A new tool for the quantification of microorganism interaction dynamics

A two-reservoir, membrane bioreactor for carrying out studies of mixed popu lation dynamics in batch fermentation is presented. Mixing requirements and design aspects for the validity of the approach are presented and discusse d. Equations describing mixing times between the reservoirs are given and c ompared to the experimental results. The validity of the approach is demons trated by the study of several types of situations in the bioreactor. The m ain validation consists of the comparison between the results obtained in a n actual mixed culture and the results obtained by keeping the strains sepa rated. Finally, this new tool is used to study the interaction kinetics bet ween two oenological bacteria. These experiments in liquid media help to de termine the seeding conditions for a chosen strain to overgrow another stra in through a quantification of the interaction dynamics.