Inulin increases the EPS biosynthesis of Lactobacillus delbrueckii ssp. bulgaricus LDB-C1

ObjectiveIts eps gene cluster, the antioxidant activity and monosaccharide composition of exopolysaccharides, the expression levels of related genes at different fermentations were analyzed for clarifying the exopolysaccharide biosynthesis mechanism of Lactobacillus delbrueckii subsp. bulgaricus LDB-C1.ResultsThe comparison analysis of eps gene clusters indicated that the gene clusters present diversity and strain specificity. The crude exopolysaccharides from LDB-C1 exhibited a good antioxidant activity. Compared with glucose, fructose, galactose, and fructooligosaccharide, inulin significantly improved the exopolysaccharide biosynthesis. The structures of EPSs were significantly different under different carbohydrate fermentation conditions. Inulin obviously increased the expressions of most EPS biosynthesis related genes at fermentation 4 h.ConclusionInulin accelerated the beginning of the exopolysaccharide production in LDB-C1, and the enzymes promoted by inulin was beneficial for the accumulation of exopolysaccharide at the whole fermentation process.

Automated summary

This study analyzed the eps gene cluster, antioxidant activity, monosaccharide composition, and gene expression levels of Lactobacillus delbrueckii subsp. bulgaricus LDB-C1 during fermentation. The results showed that eps gene clusters had diversity and strain specificity. The crude exopolysaccharides exhibited good antioxidant activity. Inulin significantly improved exopolysaccharide biosynthesis and affected the expression of related genes.