[Growth of a turbidostatic culture of yeast under conditions of thermal stress at various pH's of the media].

A turbidostat Saccharomyces cerevisiae 14 culture was grown at pH 6.0 to 2.25 and subjected to a heat pulse (the optimal temperature of 30 degrees C was elevated to 37.5 degrees C) in order to study its response. The growth rate was determined in the first cell generation after the pulse. The culture grown at pH 6-4 was shown to be thermotolerant whereas the yeast was thermosensitive at pH 2.4-2.25. The cells became thermotolerant at 37.5 degrees C after the transitions: pH 2.25----4 and pH 2.35----4. The yeast thermoresistance was shown to depend on H+ concentration. Apparently, the yeast thermotolerance was determined by the effective functioning of the chemo-osmotic system.