Compared tolerance to osmotic stress in various microorganisms: Towards a survival prediction test

Abstract

The osmotic tolerance of microbial cells of different microorganisms was investigated as a function of glycerol concentration and temperatures. Cells displayed specific sensitivity to dehydration in glycerol solutions. The viability of Gram-negative strains (Escherichia coli, Bradyrhizobium japonicum), Gram-positive strains (Lactobacillus plantarum, L. bulgaricus), and yeasts (Saccharomyces cerevisiae, Candida utilis) decreased with increasing osmotic pressure. For each strain, a characteristic osmotic pressure threshold causing a loss of 40% of the population at the growth temperature was determined: 26-40 MPa for E. coli, 15-25 MPa for B. japonicum, 7-15 MPa for L. bulgaricus, 40-133 MPa for L. plantarum, 50-100 MPa for S. cerevisiae, and 15-26 MPa for C. utilis. Because this threshold varies with temperature, it was possible to construct a diagram that could be helpful to the determination of the sensitivity of each strain to osmotic stress as a function of osmotic pressure and temperature.

Survival of microbial isolates from clouds toward simulated atmospheric stress factors

“…Similar patterns were observed in cells subject to desiccation, and this suggested that the peptidoglycan layer, thicker in Gram-positive bacteria, was involved in resistance towards osmotic variations (Nocker et al, 2012). Nevertheless, Mille et al (2005) studied the survival rates of 2 yeasts, 2 Grampositive bacteria and 2 Gram-negative bacteria subjected to osmotic variations and demonstrated that cell type alone cannot explain increased tolerance, but that intra-species membrane composition characteristics also have to be considered. The composition in fatty acids notably strongly influences membrane fluidity and its susceptibility to mechanical damages.…”

Farnesol production from Escherichia coli by harnessing the exogenous mevalonate pathway

“…This competition results in cell growth inhibition and low FOH production. A supply of glycerol can alleviate the shortage of acetyl-CoA, however, extraordinary high glycerol concentrations (e.g., 4% (v/v)), might change the medium properties such as osmosis, which has been reported to affect microorganism viability (Karlgren et al, 2005;Mille et al, 2005). Under such unfavorable condition, the capacity of E. coli to produce FOH might be weakened and led to low FOH production after the addition of 4% (v/v) glycerol.…”

Effect of respiration and manganese on oxidative stress resistance of Lactobacillus plantarum WCFS1

“…The adaptive response of Lb. plantarum WCFS1 to a range of stresses has been investigated, including high temperature (Fiocco et al, 2007), high osmotic pressure (Mille et al, 2005), bile salts (Elkins & Mullis, 2004), low pH (Ingham et al, 2008) and oxidative stress (Serrano et al, 2007). However, the Lb.…”