Structure and effect on Bifidobacterium longum of exopolysaccharide produced by Weissella cibaria using cost-effective substrates

Maize straw, an abundant agricultural residue, has a potential as eco-friendly resource. The aim of this study was to investigate the structure and effect on Bifidobacterium longum of exopolysaccharide produced by Weissella cibaria using maize straw as carbon source. In the work, an exopolysaccharide producing strain was isolated from the vegetable juice, which was identified as Weissella cibaria. Our results demonstrated that exopolysaccharide produced by Weissella cibaria is a linear glucan contains α-1,6 glycosidic bond with a molecular weight of 9462 Da. In addition, scanning electron microscopy of exopolysaccharide from Weissella cibaria appeared the flakes structures. In vitro assays showed that the exopolysaccharide from Weissella cibaria has the ability to stimulate the proliferation of Bifidobacterium longum strain and its metabolism to produce acetic acid. This work provided a scientific reference for the potential application of maize straw, and exhibited a new insight into eco-friendly carbon source to produce exopolysaccharide.