The adhesion of the gut microbiota to insoluble dietary fiber from soy hulls promoted the proliferation of probiotics in vitro

Soy hull insoluble dietary fiber (SHIDF) extracted from soybean water-soluble polysaccharides enzymatically is a good carbon source for the growth of gut microbiota. Genomics, co-precipitation and proteomics analyses were used to investigate adhesion behavior of the gut microbiota toward SHIDF in vitro. After gut microbiota fermentation, the content of total and reducing sugars decreased with increasing fermentation time, but the content of NH3–N first increased and then decreased, and gas was produced mainly during 8–16 h. The structure and abundance of the gut microbiota were regulated after fermentation. Proliferation of beneficial bacteria increased, particularly Lactobacillus and Bifidobacterium. The adhesion of Lactobacillus plantarum and Bifidobacterium longum to SHIDF increased gradually with increasing adhesion time. The adhesion of two probiotics to IDF first increased and then decreased with increasing bacterial age (6, 12, 24, and 36 h). SDS, EDTA, bile salts, trypsin and proteinase K in the adhesion environment affected probiotic adhesion to SHIDF to a certain extent. Lactobacillus plantarum and Bifidobacterium longum showed significant differences in adhesion membrane proteins after SHIDF treatment. The 30S ribosomal protein S21 and GAPDH (glyceraldehyde 3-phosphate dehydrogenase), a surface protein involved in intestinal adhesion, were found to be significantly upregulated through label free proteomic analysis. •The maximum consumption of SHIDF was 50.92% after gut microbiota fermentation.•SHIDF promoted the proliferation of Lactobacillus and Bifidobacterium in vitro.•Gut microbiota adhesion to SHIDF was useful for the proliferation of bacteria.