title: Two-stage acidic-alkaline hydrothermal pretreatment of lignocellulose for the high recovery of cellulose and hemicellulose sugars.
abstract: The focus of this work was to develop a combined acid and alkaline hydrothermal pretreatment of lignocellulose that ensures high recovery of both hexose and pentose. Dilute sulfuric acid and lime pretreatments were employed sequentially. Process performance was optimized in terms of catalyst concentration, retention time, and temperature using response surface methodology. Medium operational conditions in the acid stage and harsh conditions in the alkaline stage were desirable with optimal performance at 0.73 wt% H(2)SO(4), 150 °C, 6.1 min in the first stage, and 0.024 g lime/g biomass, 202 °C, 30 min in the second stage. In comparison to single-stage pretreatments with high recovery of either glucose or xylose, two-stage process showed great promises with >80 % glucose and >70 % xylose recovery. In addition, the method greatly improved ethanol fermentation with yields up to 0.145 g/g Miscanthus, due to significantly reduced formation of inhibitory by-products such as weak acids, furans, and phenols. Supplementing biomimetic acids would further increase glucose yield by up to 15 % and xylose yield by 25 %.
authors.affiliation: Dept. of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Newmark Lab, 205 N. Mathews Ave, Urbana, IL 61801, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Guo
authors.forename: Yuanhui
authors.initials: Y
authors.lastname: Zhang
authors.forename: Guo
authors.initials: G
authors.lastname: Yu
authors.forename: Won-Heong
authors.initials: WH
authors.lastname: Lee
authors.forename: Yong-Su
authors.initials: YS
authors.lastname: Jin
authors.forename: Eberhard
authors.initials: E
authors.lastname: Morgenroth
mesh_terms: D000143:Acids / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D013696:Temperature; D014994:Xylose / Q000737:chemistry
chemical_list: D000143:Acids; D011134:Polysaccharides; C036909:lignocellulose; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin; D014994:Xylose; D005947:Glucose