Effects of saccharide in medium on stress tolerance of yeast

Abstract

Effects of saccharides (glucose, fructose, galactose, mannose, lactose, maltose, sucrose, trehalose) in medium on stress tolerance of yeast (Saccharomyces cerevisiae) were studied by colony counting method. The protection effect of various saccharides for yeast cells against high pressure and high temperature was estimated with survivals. Saccharides at the concentration of 0.5 mol/l or 1.0 mol/l added to YPD culture medium apparently increased the survivals of the yeast during subjected high pressure and high temperature. Barotolerance (150 MPa, 1 hour) of the yeast cell increased with increasing concentration of saccharides. Trehalose, induced maximum barotolerance to the yeast cells and disaccharides endowed the yeast cells, with higher tolerance compared with monosaccharides. Thermotolerance (51°C, 10 min) also showed a similar pattern of survival vs. saccharide concentration, to barotolerance. The protection effects of saccharides against high pressure and high temperature were explained by the mean number of equatorial OH groups in saccharide molecule. Stress tolerance of pressure-shocked yeast in the medium containing saccharides was also estimated.