Characterization of factors affecting attachment of Bifidobacterium species to amylomaize starch granules

Aims: Two human-derived Bifidobacterium strains, PL1 and PL2, were tested for their ability to attach to amylomaize starch granules, and factors affecting binding were assessed. Methods and Results: Good binding to granules was observed when the strains were grown on maltose or amylomaize starch, but not on glucose. Binding activity was localized to cell wall components and was sensitive to treatment with proteolytic enzymes. Several methodologies were employed to confirm these observations, including studies using radiolabelled cells, dot blot assays and scanning electron microscopy (SEM) analysis. Conclusions: Results from this study indicated that binding of strains PL1 and PL2 to amylomaize starch granules was mediated by a cell wall-associated proteinaceous factor that was induced when the strains were grown on starch or a related substrate, but not glucose. Significance and Impact of the Study: Attachment of probiotic strains to starch or other dietary fibres is believed to offer a selective advantage in the host intestine and may even prolong viability in adverse food environments. Therefore, characterizing the mechanisms of attachment has commercial implications in the design of synbiotic products.