Cell surface properties of Lactobacillus salivarius under osmotic stress

The modifications of cell morphology and surface properties of Lactobacillus salivarius under osmotic stress were investigated. When deMan-Rogosa-Sharpe (MRS) medium was supplemented with NaCl (0.8 mol l(-1)), changes in cell size and shape of L. salivarius cells occurred. A higher autoaggregation percentage and a lower hydrophobicity of L. salivarius determined by microbial adhesion to hydrocarbons were observed under osmotic stress. Moreover, coaggregation was strain specific and depended on incubation time as well as growth medium. On the other hand, fatty acid analysis by gas chromatograph-mass spectrometer revealed increases in the ratio of saturated/unsaturated fatty acids and cyclopropaneoctanoic acid, which is a useful way to enhance their osmotic resistance for maintaining the structural and functional integrity of cell membranes.