title: Alkaline hydrogen peroxide pretreatment of softwood: hemicellulose degradation pathways.
abstract: This study investigated softwood hemicelluloses degradation pathways during alkaline hydrogen peroxide (AHP) pretreatment of Douglas fir. It was found that glucomannan is much more susceptible to alkaline pretreatment than xylan. Organic acids, including lactic, succinic, glycolic and formic acid are the predominant products from glucomannan degradation. At low treatment temperature (90°C), a small amount of formic acid is produced from glucomannan, whereas glucomannan degradation to lactic acid and succinic acid becomes the main reactions at 140°C and 180°C. The addition of H2O2 during alkaline pretreatment of D. fir led to a significant removal of lignin, which subsequently facilitated glucomannan solubilization. However, H2O2 has little direct effect on the glucomannan degradation reaction. The main degradation pathways involved in glucomannan conversion to organics acids are elucidated. The results from this study demonstrate the potential to optimize pretreatment conditions to maximize the value of biomass hemicellulose.
authors.affiliation: Voiland School of Chemical Engineering and Bioengineering, Bioproducts, Science and Engineering Laboratory, Washington State University, Richland, WA 99354, United States.
authors.forename: Carlos
authors.initials: C
authors.lastname: Alvarez-Vasco
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D002264:Carboxylic Acids / Q000032:analysis; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008351:Mannans / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D028224:Pseudotsuga / Q000187:drug effects*; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry; D014934:Wood / Q000187:drug effects*
chemical_list: D000468:Alkalies; D002264:Carboxylic Acids; D008351:Mannans; D011134:Polysaccharides; D014867:Water; C022901:(1-6)-alpha-glucomannan; C007916:hemicellulose; D006861:Hydrogen Peroxide
keywords: Alkaline hydrogen peroxide; Carboxylic acids; Endwise depolymerization; Glucomannan; Softwood