초록
<P><B>ABSTRACT</B></P><P>The glucose‐mediated carbon catabolite repression (CCR) in <I>Clostridium tyrobutyricum</I> impedes efficient utilization of xylose present in lignocellulosic biomass hydrolysates. In order to relieve the CCR and enhance xylose utilization, three genes (<I>xylT</I>, <I>xylA</I>, and <I>xylB</I>) encoding a xylose proton‐symporter, a xylose isomerase and a xylulokinase, respectively, from <I>Clostridium acetobutylicum</I> ATCC 824 were co‐overexpressed with aldehyde/alcohol dehydrogenase (adhE2) in <I>C. tyrobutyricum</I> (Δ<I>ack</I>). Compared to the strain Ct(Δ<I>ack</I>)‐pM2 expressing only <I>adhE2</I>, the mutant Ct(Δ<I>ack</I>)‐pTBA had a higher xylose uptake rate and was able to simultaneously consume glucose and xylose at comparable rates for butanol production. Ct(Δ<I>ack</I>)‐pTBA produced more butanol (12.0 vs. 3.2 g/L) with a higher butanol yield (0.12 vs. 0.07 g/g) and productivity (0.17 vs. 0.07 g/L · h) from both glucose and xylose, while Ct(Δ<I>ack</I>)‐pM2 consumed little xylose in the fermentation. The results confirmed that the CCR in <I>C. tyrobutyricum</I> could be overcome through overexpressing <I>xylT</I>, <I>xylA</I>, and <I>xylB</I>. The mutant was also able to co‐utilize glucose and xylose present in soybean hull hydrolysate (SHH) for butanol production, achieving a high butanol titer of 15.7 g/L, butanol yield of 0.24 g/g, and productivity of 0.29 g/L · h. This study demonstrated the potential application of Ct(Δ<I>ack</I>)‐pTBA for industrial biobutanol production from lignocellulosic biomass. Biotechnol. Bioeng. 2015;112: 2134–2141. © 2015 Wiley Periodicals, Inc.</P>