Novel approaches for the production of fuels and chemicals in Escherichia coli

Volatility of oil prices along with major concerns about climate change, oil supply security and depleting reserves have sparked renewed interest in the production of biofuels and biochemicals. While the carbohydrate portion of edible crops is currently used as the primary feedstock in the biological production of fuels and chemicals, the availability of fatty acid (FA)-rich feedstocks and recent progress in the development of oil-accumulating organisms have drawn the attention to FAs as an attractive alternative. However, microbial platforms to enable this were nearly absent. To this end, we engineered native and heterologous fermentative pathways in E. coli to enable the efficient synthesis of fuels and chemicals from FAs. The current de facto strategy for the synthesis of non-native products in model organisms is He terologous M etabolic E ngineering (HeME), which consists of recruiting foreign genes from native producers. However, the relative incompatibility of the heterologous pathways with the host metabolism may be considered a drawback. As an alternative approach, the HoME ( Ho mologous M etabolic E ngineering) strategy that we propose overcomes this limitation by harnessing the metabolic potential of the host strain. HoME aims at reconstructing heterologous pathways to enable biosynthesis of non-natural products by identifying and assembling native functional surrogates. Implementation of both HeME and HoME strategies in the context of fuels and chemicals biosynthesis has usually been directed to the conversion of feedstocks constituents into a specific product. However, we demonstrated a novel metabolic platform based on a functional reversal of the fatty acid catabolic pathway (β-oxidation) as a means of synthesizing a wide array of products with various chain lengths and functionalities

The path to next generation biofuels: successes and challenges in the era of synthetic biology

Volatility of oil prices along with major concerns about climate change, oil supply security and depleting reserves have sparked renewed interest in the production of fuels from renewable resources. Recent advances in synthetic biology provide new tools for metabolic engineers to direct their strategies and construct optimal biocatalysts for the sustainable production of biofuels. Metabolic engineering and synthetic biology efforts entailing the engineering of native and de novo pathways for conversion of biomass constituents to short-chain alcohols and advanced biofuels are herewith reviewed. In the foreseeable future, formal integration of functional genomics and systems biology with synthetic biology and metabolic engineering will undoubtedly support the discovery, characterization, and engineering of new metabolic routes and more efficient microbial systems for the production of biofuels