Compared tolerance to osmotic stress in various microorganisms: towards a survival prediction test.
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.
Mille
Yannick
Y
Laboratoire de Génie des Procédés Alimentaires et Biotechnologiques, Ecole Nationale Supérieure de Biologie Appliquée à la Nutrition et à l'Alimentation, Dijon, France.
Beney
Laurent
L
Gervais
Patrick
P
D006090:Gram-Negative Bacteria / Q000254:growth & development*; D006094:Gram-Positive Bacteria / Q000254:growth & development*; D009995:Osmosis; D009997:Osmotic Pressure; D011237:Predictive Value of Tests; D013045:Species Specificity; D013696:Temperature; D015003:Yeasts / Q000254:growth & development*