초록
<P><B>Background</B></P><P>It remains a challenge for recombinant <I>S. cerevisiae</I> to convert xylose in lignocellulosic biomass hydrolysates to ethanol. Although industrial diploid strains are more robust compared to laboratory haploid strains, however, industrial diploid <I>S. cerevisiae</I> strains have been less pursued in previous studies. This work aims to construct fast xylose-fermenting yeast using an industrial ethanol-producing diploid <I>S. cerevisiae</I> strain as a host.</P><P><B>Results</B></P><P>Fast xylose-fermenting yeast was constructed by genome integration of xylose-utilizing genes and adaptive evolution, including 1) <I>Piromyces XYLA</I> was introduced to enable the host strain to convert xylose to xylulose; 2) endogenous genes (<I>XKS1, RKI1, RPE1, TKL1</I>, and <I>TAL1</I>) were overexpressed to accelerate conversion of xylulose to ethanol; 3) <I>Candida intermedia GXF1</I>, which encodes a xylose transporter, was introduced at the <I>GRE3</I> locus to improve xylose uptake; 4) aerobic evolution in rich xylose media was carried out to increase growth and xylose consumption rates. The best evolved strain CIBTS0735 consumed 80 g/l glucose and 40 g/l xylose in rich media within 24 hours at an initial OD<SUB>600</SUB> of 1.0 (0.63 g DCW/l) and produced 53 g/l ethanol.</P><P><B>Conclusions</B></P><P>Based on the above fermentation performance, we conclude that CIBTS0735 shows great potential for ethanol production from lignocellulosic biomass.</P>