Metabolic Engineering for 1-Butanol Production From Glucose or Carbon Dioxide

Production of chemicals or fuels from renewable sources is an attractive approach to solving the energy and environmental problems. 1-Butanol, a chemical feedstock and potential fuel, has been produced by fermentation of carbohydrates, both in native Clostridium species and various engineered hosts. Clostridial or CoA-dependent 1-butanol production pathway utilizes the same chemistry as the fatty acid biosynthesis. Therefore this pathway may be extended further for the production of other even-number longer chain alcohols. We demonstrate that high titer and high yield 1-butanol production from glucose in E. coli is enabled by engineering driving forces. Production of 1-butanol directly from CO₂ using genetically modified cyanobacteria will also be discussed. Together, these results demonstrate the feasibility of producing even-number longer chain alcohols from renewable sources.