Functional characterization and biotechnological applications of exopolysaccharides produced by newly isolated Enterococcus hirae MLG3-25-1.

Abstract

This study investigated the potential applications of Enterococcus hirae MLG3-25-1 exopolysaccharides (EPS), with a focus on their isolation, identification, production, and functional characteristics. After the bacterial strain was cultured in De Man-Rogosa-Sharpe (MRS) medium containing 1% glucose at 37°C, the EPS was refined, and the highest yield of 0.85mg/mL was achieved at the 24-h incubation period. Enterococcus hirae MLG3-25-1 was found to be able to produce EPS. The study explored the microstructure of the EPS, which resembles polysaccharide sheets with smooth surfaces, through scanning electron microscope (SEM) analysis. Through Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance(NMR) analysis, the chemical composition, aligning with glycosidic bond characteristics, has been deciphered. Furthermore, the antimicrobial and antibiofilm activities against pathogenic bacteria, particularly Bacillus sp., demonstrated potential applications in combating antibiotic resistance. The EPS exhibited notable antioxidant activity (89.36% DPPH scavenging), along with high water-holding capacity (575%), emulsifying activity, and flocculation activity, suggesting its potential as a stabilizing agent in the food industry. Overall, this study provides a comprehensive characterization of Enterococcus hirae MLG3-25-1 EPS, emphasizing its diverse applications in antimicrobial, antioxidant, and food-related industries. These findings lay the groundwork for further exploration and utilization of this EPS in various sectors.