Analysis of the effect of oat β-glucan on gut microbiota and clarification of their interaction relationship

Oat β-glucan is catabolized by gut microbiota, however, the interaction relationship between β-glucan and gut microbiota is unclear. We aim to investigate the primary intestinal microbial species responsible for oat β-glucan degradation and explore their interaction. The result of in vitro fermentation showed that β-glucan significantly altered gut microbiota composition and primary microbial species responding to β-glucan was Lactobacillus. A total of 4 strains of Lactobacillus murinus were in vitro obtained and inoculated in the medium containing β-glucan as the sole carbon source to verify their association with β-glucan, and result showed that 4 strains of L. murinus could indeed degrade β-glucan. Genome analysis suggested that 4 strains of L. murinus contained abundant carbohydrate enzymes-encoding genes, among which genes encoding glycoside hydrolases family 1 (GH1) were most likely associated with β-glucan degradation. Further analysis revealed that GH1 could bind to β-glucan units through hydrogen bonding. Our study provides a novel insight into the research on interplay between dietary components and gut microbiota, and strategy for the exploration of potential carbohydrate hydrolase from gut microbiota for cereal β-glucan processing.