Adaptive laboratory evolution of microbial co-cultures for improved metabolite secretion

Area of Science:

• Microbiology
• Metabolic Engineering
• Synthetic Biology

Background:

• Adaptive laboratory evolution is limited to traits positively linked to cell fitness.
• Engineering microorganisms for secreting fitness-costly metabolites remains challenging.
• Metabolic cross-feeding strategies can link costly secretions to community survival.

Purpose of the Study:

• To develop a coevolution strategy for enhancing the secretion of fitness-costly metabolites.
• To improve the production of B-group vitamins (riboflavin and folate) in lactic acid bacteria.
• To demonstrate the adaptation of microbial metabolism to mutualistic lifestyles.

Main Methods:

• Co-evolution of lactic acid bacteria and engineered Saccharomyces cerevisiae.
• Utilizing a synthetic growth medium with metabolic cross-feeding.
• Employing genomic, proteomic, metabolomic, and flux balance analyses.

Main Results:

• Isolated bacterial strains exhibited enhanced secretion of riboflavin and folate.
• Increased vitamin production was observed in both synthetic and complex (milk) environments.
• Metabolic analyses revealed altered regulation favoring vitamin precursor supply.

Conclusions:

• Coevolution of mutualistic communities is an effective strategy for improving secretion of fitness-costly metabolites.
• Microbial metabolism adapts to mutualistic lifestyles through enhanced metabolite exchange.
• This approach offers a new avenue for microbial strain improvement in biotechnology.