Investigating the Role of the Exopolysaccharide Gene Cluster in Lactiplantibacillus plantarum CSK: Phenotypic Modulation and Its Effect on the Rheological Properties of Fermented Soymilk Gel

In this study, a comprehensive gene annotation analysis was conducted on Lactiplantibacillus plantarum CSK, revealing the presence of three eps (exopolysaccharide) clusters within its genome. Three mutant strains with deletions in the eps clusters were constructed, and their phenotypic characteristics, along with the rheological properties of fermented soymilk gels, were compared to those of L. plantarum CSK. The deletion of eps clusters in the mutant strains was found to result in a reduction of biofilm formation, autoaggregation ability, and EPS production. Differences were observed between soymilk gels fermented by L. plantarum CSK and that fermented by the mutant strains. In fermented soymilk gels, the mutant strains resulted in a reduction in the water-holding capacity and altered rheological properties. This study provides a theoretical basis for further exploring the impact of eps clusters on the phenotypes of lactic acid bacteria and their application in fermented soymilk gels.