title: Engineering the iron-oxidizing chemolithoautotroph Acidithiobacillus ferrooxidans for biochemical production.
abstract: There is growing interest in developing non-photosynthetic routes for the conversion of CO2 to fuels and chemicals. One underexplored approach is the transfer of energy to the metabolism of genetically modified chemolithoautotrophic bacteria. Acidithiobacillus ferrooxidans is an obligate chemolithoautotroph that derives its metabolic energy from the oxidation of iron or sulfur at low pH. Two heterologous biosynthetic pathways have been expressed in A. ferrooxidans to produce either isobutyric acid or heptadecane from CO2 and the oxidation of Fe(2+). A sevenfold improvement in productivity of isobutyric acid was obtained through improved media formulations in batch cultures. Steady-state efficiencies were lower in continuous cultures, likely due to ferric inhibition. If coupled to solar panels, the photon-to-fuel efficiency of this proof-of-principle process approaches estimates for agriculture-derived biofuels. These efforts lay the foundation for the utilization of this organism in the exploitation of electrical energy for biochemical synthesis.
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W. 120th Street, New York City, New York, 10027.
authors.forename: Timothy
authors.initials: T
authors.lastname: Kernan
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W. 120th Street, New York City, New York, 10027.
authors.forename: Sudipta
authors.initials: S
authors.lastname: Majumdar
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W. 120th Street, New York City, New York, 10027.
authors.forename: Xiaozheng
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W. 120th Street, New York City, New York, 10027.
authors.forename: Jingyang
authors.initials: J
authors.lastname: Guan
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W. 120th Street, New York City, New York, 10027.
authors.forename: Alan C
authors.initials: AC
authors.lastname: West
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W. 120th Street, New York City, New York, 10027. sbanta@columbia.edu.
authors.forename: Scott
authors.initials: S
authors.lastname: Banta
mesh_terms: D042763:Acidithiobacillus / Q000235:genetics* / Q000378:metabolism*; D000473:Alkanes / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism*; D052837:Chemoautotrophic Growth; D003470:Culture Media / Q000737:chemistry; D007501:Iron / Q000378:metabolism; D058610:Isobutyrates / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D010084:Oxidation-Reduction
chemical_list: D000473:Alkanes; D003470:Culture Media; D058610:Isobutyrates; D002245:Carbon Dioxide; C020380:isobutyric acid; D007501:Iron; C016486:heptadecane
keywords: alkanes; biofuels; electrofuels; isobutyraldehyde; isobutyric acid; metabolic engineering