THE IMPACT OF CALCIUM ION ON FERMENTATION PERFORMANCE AND STRESS TOLERANCE OF THE YEAST Saccharomyces cerevisiae.

Metal ions in fermentation media is very crucial for yeast growth and fermentation performance. Other than that, they also have roles for protecting yeast cells against environmental stress factors. In the present study, we investigate the role of calcium ions on fermentation performance and stress tolerance. Most study focus only on one stress factor, while in the present study we tested the effect of calcium ion supplementation against four stress factors, namely ethanol, hyperosmotic, weak acid, and oxidative stresses. The results of the present study indicate that calcium ion has positive role in cell growth and fermentation performance as indicated by significantly higher OD600 nm and higher ethanol produced when calcium ion present in the fermentation media. Calcium ion was also found improving the yeast cell tolerance to all stress factors tested. Therefore, we propose that calcium ion act as general stress protectant for the yeast strain used in this study. [ABSTRACT FROM AUTHOR]