초록
<P><B>Abstract</B></P> <P>The production of <I>n</I>-butanol from sugarcane juice by metabolically engineered <I>Clostridium tyrobutyricum</I> Ct(Δack)-pscrBAK overexpressing <I>scr</I> operon genes (<I>scrB</I>, <I>scrA</I>, and <I>scrK</I>) for sucrose catabolism and an aldehyde/alcohol dehydrogenase gene (<I>adhE2</I>) for butanol biosynthesis was studied with corn steep liquor (CSL) as a low-cost nitrogen source. In free cell fermentation, butanol production of ∼16g/L at a yield of 0.31±0.02g/g and productivity of 0.33±0.02g/L·h was obtained from sucrose and yield of 0.24±0.02g/g and productivity of 0.30±0.01g/L·h from sugarcane juice containing sucrose, glucose and fructose. The fermentation was also studied in a fibrous bed bioreactor (FBB) operated in a repeated batch mode for 10 consecutive cycles in 10days, achieving an average butanol yield of 0.21±0.02g/g and productivity of 0.53±0.05g/L·h from sugarcane juice, demonstrating its long-term stability without applying the antibiotic selection pressure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>C. tyrobutyricum</I> was engineered to produce <I>n</I>-butanol from sucrose. </LI> <LI> Sucrose utilization was not repressed by glucose and fructose in sugarcane juice. </LI> <LI> Corn steep liquor as low-cost N source was used to increase butanol production. </LI> <LI> 16g/L of butanol at 0.31g/g yield and 0.33g/L·h productivity was obtained. </LI> <LI> Cells in a fibrous bed bioreactor gave stable butanol production in repeated batches. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>