Structural characterization and partial properties of dextran produced by Leuconostoc mesenteroides RSG7 from pepino

• Published in: Frontiers in microbiology Vol. 14; p. 1108120
• Main Authors: Wang, Binbin, Sun, Xiaoling, Xu, Min, Wang, Fengyi, Liu, Weizhong, Wu, Baomei
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 02.02.2023
• Subjects: dextran; Leuconostoc mesenteroides RSG7; Microbiology; pepino; physical–chemical properties; structural characterization; dextran; physical–chemical properties; structural characterization; pepino; Leuconostoc mesenteroides RSG7
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2023.1108120

Exopolysaccharides (EPSs) produced by lactic acid bacteria possess various bioactivities and potential attractions for scientific exploration and commercial development. An EPS-producing bacterial strain, RSG7, was previously isolated from the pepino and identified as . Based on the analyses of high-performance size exclusion chromatography, high-performance ion chromatography, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and methylation, the RSG7 EPS was identified as a dextran with a molecular weight of 5.47 × 10 Da and consisted of α-(1→6) glycosidic linkages as backbone and α-(1→2), α-(1→3), α-(1→4), and α-(1→6) glycosidic linkages as side chains. Scanning electron microscopy observed a honeycomb-like porous structure of RSG7 dextran, and this dextran formed aggregations with irregular hill-shaped lumps according to atomic force microscopy analysis. Physical-chemical investigations suggested that RSG7 dextran possessed excellent viscosity at high concentration, low temperature, and high pH; showed a superior emulsifying capacity of tested vegetable oils than that of hydrocarbons; and owned the maximal flocculating activity (10.74 ± 0.23) and flocculating rate (93.46 ± 0.07%) in the suspended solid of activated carbon. In addition, the dextran could coagulate sucrose-supplemented milk and implied potential probiotics . Together, these results collectively describe a valuable dextran with unique characteristics for exploitation in food applications.