Interactive effects of sodium chloride and heat shock on trehalose accumulation and glycerol production by Saccharomyces cerevisiae

Trehalose and glycerol may act as protectors inducing a high tolerance to a range of stresses which appear in the production and industrial utilizatio n of yeast Accumulation of trehalose and glycerol production in Saccharomyc es cerevisiae cultures as a response to environmental changes in temperatur e (30-44 degrees C) and osmotic pressure (0-1 M) was studied, using a Doehl ert experimental distribution. Maximum amounts of both compounds were obtai ned at NaCl concentration of 0.75 M and heat shock temperature of 44 degree s C. A reduction of NaCl concentration to 0.25 nn while maintaining the tem perature at 44 degrees C resulted in 73 and 51% reductions for trehalose an d glycerol concentrations. The lowest amounts of both solutes were produced in the absence of NaCl at 37 degrees C heat shock. The amounts of both sub stances nearly doubled when a heat shock to 37 degrees C was performed on 0 .5 M of NaCl grown cultures. The increase of NaCl to I nn produced 29.5% mo re trehalose and 5.5% more glycerol. in trehalose accumulation both NaCl co ncentration and heat shock temperature contribute in an interactive manner, leading to a more effective synthesis of trehalose than each one per se. N aCl was found to be more important than temperature in glycerol production but the combination of the two factors still encloses a considerable synerg istic effect. NaCl contributes with an effect fivefold that of temperature on both responses. General quantification of NaCl inhibition was determined by evaluating the growth inhibition constant (K-i) which was of 2.40 M-1 i ndicating a reasonable resistance to osmotic stress. (C) 1999 Academic Pres s.