초록
<P><B>Background</B></P><P>To produce 1-propanol as a potential biofuel, metabolic engineering of microorganisms, such as <I>E. coli</I>, has been studied. However, 1-propanol production using metabolically engineered <I>Saccharomyces cerevisiae</I>, which has an amazing ability to produce ethanol and is thus alcohol-tolerant, has infrequently been reported. Therefore, in this study, we aimed to engineer <I>S. cerevisiae</I> strains capable of producing 1-propanol at high levels.</P><P><B>Results</B></P><P>We found that the activity of endogenous 2-keto acid decarboxylase and alcohol/aldehyde dehydrogenase is sufficient to convert 2-ketobutyrate (2 KB) to 500 mg/L 1-propanol in yeast. Production of 1-propanol could be increased by: (i) the construction of an artificial 2 KB biosynthetic pathway from pyruvate via citramalate (<I>cimA</I>); (ii) overexpression of threonine dehydratase (<I>tdcB</I>); (iii) enhancement of threonine biosynthesis from aspartate (<I>thrA</I>, <I>thrB</I> and <I>thrC</I>); and (iv) deletion of the <I>GLY1</I> gene that regulates a competing pathway converting threonine to glycine. With high-density anaerobic fermentation of the engineered <I>S. cerevisiae</I> strain YG5C4231, we succeeded in producing 180 mg/L 1-propanol from glucose.</P><P><B>Conclusion</B></P><P>These results indicate that the engineering of a citramalate-mediated pathway as a production method for 1-propanol in <I>S. cerevisiae</I> is effective. Although optimization of the carbon flux in <I>S. cerevisiae</I> is necessary to harness this pathway, it is a promising candidate for the large-scale production of 1-propanol.</P><P><B>Electronic supplementary material</B></P><P>The online version of this article (10.1186/s12934-018-0883-1) contains supplementary material, which is available to authorized users.</P>