title: Co-hydrolysis of hydrothermal and dilute acid pretreated populus slurries to support development of a high-throughput pretreatment system.
abstract: BACKGROUND
  The BioEnergy Science Center (BESC) developed a high-throughput screening method to rapidly identify low-recalcitrance biomass variants. Because the customary separation and analysis of liquid and solids between pretreatment and enzymatic hydrolysis used in conventional analyses is slow, labor-intensive and very difficult to automate, a streamlined approach we term 'co-hydrolysis' was developed. In this method, the solids and liquid in the pretreated biomass slurry are not separated, but instead hydrolysis is performed by adding enzymes to the whole pretreated slurry. The effects of pretreatment method, severity and solids loading on co-hydrolysis performance were investigated.
  
  
  RESULTS
  For hydrothermal pretreatment at solids concentrations of 0.5 to 2%, high enzyme protein loadings of about 100 mg/g of substrate (glucan plus xylan) in the original poplar wood achieved glucose and xylose yields for co-hydrolysis that were comparable with those for washed solids. In addition, although poplar wood sugar yields from co-hydrolysis at 2% solids concentrations fell short of those from hydrolysis of washed solids after dilute sulfuric acid pretreatment even at high enzyme loadings, pretreatment at 0.5% solids concentrations resulted in similar yields for all but the lowest enzyme loading.
  
  
  CONCLUSIONS
  Overall, the influence of severity on susceptibility of pretreated substrates to enzymatic hydrolysis was clearly discernable, showing co-hydrolysis to be a viable approach for identifying plant-pretreatment-enzyme combinations with substantial advantages for sugar production.
authors.affiliation: Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, 1084 Columbia Avenue, Riverside, CA 92507, USA.|BESC BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA.|Current address: Institute of Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Sonneggstr. 3, CH-8092 Zurich, Switzerland.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Studer
authors.affiliation: Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, 1084 Columbia Avenue, Riverside, CA 92507, USA.|Current address: Institute of Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Sonneggstr. 3, CH-8092 Zurich, Switzerland.
authors.forename: Simone
authors.initials: S
authors.lastname: Brethauer
authors.affiliation: Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, 1084 Columbia Avenue, Riverside, CA 92507, USA.|BESC BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA.
authors.forename: Jaclyn D
authors.initials: JD
authors.lastname: DeMartini
authors.affiliation: Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, 1084 Columbia Avenue, Riverside, CA 92507, USA.|BESC BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA.
authors.forename: Heather L
authors.initials: HL
authors.lastname: McKenzie
authors.affiliation: Department of Chemical and Environmental Engineering and Center for Environmental Research and Technology, Bourns College of Engineering, University of California Riverside, 1084 Columbia Avenue, Riverside, CA 92507, USA.|BESC BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6422, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Wyman