Work

Characterisation and bioactivity of an exopolysaccharide isolated from Lactobacillus rhamnosus LRH30 cultivations

Year: 2025

Type: article

Abstract: This study presents the first characterisation of the exopolysaccharide (EPS) produced by Lactobacillus rhamnosus LRH30 (L. rhamnosus LRH30) in skim milk-based bioprocesses. EPS yields varied significantly with cultivation mode, reaching 200.8 mg/L in shake flask, 427 mg/L in batch, and 1866 mg/L in fed-batch fermentation. When dissolved in milk, the EPS exhibited shear-thinning behaviour, indicating its suitability for texture enhancement in dairy applications. Morphological analysis via scanning electron microscopy (SEM) revealed a flaky, spherical microstructure. Fourier-transform infrared spectroscopy (FTIR) showed characteristic polysaccharide peaks, with similarities to commercial dextran . Monosaccharide composition analysis by high-performance liquid chromatography (HPLC) identified glucose and rhamnose as the dominant constituents. Bioactivity assays demonstrated dose-dependent immunomodulatory effects: EPS at 50 µg/mL significantly increased IL-10 and decreased TNF-α in LPS-stimulated macrophages. Additionally, IL-6 was reduced at 5 µg/mL, while IL-1β increased at 50 µg/mL. The EPS also exhibited moderate antioxidant activity , with a maximum radical scavenging capacity of 39.2 %. These findings highlight the potential of the EPS from L. rhamnosus LRH30 EPS as a novel, multifunctional ingredient for use in dairy-based functional foods.

Source: Carbohydrate Polymer Technologies and Applications

DOI: 10.1016/j.carpta.2025.100857