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  • 1. Dax, Daniel
    et al.
    Chavez Bastidas, Maria Soledad
    Teixeira Mendonca, Regis
    Sanchez Poblete, Julio Antonio
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Abo Akad Univ, Finland.
    Willfor, Stefan
    Synthesis of novel cationic hydrogels from spruce O-acetyl galactoglucomannan for metal ion removal2014Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247, s. 226-CELL-Artikel i tidskrift (Övrigt vetenskapligt)
  • 2. Dax, Daniel
    et al.
    Eklund, Patrik
    Hemming, Jarl
    Sarfraz, Jawad
    Backman, Peter
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Willfor, Stefan
    Amphiphilic Spruce Galactoglucomannan Derivatives Based on Naturally-Occurring Fatty Acids2013Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, nr 3, s. 3771-3790Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A class of nonionic polysaccharides-based surfactants were synthesised from O-acetyl galactoglucomannan (GGM), water-soluble hemicelluloses from spruce, using naturally-occurring saturated fatty acids, CH3(CH2)(n)COOH (n = 7, 12, and 16). Hemicelluloses can be recovered from waste-streams of papermaking and agricultural processes or isolated by hot water extraction of plant tissues integrated into a biorefinery process. Fatty acids can be recovered as byproducts of the agricultural and food industries. Different synthesis routes were applied to yield amphiphilic derivatives with either a grafted or block structure. Fatty acids activated with 1,1'-carbonyldiimidazole (CDI) were grafted to the backbone of GGM molecules on their hydroxyl groups. Alternatively, synthesised amino-activated fatty acids using ethylenediamine were reacted with the reducing end of GGM. By adjusting the reagent ratios, GGM-based surfactants with different hydrophilic to hydrophobic ratios were prepared. Their surface activity was assessed by measuring the surface tension in water. This study presents an approach to design carbohydrate-based surfactants using naturally-occurring fatty acids that may find potential applications in such areas as food, cosmetic, and paint formulations.

  • 3. Dax, Daniel
    et al.
    Soledad Chavez, Maria
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Process Chemistry Centre, C/o Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Finland .
    Willfor, Stefan
    Teixeira Mendonca, Regis
    Sanchez, Julio
    Cationic hemicellulose-based hydrogels for arsenic and chromium removal from aqueous solutions2014Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 111, s. 797-805Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work the synthesis of hemicellulose-based hydrogels and their application for the removal of arsenic and chromium ions is described. In a first step O-acetyl galactoglucomannan (GGM) was subjected to a transesterification applying glycidyl methacrylate (GMA) for the synthesis of novel GGM macromonomers. Two distinguished and purified GGM fractions with molar mass of 7.1 and 28 kDa were used as starting materials. The resulting GGM macromonomers (GGM-MA) contained well-defined amounts of methacrylate groups as determined by H-1 NMR spectroscopy. Selected GGM-MA derivatives were consecutively applied as a crosslinker in the synthesis of tailored hydrogels using [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA) as monomer. The swelling rate of the hydrogels was determined and the coherence between the swelling rate and the hydrogel composition was examined. The morphology of the GGM-based hydrogels was analysed by SEM and the hydrogels revealed a high surface area and were assessed in respect to their ability to remove arsenate and chromate ions from aqueous solutions. The presented bio-based hydrogels are of high interest especially for the mining industries as a sustainable material for the treatment of their highly contaminated wastewaters.

  • 4. Dax, Daniel
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Langvik, Otto
    Hemming, Jarl
    Backman, Peter
    Willför, Stefan
    Synthesis of SET-LRP-Induced Galactoglucomannan-Diblock Copolymers2013Ingår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 51, nr 23, s. 5100-5110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polysaccharides are biorenewable and biodegradable starting materials for the development of functional materials. The synthesis of a monofunctional macroinitiator for single electron transfer-living radical polymerization was successfully developed from a wood polysaccharide-O-acetyl galactoglucomannan (GGM) using a beforehand synthesized amino-functional -bromoisobutyryl derivative applying reductive amination. The GGM macroinitiator was employed to initiate a controlled radical polymerization of [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA), methyl methacrylate (MMA), and N-isopropylacrylamide (NIPAM) using Cu-0/Me-6-Tren as a catalyst. The either charged or amphiphilic GGM-b-copolymers with different chain lengths of the synthetic block were successfully synthesized without prior hydrophobization of the GGM chain and dimethyl sulfoxide (DMSO) or DMSO/water mixtures were used as solvents. This novel synthetic approach may find untapped potentials particularly for the development of polysaccharide-based amphiphilic additives for cosmetics or paints and for the design of novel temperature or pH responsive polymers with such potential applications as in drug delivery systems or in biocomposites.

  • 5. Doliška, A.
    et al.
    Willför, S.
    Strnad, S.
    Ribitsch, V.
    Kleinschek, K. S.
    Eklund, P.
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Antithrombotic properties of sulfated wood-derived galactoglucomannans2012Ingår i: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 66, nr 2, s. 149-154Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Galactoglucomannans (GGMs) are water-soluble polysaccharides released and accumulated in process waters in the production of thermomechanical pulp. The general trend in the forestry industry is moving towards bio-refineries, for example utilizing these hemicelluloses as bioactive substances. At present, there is no industrial use of wood-derived mannans. In this study, GGMs extracted from thermomechanical pulp, as well as further carboxymethyl-ated galactoglucomannans (CM-GGMs), were sulfated to increase their antithrombotic properties. The products were characterized with Fourier transform infrared spectroscopy, nuclear magnetic resonance and capillary electrophoresis. The carbohydrate composition and sulfur amounts were determined. The products' total charges were determined by polyelectrolyte titrations and their antithrombotic effect was measured based on the activated partial thromboplastin time. The results showed a significant increase in the antithrombotic effect of the sulfated galactoglucomannans from spruce wood and thus a potential new use for wood-derived mannans.

  • 6.
    Honorato, Camila
    et al.
    Abo Akad Univ, Proc Chem Ctr, Lab Wood & Paper Chem, SF-20500 Turku, Finland..
    Kumar, Vinay
    Abo Akad Univ, Ctr Funct Mat, Lab Paper Coating & Converting, SF-20500 Turku, Finland..
    Liu, Jun
    Abo Akad Univ, Proc Chem Ctr, Lab Wood & Paper Chem, SF-20500 Turku, Finland..
    Koivula, Hanna
    Univ Helsinki, Dept Food & Environm Sci, FIN-00014 Helsinki, Finland..
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Process Chemistry Centre, Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Porthansgatan 3, Åbo/Turku, Finland.
    Toivakka, Martti
    Abo Akad Univ, Ctr Funct Mat, Lab Paper Coating & Converting, SF-20500 Turku, Finland..
    Transparent nanocellulose-pigment composite films2015Ingår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 50, nr 22, s. 7343-7352Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biodegradable coatings and films of cellulose nanofibers (CNFs) or a combination of CNFs and inorganic fillers, such as clay or calcium carbonate (CaCO3), can provide a replacement for non-biodegradable plastic coatings as barrier layers in packaging boards. In this work, transparent composite films were prepared from CNFs of Pinus radiata and Eucalyptus using different amounts of clay and CaCO3 as fillers. The impact of raw material (softwood vs. hardwood), TEMPO oxidation levels and filler type (clay vs. CaCO3) on film properties was studied. Pinus radiata CNF films had superior mechanical properties to Eucalyptus CNF films, but no significant differences were observed in the barrier and optical properties. Clay seemed to work better as filler compared to CaCO3, in terms of its impact on film properties. Composite films with CaCO3 as filler were highly brittle with inferior properties to clay-CNF films, and an uneven distribution and agglomeration of the CaCO3 mineral particles was evident in SEM images. Based on the results, clay as filler in CNF coatings is preferred for targeting packaging board applications. Rheological characterisation of the CNF suspensions revealed shear-thinning behaviour, with the CNF from Eucalyptus having higher viscosities and lower power-law indices when compared to the CNF from P. radiata.

  • 7. Kisonen, Victor
    et al.
    Prakobna, Kasinee
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Salminen, Arto
    Mikkonen, Kirsi S.
    Valtakari, Dimitar
    Eklund, Patrik
    Seppala, Jukka
    Tenkanen, Maija
    Willfor, Stefan
    Composite films of nanofibrillated cellulose and O-acetyl galactoglucomannan (GGM) coated with succinic esters of GGM showing potential as barrier material in food packaging2015Ingår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 50, nr 8, s. 3189-3199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanofibrillated cellulose (NFC)-Norway spruce O-acetyl-galactoglucomannan (GGM) composite films were coated either with a novel succinic ester of GGM or with native GGM. NFC films were made for reference. The succinic ester of GGM was synthesised at low (GGM-Su1) and high (GGM-Su2) degree of substitution to obtain different level of water repellence. GGM and its succinic esters had good affinity with NFC substrate. This made it possible to implement the barrier functionality on the NFC network with the adequate mechanical properties. The coatings further enhanced the already excellent oxygen permeability properties, achieving 0.1 [(cm(3) A mu m)(m(2) kPa d)] as the lowest value with the NFC-GGM film double-coated with GGM-Su2. The films demonstrated pronounced stiffness by adding GGM to the NFC, as well as coating of GGM-Su2 on the NFC-GGM films at 0-90 % relative humidity. The films turned out to be impenetrable with grease even at high temperatures. NFC-GGM film with GGM-Su2 coating exhibited hydrophobic characteristics according to the water contact angle measurements. It was shown that adding 5.5 wt% of GGM to a NFC film and further 5.4 wt% of coating of GGM-Su or GGM on the film may highly enhance the feasibility of the biocomposites to be used for food packaging to replace typical oil-based non-biodegradable plastics currently used.

  • 8. Kisonen, Victor
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Bollström, Roger
    Hartman, Jonas
    Rautkoski, Hille
    Nurmi, Maristiina
    Hemming, Jarl
    Eklund, Patrik
    Willför, Stefan
    O-acetyl galactoglucomannan esters for barrier coatings2014Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 6, s. 4497-4509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A major enhancement of grease and water vapor barrier properties was accomplished with a 1-10 g/m(2) coating of O-acetyl galactoglucomannan (GGM) ester or with GGM coatings applied as water dispersions on cartonboard. GGMs were esterified with phthalic and benzoic anhydrides, respectively. The novel phthalic esters of GGM (GGM-Ph) were characterized with HPLC, NMR, and matrix-assisted laser desorption/ionization with mass spectrometry (MALDI-TOF-MS). The degree of substitution of GGM-Ph was obtained by H-1 NMR, C-13 NMR, and HPLC. The GGM esters and GGM were coated onto cartonboard, and they demonstrated good moisture and very good grease resistance even with thin 1-3 g/m(2) coatings. The time for penetration of 0.1 % rapeseed oil was 54 h with the 2.4 g/m(2) coating thickness. The lowest water vapor transmission value was 39 g/m(2)/24 h with 9.7 g/m(2) coating. The GGM esters had clearly higher water resistance and slightly higher grease barrier values than native GGM. High-molar-mass-based GGM (50 kg/mol) and GGM-Ph rendered better water vapor and grease barrier properties than low-molar-mass GGM (9 kg/mol) and GGM-Ph. The GGM-based coatings can be safely used on an industrial scale as water was used as a solvent. As obtained from non-food-based side-stream wood-based resources, GGM and GGM esters project a sustainable and modern conception for barrier purposes in food packaging.

  • 9. Kisonen, Victor
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Eklund, Patrik
    Lindqvist, Hanna
    Sundberg, Anna
    Pranovich, Andrey
    Sinkkonen, Jari
    Vilaplana, Francisco
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Willför, Stefan
    Cationised O-acetyl galactoglucomannans: Synthesis and characterisation2014Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 99, s. 755-764Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Water-soluble O-acetyl-galactoglucomannans (GGMs) can be obtained from Norway spruce by hot-water-extraction of the wood or as a side product by ultrafiltration of mechanical pulping waters. Cationic and amphiphilic polysaccharides and their derivatives are of interest for a number of applications and thus quaternary nitrogen moieties with cationic charge were grafted onto GGMs in the heterogeneous reaction to render a cationic polyelectrolyte. The degree of substitution was measured by elemental analysis of nitrogen, by quantitative C-13 NMR and interestingly also by polyelectrolyte titration and the results were congruent. NMR, matrix-assisted laser desorption/ionisation mass spectroscopy (MALDI-TOF-MS), and FT-IR analysis were used to characterise the product. THF or DMSO with water enhanced the reaction efficiency and decreased M-w reduction in comparison to plain water as a reaction media. Cationised GGM was also successfully acetylated. The cationic derivatives of hemicelluloses can potentially be utilised as polyelectrolyte layers in packaging and pharmaceutical applications.

  • 10. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Eklund, Patrik
    Lucenius, Jessica
    Österberg, Monika
    Willför, Stefan
    Targeted functionalization of spruce O-acetyl galactoglucomannans-2,2,6,6-tetramethylpiperidin-1-oxyl-oxidation and carbodiimide-mediated amidation2013Ingår i: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 130, nr 5, s. 3122-3129Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modified spruce O-acetyl galactoglucomannans (GGMs) can be used as molecular anchors to alter the surface properties or to activate the surface of cellulose. To selectively introduce functionalities, GGMs were oxidized on C-6 of hexoses by 2,2,6,6-tetramethylpiperidin-1-oxyl-mediated oxidation. Different degrees of oxidation were successfully obtained by varying the reaction parameters. Low degrees could be obtained by performing the oxidations in bromide-free conditions. The formed uronic acids were further modified by a carbodiimide-mediated amidation reaction, which opens a window for introducing various functionalities selectively on hexoses. The adsorption of the modified GGMs to various cellulose samples was investigated. Indirect bulk sorption to fibers was compared to direct adsorption to nanofibrillated cellulose ultrathin films. GGMs with low degrees of oxidation showed high affinity to cellulose surfaces and could be sorbed onto cellulose in pure water. Moderate amounts of GGMs with high degree of oxidation could be sorbed onto cellulose in the presence of salts.

  • 11. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Liu, Jun
    Wang, Xiaoju
    Pesonen, Markus
    Willfoer, Stefan
    Anionic Polysaccharides as Templates for the Synthesis of Conducting Polyaniline and as Structural Matrix for Conducting Biocomposites2013Ingår i: Macromolecular rapid communications, ISSN 1022-1336, E-ISSN 1521-3927, Vol. 34, nr 13, s. 1056-1061Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A green chemoenzymatic pathway for the synthesis of conducting polyaniline (PANI) composites is presented. Laccase-catalyzed polymerization in combination with anionic polysaccharides is used to produce polysaccharide/PANI composites, which can be processed into flexible films or coated onto cellulose surfaces. Different polysaccharide templates are assessed, including -carrageenan, native spruce O-acetyl galactoglucomannan (GGM), and TEMPO-oxidized cellulose and GGM. The resulted conducting biocomposites derived from natural materials provide a broad range of potential applications, such as in biosensors, electronic devices, and tissue engineering.

  • 12. Leppänen, Ann-Sofie
    et al.
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Parikka, Kirsti
    Eklund, Patrik
    Sjöholm, Rainer
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Tenkanen, Maija
    Willför, Stefan
    Targeted allylation and propargylation of galactose-containing polysaccharides in water2014Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 100, s. 46-54Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Galactose units of spruce galactoglucomannan (GGM), guar galactomannan (GM), and tamarind (galacto)xyloglucan (XG) were selectively allylated. Firstly aldehyde functionalities were formed at the C-6 position via enzymatic oxidation by galactose oxidase. The formed aldehydes were further derivatized by an indium mediated Barbier-Grignard type reaction, resulting in the formation of homoallylic alcohols. In addition to allylic halides, the same reaction procedure was also applicable for GGM, when using propargyl bromide as halide. All reaction steps were done in water, thus the polysaccharides were modified in a one-pot reaction. The formation of the allylated, or propargylated, product was identified by MALDI-TOF-MS. All polysaccharide products were isolated and further characterized by GC-MS or NMR spectroscopy. By this chemo-enzymatic process, we have demonstrated a novel method for derivatization of GGM and other galactose-containing polysaccharides. The derivatized polysaccharides are potential platforms for further functionalizations.

  • 13. Liu, Jun
    et al.
    Korpinen, Risto
    Mikkonen, Kirsi S.
    Willfor, Stefan
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Process Chemistry Centre, c/o Laboratory Wood and Paper Chemistry, Åbo Akademi University, Finland.
    Nanofibrillated cellulose originated from birch sawdust after sequential extractions: a promising polymeric material from waste to films2014Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, nr 4, s. 2587-2598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The residual cellulose of wood processing waste, sawdust, which was leftover after sequential hot-water extraction processes to isolate hemicelluloses and lignin in a novel forest biorefinery concept, was explored as the starting material for preparation of a highly value-added polymeric material, nanofibrillated cellulose (NFC) also widely termed as cellulose nanofiber, which has provided an alternative efficient way to upgrade sawdust waste. The residual cellulose in sawdust was converted to a transparent NFC suspension in water through the 2,2,6,6-tetramethylpiperidine-1-oxyl radical/NaClO/NaBr oxidization approach. The resultant NFC with a dimension of ca. 5 nm in width and hundreds of nanometers in length were further processed into NFC films. The morphological features of the NFC suspension and its films were assessed by transmission electron microscopy and scanning electron microscopy. Highly even dispersion of NFC fibrils in the films originated from sawdust feasibly contributes to the outstanding mechanical performance of the films. NFC suspension with higher carboxylate content and its resultant NFC films were found to show higher transmission of light.

  • 14.
    Liu, Jun
    et al.
    Abo Akad Univ, Johan Gadolin Proc Chem Ctr, Lab Wood & Paper Chem, Porthansgatan 3-5, FI-20500 Turku, Finland.;Jiangsu Univ, Dept Environm & Safety, Biofuels Inst, Zhenjiang 212013, Peoples R China..
    Leppanen, Ann-Sofie
    Abo Akad Univ, Johan Gadolin Proc Chem Ctr, Lab Wood & Paper Chem, Porthansgatan 3-5, FI-20500 Turku, Finland..
    Kisonen, Victor
    Abo Akad Univ, Johan Gadolin Proc Chem Ctr, Lab Wood & Paper Chem, Porthansgatan 3-5, FI-20500 Turku, Finland..
    Willfor, Stefan
    Abo Akad Univ, Johan Gadolin Proc Chem Ctr, Lab Wood & Paper Chem, Porthansgatan 3-5, FI-20500 Turku, Finland..
    Xu, Chunlin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. Abo Akad Univ, Johan Gadolin Proc Chem Ctr, Lab Wood & Paper Chem, Porthansgatan 3-5, FI-20500 Turku, Finland..
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för bioteknologi (BIO), Centra, Albanova VinnExcellence Center for Protein Technology, ProNova. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Insights on the distribution of substitutions in spruce galactoglucomannan and its derivatives using integrated chemo-enzymatic deconstruction, chromatography and mass spectrometry2018Ingår i: International Journal of Biological Macromolecules, ISSN 0141-8130, E-ISSN 1879-0003, Vol. 112, s. 616-625Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate determination of the distribution of substitutions in the primary molecular structure of heteropolysaccharides and their derivatives is a prerequisite for their increasing application in the pharmaceutical and biomedical fields, which is unfortunately hindered due to the lack of effective analytical techniques. Acetylated galactoglucomannan (GGM) is an abundant plant polysaccharide as the main hemicellulose in softwoods, and therefore constitutes an important renewable resource from lignocellulosic biomass for the development of bioactive and functional materials. Here we present a methodology for profiling the intramolecular structure of spruce GGM and its chemical derivatives (cationic, anionic, and benzoylated) by combining chemo-enzymatic hydrolysis, liquid chromatography, and mass spectrometry. Fast identification and qualitative mass profiling of GGM and its derivatives was conducted using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionization mass spectrometry (ESI-MS). Tandem mass fragmentation analysis and its hyphenation with hydrophilic interaction liquid chromatography (HILIC-ESI-MS/MS) provide further insights on the substitution placement of the GGM oligosaccharides and its derivatives. This method will be useful in understanding the structure-function relationships of native GGM and their derivatives, and therefore facilitate their potential application. 

  • 15. Lozhechnikova, A.
    et al.
    Dax, D.
    Vartiainen, J.
    Willför, S.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. Aalto University, Finland.
    Österberg, M.
    Modification of nanofibrillated cellulose using amphiphilic block-structured galactoglucomannans2014Ingår i: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 110, s. 163-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanofibrillated cellulose (NFC) and hemicelluloses have shown to be highly promising renewable components both as barrier materials and in novel biocomposites. However, the hydrophilic nature of these materials restricts their use in some applications. In this work, the usability of modified O-acetyl galactoglucomannan (GGM) for modification of NFC surface properties was studied. Four GGM-block-structured, amphiphilic derivatives were synthesized using either fatty acids or polydimethylsiloxane as hydrophobic tails. The adsorption of these GGM derivatives was consecutively examined in aqueous solution using a quartz crystal microbalance with dissipation monitoring (QCM-D). It was found that the hydrophobic tails did not hinder adsorption of the GGM derivatives to cellulose, which was concluded to be due to the presence of the native GGM-block with high affinity to cellulose. The layer properties of the adsorbed block-co-polymers were discussed and evaluated. Self-standing NFC films were further prepared and coated with the GGM derivatives and the effect of the surface modification on wetting properties and oxygen permeability (OP) of the modified films was assessed.

  • 16. Mikkonen, K. S.
    et al.
    Mathew, A. P.
    Pirkkalainen, K.
    Serimaa, R.
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. Åbo Akademi University.
    Willför, S.
    Oksman, K.
    Tenkanen, M.
    Glucomannan composite films with cellulose nanowhiskers2010Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 17, nr 1, s. 69-81Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spruce galactoglucomannans (GGM) and konjac glucomannan (KGM) were mixed with cellulose nanowhiskers (CNW) to form composite films. Remarkable effects of CNW on the appearance of the films were detected when viewed with regular and polarizing optical microscopes and with a scanning electron microscope. Addition of CNW to KGM-based films induced the formation of fiberlike structures with lengths of several millimeters. In GGM-based films, rodlike structures with lengths of several tens of micrometers were formed. The degree of crystallinity of mannan in the plasticized KGM-based films increased slightly when CNW were added, from 25 to 30%. The tensile strength of the KGM-based films not containing glycerol increased with increasing CNW content from 57 to 74 MPa, but that of glycerol-plasticized KGM and GGM films was not affected. Interestingly, the notable differences in the film structure did not appear to be related to the thermal properties of the films.

  • 17.
    Nordgren, Niklas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Johansson, Erik
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Functionalized xyloglucan assemblies on gold: A prospective biomimetic anchor for cellulose2011Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 241Artikel i tidskrift (Övrigt vetenskapligt)
  • 18. Parikka, K.
    et al.
    Leppänen, A. -S
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Pitkänen, L.
    Eronen, P.
    Österberg, M.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Willför, S.
    Tenkanen, M.
    Functional and anionic cellulose-interacting polymers by selective chemo-enzymatic carboxylation of galactose-containing polysaccharides2012Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 13, nr 8, s. 2418-2428Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carboxylated, anionic polysaccharides were selectively prepared using a combination of enzymatic and chemical reactions. The galactose-containing polysaccharides studied were spruce galactoglucomannan, guar galactomannan, and tamarind galactoxyloglucan. The galactosyl units of the polysaccharides were first oxidized with galactose oxidase (EC 1.1.3.9) and then selectively carboxylated, resulting in the galacturonic acid derivatives with good conversion and yield. The degrees of oxidation (DO) of the products were determined by gas chromatography-mass spectrometry (GC-MS). A novel feasible electrospray ionization-mass spectrometry (ESI-MS) method was also developed for the determination of DO. The solution properties and charge densities of the products were investigated. The interaction of the products with cellulose was studied by two methods, bulk sorption onto bleached birch kraft pulp and adsorption onto nanocellulose ultrathin films by quartz crystal microbalance with dissipation (QCM-D). To study the effect of the location of the carboxylic acid groups on the physicochemical properties, polysaccharides were also oxidized by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated reaction producing polyuronic acids. The chemo-enzymatically oxidized galacturonic polysaccharides with an unmodified backbone had a better ability to interact with cellulose than the TEMPO-oxidized products. The selectively carboxylated polysaccharides can be further exploited, as such, or in the targeted functionalization of cellulose surfaces.

  • 19.
    Prakobna, Kasinee
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Kisonen, Victor
    Xu, Chunlin
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Strong effects from galactoglucomannan hemicellulose on mechanical behavior of wet cellulose nanofiber gelsManuskript (preprint) (Övrigt vetenskapligt)
  • 20.
    Spadiut, Oliver
    et al.
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Ibatullin, Farid M.
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Peart, Jonelle
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Gullfot, Fredrika
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Martinez-Fleites, Carlos
    Ruda, Marcus
    Xu, Chunlin
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Sundqvist, Gustav
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Davies, Gideon J.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Building Custom Polysaccharides in Vitro with an Efficient, Broad-Specificity Xyloglucan Glycosynthase and a Fucosyltransferase2011Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 133, nr 28, s. 10892-10900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current drive for applications of biomass-derived compounds, for energy and advanced materials, has led to a resurgence of interest in the manipulation of plant polymers. The xyloglucans, a family of structurally complex plant polysaccharides, have attracted significant interest due to their intrinsic high affinity for cellulose, both in muro and in technical applications. Moreover, current cell wall models are limited by the lack of detailed structure-property relationships of xyloglucans, due to a lack of molecules with well-defined branching patterns. Here, we have developed a new, broad-specificity "xyloglucan glycosynthase", selected from active-site mutants of a bacterial endoxyloglucanase, which catalyzed the synthesis of high molar mass polysaccharides, with complex side-chain structures, from suitable glycosyl fluoride donor substrates. The product range was further extended by combination with an Arabidopsis thaliana alpha(1 -> 2)-fucosyltransferase to achieve the in vitro synthesis of fucosylated xyloglucans typical of dicot primary cell walls. These enzymes thus comprise a toolkit for the controlled enzymatic synthesis of xyloglucans that are otherwise impossible to obtain from native sources. Moreover, this study demonstrates the validity of a chemo-enzymatic approach to polysaccharide synthesis, in which the simplicity and economy of glycosynthase technology is harnessed together with the exquisite specificity of glycosyltransferases to control molecular complexity.

  • 21.
    Stevanic, Jasna S.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Mikkonen, Kirsi S.
    Xu, Chunlin
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Tenkanen, Maija
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Salmén, Lennart
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Wood cell wall mimicking for composite films of spruce nanofibrillated cellulose with spruce galactoglucomannan and arabinoglucuronoxylan2014Ingår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 49, nr 14, s. 5043-5055Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two hemicelluloses (HCs), galactoglucomannan (GGM) and arabinoglucuronoxylan (AGX), and nanofibrillated cellulose (NFC) were isolated from spruce wood and used for the preparation of composite films containing high amounts of cellulose, i.e. 85 and 80 wt% of NFC, respectively. The films were prepared in two ways: (i) by the pre-sorption of HCs on NFC and (ii) by the mixing of components in the usual way. Pre-sorption was applied in an attempt to mimic the carbohydrate biosynthesis pattern during wood cell wall development, where HCs were deposited on the cellulose fibrils prior to lignification taking place. It was assumed that pre-sorption would result in a better film-forming as well as stronger and denser composite films. The mechanical, thermal, structural, moisture sorption and oxygen barrier characteristics of such composite films were tested in order to examine whether the performance of composite films prepared by pre-sorption was better, when compared to the performance of composite films prepared by mixing. The performance of composite films was also tested with respect to the HCs used. All the films showed quite similar barrier and mechanical properties. In general, stiff, strong and quite ductile films were produced. The moisture sorption of the films was comparably low. The oxygen barrier properties of the films were in the range of commercially used poly ethylene vinyl alcohol films. However, the pre-sorption procedure for the preparation of composite films resulted in no additional improvement in the performance of the films compared to the corresponding composite films that had been prepared using the mixing process. Almost certainly, the applied mixing process led to an optimal mixing of components for the film performance achieved. The GGM contributed to a somewhat better film performance than the AGX did. Indications were observed for stronger interactions between the GGM and NFC than that for the AGX and NFC.

  • 22.
    Xu, Chunlin
    et al.
    KTH, Skolan för bioteknologi (BIO).
    Eckerman, Christer
    Smeds, Annika
    Reunanen, Markku
    Eklund, Patrik C.
    Sjoholm, Rainer
    Willfor, Stefan
    Carboxymethylated spruce galactoglucomannans: preparation, characterisation, dispersion stability, water-in-oil emulsion stability, and sorption on cellulose surface2011Ingår i: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 26, nr 2, s. 167-178Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Natively acetylated galactoglucomannans (GGMs) is the main hemicellulose type in most softwood species and can be utilised as, for example, bioactive polymers, hydrocolloids, papermaking chemicals, or coating polymers. In this study, carboxymethylated GGMs (CM-GGMs) were prepared and characterised by GC-MS, H-1 and C-13 NMR and FTIR spectroscopy, and SEC-MALLS. The thermal stability of the products was investigated by DSC-TGA. The accessibility of different C-positions in mannose and glucose was investigated. The emulsion stability of CM-GGMs in resin dispersion was studied and it was shown that CM-GGMs can stabilise the resin dispersion also in presence of CaCl2. The possibility of using CM-GGMs as emulsifiers in water-in-oil emulsions was assessed. A CM-GGM with a DS value of 0.25 at a concentration higher than 3% performed the best. Finally, the study of sorption of CM-GGM onto cellulose surface exhibited a decrease in binding ability with an increase in the degree of substitution (DS).

  • 23.
    Xu, Chunlin
    et al.
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Spadiut, Oliver
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Araujo, Ana Catarina
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Nakhai, Azadeh
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Willfor, Stefan
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Chemo-enzymatic assembly of clickable cellulose surfaces via multivalent polysaccharides2012Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 243Artikel i tidskrift (Övrigt vetenskapligt)
  • 24.
    Xu, Chunlin
    et al.
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Spadiut, Oliver
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Araújo, Ana Catarina
    KTH, Skolan för bioteknologi (BIO).
    Nakhai, Azadeh
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Chemo-enzymatic Assembly of Clickable Cellulose Surfaces via Multivalent Polysaccharides2012Ingår i: ChemSusChem, ISSN 1864-5631, Vol. 5, nr 4, s. 661-665Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chemist′s guide to the galactosyl unit: A chemo-enzymatic process is developed for the multivalent functionalization of cellulose surfaces via regioselective oxidation of heteropolysaccharides with galactose 6-oxidase. Reductive amination, surface sorption, and click chemistry enable the assembly of (bio)chemically active cellulose surfaces for applications ranging from functional biocomposites to in vitro diagnostics.

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