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Abstract
The rapid consumption of oil for fuel and chemicals is leading to carbon dioxide emission at vast quantities each year. At this hour the need is to gradually reduce the reliance on oil for large scale manufacture of fuels and chemicals. The development of renewable/ alternative energy technologies and the production of green chemicals provide a means to address these concerns. The biological manufacture of C3-C6 commodity chemicals has gained much attention over the past decade due to their large annual market and wide industrial applications. Metabolic engineering has enabled the biological manufacture of these chemicals via construction of novel metabolic pathways or enhancement of existing ones. In this work, we engineer Escherichia coli for the production high value bulk chemicals 1,2-propanediol, 1-propanol and 1,4-butanediol. We systematically engineer E. coli to enhance the production of 1,2-propanediol to maximize yield from glucose. Building on this work, we identify an optimal diol dehydratase and expand the 1,2-propanediol pathway to establish a novel platform for 1-propanol production from glucose. Deriving inspiration from rational design approaches we then engineer the diol dehydratase to enhance activity toward a non-native substrate. We demonstrate an alliance of protein engineering strategies and metabolic engineering strategies to achieve the production of 1,4-butanediol from xylose via a novel pathway. Overall, by establishing novel synthetic pathways and engineering the cells native metabolism we demonstrate efficient and reliable production of C3 and C4 bulk chemicals in a prokaryotic system. In doing so, we intend to reduce the overdependence on oil for manufacture of fuels and chemicals.