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Response of Lactobacillus plantarum VAL6 to challenges of pH and sodium chloride stresses

2021; Nature Portfolio; Volume: 11; Issue: 1 Linguagem: Inglês

10.1038/s41598-020-80634-1

2045-2322

Phu-Tho Nguyen, Thi-Tho Nguyen, Thi-Ngoc-Tuyen Vo, Thi-Thanh-Xuan Nguyen, Quoc-Khanh Hoang, Huu‐Thanh Nguyen,

Polysaccharides and Plant Cell Walls

Abstract To investigate the effect of environmental stresses on the exopolysaccharide biosynthesis, after 24 h of culture at 37 °C with pH 6.8 and without sodium chloride, Lactobacillus plantarum VAL6 was exposed to different stress conditions, including pH (pHs of 3 and 8) and high sodium chloride concentration treatments. The results found that Lactobacillus plantarum VAL6 exposed to stress at pH 3 for 3 h gives the highest exopolysaccharide yield (50.44 g/L) which is 6.4 fold higher than non-stress. Under pH and sodium chloride stresses, the mannose content in exopolysaccharides decreased while the glucose increased in comparison with non-stress condition. The galactose content was highest under stress condition of pH 8 meantime rhamnose content increased sharply when Lactobacillus plantarum VAL6 was stressed at pH 3. The arabinose content in exopolysaccharides was not detected under non-stress condition but it was recorded in great amounts after 3 h of stress at pH 3. In addition, stress of pH 8 triggered the mRNA expression of eps F gene resulting in galactose-rich EPS synthesis. According to our results, the stresses of pH and sodium chloride enhance the production and change the mRNA expression of eps F gene, leading to differences in the monosaccharide composition of exopolysaccharides.