Physiological and genome-wide transcriptional responses of Saccharomyees cerevisiae to high carbon dioxide concentrations

Physiological effects of carbon dioxide and impact on genome-wide transcript profiles were analysed in chemostat cultures of Saccharomyces cerevisiae. In anaerobic, glucose-limited chemostat cultures grown at atmospheric pressure, cultivation under CO2-saturated conditions had only a marginal (< 10%) impact on the biomass yield. Conversely, a 25% decrease of the biomass yield was found in aerobic, glucose-limited chemostat cultures aerated with a mixture of 79% CO2 and 21% O-2. This observation indicated that respiratory metabolism is more sensitive to CO, than fermentative metabolism. Consistent with the more pronounced physiological effects Of CO2 in respiratory cultures, the number Of CO2-responsive transcripts was higher in aerobic cultures than in anaerobic cultures. Many genes involved in mitochondrial functions showed a transcriptional response to elevated CO2 concentrations. This is consistent with an uncoupling effect Of CO2 and/or intracellular bicarbonate on the mitochondrial inner membrane. Other transcripts that showed a significant transcriptional response to elevated CO2 included NCEI03 (probably encoding carbonic anhydrase), PCK1 (encoding PEP carboxykinase) and members of the IMD gene family (encoding isozymes of inosine monophosphate dehydrogenase). (c) 2004 Published by Elsevier B.V. on behalf of the Federation of European Microbiological Societies.