Carbohydrate Metabolism in Bifidobacteria

Bifidobacteria constitute a specific group of commensal bacteria, which inhabit the gastrointestinal tract of humans and other mammals. As saccharolytic organisms, the ability of bifidobacteria to colonize the gastrointestinal tract is largely dependent on their ability to utilize the complex carbohydrates ubiquitous in this environment. Due to their perceived health benefits, bifidobacteria are typically the target of (saccharidic) prebiotics, which explains why bifidobacterial carbohydrate metabolism has been intensively studied. Various aspects of carbohydrate metabolism will be discussed in this chapter, including the characteristic fructose-6-phosphate phosphoketolase pathway, carbohydrate uptake systems, glycosyl hydrolases, and the transcriptional regulation of carbohydrate metabolism in bifidobacteria. Particular attention will focus on the species- and strain-specific utilization of certain diet- and/or host-derived carbohydrates, including various potential prebiotics, as well as the mucin glycoprotein.