Cereal arabinoxylans (AX) are complex non-digestible polysaccharides whose
highly polymeric structure and extensive branching patterns significantly
limit their fermentation efficiency and immunomodulatory potential. Native
AX's structural complexity—characterized by high molecular weight (>300
kDa) and dense arabinose substitution—restricts microbial accessibility in
the colon, thereby limiting prebiotic efficacy. This study employed a
rational enzymatic engineering approach utilizing glycoside hydrolases
(endo-xylanase, α-L-arabinofuranosidase, and feruloyl esterase) to precisely
control the degree of polymerization and side-chain substitution patterns,
generating arabinoxylan oligosaccharides (AXOS) with defined structural
parameters optimized for selective microbial utilization.
In DSS-induced colitis mouse models, enzymatically tailored AXOS
demonstrated markedly superior anti-inflammatory efficacy compared to native
AX. Integrated multi-omics analyses combining 16S rRNA sequencing,
untargeted metabolomics, and targeted SCFA quantification revealed that
structure-specific substrate recognition enabled preferential fermentation
by beneficial bacteria including Akkermansia,
Faecalibaculum
, and Dubosiella, while simultaneously suppressing
inflammation-associated pathogenic taxa such as Bacteroides and
Helicobacter. This selective microbiota modulation occurred through
dual mechanisms: ecological competition for nutritional niches and
metabolite-mediated inhibition via enhanced production of short-chain fatty
acids (acetate, propionate, butyrate) and secondary bile acids. The
resulting metabolic reprogramming activated anti-inflammatory signaling
pathways (FXR/TGR5, GPR41/43), restored intestinal barrier integrity through
upregulation of tight junction proteins (ZO-1, occludin), and significantly
reduced hepatic oxidative stress. Our findings establish that enzymatic
structural optimization transforms complex polysaccharides into precision
prebiotics with targeted immunomodulatory functions. This structure-directed
approach offers a systematic framework for developing next-generation
dietary interventions that strategically leverage the gut
microbiota-metabolite-host axis for managing inflammatory bowel diseases,
demonstrating clear translational potential from enzymatic modification
through selective microbial enrichment to downstream therapeutic outcomes.