Metabolic engineering of Escherichia coli for 1-butanol biosynthesis through the inverted aerobic fatty acid β-oxidation pathway.

The basic reactions of the clostridial 1-butanol biosynthesis pathway can be regarded to be the inverted reactions of the fatty acid β-oxidation pathway. A pathway for the biosynthesis of fuels and chemicals was recently engineered by combining enzymes from both aerobic and anaerobic fatty acid β-oxidation as well as enzymes from other metabolic pathways. In the current study, we demonstrate the inversion of the entire aerobic fatty acid β-oxidation cycle for 1-butanol biosynthesis. The constructed markerless and plasmidless Escherichia coli strain BOX-3 (MG1655 lacI(Q) attB-P(trc-ideal-4)-SD(φ10)-adhE(Glu568Lys) attB-P(trc-ideal-4)-SD(φ10)-atoB attB-P(trc-ideal-4)-SD(φ10)-fadB attB-P(trc-ideal-4)-SD(φ10)-fadE) synthesises 0.3-1 mg 1-butanol/l in the presence of the specific inducer. No 1-butanol production was detected in the absence of the inducer.