Enhanced Population Control in a Synthetic Bacterial Consortium by Interconnected Carbon Cross-Feeding

Area of Science:

• Synthetic biology
• Microbial ecology
• Metabolic engineering

Background:

• Microbial consortia offer advantages over monocultures, including substrate utilization and task division.
• Maintaining stability and population control in multispecies cultures remains a significant challenge.

Purpose of the Study:

• To model and construct a synthetic symbiotic consortium with a genetically encoded carbon cross-feeding system.
• To investigate the robustness and population control of this consortium under varying conditions.
• To demonstrate the system's potential for dividing genetic circuits in microbial consortia.

Main Methods:

• Engineering strains of Escherichia coli and Acinetobacter baylyi ADP1 for mutualistic growth on glucose via cross-feeding.
• Experimental and modeling approaches to assess system stability, population balance, and robustness.
• Utilizing fluorescent proteins to monitor circuit performance and susceptibility to variability.

Main Results:

• The synthetic consortium demonstrated stable and linear growth, with inherent population balance controlled by carbon cross-feeding.
• System robustness was confirmed across different inoculation ratios, substrate concentrations, and cultivation scales.
• Consistent circuit performance was observed, indicating resilience to external and internal variability.

Conclusions:

• The developed cross-feeding system provides a simple and reliable method for population control in microbial consortia.
• This approach eliminates the need for non-native elements or external inducers.
• The system is potentially applicable to consortia requiring precisely defined cell tasks and division of labor.