title: Driving forces enable high-titer anaerobic 1-butanol synthesis in Escherichia coli.
abstract: 1-Butanol, an important chemical feedstock and advanced biofuel, is produced by Clostridium species. Various efforts have been made to transfer the clostridial 1-butanol pathway into other microorganisms. However, in contrast to similar compounds, only limited titers of 1-butanol were attained. In this work, we constructed a modified clostridial 1-butanol pathway in Escherichia coli to provide an irreversible reaction catalyzed by trans-enoyl-coenzyme A (CoA) reductase (Ter) and created NADH and acetyl-CoA driving forces to direct the flux. We achieved high-titer (30 g/liter) and high-yield (70 to 88% of the theoretical) production of 1-butanol anaerobically, comparable to or exceeding the levels demonstrated by native producers. Without the NADH and acetyl-CoA driving forces, the Ter reaction alone only achieved about 1/10 the level of production. The engineered host platform also enables the selection of essential enzymes with better catalytic efficiency or expression by anaerobic growth rescue. These results demonstrate the importance of driving forces in the efficient production of nonnative products.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Claire R
authors.initials: CR
authors.lastname: Shen
authors.forename: Ethan I
authors.initials: EI
authors.lastname: Lan
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Dekishima
authors.forename: Antonino
authors.initials: A
authors.lastname: Baez
authors.forename: Kwang Myung
authors.initials: KM
authors.lastname: Cho
authors.forename: James C
authors.initials: JC
authors.lastname: Liao
mesh_terms: D020001:1-Butanol / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000378:metabolism; D044944:Acyl-CoA Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000693:Anaerobiosis; D003013:Clostridium / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D009243:NAD / Q000378:metabolism
chemical_list: D009243:NAD; D000105:Acetyl Coenzyme A; D020001:1-Butanol; D044944:Acyl-CoA Dehydrogenases; C100154:acyl-CoA dehydrogenase (NADP+)