Effect Of Saline Stress On The Physiological Characteristics Of Saccharomyces Cerevisiae

Yeast is a good organism and a valuable biomaterial in industrial production. Inbiochemical process with whole cell used, Saccharomyces cerevisiae may encounter severalenvironmental stresses, such as saline stress, sugar stress. To evaluate the impacts of salinestress, sodium chloride had been chosen for osmolyte in order to reveal the impacts of salinestress on cellular proliferation, morphology and metabolism. In this study Saccharomycescerevisiae2144had been chosen for research.1. Experiments indicated that, upon NaCl treatment, the formation of yeast colony wasinhibited and the viable count was significantly declined. Upon exposure to0.3mol/LNaCl, the time which the cells reached stationary phase was the same as the contror group.While in the0.6mol/L NaCl and1.0mol/L NaCl treatment, log phase was extended. Withthe increase of the sodium chloride concentration the cells contracted and colonyquantities reduced. Compared to the control group,0.6mol/L NaCl and1.0mol/L NaCldefered glucose consumption rate, at the end of fermentation the broth pH of the stressgroups were lower than the control.2. Effect of sodium chloride stress on Saccharomyces cerevisiae extracellular protein wasalso studied. Results indicated that, upon exposure to NaCl, a new53kDa protein wasfound. With the increase of the sodium chloride concentration, this protein expression wasdeferred. When the cell cultured to10h two new proteins which molecular mass were61kDa,65kDa were found in the0.3mol/L NaCl and0.6mol/L NaCl treatment.3. The characterization of Na+absorption was also studied. The result showed that with thesodium chloride concentration stepped up, the intracellular content of Na+increased whileK+decreased the ratio of Na+/K+exhibited an increase tendency. The stress groups’Na+/K+were higher than the control group.4. Relationship among trehalose, glycerol and NaCl tolerance in Saccharomyces cerevisiawere also studied. Stress groups had produced more trehalose than the control group. Thecells would accumulate intracellular glycerol to adapt hyper-osmotic stress while theydidn’t generate glycerol in normal culture. As NaCl concentration heightened the intracellular glycerol was clearly increased. The extracellular glycerol was added by thestress time prolonging. They manifested a tendency which was descending after risingfirst.5. Separated the saline stress Saccharomyces cerevisiae seretory protein with Sephadex G-25filtration chromatography. The results showed that closing to the thirtieth tube a peakvalue had found in both control group and stress groups when cell cultured to eighth hour.A peak value tube found in40nearby which was not find in the control group in eighthhour. When cultivated to the sixteenth hour, two peak value tubes were detected in thetwenty-eight and forty-two seperatedly in all the groups. A peak value was detected ineleventh tube in control group and with0.3mol/L NaCl stress group, but didn’t find inother groups. A peak value tube found in fifty-seventh in0.3mol/L NaCl stress groupwhich didn’t finding in other groups.