title: Metabolism of Multiple Aromatic Compounds in Corn Stover Hydrolysate by Rhodopseudomonas palustris.
abstract: Lignocellulosic biomass hydrolysates hold great potential as a feedstock for microbial biofuel production, due to their high concentration of fermentable sugars. Present at lower concentrations are a suite of aromatic compounds that can inhibit fermentation by biofuel-producing microbes. We have developed a microbial-mediated strategy for removing these aromatic compounds, using the purple nonsulfur bacterium Rhodopseudomonas palustris. When grown photoheterotrophically in an anaerobic environment, R. palustris removes most of the aromatics from ammonia fiber expansion (AFEX) treated corn stover hydrolysate (ACSH), while leaving the sugars mostly intact. We show that R. palustris can metabolize a host of aromatic substrates in ACSH that have either been previously described as unable to support growth, such as methoxylated aromatics, and those that have not yet been tested, such as aromatic amides. Removing the aromatics from ACSH with R. palustris, allowed growth of a second microbe that could not grow in the untreated ACSH. By using defined mutants, we show that most of these aromatic compounds are metabolized by the benzoyl-CoA pathway. We also show that loss of enzymes in the benzoyl-CoA pathway prevents total degradation of the aromatics in the hydrolysate, and instead allows for biological transformation of this suite of aromatics into selected aromatic compounds potentially recoverable as an additional bioproduct.
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Samantha
authors.initials: S
authors.lastname: Austin
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Wayne S
authors.initials: WS
authors.lastname: Kontur
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Arne
authors.initials: A
authors.lastname: Ulbrich
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: J Zachary
authors.initials: JZ
authors.lastname: Oshlag
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Weiping
authors.initials: W
authors.lastname: Zhang
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Alan
authors.initials: A
authors.lastname: Higbee
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Yaoping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Coon
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: David B
authors.initials: DB
authors.lastname: Hodge
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Donohue
authors.affiliation: †Department of Civil and Environmental Engineering, ‡Department of Bacteriology, §DOE Great Lakes Bioenergy Research Center, ∥Department of Chemistry, ⊥Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Noguera
mesh_terms: D000641:Ammonia / Q000494:pharmacology; D000693:Anaerobiosis / Q000187:drug effects; D019817:Benzoic Acid / Q000737:chemistry; D001673:Biodegradation, Environmental / Q000187:drug effects; D018533:Biomass; D001711:Biotransformation / Q000187:drug effects; D002241:Carbohydrates / Q000032:analysis; D006841:Hydrocarbons, Aromatic / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D009154:Mutation; D012242:Rhodobacter sphaeroides / Q000187:drug effects / Q000378:metabolism; D012241:Rhodopseudomonas / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D014866:Waste Products; D003313:Zea mays / Q000737:chemistry* / Q000187:drug effects
chemical_list: D002241:Carbohydrates; D006841:Hydrocarbons, Aromatic; D014866:Waste Products; C036909:lignocellulose; D000641:Ammonia; D019817:Benzoic Acid; D008031:Lignin