(PTFS14-02-26) Polysaccharide Utilization Loci Link Dietary Fiber Degradation to Metabolite Profiles in Human Gut Bacteroides

Monday, July 27, 2026

11:04 AM - 11:08 AM ET

Location: Prince George's Hall B-E (The Hub) - Poster Theater 2 / Poster Board Number: PT2-2

Presenting Author(s)

Manal Alhawsawi, MS, PhD candidate

PhD candidate
University of Illinois Urbana-Champaign
savoy, Illinois, United States

Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

Co-Author(s)

AH

Ahmed Hetta

University of Illinois Urbana Champaign
Urbana, Illinois, United States
GP

Gabriel V. Pereira

Carl R Woese Institute for Genomic Biology, University of Illinois, Illinois, United States
MS

Miyako Shiraishi

Carl R Woese Institute for Genomic Biology, University of Illinois, United States
DB

David Bianchi

University of Illinois Urbana-Campaign, Illinois, United States
RM

Roderick Mackie, PhD

University of Illinois Urbana-Champaign
urbana, Illinois, United States
CF

Christina Fliege

University of Illinois Urbana Champaign, Illinois, United States
JC

Janaina Cavalcante

University of Illinois Urbana Champaign, Illinois, United States
IC

Isaac Cann, PhD

University of Illinois Urbana Champaign
Urbana, Illinois, United States

Disclosure(s):

Manal Alhawsawi, MS, PhD candidate: No relevant financial relationship(s) with ineligible companies to disclose.

Objectives: Microbiota produce various carbohydrate-active enzymes (CAZymes). In Bacteroidota, these are encoded within Polysaccharide Utilization Loci (PULs). Given the rise of inflammatory and metabolic diseases linked to gut dysbiosis, understanding microbial metabolites and dietary factors that influence their production is important. Hypothesis: Polysaccharide Utilization Loci (PULs) upregulated during fermentation of distinct dietary fibers by human gut Bacteroides can be linked to characteristic metabolite profiles with health benefits to the host.

Objectives: (I) to identify PULs involved in the degradation of pectin, insoluble wheat arabinoxylan, and arabinan, and (II) to explore the metabolomic profiles of Bacteroides spp. during growth on apple and citrus pectin, as well as insoluble wheat and corn arabinoxylans, compared to galacturonic acid and xylose, respectively, as monomer sugars.

Methods: RNAseq was used to identify the PULs in Bacteroides spp. Untargeted metabolomics and computational analysis were used to identify the metabolites associated with different polysaccharides.

Results: PULs activated by different dietary polysaccharides were distinct and substrate-specific. Metabolomic analysis identified key metabolites, including 26 compounds that were prominently produced during pectin fermentation. Gamma-hydroxybutyric acid, inositol, jasmonic acid, and other compounds varied among species and fermentation stages. B. intestinalis and B. cellulosilyticus showed high metabolite production, while B. eggerthii produced fewer. Also, 4-methylesculetin, short-chain fatty acids, and GABA, with caffeic acid and cleomiscin A were specific to corn arabinoxylan fermentation. These findings highlight species-specific metabolic responses and identify potential bioactive compounds with potent health-related benefits, including anti-inflammatory and immunomodulatory properties, allowing us to link each PUL to a metabolite profile.

Conclusions: This study provides insights that could inform targeted dietary interventions and the rational design of fiber-based prebiotics and probiotic strategies to support gut and overall health.

Funding Sources: This work is funded by the National Institute of General Medical Sciences of the National Institute of Health under Award Number RO1GM140306.