A two-reservoir, hollow-fiber bioreactor for the study of mixed-populationdynamics: Design aspects and validation of the approach

A two-reservoir, membrane bioreactor for carrying out studies of mixed-popu lation dynamics in batch fermentations is presented. Mixing requirements an d design aspects for the validity of the approach are given and discussed. Equations describing mixing times between the reservoirs are presented and compared to the experimental results. The validity of the approach is demon strated by the study of an amensalistic-type interaction, the protein-media ted killer phenomenon between two Saccharomyces cerevisiae strains. The val idation consisted in the comparison between the results obtained in actual mixed culture and the results obtained by keeping the strains separated. A good agreement was found which demonstrates the viability of the designed b ioreactor. (C) 2000 John Wiley & Sons, Inc.