title: High-yield hydrogen production from biomass by in vitro metabolic engineering: Mixed sugars coutilization and kinetic modeling.
abstract: The use of hydrogen (H2) as a fuel offers enhanced energy conversion efficiency and tremendous potential to decrease greenhouse gas emissions, but producing it in a distributed, carbon-neutral, low-cost manner requires new technologies. Herein we demonstrate the complete conversion of glucose and xylose from plant biomass to H2 and CO2 based on an in vitro synthetic enzymatic pathway. Glucose and xylose were simultaneously converted to H2 with a yield of two H2 per carbon, the maximum possible yield. Parameters of a nonlinear kinetic model were fitted with experimental data using a genetic algorithm, and a global sensitivity analysis was used to identify the enzymes that have the greatest impact on reaction rate and yield. After optimizing enzyme loadings using this model, volumetric H2 productivity was increased 3-fold to 32 mmol H2⋅L(-1)⋅h(-1). The productivity was further enhanced to 54 mmol H2⋅L(-1)⋅h(-1) by increasing reaction temperature, substrate, and enzyme concentrations--an increase of 67-fold compared with the initial studies using this method. The production of hydrogen from locally produced biomass is a promising means to achieve global green energy production.
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061; Cell-Free Bioinnovations, Blacksburg, VA 24060;
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Rollin
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061;
authors.forename: Julia
authors.initials: J
authors.lastname: Martin del Campo
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061; Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, VA 24061;
authors.forename: Suwan
authors.initials: S
authors.lastname: Myung
authors.affiliation: Cell-Free Bioinnovations, Blacksburg, VA 24060;
authors.forename: Fangfang
authors.initials: F
authors.lastname: Sun
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061; Cell-Free Bioinnovations, Blacksburg, VA 24060;
authors.forename: Chun
authors.initials: C
authors.lastname: You
authors.affiliation: Department of Physics and Chemistry, Milwaukee School of Engineering, Milwaukee, WI 53202;
authors.forename: Allison
authors.initials: A
authors.lastname: Bakovic
authors.affiliation: Department of Chemical and Natural Gas Engineering, Texas A&M University, Kingsville, TX 78363;
authors.forename: Roberto
authors.initials: R
authors.lastname: Castro
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602;
authors.forename: Sanjeev K
authors.initials: SK
authors.lastname: Chandrayan
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602;
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602; Department of Energy BioEnergy Science Center, Oak Ridge, TN 37831; and.
authors.forename: Michael W W
authors.initials: MW
authors.lastname: Adams
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061;
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Senger
authors.affiliation: Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA 24061; Cell-Free Bioinnovations, Blacksburg, VA 24060; Institute for Critical Technology and Applied Science, Virginia Tech, Blacksburg, VA 24061; Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China ypzhang@vt.edu.
authors.forename: Y-H Percival
authors.initials: YH
authors.lastname: Zhang
mesh_terms: D018533:Biomass; D050260:Carbohydrate Metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D007700:Kinetics; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways; D008962:Models, Theoretical; D015203:Reproducibility of Results
chemical_list: D002245:Carbon Dioxide; D006859:Hydrogen
keywords: biomass; global sensitivity analysis; hydrogen; in vitro metabolic engineering; metabolic network modeling
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