Related Experiment Video
Updated: Jul 14, 2026

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Modelling the competition of planktonic and sessile aerobic heterotrophs for complementary nutrients in biofilm
T Lu1, P E Saikaly, D B Oerther
1Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA. lutg@email.uc.edu
Abstract:
A comprehensive, simplified microbial biofilm model was developed to evaluate the impact of bioreactor operating parameters on changes in microbial population abundance. Biofilm simulations were conducted using three special cases: fully penetrated, internal mass transfer resistance and external mass transfer resistance. The results of model simulations showed that for certain operating conditions, competition for growth limiting nutrients generated oscillations in the abundance of planktonic and sessile microbial populations. These oscillations resulted in the violation of the competitive exclusion principle where the number of microbial populations was greater than the number of growth limiting nutrients. However, the operating conditions which impacted microbial community diversity were different for the three special cases. Comparing the results of model simulations for dispersed-growth, biofilms and bioflocs showed that oscillations and microbial community diversity were a function of competition as well as other key features of the ecosystem. The significance of the current study is that it is the first to examine competition as a mechanism for controlling microbial community diversity in biofilm reactors.
Related Concept Videos
Microbial Interactions: Competition
Microbial Mats
Marine Microbial Ecology
Freshwater Microbial Ecology
Bioreactor Controls-II
Microbial Wastewater Treatment

