Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota

Matthew Ostrowski , Sabina Leanti La Rosa (1) , Benoit Kunath (2) , Andrew Robertson , Gabriel Pereira , Live Hagen (1) , Neha Varghese (3, 4) , Ling Qiu , Tianming Yao , Gabrielle Flint , James Li , Sean Mcdonald , Duna Buttner , Nicholas Pudlo (5) , Matthew Schnizlein , Vincent Young , Harry Brumer (6) , Thomas Schmidt (7) , Nicolas Terrapon , Vincent Lombard (8) , Bernard Henrissat , Bruce Hamaker , Emiley Eloe-Fadrosh , Ashootosh Tripathi , Phillip Pope , Eric Martens

1 NMBU - Norwegian University of Life Sciences
2 LCSB - Luxembourg Centre For Systems Biomedicine
3 US Department of Energy Joint Genome Institute, Walnut Creek CA, USA
4 DOE Joint Genome Institute [Walnut Creek]
5 Department of Microbiology and Immunology, University of Michigan Medical School
6 UBC - University of British Columbia
7 PSI - Paul Scherrer Institute
8 AFMB - Architecture et fonction des macromolécules biologiques

Processed foods often include food additives such as xanthan gum, a complex polysaccharide with unique rheological properties, that has established widespread use as a stabilizer and thickening agent. Xanthan gum's chemical structure is distinct from those of host and dietary polysaccharides that are more commonly expected to transit the gastrointestinal tract, and little is known about its direct interaction with the gut microbiota, which plays a central role in digestion of other dietary fibre polysaccharides. Here we show that the ability to digest xanthan gum is common in human gut microbiomes from industrialized countries and appears contingent on a single uncultured bacterium in the family Ruminococcaceae. Our data reveal that this primary degrader cleaves the xanthan gum backbone before processing the released oligosaccharides using additional enzymes. Some individuals harbour Bacteroides intestinalis that is incapable of consuming polymeric xanthan gum but grows on oligosaccharide products generated by the Ruminococcaceae. Feeding xanthan gum to germfree mice colonized with a human microbiota containing the uncultured Ruminococcaceae supports the idea that the additive xanthan gum can drive expansion of the primary degrader Ruminococcaceae, along with exogenously introduced B. intestinalis. Our work demonstrates the existence of a potential xanthan gum food chain involving at least two members of different phyla of gut bacteria and provides an initial framework for understanding how widespread consumption of a recently introduced food additive influences human microbiomes.

Domaines: Sciences du Vivant [q-bio]

Matthew Ostrowski, Sabina Leanti La Rosa, Benoit Kunath, Andrew Robertson, Gabriel Pereira, et al.. Mechanistic insights into consumption of the food additive xanthan gum by the human gut microbiota. 2024. ⟨hal-03666905⟩