The petroleum shortage and environmental concern, has motivated the displacement of petrochemical products for green alternatives, including biomass derived fuels and chemicals. Butanol is one of the most promising biofuels. Metabolic engineering of Escherichia coli has shown it's potential as butanol producer. In spite of it, low solvent tolerance is one of the main challenges in the use of microorganisms for solvent production, with the highest concentration of butanol tolerated by these bacteria being only around 2%.
Using a novel experimental adaptive evolution strategy, we were able to isolate mutant strains, with increased solvent tolerance in comparison with wild type. The molecular mechanisms involved in butanol tolerance in the isolated adaptive mutants are investigated.