Effect of environmental stress on cell surface and membrane fatty acids of Lactobacillus plantarum.

Adhesion has been regarded as one of the basic features of probiotics. We undertake this study in the aim to give new insight about the change in cellular physiological state under heat and acid treatments of Lactobacillus plantarum. Different cell properties have been investigated such as adhesive ability to abiotic surfaces, the cell surface hydrophobicity and the fatty acids profiles. The results of cell surface properties and Gas chromatography analysis demonstrated a modification in term adhesive ability and fatty acid (FA) composition of the tested strain under stressful conditions. In fact, after the exposure of the strain to heat and acid treatments, an increase in the hydrophobicity level and the adhesion capacity on HeLa cells was shown. Our findings revealed that high temperature and low pH change the fatty acids profiles of the treated cells, especially the proportions of unsaturated and saturated fatty acid. In this context, our data revealed that the unsaturated FA-to-saturated FA ratio was increased significantly (P < 0.05) for stressed strains compared with control cells. The results of the present finding suggest that the tested strain have suffered changes like the modifications on bacterial membrane as a cellular response to survive the hard environmental conditions, allowing them to withstand harsh conditions and sudden environmental changes to survive under.