Genomic insights into exopolysaccharide biosynthesis pathways in novel Lactiplantibacillus plantarum and Leuconostoc mesenteroides strains

Lactic acid bacteria (LAB) are known for their ability to synthesise exopolysaccharides (EPS) which have many applications in the food industry. This research employed a genomic approach, utilising a bioinformatics workflow that uses raw bacterial whole genome sequences and a customisable database for predicting specific target attributes. The workflow was used to assess the EPS production potential of 26 novel strains of Lactiplantibacillus plantarum and Leuconostoc mesenteroides, along with experimental evaluation of their actual EPS production capabilities. The genomic analysis revealed that strains Leu. mesenteroides C13, C18, and C20 possess the highest genetic potential for EPS production among the studied strains, which was confirmed by experimental EPS production quantification. These three strains contain 50, 51, and 39 EPS production-related genes, respectively, and produced 1.67 mg/mL, 1.57 mg/mL, and 0.82 mg/mL of EPS, respectively, during cultivation at 37 °C for 20 h in MRS medium with 10% (w/v) sucrose supplementation. The strains predominantly utilise the extracellular EPS biosynthesis pathway, suggesting that they primarily produce homopolysaccharides (HoPS), viz. dextran and levan. Hence, these strains can be potentially used for production of EPS for food and other biotechnological applications.