medium containing a non-limiting amount of glucose, produce reproducible and intelligible variations of the electric potential between a gold electrode and a reference electrode. A simple quasi-stationary mathematical model leads to analytical expressions of the electric potential in function of the experimental conditions and of time. The effects of active or passive transport of lipoic acid are distinguishable. An experimental method results in detecting and following bacterial activity.