(P06-020-25) Gut Microbial Degradation of Food-Grade Lambda-Carrageenan by Bacteroides xylanisolvens: Implications for Promoting Inflammation

Objectives: This study aimed to investigate the role of gut microbiota in the degradation of food-grade lambda-carrageenan (L-CGN) and assess the inflammatory effects of the resulting degraded carrageenans (dCGNs). Additionally, it explored the molecular pathways involved in dCGN-induced inflammation and their implications for colon health and inflammatory diseases.

Methods: Bacteroides xylanisolvens C3 was identified as a key gut bacterium capable of degrading L-CGN. The degradation process was confirmed using high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), and metabolic analysis. The inflammatory effects of microbiota-generated dCGNs were evaluated by measuring nitric oxide (NO) and COX-2 production and analyzing the expression of pro-inflammatory genes, including IL-1β, TNF-α, and IL-6, in macrophages. The study also examined the activation of Nrf2 and NLRP3 pathways in response to dCGNs.

Results: Bacteroides xylanisolvens C3 was confirmed to degrade L-CGN, generating dCGNs that significantly increased NO and COX-2 production and upregulated pro-inflammatory genes in macrophages. The inflammatory effects were linked to the activation of Nrf2 and NLRP3 pathways, highlighting the role of dCGNs in promoting inflammation.

Conclusions: This study demonstrates that microbial degradation of L-CGN produces dCGNs that induce inflammation by activating pro-inflammatory mediators and molecular pathways. These findings highlight the need for further research on the interaction between gut microbiota and L-CGN to better understand its impact on colon health and inflammation-related diseases, such as inflammatory bowel disease.

Funding Sources: USDA NIFA