Microbial communities consist of a diversity of microorganisms that collectively conduct a spectacular range of metabolism in the natural world. Within the communities, nutrients and resources are shared and the microbes compete and cooperate with one another to build a stable network of interactions. 

Vitamins such as B₁, B₃, B₆, B₇ and B₁₂ are among the repertoire of critical nutrients that are exchanged in the human gut and marine microbial communities. The modular nature of the biosynthesis pathways of vitamin B₁ and B₆ is well-suited for different microbes to produce intermediates, which can then be combined to synthesize the whole vitamin. In our lab, we have created synthetic microbial co-cultures that rely on the exchange of biosynthesis intermediates of vitamin B₁ and B₆. Using these co-cultures, we show how vitamins B₁ and B₆ can be synthesized and exchanged and the microbial co-culture dynamics that allow for stable co-cultures to form. Further, we use microscopy and modelling studies to understand why and how they localize themselves to optimize sharing of metabolites. Our molecular level studies in the context of synthetic microbial consortia provide mechanistic and functional insights into how vitamins and other metabolites might be synthesized and shared among microbes in complex communities.