Physiological properties evaluation and exopolysaccharide biosynthesis of Limosilactobacillus fermentum JL-2 from Chinese traditional fermented dairy product based on genomic insight

Limosilactobacillus fermentum JL-2 with high production of exopolysaccharide (EPS) was screened from the traditional fermented dairy product in Xinjiang district (China) in our previous work. In this study, the whole genome of L. fermentum JL-2 was sequenced and the genomic information and function were studied to excavate its genotype, safety and probiotic properties. The safety evaluation in vitro showed that L. fermentum JL-2 was not hemolytic, sensitive to common antibiotics, and it had a weak biogenic amine production capacity. The genes related to EPS biosynthesis and their relationship with EPS production were discussed. The EPS production of L. fermentum JL-2 was 553.6 mg/L. The genome of L. fermentum JL-2 consisted of a circular 1.98 Mbp chromosome. A variety of genes related to probiotic properties such as acid tolerance, bile salt tolerance, adhesion to gut mucosa and environmental stress resistance were contained. A complete EPS gene cluster was found in the genome of L. fermentum JL-2, and the genes related to EPS biosynthesis such as epsA and epsB were found in L. fermentum JL-2. It is worth noting that EPS biosynthesis protein (gene0099) seemed to play a key role in the EPS synthesis of L. fermentum JL-2. These results revealed the potential of L. fermentum JL-2 as a probiotic at the gene level. Therefore, this study laid a theoretical foundation for further research into its potential probiotic function and its application in practice.