- Umeå University
Normark, Monica; Winestrand, Sandra; Lestander, Torbjörn; Jönsson, Leif
Background:Forestry residues consisting of softwood are a major lignocellulosic resource for productionof liquid biofuels. Scots pine, a commercially important forest tree, was fractionated into seven fractions ofchips: juvenile heartwood, mature heartwood, juvenile sapwood, mature sapwood, bark, top parts, and knotwood.The different fractions were characterized analytically with regard to chemical composition and susceptibility todilute-acid pretreatment and enzymatic saccharification.Results:All fractions were characterized by a high glucan content (38-43%) and a high content of othercarbohydrates (11-14% mannan, 2-4% galactan) that generate easily convertible hexose sugars, and by a lowcontent of inorganic material (0.2-0.9% ash). The lignin content was relatively uniform (27-32%) and thesyringyl-guaiacyl ratio of the different fractions were within the range 0.021-0.025. The knotwood had a highcontent of extractives (9%) compared to the other fractions. The effects of pretreatment and enzymaticsaccharification were relatively similar, but without pretreatment the bark fraction was considerably moresusceptible to enzymatic saccharification.Conclusions:Since sawn timber is a main product from softwood species such as Scots pine, it is an importantissue whether different parts of the tree are equally suitable for bioconversion processes. The investigation showsthat bioconversion of Scots pine is facilitated by that most of the different fractions exhibit relatively similarproperties with regard to chemical composition and susceptibility to techniques used for bioconversion ofwoody biomass.
Scots pine; Chemical composition; Dilute-acid pretreatment; Enzymatic saccharification
2014, Volume: 14, article number: 20
Biochemistry and Molecular Biology