Enhancement of sucrose metabolism in Clostridium saccharoperbutylacetonicum N1-4 through metabolic engineering for improved acetone-butanol-ethanol (ABE) fermentation

This work investigated sucrose metabolism in C. saccharoperbutylacetonicum. Inactivation of sucrose catabolism operon resulted in 28.9% decrease in sucrose consumption and 44.1% decrease in ABE production with sucrose as sole carbon source. Interestingly, a large amount of colloid-like polysaccharides were generated in the mutant, which might be due to inefficient intracellular sucrose metabolism. Deletion of transcriptional repressor gene successfully alleviated CCR and enhanced ABE production by 24.7%. Additional overexpression of endogenous sucrose pathway further elevated sucrose consumption and enhanced ABE production by 17.2%, 45.7%, or 22.5% compared to wild type with sucrose, mixed sugars or sugarcane juice as substrate, respectively. The engineered strain could be a robust platform for efficient biofuel production from inexpensive sucrose-based carbon sources.