Exopolysaccharide Produced by a Human- Milk–Derived Lactiplantibacillus plantarum LH04: Compositional and Physicochemical Insights

Microbial fermentation represents a sustainable strategy for producing novel polysaccharides with desirable properties for biomaterial applications, particularly those synthesized by food grade bacteria. Lactic acid bacteria, including Lactobacillus, Leuconostoc, Weissella, Lactococcus, Streptococcus, Pediococcus, and Bifidobacterium spp., are known to produce extracellular polysaccharides that can be classified according to their chemical composition and structural features. In this context, the present study provides a comprehensive chemical and physicochemical characterization of the exopolysaccharide (EPS) synthesized by Lactiplantibacillus plantarum LH04, a strain isolated from human milk. The EPS was identified as a heteropolysaccharide composed primarily of glucose, galactose, fructose, N acetylglucosamine, and succinic acid. The extraction and purification process yielded 1.09 g·L⁻¹ of EPS, containing 86.38% (w/w) total carbohydrates, 0.3% (w/w) protein, and less than 0.001% (w/w) reducing sugars. The EPS exhibited notable thermal stability, with decomposition occurring above 259 °C, and displayed a predominantly amorphous structure, as confirmed by X-ray diffraction analysis, with a crystallinity index of 1.8%. Additionally, it showed an uncommon solubility profile, being insoluble in water and organic solvents but fully soluble in NaOH and KOH. Overall, the compositional and physicochemical characteristics of this HePS underscore its potential for diverse applications in food, biomedical, and environmental technologies. This is ultimately followed by the convergence of finely, tuned epigenetic switches and the synthetic biology, leading to a safer, more precise, and diverse process of disease modeling as well as the therapeutic intervention.