Functional Properties of Exopolysaccharides of <i>Bacillus thuringiensis</i> and Effects on Gut Microbiota from Ulcerative Colitis <i>In Vitro</i>

We previously reported the immune-activating effect of BPS-2, an enriched exopolysaccharide of Bacillus thuringiensis IX-01, on RAW 264.7 cells and on resolving its chemical structure. In the present study, the apparent morphology and spatial conformation of BPS-2 were analyzed further, and several functional properties were investigated. The results showed that BPS-2 was a poly-meric straight-chain polysaccharide with good thermal stability, exhibiting non-Newtonian prop-erties and good antioxidant and anticancer activities. Notably, we investigated the effect of BPS-2 on the intestinal flora of ulcerative colitis patients by in vitro fermentation of fecal bacteria collected from six volunteers and found that BPS-2 had a positive effect on the intestinal flora of ulcerative colitis patients, increasing the secretion of short-chain fatty acids and helping increase the relative abundance of Bifidobacterium. These results suggest that BPS-2 has the potential to be a food addi-tive for suppressing ulcerative colitis and for other medically related applications.