title: Pretreatment of wheat straw with potassium hydroxide for increasing enzymatic and microbial degradability.
abstract: The pretreatment of wheat straw with potassium hydroxide (KOH) at ambient temperature (20°C) was investigated. The pretreatment effects on chemical composition and physical structures, and subsequent enzymatic hydrolysis and anaerobic digestion were evaluated. Wheat straw at 10% total solids (TS) was treated with KOH solution for 24h at a wide range of KOH loadings from 2% to 50% (w/w dry basis). Higher KOH loading resulted in higher lignin reduction from the straw and chemical oxygen demand (COD) in the resulting black liquor. Maximum lignin reduction of 54.7% was observed at 50% KOH loading. In comparison to untreated straw, specific hydrolysis yields achieved 14.0-92.3% over the range of 2-50% KOH loading, and methane yields increased 16.7-77.5% for KOH loadings of 10-50%, respectively. Accounting for losses during pretreatment, 20% KOH loading resulted in maximum overall reducing sugar yield and methane yield and therefore is the recommended loading for pretreatment under these conditions.
authors.affiliation: Biomass Energy and Environmental Engineering Research Center, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, United States.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, United States.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Zicari
authors.affiliation: Biomass Energy and Environmental Engineering Research Center, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Guangqing
authors.initials: G
authors.lastname: Liu
authors.affiliation: Institute of New Energy, China University of Petroleum, Beijing 102249, China.
authors.forename: Yeqing
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, CA 95616, United States; Biomass Energy and Environmental Engineering Research Center, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China. Electronic address: rhzhang@ucdavis.edu.
authors.forename: Ruihong
authors.initials: R
authors.lastname: Zhang
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004789:Enzyme Activation; D006878:Hydroxides / Q000737:chemistry*; D008697:Methane / Q000302:isolation & purification / Q000378:metabolism*; D035261:Plant Components, Aerial / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry* / Q000382:microbiology*
chemical_list: D006878:Hydroxides; D017680:Potassium Compounds; D008697:Methane; C029943:potassium hydroxide
keywords: Anaerobic digestion; Enzymatic hydrolysis; Kinetic modeling; Potassium hydroxide pretreatment; Wheat straw