초록
<P><B>Background</B></P><P>Multiple lignocellulose-derived inhibitors represent great challenges for bioethanol production from lignocellulosic materials. These inhibitors that are related to the levels of intracellular reactive oxidative species (ROS) make oxidoreductases a potential target for an enhanced tolerance in yeasts.</P><P><B>Results</B></P><P>In this study, the thioredoxin and its reductase from <I>Kluyveromyces marxianus</I> Y179 was identified, which was subsequently achieved over-expression in <I>Saccharomyces cerevisiae</I> 280. In spite of the negative effects by expression of thioredoxin gene (<I>KmTRX</I>), the thioredoxin reductase (<I>KmTrxR</I>) helped to enhance tolerance to multiple lignocellulose-derived inhibitors, such as formic acid and acetic acid. In particular, compared with each gene expression, the double over-expression of <I>KmTRX2</I> and <I>KmTrxR</I> achieved a better ethanol fermentative profiles under a mixture of formic acid, acetic acid, and furfural (FAF) with a shorter lag period. At last, the mechanism that improves the tolerance depended on a normal level of intracellular ROS for cell survival under stress.</P><P><B>Conclusions</B></P><P>The synergistic effect of <I>KmTrxR</I> and <I>KmTRX2</I> provided the potential possibility for ethanol production from lignocellulosic materials, and give a general insight into the possible toxicity mechanisms for further theoretical research.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s12934-017-0795-5) contains supplementary material, which is available to authorized users.</P>