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Updated: Sep 19, 2025
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Daily Transfers, Archiving Populations, and Measuring Fitness in the Long-Term Evolution Experiment with Escherichia coli
Published on: August 18, 2023
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When is microbial cross-feeding evolutionarily stable?
Jamie Alcira Lopez1,2,3, Bo Liu4,5, Zhiyuan Li6,7
1Lewis-Sigler Institute for Integrative Genomics, Princeton University, New Jersey 08544, USA.
Biorxiv : the Preprint Server for Biology
|June 6, 2025
Summary
Waste-product cross-feeding, where microbes share metabolic byproducts, is common but poorly understood. This study reveals generalized intracellular metabolite toxicity as a key mechanism enabling stable cross-feeding microbial consortia.
Area of Science:
- Microbial Ecology
- Evolutionary Biology
- Biochemistry
Background:
- Cross-feeding, the exchange of metabolites between organisms, is prevalent in microbial communities.
- Waste-product cross-feeding, a unidirectional interaction, is a common form where one microbe's waste supports another's growth.
- The evolutionary persistence of waste-product cross-feeding, despite potential for single-organism efficiency, remains unclear.
Purpose of the Study:
- To investigate the evolutionary stability of waste-product cross-feeding.
- To identify mechanisms that explain why microbial consortia engage in cross-feeding.
- To understand the conditions promoting the stability of cross-feeding interactions.
Main Methods:
- Analysis of cross-feeding evolution using a minimal model of microbial metabolism.
- Thermodynamically correct formulation of multi-step energy extraction.
- Investigation of models with complex growth functions to identify stability mechanisms.
Main Results:
- Cross-feeding was not evolutionarily stable in the minimal metabolic model.
- Generalized intracellular metabolite toxicity was identified as a novel mechanism for cross-feeding stability.
- Nonlinear scaling of growth penalties with intracellular metabolite levels promotes cross-feeding.
Conclusions:
- Generalized intracellular metabolite toxicity can stabilize waste-product cross-feeding consortia.
- Consortia can divide toxic metabolite burdens for greater collective efficiency.
- Cross-feeding stability mechanisms can lead to complex population dynamics, including biomass discontinuities.
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