(347e) Modeling of Environment-Dependent Microbial Interactions and Dynamics

Microbial interaction networks are complex adaptive systems that are dynamically reorganized in response to environmental variations, but conventional modeling approaches adhering to constant interaction assumption fail to capture this aspect. Here, we propose a new modeling framework to fill the gap. Our model formulates interaction parameters as a function of substrate concentrations, thereby successfully describing the continuous shifts in interactions between competition and cooperation in dynamically varying environments. Analysis of the resulting model also led to the identification of a general stability criterion for microbial communities. We validated the proposed modeling concept and theoretical predictions through our co-culture experiments using two metabolically dependent E. coli mutant strains. This work provides deeper ecological insights into context-dependent interactions required for engineering stable and productive ecological systems.