title: Chemical characterization of hydrothermally pretreated and enzyme-digested wheat straw: An evaluation of recalcitrance.
abstract: There is great interest in understanding changes that occur to cell wall constituents during saccharification of pretreated lignocellulose, particularly in relation to recalcitrance of the residues. This paper reports the effects of hydrothermal pretreatment followed by enzyme hydrolysis on the extractability and properties of recalcitrant wheat straw polymers. The results show that the undigested residue had lost much of its archestructure. Compositional analysis portrayed a considerable loss of cross-linking di-ferulic acid phenolics, hemicellulosic and cellulosic sugars. The remaining cellulosic and non-cellulosic polysaccharides were much more readily extractable in alkali and molecular profiling revealed the presence of low Mw oligomers in the fractions suggesting the partial enzyme hydrolysis of hemicelluloses and cellulose. Simultaneous saccharification and fermentation of the pretreated and enzyme-digested residues surprisingly resulted in ethanol yields of up to 99% of the theoretical. This is discussed in relation to the "recalcitrant" nature of the original pretreated and enzyme digested biomass.
authors.affiliation: The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
authors.forename: Zara
authors.initials: Z
authors.lastname: Merali
authors.affiliation: VTT, Technical Research Centre of Finland, PO Box 1000, FIN-02044, Finland.
authors.forename: Kaisa
authors.initials: K
authors.lastname: Marjamaa
authors.affiliation: Biogold OÜ, Lossi 19A, Tallinn 12616, Estonia.
authors.forename: Andres
authors.initials: A
authors.lastname: Käsper
authors.affiliation: VTT, Technical Research Centre of Finland, PO Box 1000, FIN-02044, Finland.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Kruus
authors.affiliation: The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
authors.forename: A Patrick
authors.initials: AP
authors.lastname: Gunning
authors.affiliation: The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
authors.forename: Vic J
authors.initials: VJ
authors.lastname: Morris
authors.affiliation: The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK. Electronic address: keith.waldron@ifr.ac.uk.
authors.forename: Keith W
authors.initials: KW
authors.lastname: Waldron
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D005285:Fermentation; D006868:Hydrolysis; D011134:Polysaccharides / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry*
chemical_list: D011134:Polysaccharides; C007916:hemicellulose; D002482:Cellulose
keywords: Alkali extraction; Biofuels; Diferulic acid (CID: 5281770); Enzyme saccharification; Ferulic acid (CID: 445858); Hydrothermal pretreatment; Wheat straw; d-Glucose (CID: 53782692); d-Xylose (CID: 135191)