Correlation between exopolysaccharide biosynthesis and gastrointestinal tolerance of Lactiplantibacillus plantarum

This study aimed to investigate the correlation between the level of exopolysaccharide (EPS) biosynthesis and gastrointestinal tolerance of 12 Lactiplantibacillus plantarum strains.

In this study, the EPS production and survival rate of 12 strains of L. plantarum under gastrointestinal stress were determined. Results showed that the EPS biosynthesis level of L. plantarum in semi-defined medium ranged from 9.84 to 26.05 mg/L. The survival rates of all strains in simulated gastric juice at pH 3.0 ranged from 43.52% to 112.73%. Among them, eight strains were higher than 90%, while only one strain was lower than 50%. The survival rates of all strains in simulated intestinal juice ranged from 50.36% to 125.39%, among which eight strains were higher than 80%. The survival rates of all strains under 0.1% bile salt stress ranged from 3.39% to 109.34%, among which four strains were higher than 80% and three strains were lower than 60%. Besides, the survival rates of all strains under 0.5% bile salt stress ranged from 0.42% to 95.34%. The results indicated that the 12 L. plantarum strains had good tolerance to simulated gastric juice at pH 3.0, simulated intestinal juice and 0.1% bile salt. Notably, it was observed that the survival rates of L. plantarum strains under simulated gastric juice at pH 3.0 and simulated intestinal juice were significantly positively correlated with EPS biosynthesis (p < 0.01).

The yield of EPS of L. plantarum was related to simulated gastric juice and simulated intestinal juice environment.

It was speculated that the production of EPS may be one of the strategies for L. plantarum to adapt to the part of gastrointestinal environment. In the future, we could analyse the protection mechanism of EPS from the gene level.