The global regulator IrrE from Deinococcus radiodurans enhances the furfural tolerance of Saccharomyces cerevisiae

High tolerance to inhibitors is crucial for microorganisms and difficult to achieve by manipulating single genes because strain tolerance involves multiple genes and several complicated regulation mechanisms. The present study demonstrated that irrE gene from Deinococcus radiodurans R1 promoted the furfural resistance of Saccharomyces cerevisiae through directed evolution. Compared to the wild-type strain, the FR mutant not only showed improved tolerance to single- or multi- inhibitors (furfural, 5-hydroxymethylfurfural, formic and acetic acid), but also obtained better ability of eliminating reactive oxygen species. Consequently, batch fermentation of the FR mutant in synthetic medium (200 g/L glucose and 2.0 g/L furfural) resulted in an 37% increase in ethanol productivity, although ethanol titer (∼88 g/L) was comparable to that of the control. This study provides the first evidence that an exogenous global regulator can improve the stress tolerance of yeast, which is significant for production of industrial products from lignocellulose by S. cerevisiae.