Differential metabolism of Exopolysaccharides from probiotic Lactobacilli by the human gut symbiont Bacteroides thetaiotaomicron

Alica Lammerts van Bueren, Aakanksha Saraf, Eric C Martens, Lubbert Dijkhuizen

Research output: Contribution to journalArticleAcademicpeer-review

34 Citations (Scopus)

Abstract

Probiotic microorganisms are ingested as food or supplements and impart positive health benefits to consumers. Previous studies have indicated that probiotics transiently reside in the gastrointestinal tract and in addition to modulating commensal species diversity, also increase the expression of genes for carbohydrate metabolism in resident commensal bacterial species. In this study, it is demonstrated that the human gut commensal strain Bacteroides thetaiotaomicron efficiently metabolizes fructan exopolysaccharide (EPS) synthesized by probiotic Lactobacillus reuteri 121 strain, while only partially degrading reuteran and IsoMalto/Malto-Polysaccharides (IMMPs) α-glucan EPS polymers. B. thetaiotaomicron metabolized these EPS molecules via the activation of enzymes and transport systems encoded in dedicated polysaccharide utilization loci specific for β-fructans and α-glucans. Reduced metabolism of reuteran and IMMP α-glucan EPS molecules may be due to reduced substrate binding by components of the starch utilization system (sus). This study reveals that microbial EPS substrates activate genes for carbohydrate metabolism in B. thetaiotaomicron and suggests that microbial-derived carbohydrates may provide a carbohydrate-rich reservoir for B. thetaiotaomicron nutrient acquisition in the gastrointestinal tract.

Original languageEnglish
Pages (from-to)3973-3983
Number of pages11
JournalApplied and environmental microbiology
Volume81
Issue number12
DOIs
Publication statusPublished - 3-Apr-2015

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