11-21: The use of alternative pathways in 1-butanol production from Escherichia coli

Currently ethanol is the most utilised biofuel to supplement conventional gasoline; however recently n-butanol has emerged as a potential alternative fuel additive due to advantages over ethanol such as a higher energy content.  1-butanol is synthesised as a fermentation product by solventogenic Clostridia spp. and genes encoding the butanol pathway in these microorganisms has previously been expressed in Escherichia coli.  In order to engineer a novel synthetic butanol pathway in Escherichia coli non-clostridial genes encoding enzymes resulting in the overall synthesis of 1-butanol were expressed from a P_BAD promoter.  Competing metabolic pathways in the host E. coli were deleted and the effects of these deletions assessed.