Genetic determinants of ethanol tolerance in E. coli

Research carried out by Thomas Schalck

Ethanol is an important microbial product that can be applied as a fuel and as precursor for numerous polymers (including polyethylene and polyethylene glycol). However, high alcohol levels are toxic for the producer strains and as a result drastically reduce ethanol productivity (Schalck et al. 2021). Hence, improving the intrinsic alcohol tolerance has the potential to increase product outputs. Previously, we have demonstrated that adaptation to lethal ethanol concentrations is a complex process in which multiple pathways are involved (Swings et al. 2017; Swings, Weytjens et al. 2017).

Ethanol poisons the cell in many ways. This alcohol damages the membranes, inhibits transcription and translation processes, reduces enzyme activity and elicits production of reactive oxygen species (ROS).

The aim of this research project is to identify genetic determinants conferring ethanol tolerance in E. coli and to investigate the mechanisms underlying these adaptive pathways and mutations. Furthermore, we are validating the identified genetic determinants in small-scale batch fermentations to estimate their production potential. 

To achieve these goals, we are frequently making use of the recently developed CRISPR-FRT technique to screen for the effect of adaptive mutations on ethanol tolerance in an in vivo context (Swings, Marciano et al. 2018). 


  • Schalck T., Van den Bergh B., Michiels J. (2021). Increasing solvent tolerance to improve microbial production of alcohols, terpenoids and aromatics. Microorganisms 9(2):249.

  • Swings T., Van den Bergh B., Wuyts S., Oeyen E., Voordeckers K., Verstrepen K., Fauvart M., Verstraeten N., Michiels J. (2017). Adaptive tuning of mutation rates allows fast response to lethal stress in Escherichia coli. eLife, 6:e22939
  • Swings T.#, Weytjens B.#, Schalck T., Bonte C., Verstraeten N., Michiels J.*, Marchal K.* (2017). Network-based identification of adaptive pathways in evolved ethanol-tolerant bacterial populations. Molecular Biology and Evolution, 34(11):2927-2943.
  • Swings T.#, Marciano DC.#, Atri B., Bosserman RE., Wang C., Leysen M., Bonte C., Schalck T., Furey I., Van den Bergh B., Verstraeten N., Christie PJ., Herman C., Lichtarge O.*, Michiels J.* (2018). CRISPR-FRT targets shared sites in a knock-out collection for off-the-shelf genome editing. Nature Communications, 9(1):2231.