Screening of polysaccharide-based prebiotics and in vitro fermentation characteristics of Bacillus coagulans

Abstract:

[Objective] To investigate the effects of nine polysaccharides on the proliferation and enzyme production characteristics of Bacillus coagulans. [Methods] B. coagulans was co-fermented with inulin polysaccharide, Eleutherococcus senticosus polysaccharide, chitosan oligosaccharide, Saposhnikovia divaricata polysaccharide, xylo-oligosaccharide, Astragalus polysaccharide, d-mannose, Atractylodes macrocephala Koidz polysaccharide, and Yu Ping Feng polysaccharide as the only carbon source in the medium, respectively. The optimal polysaccharides were screened based on the strain growth, enzyme activities, and in vitro anaerobic fermentation performance. [Results] B. coagulans could well utilize the polysaccharides of Astragalus, S. divaricata, A. macrocephala, and Yu Ping Feng. The significant differences in pH and protease activity (P<0.05) after fermentation were found between 4% A. macrocephala polysaccharide and 4% S. divaricata polysaccharide. After in vitro fermentation, the lactic acid content and total protease activity increased, which were the highest in the 4% A. macrocephala polysaccharide group (P<0.05). The results of 16S rRNA gene sequencing of intestinal contents fermentation liquid showed that B. coagulans fermented with Astragalus polysaccharide, S. divaricata polysaccharide, and d-mannose significantly reduced the relative abundance of pathogenic bacteria such as Aeromonas, α-Proteobacteria, Streptococcus, and Shigella and improved that of Lactobacillus, Firmicutes, Lactococcus lactis, and Acidobacteria compared with the control group. [Conclusion] B. coagulans fermented with 4% A. macrocephala polysaccharide has good enzyme production and probiotic properties, which has a good potential for application in aquatic feed.