When simplicity triumphs: niche specialization of gut bacteria exists even for simple fiber structures

• Published in: ISME Communications 2024-01, Vol.4 (1), p.ycae037-ycae037
• Main Authors: Xu, Haidi, Pudlo, Nicholas A, Cantu-Jungles, Thaisa M, Tuncil, Yunus E, Nie, Xin, Kaur, Amandeep, Reuhs, Bradley L, Martens, Eric C, Hamaker, Bruce R
• Format: Article
• Language: English
• ISSN: 2730-6151; 2730-6151
• DOI: 10.1093/ismeco/ycae037

Structurally complex corn bran arabinoxylan (CAX) was used as a model glycan to investigate gut bacteria growth and competition on different AX-based fine structures. Nine hydrolyzate segments of the CAX polymer varying in chemical structure (sugars and linkages), CAX, five less complex non-corn arabinoxylans, and xylose and glucose were ranked from structurally complex to simple. The substrate panel promoted different overall growth and rates of growth of eight xylan-degrading strains. For example, DSM 14838 ( ) grew well on an array of complex and simple structures, while 3-1-23 grew well only on the simple structures. In a competition experiment, growth was favored over on the complex AX-based structure. On the other hand, on the simple structure, strongly outcompeted , which was eliminated from the competitive environment by Day 11. This adaptation to fine structure and resulting competition dynamics indicate that dietary fiber chemical structures, whether complex or simple, favor certain gut bacteria. Overall, this work supports a concept that fiber degraders diversify their competitive abilities to access substrates across the spectrum of heterogeneity of fine structural features of dietary fibers.