Structural characterization and bioactivity of novel exopolysaccharides produced by Tetragenococcus halophilus

In this study, exopolysaccharides produced by Tetragenococcus halophilus were extracted and purified. Two fractions named EPS-1 and EPS-2 were obtained with average molecular weights of 2613.4 and 93.4 kDa, respectively. Analysis of the structures demonstrated that EPS-1 was mainly composed of galactose, glucose, mannose and glucuronic acid, and EPS-2 mostly consisted of glucose and mannose. 800 MHz nuclear magnetic resonance spectroscopy elucidated different and partial primary structures of EPS-1 and EPS-2. The micro topography was observed by atomic force microscope and scanning electron microscope. In addition, the two fractions exhibited antioxidant activities on DPPH, hydroxyl and ABTS(center dot+) radicals. Furthermore, EPS-1 and EPS-2 could protect Lactococcus lactis against cryogenic and lyophilized stress. These results indicated that exopolysaccharides from T. halophilus in this study would have great potential in the application of food and pharmaceutical industry.

Automated summary

In this study, exopolysaccharides produced by Tetragenococcus halophilus were extracted and purified. The analysis of the structures and micro topography revealed their potential application in the food and pharmaceutical industry due to their antioxidant activities and ability to protect Lactococcus lactis against stress.