Microbial communities contribute important functions towards human health and biotechnology. Two examples are the many microbes associated with the human body (e.g., gut microbiome) and species that contribute to soil fertility and plant health. These natural microbial consortia that contain many different species, are often composed of poorly-characterized microbes. They also have complicated signaling networks of compounds and metabolites that are exchanged between community members. The complexity of natural consortia makes them difficult to study and can obscure identification of common principles that underlie many different communities. Consequently, many fundamental questions remain about how microbial consortia are organized to maintain productivity and resilience in the face of dynamic environmental conditions. This project makes use of artificial microbial communities that are relatively simple and composed of well-characterized microbes. These features of the artificial communities are chosen to facilitate an investigation that would lead to insight into underlying principles that guide the structure and function of microbial communities. The research activities increase knowledge of interaction dynamics in microbial communities, potentially improving the ability to engineer microbial consortia. The research also provides insight into the evolution of natural microbial symbioses. Through this project two graduate students and one postdoctoral fellow are trained. In addition, there are multiple undergraduate research experience opportunities. The project also involves promoting the development of public forums for the discussion of potential benefits and ethical concerns of bioengineering. These forums are hosted in the Michigan Science Center in Detroit.
The research team is using a cyanobacterium (Synechococcus elongatus PCC 7942) that produces and secretes large quantities of sucrose from light and CO2. The PI has demonstrated that a variety of other microbes can be cultivated in the same media in a "modular" fashion. In these circumstances the co-cultured partner consumes the sucrose produced by the cyanobacteria. The flexibility in the design of these artificial microbial communities allows different heterotrophic bacteria to be cultivated with the cyanobacterium. In this way, common themes and mechanisms of interaction between the co-cultured species are identified. Approaches that include rational engineering, forward genetics, directed evolution, metabolic modeling, and individual-based simulations are used to identify the metabolites and signals exchanged between species. These approaches are also used to determine how metabolite exchanges contribute to consortia robustness. The knowledge gained is used to rationally design microbial communities that are more robust in the face of environmental pressures, such as invasion by "non-cooperating" microbial species. It is anticipated that the research efforts from this proposal will provide insights into fundamental interactions underpinning natural microbial symbioses, with translational impacts for the development of environmentally-sustainable cyanobacterial biotechnologies.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
