title: Production of an acetone-butanol-ethanol mixture from Clostridium acetobutylicum and its conversion to high-value biofuels.
abstract: Clostridium acetobutylicum is a bacterial species that ferments sugar to a mixture of organic solvents (acetone, butanol and ethanol). This protocol delineates a methodology to combine solventogenic clostridial fermentation and chemical catalysis via extractive fermentation for the production of biofuel blendstocks. Extractive fermentation of C. acetobutylicum is operated in fed-batch mode with a concentrated feed solution (500 grams per liter glucose and 50 grams per liter yeast extract) for 60 h, producing in excess of 40 g of solvents (acetone, butanol and ethanol) between the completely immiscible extractant and aqueous phases of the bioreactor. After distillation of the extractant phase, the acetone, butanol and ethanol mixture is upgraded to long-chain ketones over a palladium-hydrotalcite (Pd-HT) catalyst. This reaction is generally carried out in batch with a high-pressure Q-tube for 20 h at 250 °C. Following this protocol enables the production of ∼0.5 g of high-value biofuel precursors from a 1.7-g portion of fermentation solvents.
authors.affiliation: 1] Department of Chemistry, University of California, Berkeley, California, USA. [2] Energy Biosciences Institute, University of California, Berkeley, California, USA.
authors.forename: Sanil
authors.initials: S
authors.lastname: Sreekumar
authors.affiliation: 1] Energy Biosciences Institute, University of California, Berkeley, California, USA. [2] Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA.
authors.forename: Zachary C
authors.initials: ZC
authors.lastname: Baer
authors.affiliation: 1] Department of Chemistry, University of California, Berkeley, California, USA. [2] Energy Biosciences Institute, University of California, Berkeley, California, USA.
authors.forename: Anbarasan
authors.initials: A
authors.lastname: Pazhamalai
authors.affiliation: 1] Department of Chemistry, University of California, Berkeley, California, USA. [2] Energy Biosciences Institute, University of California, Berkeley, California, USA.
authors.forename: Gorkem
authors.initials: G
authors.lastname: Gunbas
authors.affiliation: 1] Department of Chemistry, University of California, Berkeley, California, USA. [2] Energy Biosciences Institute, University of California, Berkeley, California, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Grippo
authors.affiliation: 1] Energy Biosciences Institute, University of California, Berkeley, California, USA. [2] Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA.
authors.forename: Harvey W
authors.initials: HW
authors.lastname: Blanch
authors.affiliation: 1] Energy Biosciences Institute, University of California, Berkeley, California, USA. [2] Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California, USA.
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Clark
authors.affiliation: 1] Department of Chemistry, University of California, Berkeley, California, USA. [2] Energy Biosciences Institute, University of California, Berkeley, California, USA.
authors.forename: F Dean
authors.initials: FD
authors.lastname: Toste
mesh_terms: D000096:Acetone / Q000378:metabolism*; D000536:Aluminum Hydroxide; D056804:Biofuels / Q000032:analysis* / Q000382:microbiology; D019149:Bioreactors; D053898:Biosynthetic Pathways / Q000502:physiology*; D000440:Butanols / Q000378:metabolism*; D046969:Clostridium acetobutylicum / Q000378:metabolism / Q000502:physiology*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D007659:Ketones / Q000378:metabolism; D008276:Magnesium Hydroxide; D010165:Palladium
chemical_list: D056804:Biofuels; D000440:Butanols; D007659:Ketones; D000096:Acetone; C010467:hydrotalcite; D000431:Ethanol; D000536:Aluminum Hydroxide; D010165:Palladium; D008276:Magnesium Hydroxide