Escherichia coli for biofuel production: bridging the gap from promise to practice

The anticipated shift of biofuel feedstocks from maize to lignocellulose presents challenges in developing effective biomass pretreatment approaches, which impacts the selection and capabilities of fuel-producing organisms. For a viable biofuel production process, the ideal fuel-producing organism must be able to efficiently convert a variety of sugars to fuels anaerobically at near-theoretical yields, resist inhibitors generated by biomass pretreatment and exhibit low product toxicity. Escherichia coli finds extensive use as a model system, but has not been widely used as an industrial host. This review highlights recent advances in metabolic engineering of biofuel-synthesis pathways in E. coli and summarizes insights gained into regulation of those pathways, and describes progress toward overcoming the challenges facing its adoption as a biofuel-production strain.