The Effect of Compatible Solutes on the Cell Membrane of Lactobacillus delbrueckii subsp. bulgaricus 3

Compatible solutes can reduce the impact of salt stress on bacteria. This work describes the changes in Lactobacillus delbrueckii subsp. bulgaricus 3 ( L . bulgaricus 3) cell morphology, viability, cell membrane permeability, Zeta potential, and fluidity under salt stress. The results showed that compatible solutes shortened the transition of bacterial cells to the stationary phase under salt stress from 25 to 22 h. The cell diameter decreased from 831 to 515 nm. Compatible solutes increased the number of bacteria and promoted cell growth. The number of viable bacteria increased from 4.33 × 10 6 to 5.71 × 10 8 CFU/mL. Application of compatible solutes also improved stability of the cell membrane and maintained integrity under salt stress. According to the results of fluorescence anisotropy analysis, compatible solutes increased the fluidity of the cell membrane under salt stress. These observations suggested that compatible solutes could decrease cell growth inhibition under salt stress by changing cell morphology and the cell membrane properties.