Updated project metadata. This dataset provides a comprehensive proteomic characterization of a defined five-strain human gut bacterial consortium, including Bifidobacterium and Roseburia species. The consortium was grown on different carbohydrate sources, human milk oligosaccharides, dietary fibers, or a combination of both, to investigate how substrate availability influences microbial protein expression and metabolic activity. The resulting data captures functional responses and interactions within the community, offering insights into carbohydrate utilization, cross-feeding dynamics, and gut microbial ecology. This resource can support studies of microbiome function, microbial interactions, and dietary modulation of gut microbiota.