On-line measurement of intracellular ATP of Saccharomyces cerevisiae and pyruvate during sake mashing

The concentrations of intracellular ATP of Saccharomyces cerevisiae and pyr uvate in a medium were instantaneously increased by pulse addition of gluco se during starvation. They were reduced rapidly by alcohol fortification of the medium, accompanied by simultaneous increases of acetaldehyde concentr ation and inviability of yeast cells. These results were monitored during f ermentation of sake mash by an on-line measuring method. Intracellular ATP and pyruvate concentrations were considered to be indicators of the physiol ogical state of the yeast in sake mash. During sake mashing, it was observe d that an increase in temperature enhanced the intracellular ATP concentrat ion and the pyruvate production of the yeast. Since pyruvate production was not affected intensely by changes in temperature during cultivation in a g lucose-limited chemostat, this effect was thought to be due to the enhanced rates of cell-growth and/or alcohol production. This suggests that the con trol of mashing temperature during cell growth until about 10% alcohol accu mulation is achieved is important for the control of the pyruvate concentra tion in sake mash.