title: Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes.
abstract: A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, (13)C-solid-state NMR and morphological alterations after pretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while during hydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes.
authors.affiliation: Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå 971 87, Sweden. anthi.karnaouri@ltu.se.
authors.forename: Anthi
authors.initials: A
authors.lastname: Karnaouri
authors.affiliation: Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå 971 87, Sweden. Ulrika.Rova@ltu.se.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Rova
authors.affiliation: Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå 971 87, Sweden. paul.christakopoulos@ltu.se.
authors.forename: Paul
authors.initials: P
authors.lastname: Christakopoulos
mesh_terms: D029662:Betula / Q000737:chemistry*; D001673:Biodegradation, Environmental; D008031:Lignin / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D009005:Monosaccharides / Q000737:chemistry; D024301:Plant Bark / Q000737:chemistry*
chemical_list: D008055:Lipids; D009005:Monosaccharides; C065875:suberin; D008031:Lignin
keywords: Betula pendula; chemical composition; organosolv pretreatment; outer bark; steam explosion pretreatment; suberin