Bacterial cross-feeding data

Nutritional interdependence is widespread within microbial communities. However, co-inoculation of most auxotrophic microorganisms often fails to establish stable metabolite exchange relationship. We used lysine and arginine auxotrophic <i>Escherichia coli</i> genotypes to examined their interactions over 25 days. Our results indicate that co-inoculation renders both amino acid production and utilization of auxotrophs unstable. We found that one strain (ΔL) consistently outcompeted the other (ΔA) due to faster metabolic responses. ΔL cells exhibited lysine utilization positively correlated with lysine production by ΔA, stabilizing their population size despite fluctuating lysine supply from ΔA. Conversely, ΔA individuals lack this metabolic pattern, resulting in the ΔL population exploiting the ΔA population. These findings highlight that metabolic asymmetries and specific utilization patterns destabilize microbial syntrophy. Our work underscores the importance of balanced metabolic exchanges for developing sustainable synthetic microbial consortia and offers insights into the evolutionary dynamics of microbial cooperation.