초록
<P>In order to achieve rapid xylose utilization in the presence of acetate, improved yeast strains were engineered for higher bioethanol production. First, a six-gene cluster, including <I>XYL1</I>/<I>XYL2</I>/<I>XKS1</I>/<I>TAL1</I>/<I>PYK1</I>/<I>MGT05196</I>, was generated by using an in-depth two-stage (glucose and xylose) transcription reprogramming strategy in an evolutionary adapted strain of CE7, resulting in two improved engineered strains WXY46 and WXY53. Through a combined screening of xylose and glucose stage-specific promoters between tricarboxylic acid (TCA)/HSP and constitutive types, respectively, WXY46 with the constitutive promoters showed a much higher ethanol yield than that of WXY53 with the TCA/HSP promoters. Second, an optimized strain WXY74 was obtained by using more copies of a six-gene cluster, which resulted in a higher ethanol yield of 0.500 g/g total sugars with acetate conditions. At last, simultaneous saccharification and co-fermentation were performed by using the evolved WXY74 strain, which produced 58.4 g/L of ethanol from wheat straw waste and outperformed previous haploid XR-XDH strains.</P><BR>[FIG OMISSION]</BR>