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

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 epsF 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 epsF gene, leading to differences in the monosaccharide composition of exopolysaccharides.

Spatiotemporal bio-shielding of bacteria through consolidated geometrical structuring

“…S7 ). A recent study has shown that the exopolysaccharides (EPS) production could be upregulated in L. plantarum cells grown at acidic pH, which supports our observation 28 . Biofilm formation by probiotic species is a propitious tactic to control pathogenic biofilms, which is relatively based on the competitive-exclusion principle 29 , 30 .…”

Limosilactobacillus fermentum from buffalo milk is suitable for potential biotechnological process development and inhibits Helicobacter pylori in a gastric epithelial cell model

“…Some of these units could belong to the HePS, thus confirming the previous hypothesis. Finally, albeit the hexose units are frequent in lactobacilli EPS [12] , the presence of arabinose has been detected and associated to bacterial stress resistance [44] .…”

Functional Insights of Salinity Stress-Related Pathways in Metagenome-Resolved Methanothrix Genomes

“…The secretion of EPS is also recognized as a fundamental microbial adaptation to salinity, providing osmotic tolerance and limiting dehydration ( 35 ). The composition of excreted EPS can change in response to salinity fluctuations ( 36 – 38 ), as has been observed in the halophilic archaeon Haloferax volcanii when salinity decreases ( 39 ). A similar adaptation strategy observed within halophilic archaea is the production and inclusion of isoprenoid derivatives and carotenoids into lipid membranes, which helps in maintaining their fluidity in response to changes in the osmotic conditions ( 40 ).…”