title: Quantifying second generation ethanol inhibition: Design of Experiments approach and kinetic model development.
abstract: While softwoods represent a potential feedstock for second generation ethanol production, compounds present in their hydrolysates can inhibit fermentation. In this study, a novel Design of Experiments (DoE) approach was used to identify significant inhibitory effects on Saccharomyces cerevisiae D5A for the purpose of guiding kinetic model development. Although acetic acid, furfural and 5-hydroxymethyl furfural (HMF) were present at potentially inhibitory levels, initial factorial experiments only identified ethanol as a significant rate inhibitor. It was hypothesized that high ethanol levels masked the effects of other inhibitors, and a subsequent factorial design without ethanol found significant effects for all other compounds. When these non-ethanol effects were accounted for in the kinetic model, R¯(2) was significantly improved over an ethanol-inhibition only model (R¯(2)=0.80 vs. 0.76). In conclusion, when ethanol masking effects are removed, DoE is a valuable tool to identify significant non-ethanol inhibitors and guide kinetic model development.
authors.affiliation: Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, United States.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Schneiderman
authors.affiliation: Department of Mathematics and Computer Science, South Dakota School of Mines and Technology, Rapid City, SD 57701, United States.
authors.forename: Roger W
authors.initials: RW
authors.lastname: Johnson
authors.affiliation: Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, United States.
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Menkhaus
authors.affiliation: Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701, United States. Electronic address: Patrick.Gilcrease@sdsmt.edu.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Gilcrease
mesh_terms: D000704:Analysis of Variance; D000431:Ethanol / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008962:Models, Theoretical; D012107:Research Design; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: D000431:Ethanol
keywords: Design of Experiments; Ethanol fermentation; Fermentation inhibitors; Kinetic modeling; Softwoods