The human gut microbiome is a highly dynamic ecosystem shaped by diet and host health, influencing key processes such as nutrient absorption and disease resistance. Among its major inhabitants, bacteria from the Prevotellaceae and Bacteroidaceae families play pivotal roles. Prevotellaceae, including Segatella copri, thrive in fibre-rich diets and are linked to greater microbial diversity, whereas Bacteroidaceae dominate in Westernised diets and are associated with reduced diversity and higher risk of chronic disease. This project aims to uncover the mechanisms that enable S. copri to adapt to its ecological niche and interact with other gut microbes. Using recently isolated S. copri strains, we explore their metabolic versatility, focusing on the degradation of diverse carbon sources and competition with Bacteroidaceae in defined microbial communities. Integrating complementary omics methods, we seek to characterize the molecular and microbial mechanisms that are context-dependent and contribute to nutrient competition and cross-feeding. Additionally, dietary interventions in vivo will reveal how fibre-rich and fibre-poor diets shape S. copri-centred community dynamics. Loss-of-function studies will help assign functions to uncharacterised genes involved in competition. Together, these insights will clarify the ecological and metabolic role of S. copri in maintaining gut microbiome balance.