Competition-driven strategies for controlling multistable microbial communities

Microbial communities often need particular species compositions, or community states, to perform a certain function. Because these communities play crucial roles in human health and industry, we need to maintain them in particular desirable states, and prevent them from reaching undesirable ones. What makes this task especially challenging is that microbial communities are often multistable; both desirable and undesirable states may be possible in the same environmental conditions. Due to these complications, we still lack pragmatic and reliable strategies to fulfill this task. Here, we propose two strategies to control multistable microbial communities: that of controlling the colonization order in which species are introduced into a community, and that of controlling the supply of nutrients to a community. Both strategies are driven by competition for nutrients between microbial species. As a proof of concept, we illustrate their implementation in a resource-explicit model. Our proposed strategies have the potential to greatly improve existing methods to engineer and manipulate real microbial communities, such as in industrial bioreactors and the human gut.