Exopolysaccharide from Leuconostoc mesenteroides XR1: Yield optimization, partial characterization and properties

Area of Science:

• Microbiology
• Biochemistry
• Materials Science

Background:

• Exopolysaccharides (EPS) are microbial polymers with diverse applications.
• Optimizing EPS production is crucial for industrial viability.
• Leuconostoc mesenteroides XR1 is a potential source of valuable EPS.

Purpose of the Study:

• To optimize the production conditions for exopolysaccharide (EPS) from Leuconostoc mesenteroides XR1 using response surface methodology (RSM).
• To characterize the structural, physical, and functional properties of the optimized EPS.
• To evaluate the potential commercial applications of the produced EPS.

Main Methods:

• Response surface methodology (RSM) for optimizing fermentation parameters (ammonium citrate concentration, initial pH, temperature).
• Congo red test and circular dichroism (CD) for analyzing EPS chain conformation.
• Analysis of polydispersity index (PDI), thermal degradation temperature, free radical scavenging activity, and hydrogel formation.

Main Results:

• Optimized conditions (2.6 g/L ammonium citrate, pH 6.5, 23°C) significantly increased EPS yield by 6.21-fold to 56.59 g/L.
• EPS demonstrated a stable random coil structure, high thermal stability (degradation at 253.11°C), and uniform distribution (PDI 27.16%).
• EPS exhibited significant antioxidant activity, protected DNA from oxidative damage, and formed stable hydrogels above 5% (w/v).

Conclusions:

• The optimized production process substantially enhanced EPS yield from Leuconostoc mesenteroides XR1.
• The characterized EPS possesses desirable properties including high stability and potent antioxidant capabilities.
• EPS shows significant potential for commercial use as an antioxidant and a drug delivery carrier.