Optimization, structural characterization, and biological applications of exopolysaccharide produced by Enterococcus...

Area of Science:

• Microbiology
• Biochemistry
• Materials Science

Background:

• Exopolysaccharides (EPS) are microbial polymers with diverse applications.
• Enterococcus strains are known producers of bioactive compounds.
• Optimizing EPS production and characterizing its properties is crucial for potential applications.

Purpose of the Study:

• To identify and optimize the best exopolysaccharide (EPS) producing Enterococcus strain.
• To characterize the physicochemical and biological properties of the selected EPS.
• To evaluate the potential applications of the EPS in food and pharmaceutical industries.

Main Methods:

• Screening of eleven Enterococcus strains for EPS production.
• Optimization of fermentation conditions (sucrose, yeast extract, skimmed milk, temperature, time).
• Characterization using HPAEC, FTIR, 1H NMR, SEM, DLS, X-ray diffraction, and TGA.
• Evaluation of antioxidant, antimicrobial, antibiofilm, and cytotoxicity activities.

Main Results:

• Enterococcus faecium KT990028 was selected, producing 2.880 g/L EPS under optimized conditions.
• The EPS is a heteropolysaccharide (MW 166.98 kDa) with a unique microstructure and amorphous/crystalline nature.
• Demonstrated significant antioxidant, antimicrobial, and antibiofilm activities, with no cytotoxicity to Vero cells.

Conclusions:

• The EPS from E. faecium KT990028 is a safe and functional biopolymer.
• Its characterized properties suggest potential as a valuable ingredient in food and pharmaceutical products.
• Further research into its specific applications is warranted.