Ethanol, the major fermentation product of yeast, is a stress factor in yeast. We previously constructed an ethanol-tolerant mutant yeast iETS3 by using the global transcriptional machinery engineering. However, the ethanol-tolerance mechanism has not been systematically investigated. In this study, global metabolite profiling was carried out, mainly by gas chromatography/time-of-flight mass spectrometry (GC/TOF MS), to investigate the mechanisms of ethanol tolerance in iETS3. A total of 108 intracellular metabolites were identified by GC/TOF MS and high performance liquid chromatography, and these metabolites were mostly intermediates of the central carbon metabolism. The metabolite profiles of iETS3 and BY4741, cultured with or without ethanol, were significantly different based on principal component and hierarchical clustering analyses. Our metabolomic analyses identified the compositional changes in cell membranes and the activation of glutamate metabolism and the trehalose synthetic pathway as the possible mechanisms for the ethanol tolerance. These metabolic traits can be considered possible targets for further improvement of ethanol tolerance in the mutant. For example, the KGD1 deletion mutant, with up-regulated glutamate metabolism, showed increased tolerance to ethanol. This study has demonstrated that metabolomics can be a useful tool for strain improvement and phenotypic analysis of microorganisms under stress.
Bibliographical noteFunding Information:
This work was financially supported by the Pioneer Research Center Program (2011-0002327) and the Advanced Biomass R&D Center of Korea (2011-0031359) funded by the Ministry of Science, ICT & Future Planning. Experiments were carried out using the facilities of the Institute of Biomedical Science and Food Safety at the Food Safety Hall, Korea University. The authors declare no conflict of interest for this study.
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- Ethanol tolerance
- Metabolite profiling
- Saccharomyces cerevisiae
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology
- Molecular Medicine