Research on prebiotics, probiotics, and synbiotics is expanding, with marine bacterial exopolysaccharides being explored as novel prebiotics due to their potential to improve gut health. Curdlan gum, an FDA-approved bacterial exopolymer with prebiotic properties, improves food’s rheological properties and influences the gut microbiome. The present study investigated the in vitro digestibility and prebiotic effect of curdlan gum produced by a marine bacterium, Enterobacter cloacae RSW2n previously isolated and screened from red seaweed, Gracilaria foliifera. Carbon sources such as glucose, sucrose, maltose, starch, palm oil, fructose, glycerol, and date syrup were used to produce curdlan gum, and its digestibility was evaluated in vitro. Curdlan produced from various carbon sources exhibited distinct degrees of hydrolysis in vitro, probably due to the differences in molecular weight distribution and degree of branching. Curdlan produced using maltose exhibits a lower hydrolysis percentage at pH 1 and pH 3, indicating greater resistance to acidic pH and stability against digestion compared to other curdlan. In this perspective, curdlan gum produced using maltose was selected to evaluate prebiotic activity by stimulating the growth of probiotic microorganisms such as Saccharomyces cerevisiae, Lactobacillus acidophilus, and Lactobacillus casei. Acid tolerance in YEPD medium with 0.5% curdlan gum at lower pH promoted probiotic yeast viability. The study findings suggested that curdlan at 0.5% (w/v) effectively stimulated the growth of S. cerevisiae, L. acidophilus, and L. casei. Hence, curdlan gum produced by marine bacteria could serve as a potential prebiotic source for functional food development.
Pandi et al. (Sun,) studied this question.