The Corrinoid Model for Dissecting Microbial Community Interactions Across Scales

Microbial communities in different environments have major impacts on global nutrient cycling and on the health of host organisms. However, the complexity of microbial communities complicates the investigation of how interactions among numerous microbial species, each with distinct features and metabolic capabilities, affect global processes. In this review, we describe the corrinoid model for investigating microbial community interactions across scales, from individual microbes to complex natural communities. Corrinoids are the vitamin B12 (cobalamin) family of organometallic cofactors. While numerous metabolic processes across all domains of life require corrinoids, only a fraction of bacterial and archaeal species produce them. This structurally diverse set of shared nutrients influences community structure in different ways. Knowledge about corrinoid biology at each scale informs and reinforces a robust model that can be expanded to increase our understanding of microbial communities.