2022 Volume 101 Issue 4 Pages 83-87
Saccharomyces cerevisiae tolerant to an imidazolium ionic liquid, 1-butyl-3-methylimidazolium chloride ([Bmim] Cl), was isolated using adaptive laboratory evolution, in which yeast was repeatedly cultured in a medium with progressively increasing concentrations of [Bmim]Cl. Whole-genome sequencing revealed that mutations causing amino acid changes occurred in the open reading frames of two genes, GLO3 and EST2. Since no mutations were found in any of the genes that have been shown to be involved in ionic liquid tolerance, this mutant strain is assumed to have acquired ionic liquid tolerance in a novel mechanism. Using this ionic liquid-tolerant yeast strain, we succeeded in producing bioethanol in the presence of 500 mM [Bmim]Cl from glucose obtained via ionic liquid and cellulase treatment of cellulose.
