Biochemical analysis of cross‐feeding behaviour between two common gut commensals when cultivated on plant‐derived arabinogalactan

In this paper, we reveal and characterize cross‐feeding behaviour between the common gut commensal Bacteroides cellulosilyticus (Baccell) and certain bifidobacterial strains, including Bifidobacterium breve UCC2003, when grown on a medium containing Larch Wood Arabinogalactan (LW‐AG). We furthermore show that cross‐feeding is dependent on the release of β‐1,3‐galacto‐di/trisaccharides (β‐1,3‐GOS), and identified that the bga gene cluster of B. breve UCC2003 allows β‐1,3‐GOS metabolism. The product of bgaB is presumed to be responsible for the import of β‐1,3‐GOS, while the bgaA gene product, a glycoside hydrolase family 2 member, was shown to hydrolyse both β‐1,3‐galactobiose and β‐1,3‐galactotriose into galactose monomers. This study advances our understanding of strain‐specific syntrophic interactions between two glycan degraders in the human gut in the presence of AG‐type dietary polysaccharides.