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  • 51.
    Du, Xueyu
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Modification of industrial kraft lignin by amination2012Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Artikkel i tidsskrift (Annet vitenskapelig)
  • 52.
    Du, Xueyu
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Modification of lignin structure by amine group introduction2011Inngår i: Int. Symp. Wood, Fiber Pulping Chem. - Proc., ISWFPC, 2011, s. 298-303Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Amination of lignin conducted simply by Mannich reaction is an important mean for lignin structural and value upgradation. However, there is a lack of powerful analysis for quantification of the amine groups introduced and at the meantime for supplement of structural information about e.g. binding positions and side reactions etc. Various types of NMR analysis have thus been performed for the analysis of Mannich reaction products from lignin model, 4-hydroxy-3-methoxyacetophenone (HMAP), and from industrial spruce Kraft lignin. As revealed by NMRs, the reaction was very selective at C-5 position of guaiacyl lignin units and complete under acidic conditions with 11-fold amounts of reagents of piperidine (PIP) or dimethylamine (DMA) and formaldehyde over HMAP. No side reactions took place at the aromatic structure. For industrial lignin, 13.5 (by PIP) and 15 (by DMA) nitrogen atoms were introduced per 100 aromatic rings. Using other analytical methods, the aminated lignin was found with higher molecular weights, reaching Mp of 5.06kDa from the original 3.92kDa by DMA modification, and with a sharp increased solubility especially in acetic acid aqueous solution, 31.2 mg/ml after DMA modification. A preceding phenolation of the lignin resulted in a 70% increase of available aromatic rings and an introduction of 56 amine groups over 100 original aromatic rings after Mannich reaction by using DMA, which caused increases of molecular weights to 5.11kDa (Mp) and of solubility in acetic acid aqueous solution up to 77.2 mg/mL. Potential applications of these modified lignins of high values include many applications in different fields such as surfactant chemicals, polycationic materials and slow released fertilizers etc.

  • 53.
    Ekevåg, Per
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Lindström, Tom
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Gellerstedt, Göran
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Addition of carboxymethylcellulose to the kraft cook2004Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 19, nr 2, s. 200-207Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The physical attachment of carboxymethylcellulose (CMC) onto kraft pulps during cooking and the effects of subsequent bleaching in an OD(EOP)DD sequence were investigated. Two CMC grades with different molecular weights and different degrees of substitution (D.S.) were used, CMC Finnfix WRH and CMC Cekol DVG. The effect of the CMC was studied by measuring the increase in the total charge density as well as in the surface charge density. In this way, both the total amount of attached CMC and the amount of the CMC attached onto the surface of the fibres Could be determined. Hand-sheets were made to study the effects of CMC addition on the physical properties of the paper. Different amounts of CMC were added to find the optimum, which was determined to be 1% CMC on wood. The proportion of CMC attached at a level addition of 1% (on wood) was about 40%. It was, however, found that a large part of the CMC was degraded during the cook. Whereas high molecular weight CMC is attached onto the surface of fibres, the degraded CMC is attached to the interior of the cell wall, decreasing the efficiency of the CIVIC to enhance the joint strength between fibres. The tensile index increased significantly, approximately 10% after beating to 2000 PFI revolutions, when 1% CMC Finnfix WRH on wood was added. The CMC Cekol DVG grade showed the greatest increase in tensile index, approximately 12% at 2000 PFI revolutions. The results of the bleaching of a sample treated with CMC Finnfix WRH showed that a part of the effect of CMC remains after bleaching. Most of the reduction in the positive effect was due to a loss of CMC molecules from the fibre surface.

  • 54.
    Elegir, Graziano
    et al.
    Stazione Sperimentale Carta Cartoni e Paste per Carta.
    Bussini, Daniele
    Stazione Sperimentale Carta Cartoni e Paste per Carta.
    Antonsson, Stefan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Zoia, Luca
    Univ Milan, Dipartimento Sci Ambiente & Terr.
    Laccase-initiated cross-linking of lignocellulose fibres using a ultra-filtered lignin isolated from kraft black liquor2007Inngår i: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 77, nr 4, s. 809-817Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, the effect of Trametes pubescens laccase (TpL) used in combination with a low-molecular-weight ultra-filtered lignin (UFL) to improve mechanical properties of kraft liner pulp and chemi-thermo-mechanical pulp was studied. UFL was isolated by ultra-filtration from the kraft cooking black liquor obtained from softwood pulping. This by-product from the pulp industry contains an oligomeric lignin with almost twice the amount of free phenolic moieties than residual kraft pulp lignin. The reactivity of TpL on UFL and kraft pulp was studied by nuclear magnetic resonance spectroscopy and size exclusion chromatography. Laccase was shown to polymerise UFL and residual kraft pulp lignin in the fibres, seen by the increase in their average molecular weight and in the case of UFL as a decrease in the amount of phenolic hydroxyls. The laccase initiated cross-linking of lignin, mediated by UFL, which gives rise to more than a twofold increase in wet strength of kraft liner pulp handsheets without loosing other critical mechanical properties. Hence, this could be an interesting path to decrease mechano-sorptive creep that has been reported to lessen in extent as wet strength is given to papers. The laccase/2,2'azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) mediator system showed a greater increase in wet tensile strength of the resulting pulp sheets than the laccase/UFL system. However, other mechanical properties such as dry tensile strength, compression strength and Scott Bond internal strength were negatively affected by the laccase/ABTS system.

  • 55. Engström, Johan
    et al.
    Snekkenes, Vidar
    Krister, Olsson
    Gustavsson, Sören
    Christofer, Lindgren
    Mikael, Lindström
    Kvaerner Pulping AB.
    Metodo e dispositivo para o cozimento continuo de pasta de papel1998Patent (Annet (populærvitenskap, debatt, mm))
  • 56. Engström, Johan
    et al.
    Snekkenes, Vidar
    Olsson, Krister
    Gustavsson, Sören
    Lindgren, Christoffer
    Lindström, Mikael
    Kvaerner Pulping AB .
    Method and device for the continuous cooking of pulp1998Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    This invention relates to a new and improved way of continuously cooking fibre material, wherein temperatures and alkaline levels are controlled to be maintained within specific levels in different zones of the digesting process in order to optimise chemical consumption and heat-economy and at the same time achieve very good pulp properties. The fibre material is heated and impregnated by the aid of black liquor to a temperature less than 140 .degree.C and passed in con- current in an impregnation zone (A). The heated and impregnated fibre material is transferred to a con-current cooking zone (B) in the upper part of a digester (6). At least 60 % of the quantity of liquor (F) required for the cooking reaction is supplied in the up-stream end of the con- current cooking zone (B) in order to obtain a level of effective alkali exceeding 35 g/l.; The cooking temperature in the con-current cooking zone (B) is lower than 160 .degree.C. Spent liquor (E), with an amount of effective alkali of at least 13 g/l, is withdrawn from a strainer girdle (8). A substantial part of the spent liquor is supplied to the impregnation zone.

  • 57. Galysh, V.
    et al.
    Sevastyanova, Olena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Deartel, M.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Gornikov, Yu.
    Impact of ferrocyanide salts on the thermo-oxidative degradation of lignocellulosic sorbents2017Inngår i: Journal of thermal analysis and calorimetry (Print), ISSN 1388-6150, E-ISSN 1588-2926, Vol. 128, nr 2, s. 1019-1025Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The catalytic effect of ferrocyanide salts of d-metals on the thermo-oxidative degradation of lignocellulose-inorganic sorbents derived from apricot seed shells was investigated by differential thermal analysis. A comparative analysis of the thermal characteristics of the apricot seed shells and the lignocellulose matrix obtained from the shells by alkali-acid pretreatment was performed. It was shown that acid-alkali pretreatment of the apricot seed shells increases the thermal stability of the lignocellulosic material, due to the removal of low molecular weight carbohydrates and other components. The thermal degradation process of the lignocellulose-inorganic samples containing different ferrocyanides occurred at lower temperatures than the initial lignocellulose matrix, indicating the catalytic activity of modifiers. It was demonstrated that for the sorbents containing mixed salts of potassium cobalt and potassium nickel ferrocyanide, thermal destruction ends at temperatures that are 60 A degrees C lower than those for the initial lignocellulose matrix. The obtained results also show that the thermal destruction of composite lignocellulose-inorganic sorbents can be a suitable method for their disposal.

  • 58.
    Giummarella, Nicola
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. CleanFlow Black AB, Sweden.
    Lindgren, Christofer
    CleanFlow Black AB, Sweden.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. CleanFlow Black AB, Sweden.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lignin Prepared by Ultrafiltration of Black Liquor: Investigation of Solubility, Viscosity, and Ash Content2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 2, s. 3494-3510Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Technical lignin, which can be potentially obtained in large amounts as a by-product from kraft pulping, represents a potential resource for manufacturing fuels and chemicals. Upgrading of lignin, by lowering its molecular weight, is a valuable alternative to precipitation from black liquor, which occurs in the Lignoboost process. The solubility properties of Lignoboost lignin and filtered lignin in a number of technically feasible solvents were compared, and it was found that both lignins were dissolved in similar solvents. With the exception of furfural, the best lignin solvents generally were organic solvents miscible with water, such as methanol. It was possible to dissolve more filtered lignin in higher concentrations than Lignoboost lignin; additionally, the viscosities of the filtered lignin solutions were also considerably lower than those of Lignoboost lignin, especially at higher concentrations. Methods for non-organic component removal from filtrated lignin were tested, and it was concluded that several cold acidic treatments after dewatering can lower the ash content to values below 0.5% by weight.

    Fulltekst (pdf)
    fulltext
  • 59.
    Gonzalo Epelde, I.
    et al.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Lindgren, C. T.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Kinetics of wheat straw delignification in soda and kraft pulping1998Inngår i: Journal of wood chemistry and technology, ISSN 0277-3813, E-ISSN 1532-2319, Vol. 18, nr 1, s. 69-82Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Kraft and soda delignification kinetics of wheat straw, Triticum aestivum, have been studied as a function of OH- concentration, HS- concentration, and temperature. It was found that about 90% of the lignin is dissolved in the rapid initial phase. The rates of delignification in the bulk and residual phases were found to be similar to those of birch wood, Betula pubescens, The amount of residual phase lignin was found to be considerably less than in birch or spruce, Picea abies, and it was affected by the same factors, A model that accurately describes the delignification of wheat straw was derived.

  • 60. Gustavsson, Catrin
    et al.
    Backa, S.
    Lindström, Mikael
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Ragnar, Martin
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    On the nature of residual lignin2004Inngår i: Cellulose chem. techmol., ISSN 0576-9787, Vol. 35, s. 321-331Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In a recent study, the results of oxygen delignification trials on kraft, prehydrolysis kraft and magnesium sulphite pulps were compared, thus providing the basis for a theory on the nature of the lignin residual lignin remaining in pulp after cooking, and particularly after oxygen delignification, the so-called residual lignin. It is suggested that, at least after oxygen delignification, the residual lignin effectively consists of LCC-bound monolignins, a theory relating to the efficiency of oxygen delignification and bleaching, and indicating possible strategies for improving the efficiency of such processes. An efficient means of breaking the LCC bonds would lead to a more efficient bleaching, known as requiring either a complete oxidation of the LCC-bound monolignins or a peeling off the carbohydrate binding to the LCC. In any case, a mere breaking of one unsaturated bond in an aromatic ring is not sufficient to achieve depolymerisation of the residual lignin or an efficient kappa reduction.

  • 61. Gustavsson, Catrin
    et al.
    Lindgren, Christofer
    KTH, Tidigare Institutioner                               , Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    A Study of How the Amount of Residual Phase Lignin in Kraft Cooking Depends upon the Conditions in the Cook1997Inngår i: Nordic Pulp Paper Research Journal, ISSN 0283-2631, Vol. 12, nr 4, s. 225-Artikkel i tidsskrift (Fagfellevurdert)
  • 62. Gustavsson, Catrin
    et al.
    Olsson, Krister
    Lindström, Mikael
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Process for continuously cooking chemical cellulose pulp: Kontinuerlig kokning med extra uppehållstid för avdragen vätska utanför kokaren2001Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Process for continuously cooking chemical pulp in a digester system consisting of at least one vessel for impregnating and cooking comprising an inlet into which a mixture of chips and process liquid is fed. The chips are impregnated at a predetermined impregnation temperature Timp, and cooked at a predetermined cooking temperature Tcook, after which dissolved pulp is fed out at the outlet of the digester system. Process liquid which is continually extracted is retained outside the digester system during a dwell time, t, of at least 30 min, without any heating above 140 DEG , and thereafter returned to the digester system to a position which is substantially at the same level as the extraction, or downstream thereof, and thereby constitute part of the process liquid in the subsequent treatment zone. The process results in improved tear strength, beatability, bleachability and reduced colour reversion, and increased yield across the digester.

  • 63.
    Halysh, Vita
    et al.
    Igor Sikorsky Kyiv Polytech Inst, Peremogy Ave 37-4, UA-03056 Kiev, Ukraine.;Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    de Carvalho, Danila Morais
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Riazanova, Anastasiia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gomelya, Mykola
    Igor Sikorsky Kyiv Polytech Inst, Peremogy Ave 37-4, UA-03056 Kiev, Ukraine..
    Effect of oxidative treatment on composition and properties of sorbents prepared from sugarcane residues2019Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 139, artikkel-id UNSP 111566Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efficient sorbents for the removal of cationic dye were prepared from sugarcane bagasse (stalk) and straw (leaves) by oxidative pre-treatment with hydrogen peroxide (H2O2) in acetic acid. The effects of variables, such as concentration of H2O2, temperature and time on the properties of the fiber sorbents obtained were studied according to a 2(3) full-factorial design. For comparison, an oxidative treatment of sugarcane biomass with glacial acetic acid was also used. The yields of the materials obtained and their chemical composition were characterized and compared. Fourier transform infrared spectroscopy, field-emission scanning electron microscopy and benzene vapor adsorption were used to investigate the structural properties and morphology of the initial materials and sorbents. The sorption of methylene blue dye was used to assess the efficiency of dye removal by the sorbents. The pre-treatment conditions significantly affected the sorbent yield, their chemical composition (contents of cellulose, lignin and ash) as well as their sorption properties. The cellulosic sorbent (C-sorbent) from sugarcane bagasse obtained by pre-treatment with H2O2 in acetic acid and the lignocellulosic sorbent (LC-sorbent) from sugarcane straw obtained by pre-treatment with glacial acetic acid, had the highest sorption capacity for the methylene blue dye. For both types of sorbents, the sorption capacity increased with chemical pretreatment as a result of an increase in pore volume.

  • 64.
    Halysh, Vita
    et al.
    Igor Sikorsky Kyiv Polytech Inst, Fac Chem Engn, Dept Ecol & Technol Plant Polymers, Peremogy Avenu 37-4, UA-03056 Kiev, Ukraine.;Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Riazanova, Anastasia V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Pasalskiy, Bogdan
    Kyiv Natl Univ Trade & Econ, Kyoto Str 19, UA-02156 Kiev, Ukraine..
    Budnyak, Tetyana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Kartel, Mykola
    Natl Acad Sci Ukraine, OO Chuiko Inst Surface Chem, Gen Naumov Str 17, UA-03164 Kiev, Ukraine..
    Walnut shells as a potential low-cost lignocellulosic sorbent for dyes and metal ions2018Inngår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 8, s. 4729-4742Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently, it is necessary to develop new methods and materials for solving the problem of environmental pollution by various toxicants. For these purposes, vegetal materials can be used. In this study, efficient low-cost sorbents based on walnut shells, an agro-industrial by-product, were prepared by treatment with acetic acid or a mixture of acetic acid and hydrogen peroxide. It was shown that the treatments significantly affected the composition and structure of walnut shells and their sorption properties with respect to organic dyes (methylene blue, methyl violet, and murexide) and heavy metal ions. Methylene blue dye was used for additional studies on the effect of pH, contact time and kinetics of sorption. The maximum adsorption rate of the dye occurred within the first 30 min of contact, during which the concentration of methylene blue in the solution was reduced by more than half. Full sorption equilibrium was reached within 180-230 min for studied samples. The adsorption kinetics of methylene blue was found to best be described by pseudo-second-order kinetic model. It was shown that dyes adsorption processes were well described by Freundlich model, which takes into consideration the heterogeneity of the surface of the adsorbent. The obtained plant sorbents are characterized by a high sorption capacity for heavy metal ions (18-29 mg/g for Fe3+ and 33-44 mg/g for Cu-2). Due to their numerous advantages, such as the high sorption capacity, high availability and low cost of raw materials, simplicity of disposal and nontoxicity, the obtained natural sorbents may have a wide practical use in industrial wastewater treatment. [GRAPHICS] .

  • 65.
    Helander, Mikael
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Mattsson, Tuve
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Parameters Affecting the Cross-flow Filtration of Dissolved LignoBoost Kraft Lignin2015Inngår i: Journal of wood chemistry and technology, ISSN 0277-3813, E-ISSN 1532-2319, Vol. 36, nr 1, s. 1-8Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    In the kraft pulping process, the lignin-containing by-product kraft black liquor is currently combusted as an energy source. LignoBoost is a technique that extracts lignin from kraft black liquor, resulting in a lignin-lean black liquor, which is returned to the process, and an extracted kraft lignin. To facilitate the use of the extracted kraft lignin in high-value applications, it can be refined via fractionation to produce a more homogeneous starting raw material. Hence, the aim of this study is to investigate the behavior of dissolved softwood kraft lignin during cross-flow filtration. The effects of the lignin concentration, pH, and ionic strength on the fractionation of the dissolved lignin during cross-flow filtration are investigated. The results indicate that large amounts of low-molecular-weight kraft lignin can be produced from solutions having a low lignin concentration. Furthermore, the effects of pH and ionic strength on the fractionation of low-molecular-weight lignin are identified within the studied ranges.

  • 66.
    Helander, Mikaela
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Zhang, Liming
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Fractionation of Technical Lignin: Molecular Mass and pH Effects2013Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, nr 2, s. 2270-2282Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Today, lignin from kraft pulping is used mainly as fuel, with only very small amounts being used as raw material for chemicals and materials. This work focuses on using a convenient method for separating large amounts of low molecular weight lignin from the kraft process. Low molecular weight lignin contains larger amounts of phenolic structural units, which are possible modification sites and can be used as antioxidants. Moreover, a product that has reduced polydispersity, low molecular weight, and purified lignin could be a potential material for new applications. The studied process for separating lignin from weak black liquor used a membrane with a cut-off of 1000 Da. During precipitation of the 1000 Da permeate, it is necessary to prevent formation of fairly large, rigid particles/agglomerates of lignin by keeping the temperature low. To improve the dead-end filtration, higher ionic strength is needed for the weak black liquor. Additionally, reducing the end pH will cause more material to precipitate. More sulfur was found in the low molecular weight lignin and at lower precipitation pH, indicating that most sulfur left in the lignin samples might be bound to low molecular weight lignin.

  • 67.
    Helander, Mikaela
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Zhang, Liming
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lignin for new materials - molar mass and pH effects2012Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Artikkel i tidsskrift (Annet vitenskapelig)
  • 68.
    Henriksson, Gunnar
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Berglund, Jennie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wohlert, Jakob
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Aminzadeh, Selda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Non-cellulose wood polysaccharides - a need for a stricter structural and functional classification?2018Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikkel i tidsskrift (Annet vitenskapelig)
  • 69.
    Henriksson, Gunnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Shi, Chao
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    WAYS TO TAILOR-MAKE XYLAN FOR KRAFT PULPING2011Inngår i: 16TH INTERNATIONAL SYMPOSIUM ON WOOD, FIBER AND PULPING CHEMISTRY, PROCEEDINGS, VOLS I & II / [ed] Wang, L Kuang, S Hou, Q Cao, C Si, CL Zhang, HJ, CHINA LIGHT INDUSTRY PRESS , 2011, s. 596-599Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Genetic manipulation of trees in order to produce raw material with different chemical composition, which will perform better in pulping and bleaching, has gained large interest the last decade. Most efforts have been on increasing cellulose content, and modifying the lignin structure so that the pulping will be more efficient. Less interest has been focused on the hemicellulose structures, although many important chemical reactions occur on hemicelluloses during kraft pulping. For instance, hexenuronic acid is formed from 4-O-methyl glucuronic acid, a side group on xylan. This structure is a main contributor to the kappa number in the unbleached pulp, especially in hardwoods, and requires relatively strong bleaching agents for efficient removal. Remaining hexenuronic acid in the bleached pulp may furthermore cause post yellowing. In model experiments, we have simulated kraft cooking, and shown that hexenuronic acid is formed to a much lower degree from unmethylated glucuronic acid, than from 4-O-methylglucuronic acid. A tree without methyl groups on its glucuronic acid residues on xylan, is therefore expected to be pulped to a much lower kappa number, and to be easy to bleach to high brightness stability. According to a literature study, the possibilities to make such a tree by genetically manipulation appear to be promising. There might also be other ways, in which hemicelluloses structure can be manipulated.

  • 70.
    Henriksson, Gunnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Zhang, Liming
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lignin Utilization2010Inngår i: Thermochemical conversion of biomass to liquid fuels and chemicals / [ed] M. Crocker, RSC Publishing, 2010, s. 222-262Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Lignin is one of the most abundant biopolymers on Earth, carrying out important biological roles in vascular plants. It has somewhat higher energy content than polysaccharides, but has a complex and heterogeneous structure including covalent bonds to polysaccharides. The partly random structure of lignin is explained by the fact that it is created by an uncatalyzed radical polymerization. Lignin is obtained as a by-product of various types of technical processes based on biomass, of which chemical pulping of wood is the most important. These technical lignins have structures that differ from native lignin. Sulphite pulping of wood generates a water soluble lignin derivate, which among other things, is used as a dispersing agent and dust binder. Kraft pulping generates a lignin that is insoluble at neutral pH, which today is mainly burned for heat generation in the chemical recovery system of the kraft pulp mill. Recently, efficient methods have been developed for the preparation of lignin from the process liquids, for use in energy generation or other applications. Conversion of technical lignin to liquid fuels for use in combustion engines is an interesting possibility that represents a technical challenge. This chapter reviews the structure and biopolymerisation of lignin, reactions of lignin during technical processes, and different applications of technical lignins.

  • 71.
    Henriksson, Gunnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Process for the hydrolysis of cellulose2010Patent (Annet (populærvitenskap, debatt, mm))
  • 72. Hou, Yi
    et al.
    Hu, Songqing
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Feasibility of monomer aromatic substances as calibration standards for lignin quantitative analyses in Pyrolysis-GCMS2013Inngår i: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 101, s. 232-237Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article, the feasibilities of five different monomer aromatic substances as calibration standards by analytical pyrolysis with gas chromatographic separation and mass selective detection (Py-GC/MS) were applied for the quantification of lignin in paper and pulp. The stabilities of these substances in the pyrolysis process were evaluated and the curves of peak response area to mass also were obtained. The results showed that the substances with exact same substitutions on the benzene ring as lignin units had good stabilities in the pyrolysis process with good lineabilities of peak response area to the mass curves, which implicated these substances can be applied as calibration standards in the liginin quick quantitative analyse without tedious pretreatments and structure changes.

  • 73. Jedvert, K.
    et al.
    Wang, Yan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Saltberg, A.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, H.
    Mild steam explosion: A way to activate wood for enzymatic treatment, chemical pulping and biorefinery processes2012Inngår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 27, nr 5, s. 828-835Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Industrially chipped wood chips of Norway spruce (Picea abies) were subjected to mild steam explosion (115 - 160°C) in a small-scale steam explosion reactor. This was followed by kraft cooking or extraction in alkali at 130°C for two hours, or by an enzymatic treatment with a culture filtrate in order to investigate the efficiency of the process in opening wood structure. The results demonstrated that mild explosion has an effect on opening wood structure, shown by increased release of glucomannans during alkaline extraction and faster delignification in kraft cooks for steam-exploded samples. The effect was also shown by analysis of the released reducing sugars of enzymatic treated wood chips, which showed that the wood structure became accessible for enzymes even at very modest mild steam explosion conditions. This was not observed in untreated wood chips, used as reference. The enzyme activity increased with increased temperature during mild steam explosion, and the effect did not seem to be linear. The mechanical effect of steam explosion seems to be of great importance at lower temperatures, and both chemical and mechanical effects are important at higher steam explosion temperatures. Samples for enzymatic treatment were taken both from the edges of wood chips as well as from the middle part of the chips, and the effect of steam explosion was somewhat greater in samples from the middle parts.

  • 74. Jedvert, Kerstin
    et al.
    Saltberg, Anna
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Mild steam explosion and chemical pre-treatment of Norway spruce2012Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, nr 2, s. 2051-2074Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this work is to open up the structure of wood while retaining a large amount of hemicelluloses, in particular (galacto)glucomannans. The effects of pre-treatments on wood meal from spruce (Picea abies) with a reducing agent (NaBH4) combined with steam explosion at very mild conditions were investigated. The effects of steam explosion at 160 degrees C were studied for various residence times (5 to 35 min) on both water-impregnated wood meal and samples pre-treated with NaBH4. The findings showed that pre-treatment with sodium borohydride stabilized the reducing end-groups of glucomannans and that the treatment was effective both during mild steam explosion, for both long and short residence times, as well as during subsequent treatment in alkali. Extraction experiments at different pH and temperatures showed that the main part of the hemicelluloses still remained in the wood residue after treatment. The molecular weight distributions of the extracted material from the liquors indicated that there were broad molecular distributions and that the molecular weight averages were between 3 and 6 kDa.

  • 75. Jedvert, Kerstin
    et al.
    Saltberg, Anna
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Chalmers University of Technology.
    Extraction of hemicelluloses after chemical pretreatment combined with mild steam explosion2011Inngår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, 2011, s. 867-871Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of this research is to separate different wood components from softwood as a first step towards development of novel materials made from Scandinavian wood. The approach is pre-treatment with a reducing agent in combination with mild steam explosion (T< 160°C, t < 15 min); followed by extraction with different liquors. The aim is to retain an increased amount of hemicelluloses in general, and glucomannans in particular, during chemical treatments, preferably of high molecular weight. Experiments were performed on wood chips from spruce in small scale steam explosion equipment. A pre-treatment method with sodium borohydride (NaBH 4) as a reducing agent model substance was chosen. Wood chips pre-treated with NaBH 4 were compared to untreated chips, and the chips were treated with steam explosion followed by extraction in alkali. Results showed that a higher amount of glucomannan was retained in chips treated with NaBH 4 than in untreated chips. An increase in the extraction rate as an effect of steam explosion indicates a possible combination of chemical reactions that breaks up the lignin-polysaccharide network and a more porous wood structure. An experimental series with wood powder as raw material were also performed in order to study the chemical reactions during steam explosion, e. g. autohydrolysis. Water impregnated wood powder as well as wood powder treated with NaBH 4 was subjected to mild steam explosion for different retention times. It was shown that a decrease in hemicelluloses content occurred after only 5 min, and the degradation was more severe at longer residence times. However, the degradation of hemicelluloses was not as severe as in the chemical treatments at conditions corresponding to chemical pulping, and consequently might be a more prudent method to access the wood structure. Extractions after steam explosion were investigated at different pH levels, and the results showed that most of the glucomannan was still in the wood residue at the tested conditions. The stabilization of glucomannans by pre-treatment with NaBH 4 was clearly seen also in these experiments.

  • 76.
    Jedvert, Kerstin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Chalmers, Dept Forest Prod & Chem Engn, SE-41296 Gothenburg, Sweden..
    Saltberg, Anna
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Chalmers, Dept Forest Prod & Chem Engn, SE-41296 Gothenburg, Sweden..
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Chalmers, Dept Forest Prod & Chem Engn, SE-41296 Gothenburg, Sweden.
    EXTRACTION OF HEMI-CELLULOSES AFTER CHEMICAL PRETREATMENT COMBINED WITH MILD STEAM EXPLOSION2011Inngår i: 16TH INTERNATIONAL SYMPOSIUM ON WOOD, FIBER AND PULPING CHEMISTRY, PROCEEDINGS, VOLS I & II / [ed] Wang, L Kuang, S Hou, Q Cao, C Si, CL Zhang, HJ, CHINA LIGHT INDUSTRY PRESS , 2011, s. 867-871Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The aim of this research is to separate different wood components from softwood as a first step towards development of novel materials made from Scandinavian wood. The approach is pre-treatment with a reducing agent in combination with mild steam explosion (T< 160 degrees C, t < 15 min); followed by extraction with different liquors. The aim is to retain an increased amount of hemicelluloses in general, and glucomannans in particular, during chemical treatments, preferably of high molecular weight. Experiments were performed on wood chips from spruce in small scale steam explosion equipment. A pre-treatment method with sodium borohydride (NaBH4) as a reducing agent model substance was chosen. Wood chips pre-treated with NaBH4 were compared to untreated chips, and the chips were treated with steam explosion followed by extraction in alkali. Results showed that a higher amount of glucomannan was retained in chips treated with NaBH4 than in untreated chips. An increase in the extraction rate as an effect of steam explosion indicates a possible combination of chemical reactions that breaks up the lignin-polysaccharide network and a more porous wood structure. An experimental series with wood powder as raw material were also performed in order to study the chemical reactions during steam explosion, e. g. autohydrolysis. Water impregnated wood powder as well as wood powder treated with NaBH4 was subjected to mild steam explosion for different retention times. It was shown that a decrease in hemicelluloses content occurred after only 5 min, and the degradation was more severe at longer residence times. However, the degradation of hemicelluloses was not as severe as in the chemical treatments at conditions corresponding to chemical pulping, and consequently might be a more prudent method to access the wood structure. Extractions after steam explosion were investigated at different pH levels, and the results showed that most of the glucomannan was still in the wood residue at the tested conditions. The stabilization of glucomannans by pre-treatment with NaBH4 was clearly seen also in these experiments.

  • 77.
    Karlström, Katarina
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Brännvall, Elisabet
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Extended Impregnation Cooking of Norway Spruce: Effects on Pulping Uniformity and Pulp Strength Properties2009Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Extended impregnation kraft cooking is a demonstrated improvement of the kraft pulping process and offers a way to use softwood more efficiently. We demonstrate the possibility of producing Norway spruce (Picea abies) kraft pulp using a new cooking concept, producing a pulp that can be defibrated without inline refining at kappa numbers of approximately 90. The cooking concept uses the differences in reaction rate between the diffusion and consumption of hydroxide ions in the prolonged impregnation step. Lowering the impregnation temperature will favour the diffusion of cooking chemicals over neutralization reactions, thereby improving chemical distribution throughout the chips. Impregnation conditions in combination with cooking temperatures lower than those of conventional kraft pulping are demonstrated to produce pulp with a narrower kappa number distribution and comparable strength properties at a considerably higher yield.

  • 78.
    Keyoumu, Ayiguli
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Sjödahl, Ragnar
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Henriksson, Gunnar
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Gellerstedt, Göran
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Continuous Nano- and Ultrafiltration of Kraft Pulping Black Liquor with Ceramic Filters: A method for lowering the load on the recovery boiler while generating valuable side-products2004Inngår i: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 20, nr 2, s. 143-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ceramic membranes coated with ZrO2 were used for the continuous separation of a well-defined low molecular weight lignin from softwood and hardwood kraft black liquors on a pilot scale. The membranes used had M-w cut-offs of 1000, 5000, and 15,000 Da, respectively. The flux (permeate flow) through the different membranes measured as L/(m(2 .)h) was studied by varying the inlet pressure and temperature. The black liquor lignins in the permeate from the filters were isolated and studied with GPC and UV spectroscopy. The low molecular weight lignin fraction was highly phenolic and could be polymerised by one-electron oxidation.

  • 79. Kisara, K.
    et al.
    Danielsson, Sverker
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Lindstrom, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    The possibility of controlling formation and cleavage reactions of HexA during kraft pulping2006Inngår i: 2006 TAPPI Engineering, Pulping and Environmental Conference Proceedings, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    During kraft pulping, the side groups in the xylan backbone, 4-O-methyl-D-glucuronic acid (MeGlcA), are partly converted to hexenuronic acid (HexA). Simultaneously, degradation reactions of these side groups take place. In this study, the activation energies (Ea) for these reactions were determined during kraft pulping of birch from constant composition cook. The results show that Ea of bulk delignification (118kJ/mol, in accordance with earlier studies) is similar to that of HexA formation (129kJ/mol) and MeGlcA degradation (120kJ/mol), but it is lower than that of HexA degradation (141kJ/mol). The differences in activation energies imply a possibility of controlling the HexA and MeGlcA content in xylan by cooking temperature. This study demonstrated that this is indeed the case for the dissolved xylan, whereas pulp xylan is not markedly affected by a change in cooking temperature.

  • 80.
    Li, Jiebing
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Danielsson, Sverker
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Kisara, Koki
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Gellerstedt, Göran
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Quantification of uronic acid compositions by modification and integration of carbazole colorimetric and methanolysis-GC methodsManuskript (Annet vitenskapelig)
  • 81.
    Li, Jiebing
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Kisara, Koki
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Danielsson, Sverker
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Gellerstedt, Göran
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    An improved methodology for the quantification of uronic acid units in xylans and other polysaccharides2007Inngår i: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 342, nr 11, s. 1442-1449Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Uronic acids can be quantified either by a colorimetric determination after treatment with concentrated sulfuric acid and carbazole or by gas chromatography after methanolysis and subsequent acetylation. Both methods suffer from incomplete hydrolysis, an unavoidable degradation of the products to be analysed, and an inability to separate and quantify different types of uronic acids. In the present work, the fundamental chemistry involved in the two methods has been evaluated, and some modifications to increase their accuracy are suggested. By combining the two methods, a complete quantification of all individual types of urome acids present in a sample can be achieved.

  • 82.
    Li, Jiebing
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    An HPLC method for pentosans quantification in biomass, pulp and other biomass product2008Konferansepaper (Fagfellevurdert)
  • 83.
    Li, Jiebing
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Shi, Chao
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    The methoxy group of beta-O-methyl glucuronic acid is central for the formation of hexenuronic acid during kraft pulping2011Inngår i: O Papel, ISSN 0031-1057, Vol. 72, nr 1, s. 54-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hexenuronic acid is created from 4-O-methyl gluc-uronic acid – a side chain group in xylan, and one of the most important hemicelluloses in both hardwood and softwood - during alkaline conditions, such as kraft pulping. Especially in hardwood kraft pulp, hexenuronic acid corresponds to a large part of the kappa number, and the presence of this component in bleached pulp causes post yellowing. In this work it is shown that glucuronic acid that lacks a methoxy group on the 4-carbon does not form hexenuronic acid under alkaline condition to the same extent as 4-O-methylglucuronic acid. This opens up novel strategies for genetic modification of the hemicellulose structures in wood cultivated for kraft pulping.

  • 84.
    Lima, Raquel B.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Qin, Haiying
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Fan, Liangdong
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Direct lignin fuel cell for power generation2011Inngår i: 16th International Symposium on Wood, Fiber and Pulping Chemistry: Proceedings, ISWFPC, 2011, s. 257-262Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for a direct conversion into electricity using direct carbon fuel cell (DCFC). Two different types of industrial lignins were investigated: lignosulphonate (LS) and kraft lignin (KL), either directly in their commercial forms, after their blending with commercial active carbon (AC) or after alternation of their structures by a pH adjustment to pH 10. It has been found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43∼57 to 85∼101 mA/cm 2. The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.680-0.699 V and a maximum current density of 74∼79 mA/cm 2 from both lignins. Typical power density was 12 (for KL +AC) and 24 mW cm -2 (for LS +AC). It has been concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

  • 85.
    Lima, Raquel Bohn
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Qin, Haiying
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Zhu, Bin
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Direct lignin fuel cell for power generation2013Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 3, nr 15, s. 5083-5089Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lignin, the second most abundant component after cellulose in biomass, has been examined in this study as a fuel for direct conversion into electricity using direct carbon fuel cells (DCFC). Two different types of industrial lignins were investigated: Lignosulfonate (LS) and Kraft lignin (KL), in their commercial forms, after their blending with commercial active carbon (AC) or after alteration of their structures by a pH adjustment to pH 10. It was found that the open circuit voltage (OCV) of the DCFC could reach around 0.7 V in most of the trials. Addition of active carbon increased the maximum current density from 43-57 to 83-101 mA cm(-2). The pH adjustment not only increased the maximum current density but also reduced the differences between the two types of lignins, resulting in an OCV of 0.68-0.69 V and a maximum current density of 74-79 mA cm(-2) from both lignins. Typical power density was 12 (for KL + AC) and 24 mW cm(-2) (for LS + AC). It is concluded that a direct lignin fuel cell is feasible and the lignin hydrophilicity is critical for the cell performance.

  • 86. Lindgren, C.
    et al.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Thermal Decomposition of Inorganic Polysulfides at Kraft Cooking Conditions1995Inngår i: Nordic Pulp Paper Research Journal, ISSN 0283-2631, Vol. 10, nr 1, s. 41-Artikkel i tidsskrift (Fagfellevurdert)
  • 87.
    Lindgren, C. T.
    et al.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Kinetics of the bulk and residual delignification in kraft pulping of birch and factors affecting the amount of residual phase lignin   1997Inngår i: Nordic Pulp and Paper Research Journal, ISSN 0283-2631, Vol. 12, nr 2, s. 124-127Artikkel i tidsskrift (Fagfellevurdert)
  • 88.
    Lindgren, C. T.
    et al.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    The kinetics of residual delignification and factors affecting the amount of residual lignin during kraft pulping1996Inngår i: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 22, nr 8, s. J290-J295Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Kraft pulping of softwood can be divided into three phases: the initial, the bulk and the residual delignification phases. The rate of delignification in the residual phase and the amount of lignin to be removed in this slow phase have been studied as a function of the conditions in the kraft cooking of Norwegian spruce chips, Picea abies. The variables studied were concentration of OH-, concentration of HS-, ionic strength and temperature. The amount of lignin remaining undissolved in the wood residue at the transition from bulk to residual delignification is decreased by increasing the concentration of OH- and by increasing the concentration of HS- in the bulk phase. The amount of residual lignin is also decreased by a lower ionic strength in the bulk phase. The temperature in the range of 150 to 180 degrees C affected the lignin content at the transition from bulk to residual delignification but not the amount of residual lignin extrapolated to the beginning of the cook. Only the hydroxide ion concentration and the temperature seem to have an influence on the rate of delignification in the residual phase. The rate of delignification in the residual phase is well described by the following equation: dL(r)/dt = (0.0032 + 0.0020 . [OH-]) (. e) -146 000/8.314 . (1/T - 1/443.15)(Lr).

  • 89. Lindgren, Christofer
    et al.
    Engström, Johan
    Olsson, Krister
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Gustavsson, Sören
    Snekkenes, Vidar
    Förfarande och anordning vid kontinuerlig kokning av kemisk cellulosamassa: Method and device for the continuous cooking of pulp2005Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention concerns an arrangement and a method for the continuous cooking of chemical cellulose pulp in a continuous digester system (100). The continuous digester system (100) comprises an inlet (102) for the feed of a chips suspension and an outlet (103) for the output of a cooked suspension of pulp. The suspension of chips is fed in to the inlet through a line (105) at the beginning of the cook, where the chips suspension has a volume of starting cooking fluid that establishes a fluid/wood ratio that is greater than 3.5. The invention is characterised in that a final cooking fluid is present during the cook for the major part of the cook and is withdrawn through a withdrawal strainer (106) only during the final 15 minutes of the cook. The final cooking fluid ensures a fluid/wood ratio that is greater than 3.5 in association with the withdrawal. The withdrawn final cooking fluid during the final 15 minutes of the cook consists of spent black liquor, which maintains a residual alkali level that lies under 15 g/l.

  • 90.
    Lindström, Mikael E.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Some factors affecting the amount of residual phase lignin during kraft pulping1997Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The amount of lignin which needs to be removed according to the slow residual delignification phase in kraft pulping, i e residual phase lignin, has been studied as a function of the process conditions. The variebles studied were the concentrations of hydroxide ions, hydrogensulfide ions, sodium ions (ionic strength) and temperature. In addition, the amounts of residual phase ligning in the pulping of different lignocellulosic material were compared. Different additives can be applied to the kraft cook to improve the selectivity. Polysulfide sulfur is one of them and the effectt of polysulfide ions on the amount of residual phase lignin in kraft pulping was also investigated.

    It is shown, that the amounts of residual phase lignin in constant composition cooks (highliquor-to-wood ratio) of softwood (spruce), hardwood (birch) andgrass (wheat straw) are affected by the same factors in theinvestigated range. The amount of residual phase lignin isstrongly reduced by higher hydroxide ion concentration during the kraft cook and is to some extent decreased by higherhydrogensulfide ion concentration and lower sodium ionconcentration. These effects were not, however, found to bepurely additive for spruce wood, instead interactions occurred.In order to decrease the amount of residual phase lignin, it isessential to have a high concentration of hydrogensulfide ionswhen cooking with a low hydroxide ion concentration. The temperature has no effect on the amount of residual phase ligninin the range investigated.

    It is also shown that the lignin reacting according to theslow delignification phase is not a homogeneous lignin sincealteration of the conditions in the cook can make part of itreact as bulk phase lignin. This indicates that most of theresidual phase lignin is determined by the prevailing conditions,which determine how much of the native lignin reacts according tothe bulk and how much according to the residual delignificationmechanism.

    Pulping experiments carried out under the same conditions onwheat straw,  birch wood and spruce wood also showed that theamount of residual phase lignin in wheat straw is only 30% of theamount of residual phase lignin in spruce wood, and that the amount of residual phase lignin in birch wood, is5 0% of the amount of residual phase lignin in sprucewood.

    The amount of residual phase lignin was affected by apolysulfide treatment. The amount of residual phase lignin was lowered by 30% for spruce wood and 10% for birch wood with apolysulfide treatment, compared with cooks without polysulfide. An explanation for this may be the finding that polysulfide can introduce a carboxylic acid function into the lignin, which will increase its water solubility, and reduce the need for fragmentation. An additional explanation may be the ability of polysulfides to degrade enol ether structures, which are normally more or less stable during kraft pulping.

  • 91.
    Lindström, Mikael E.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Li, Jiebing
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Shi, C.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    A genetic strategy for avoiding formation of hexenuronic acid in kraft pulping?2011Konferansepaper (Annet vitenskapelig)
  • 92.
    Lindström, Mikael E.
    et al.
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Teder, Ants
    The Effect of Polysulfide Pretreatment when Kraft Pulping to Very Low Kappa Numbers1995Inngår i: Nordic Pulp Paper Research Journal, Vol. 10, nr 1, s. 8-Artikkel i tidsskrift (Fagfellevurdert)
  • 93.
    Lindström, Mikael
    et al.
    Kvaerner Pulping AB .
    Lindgren, Christofer
    Cooking of pulp with high effective alkali concentration in the residual phase1997Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    A method and device for cooking pulp by increasing the effective alkali concentration in the residual phase of the cooking process to substantially improve the residual delignification rate and thus improving the pulp properties such as the pulp strength and pulp yield at a given lignin content.

  • 94.
    Lindström, Mikael
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Snekkenes, Vidar
    Cooking of cellulose pulp in a cooking liquor containing pre-evaporated black liquor: Framställning av cellulosamassa genom kokning med en kokvätska innehållande förindunstad svartlut2002Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention concerns a method during the cooking of cellulose pulp in which the raw material, preferably in the form of chips, undergoes a successive elevation of temperature towards the cooking temperature while the chips are first impregnated with an impregnation liquor followed by cooking in a cooking liquor that is preferably alkali. Through the addition of pre-evaporated black liquor, either ass early as the impregnation stage or during the subsequent cooking stage, an improved delignification process is achieved in which the pulp obtains improved properties, primarily with respect to strength/viscosity for a given degree of delignification, and also with respect to yield. The method can be used both for continuous cooking and for batchwise cooking of cellulose pulp.

  • 95.
    Lindström, Mikael
    et al.
    KTH, Tidigare Institutioner, Fiber- och polymerteknologi.
    Snekkenes, Vidar
    Pretreatment of chips with white liquor prior to a treatment with black liquor: Förbehandling av flis med färsk vitlut före behandling med svartlut2001Patent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    The invention concerns a method for the manufacture of cooked cellulose pulp in which the starting material, preferably chips, undergoes a successive increase in temperature towards cooking temperature while the chips are first treated in a pre-treatment zone in which the main part, greater than 50%, of fresh white liquor necessary for the cooking stage is added, after which this alkali-rich treatment fluid is withdrawn and replaced to a major extent by black liquor. The alkali-rich treatment fluid that has been withdrawn after the pre-treatment to stage is then added to the cooking stage, which is why the addition of fresh white liquor to the cooking stage is reduced to an equivalent amount. Maximal yield-enhancing effect is obtained using polysulphide-rich white liquor during the pre-treatment at a temperature in the interval 60 +- 40 DEG C and retention time in the interval 2-60 minutes, preferably 2-10 minutes.

  • 96.
    Lindén, Pär A.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Stabilising mannose using sodium dithionite at alkaline conditions2020Inngår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 74, nr 2, s. 131-140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The kraft process remains the dominant-chemical pulping process but still struggles with extensive hemicellulose degradation. Such degradation has previously been mitigated through the use of anthraquinone; but due to it recently being found to have carcinogenic properties, anthraquinone is now being phased out. One alternative, sodium dithionite, was initially investigated in the 1950s but was found to be unviable. The present study investigated whether sodium dithionite could be made viable through the use of different processing parameters, using mannose as a model compound and measuring the yield of mannitol in the various systems using gas chromatography with flame ionization detection (GC-FID) and nuclear magnetic resonance (NMR). Alkalinity was found to be crucial; at pH 14 as well as pH 7, dithionite indeed proved unviable, but if pH was kept at either 8 or 10 significant reduction was seen to occur. The best results were obtained at pH 10 when a lower temperature (70 degrees C) was used to compensate for alkaline degradation of the mannose reactant.

  • 97. Lundquist, L.
    et al.
    Arpin, G.
    Leterrier, Y.
    Berthold, F.
    Lindström, Mikael
    Swed. Pulp/Paper Research Institute.
    Manson, J. A. E.
    Alkali-methanol-anthraquinone pulping of Miscanthus x giganteus for thermoplastic composite reinforcement2004Inngår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 92, nr 4, s. 2132-2143Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The potential of pulp fiber-reinforced thermoplastics is currently not fully explored in composites. One of the main reasons is that pulp fibers are extracted for the use in papermaking and are thus not optimized for use as reinforcements in thermoplastics. Furthermore, currently used processing methods constitute several severe thermomechanical steps inducing premature degradation of the fibers. A systematic development of these composite materials requires the study of both these aspects. The goal of this work was to optimize fiber extraction against properties relevant to the reinforcement of thermoplastics. To this end, thick-walled Miscanthus x giganteus pulp fibers were selected. The fibers were pulped by the alkaline-methanol-anthraquinone process. An unreplicated factorial design was applied to determine the effect of key operating variables on fiber thermal stability and mechanical properties. The thermomechanical properties of pulp fibers depend primarily on the morphology and chemical composition of the fiber resource in terms of the respective amounts of lignin, hemicellulose, and cellulose, all strongly influenced by the choice of pulping conditions. Optimal pulping parameters were identified, allowing production of fibers thermally stable up to 255 degreesC with an aspect ratio of 40, a straightness of 95%, and tensile strength as high as 890 MPa. Specific stiffness and strength values with respect to density and material cost of 56 GPa m(-3) $(-1) and 820 MPa m(-3) $(-1) were highly competitive with glass fibers, with corresponding values of 15 GPa m(-3) $(-1) and 270-490 MPa m(-3) $(-1), respectively.

  • 98. Mair, C.
    et al.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Söderberg, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Control of the porous structure of paper in a continuous process2017Inngår i: International Conference on Nanotechnology for Renewable Materials 2017, TAPPI Press , 2017Konferansepaper (Fagfellevurdert)
  • 99.
    Martinez-Abad, Antonio
    et al.
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Berglund, Jennie
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Toriz, Guillermo
    Gatenholm, Paul
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Wohlert, Jakob
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Vilaplana, Francisco
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Regular Motifs in Xylan Modulate Molecular Flexibility and Interactions with Cellulose Surfaces2017Inngår i: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 175, nr 4, s. 1579-1592Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Xylan is tightly associated with cellulose and lignin in secondary plant cell walls, contributing to its rigidity and structural integrity in vascular plants. However, the molecular features and the nanoscale forces that control the interactions among cellulose microfibrils, hemicelluloses, and lignin are still not well understood. Here, we combine comprehensive mass spectrometric glycan sequencing and molecular dynamics simulations to elucidate the substitution pattern in softwood xylans and to investigate the effect of distinct intramolecular motifs on xylan conformation and on the interaction with cellulose surfaces in Norway spruce (Picea abies). We confirm the presence of motifs with evenly spaced glycosyl decorations on the xylan backbone, together with minor motifs with consecutive glucuronation. These domains are differently enriched in xylan fractions extracted by alkali and subcritical water, which indicates their preferential positioning in the secondary plant cell wall ultrastructure. The flexibility of the 3-fold screw conformation of xylan in solution is enhanced by the presence of arabinofuranosyl decorations. Additionally, molecular dynamic simulations suggest that the glycosyl substitutions in xylan are not only sterically tolerated by the cellulose surfaces but that they increase the affinity for cellulose and favor the stabilization of the 2-fold screw conformation. This effect is more significant for the hydrophobic surface compared with the hydrophilic ones, which demonstrates the importance of nonpolar driving forces on the structural integrity of secondary plant cell walls. These novel molecular insights contribute to an improved understanding of the supramolecular architecture of plant secondary cell walls and have fundamental implications for overcoming lignocellulose recalcitrance and for the design of advanced wood-based materials.

  • 100.
    Martinez-Abad, Antonio
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Quero, Amparo Jimenez
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Berglund, Jennie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Giummarella, Nicola
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Wallenberg Wood Sci Ctr, Stockholm, Sweden.;KTH Royal Inst Technol, Fibre & Polymer Technol, Stockholm, Sweden..
    Wohlert, Jakob
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Influence of the molecular structure of wood hemicelluloses on the recalcitrance of lignocellulosic biomass2018Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikkel i tidsskrift (Annet vitenskapelig)
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