title: Development of reactor configurations for an electrofuels platform utilizing genetically modified iron oxidizing bacteria for the reduction of CO2to biochemicals.
abstract: Electrofuels processes are potentially promising platforms for biochemical production from CO2using renewable energy. When coupled to solar panels, this approach could avoid the inefficiencies of photosynthesis and there is no competition with food agriculture. In addition, these systems could potentially be used to store intermittent or stranded electricity generated from other renewable sources. Here we develop reactor configurations for continuous electrofuels processes to convert electricity and CO2to isobutyric acid (IBA) using genetically modified (GM) chemolithoautotrophic Acidithiobacillus ferrooxidans. These cells oxidize ferrous iron which can be electrochemically reduced. During two weeks of cultivation on ferrous iron, stable cell growth and continuous IBA production from CO2were achieved in a process where media was circulated between electrochemical and biochemical rectors. An alternative process with an additional electrochemical cell for accelerated ferrous production was developed, and this system achieved an almost three-fold increase in steady state cell densities, and an almost 4-fold increase in the ferrous iron oxidation rate. Combined, this led to an almost 8-fold increase in the steady state volumetric productivity of IBA up to 0.063±0.012mg/L/h, without a decline in energy efficiency from previous work. Continued development of reactor configurations which can increase the delivery of energy to the genetically modified cells will be required to increase product titers and volumetric productivities.
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
authors.forename: Jingyang
authors.initials: J
authors.lastname: Guan
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Berlinger
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
authors.forename: Xiaozheng
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
authors.forename: Zhongmou
authors.initials: Z
authors.lastname: Chao
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
authors.forename: Victor
authors.initials: V
authors.lastname: Sousa E Silva
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Banta
authors.affiliation: Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA. Electronic address: acw7@columbia.edu.
authors.forename: Alan C
authors.initials: AC
authors.lastname: West
mesh_terms: D000188:Actinobacillus / Q000235:genetics / Q000378:metabolism; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D019149:Bioreactors / Q000382:microbiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D005296:Ferrous Compounds / Q000378:metabolism*; D030781:Organisms, Genetically Modified / Q000235:genetics / Q000378:metabolism
chemical_list: D005296:Ferrous Compounds; D002245:Carbon Dioxide
keywords: Acidithiobacillus ferrooxidans; Chemolithoautotroph; Electrofuel; Isobutyric acid