Effect of glycoside hydrolase-mediated wheat arabinoxylan hydrolysate on gut microbiota and metabolite profiles

Abstract

Cereal arabinoxylans (AX) are complex non-digestible polysaccharides and their molecular structural features significantly influence their degradation and metabolic behaviors within the body. This study focuses on investigating the impact of wheat AX hydrolysates produced by different glycoside hydrolases on the gut microbiota during colonic fermentation. Endo-1,4-β-xylanase (XYN) and arabinofuranosidase (ARF) were used to hydrolyze the xylan backbone and remove the arabinose side chains, respectively. The digestive and degradation fate was analyzed through in vitro simulated gastrointestinal digestion and colonic fermentation models. Results indicated that all hydrolase-treated groups exhibited different intestinal flora community structures, characterized by enhanced diversity and reduced richness of gut microbiota, along with differentially enriched bacterial taxa compared to native AX. The glycosidase-treated group showed greater advantages in promoting the growth of beneficial bacteria such as Bacteroides, Ruminococcus, and Faecalibacterium and produced higher levels of beneficial metabolites, mainly acetate, butyrate and caproate. Lower degrees of polymerization and side-chain substitution in AX enzymatic hydrolysate, along with higher levels of arabinoxylan-oligosaccharides (AXOS) exhibited the optimal promotion effects. However, certain gut bacteria such as Prevotella and Bifidobacterium prefer structurally intact long-chain AX. This study demonstrates that AX hydrolysates with different molecular characteristics, induced by specific hydrolases selectively influence distinct microbial consortia. Higher levels of short-chain unsubstituted XOS are more effective at promoting intestinal health and maintaining intestinal homeostasis.