Synergetic Engineering of Central Carbon, Energy, and Redox Metabolisms for High Butanol Production and Productivity by Clostridium acetobutylicum

Biobutanol, as an advanced biofuel substitute, is being revived via microbial acetone-butanol-ethanol (ABE) fermentation. However, this biochemical process compromises low butanol production and productivity from glucose as the most abundant carbon source in biomass. In this study, three glucose-specific PTS-encoding genes glcG, CAC1353, and CAC1354 in Clostridium acetobutylicum were investigated by gene(s) overexpression. The data showed that CAC1353 overexpression exerted little effect on glucose utilization, butanol production, or productivity, while CAC1354 overexpression exerted a negative effect. Using the engineered strain overexpressing gene glcG, the highest butanol production and productivity of 18.3 g/L and 0.76 g/L/h were achieved with pH controlled above 5.5 and 1 mM neutral red addition, 55 and 280% increases over those of 11.8 g/L and 0.20 g/L/h obtained in the control. The demonstrated biochemical engineering approaches provided potentials for developing C. acetobutylicum as a cost-efficient microbial cell factory from biomass, making microbial butanol production economically viable and competitive.