Updated project metadata. Here, we illustrate the proteomic composition and hydrolytic capacity of outer membrane vesicles (OMVs) produced by F. succinogenes during growth on Avicel cellulose and show that the OMVs are equipped with a highly versatile polysaccharide-degrading machinery. Proteomic assessment identified an enrichment of acidic proteins as well as carbohydrate-active enzymes of varying putative functions. Further, we show that the OMVs contain a membrane-bound multiprotein complex containing four proteins.