Structural characterization of oligosaccharide from Spirulina platensis and its effect on the faecal microbiota in vitro
Bingna Cai, Xiangxi Yi, Qian Han, Jianyu Pan, Hua Chen, Huili Sun, Peng Wan
Abstract
In the present study, an oligosaccharide SPO-1 from Spirulina platensis was prepared by glycosidase from a marine bacterium. The prebiotic activity of SPO-1 on the growth of Lactobacillus paracasei and Bifidobacterium animalis, and its effect on human gut microbiota were examined in vitro. The molecular weight of the tetrasaccharide SPO-1 was 650.2 Da, and it was mainly composed of glucose with α-type glycosidic linkages. The prebiotic activity score of SPO-1 was the highest for the growth of probiotic strains L. paracasei and B. animalis. Furthermore, as fermentation proceeded, SPO-1 was gradually degraded and utilized by intestinal bacteria. The results showed that after treatment with SPO-1, carbohydrate consumption and short-chain fatty acids levels were increased, especially those of i-butyric and i-valeric acids. Moreover, SPO-1 significantly promoted the abundance, diversity and composition of gut microbiota, especially stimulating the growth of Bacteroides, Escherichia-Shigella and Megamonas. In addition, the change in intestinal microbiota function predicted by phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) after treatment with SPO-1 is mainly related to the terms “carbohydrate metabolism” and “amino acid metabolism”. These results suggest that SPO-1 is a potential oligosaccharide in regulation of intestinal microbiota.