Ethanol stress responses of Kluyveromyces marxianus CCT 7735 revealed by proteomic and metabolomic analyses

Kluyveromyces marxianus CCT 7735 offers advantages to ethanol production over Saccharomyces cerevisiae, including thermotolerance and the ability to convert lactose to ethanol. However, its growth is impaired at high ethanol concentrations. Herein we report on the protein and intracellular metabolite profiles of K. marxianus at 1 and 4h under ethanol exposure. The concentration of some amino acids, trehalose and ergosterol were also measured. We observed that proteins and metabolites from carbon pathways and translation were less abundant, mainly at 4h of ethanol stress. Nevertheless, the concentration of some amino acids and trehalose increased at 8 and 12h under ethanol stress, indicating an adaptive response. Moreover, our results show that the abundance of proteins and metabolites related to the oxidative stresses responses increased. The results obtained in this study provide insights into understanding the physiological changes in K. marxianus under ethanol stress, indicating possible targets for ethanol tolerant strains construction.