Exopolysaccharide Produced by Pediococcus pentosaceus E8: Structure, Bio-Activities, and Its Potential Application

Guangyang Jiang; Juan He; Longzhan Gan; Xiaoguang Li; Zhe Xu; Li Yang; Ran Li; Yongqiang Tian

doi:10.3389/fmicb.2022.923522

Exopolysaccharide Produced by Pediococcus pentosaceus E8: Structure, Bio-Activities, and Its Potential Application

Front Microbiol. 2022 Jun 22:13:923522. doi: 10.3389/fmicb.2022.923522. eCollection 2022.

Authors

Guangyang Jiang^{1

2}, Juan He³, Longzhan Gan^{1

2}, Xiaoguang Li^{1

2}, Zhe Xu^{1

2}, Li Yang^{1

2}, Ran Li⁴, Yongqiang Tian^{1

2}

Affiliations

¹ College of Biomass Science and Engineering, Sichuan University, Chengdu, China.
² Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China.
³ Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China.
⁴ Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland.

Abstract

The novel exopolysaccharide EPS-E8, secreted by Pediococcus pentosaceus E8, was obtained by anion-exchange and gel filtration chromatography. Structural analyses identified EPS-E8 as a heteropolysaccharide containing mannose, glucose, and galactose. Its major backbone consists of →2)-α-D-Manp-(1→2,6)-α-D-Glcp-(1→6)-α-D-Manp-(1→, and its molecular weight is 5.02 × 10⁴ g/mol. Using atomic force microscopy and scanning electron microscopy, many spherical and irregular reticular-like shapes were observed in the microstructure of EPS-E8. EPS-E8 has outstanding thermal stability (305.7°C). Both the zeta potential absolute value and average particle diameter increased gradually with increasing concentration. Moreover, at a concentration of 10 mg/ml, the antioxidant capacities of, 1-Diphenyl-2-picrylhydrazyl (DPPH), ABTS and hydroxyl radical were 50.62 ± 0.5%, 52.17 ± 1.4%, and 58.91 ± 0.7%, respectively. EPS-E8 possesses excellent emulsifying properties against several food-grade oils, and its activity is retained under various conditions (temperature, pH, and ionic strength). Finally, we found that EPS-E8 as a polysaccharide-based coating could reduce the weight loss and malondialdehyde (MDA) content of strawberry, as well as preserving the vitamin C and soluble solid content during storage at 20°C. Together, the results support the potential application of EPS-E8 as an emulsifier, and a polysaccharide-based coating in fruit preservation.

Keywords: Pediococcus pentosaceus; emulsifying activity; exopolysaccharide; strawberry preservation; structural analysis.