Influence of alternansucrase-derived oligosaccharides and other carbohydrates on alpha-galactosidase and alpha-glucosidase activity in Bifidobacterium adolescentis.

AIMS: To determine the influence of alternansucrase-derived oligosaccharides (AOS) and other carbohydrates on alpha-galactosidase and alpha-glucosidase activity in Bifidobacterium adolescentis. METHODS AND RESULTS: Activities for alpha-galactosidase and alpha-glucosidase were determined from cell extracts of B. adolescentis grown on 18 test carbohydrates including AOS. alpha-galactosidase activity was enhanced on a variety of alpha-linked or beta-linked carbohydrates regardless of a galactoside or glucoside. alpha-glucosidase, however, was enhanced only on alpha-linked carbohydrates. AOS significantly enhanced enzyme activity compared with most of the carbohydrates tested. Most of the AOS showed significant increases in activity for both enzymes over that displayed by their corresponding acceptor carbohydrates. CONCLUSIONS: alpha-galactosidase may serve as a biomarker for microbial metabolic activity within the large intestine for potential prebiotics composed of alpha-linked or beta-linked oligosaccharides whereas alpha-glucosidase activity may be restricted to assessing the influence of only alpha-linked carbohydrates. The AOS synthesis process provided a value-added component to carbohydrates by increasing metabolic activity (via alpha-galactosidase and alpha-glucosidase) over certain acceptor carbohydrates. SIGNIFICANCE AND IMPACT OF THE STUDY: Fundamental knowledge of enzyme activity in Bifidobacterium may aid in the design of more effective prebiotics and may also help identify enzyme indicators of metabolic activity when assessing influence within the intestine.