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  • 1.
    Bi, Ran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Huang, Shan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    ISOLATION OF EXCEEDINGLY LOW OXYGEN CONSUMING FUNGAL STRAINS ABLE TO UTILIZE LIGNIN AS CARBON SOURCE2016Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 50, nr 7-8, s. 811-817Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lignin biodegradation is normally related to aerobic microorganisms, and it is often claimed that microbes do not metabolize lignin as a carbon source. In this work, several fungal strains were isolated from the sediment of a small stream located in a forest and tested on agar plates with lignin as the only carbon source. All identified strains were Ascomycetes, Penicillium spinulosum, Pseudeurotium bakeri and Galactomyces geotrichum. When cultivated in shaking flasks with lignosulphonate as a carbon source, the lignin was consumed, and cell free culture filtrates appeared to depolymerize lignosulphonate to some extent. It is suggested that the strains detected are part of a symbiotic community and live in a microbiological niche in which they are able to utilize lignin residues left from brown rot and humus having extremely low oxygen content.

  • 2.
    Bi, Ran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Huang, Shan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. Linnaus University, Sweden.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Isolation of exceedingly low oxygen consuming fungal strains able to utilize lignin as carbon sourceIngår i: Cellulose Chemistry and Technology, ISSN 0576-9787Artikel i tidskrift (Refereegranskat)
  • 3.
    Bi, Ran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. 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.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Isolation and identification of microorganisms from soil able to live on lignin as acarbon source and to produce enzymes which cleave the β-o-4 bond in a lignin model compound2012Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 46, nr 3-4, s. 227-242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several strains of fungi were isolated and identified from Scandinavian soil using agar plates with lignin as a carbon source. The strains grew significantly faster on this medium than on control plates without lignin. Different types of technical lignins were used, some of which contained trace amounts of sugars, even if the increased growth rate seemed not related to the sugar content. Some strains were cultivated in shaking flask cultures with lignin as a carbon source, with lignin apparently consumed by microbes - while accumulation of the microorganism biomass occurred. The cell-free filtrates of these cultures could reduce the apparent molecular weights of lignosulphonates, while the culture filtrate of one strain could cleave the beta-O-4 bond in a lignin model compound.

  • 4.
    Bi, Ran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi. 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.
    Lawoko, Martin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Brumer, Harry
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. 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.
    Isolation and identification of microorganisms from soil able to live on lignin as a carbon source and to produce enzymes which cleave beta-O-4 bond in a lignin model compound2012Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 46, nr 3-4, s. 227-242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several strains of fungi were isolated and identified from Scandinavian soil using agar plates with lignin as a carbon source. The strains grew significantly faster on this medium than on control plates without lignin. Different types of technical lignins were used, some of which contained trace amounts of sugars, even if the increased growth rate seemed not related to the sugar content. Some strains were cultivated in shaking flask cultures with lignin as a carbon source, with lignin apparently consumed by microbes - while accumulation of the microorganism biomass occurred. The cell-free filtrates of these cultures could reduce the apparent molecular weights of lignosulphonates, while the culture filtrate of one strain could cleave the beta-O-4 bond in a lignin model compound.

  • 5.
    Bi, Ran
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Spaduit, Oliver
    KTH, Skolan för bioteknologi (BIO). KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Brumer, Harry III
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. 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.
    Isolation and identification of microorganisms from soil  able to ive on lignin as carbon source and produce enzymes that cleave beta-O-4mbond in lignin2011Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Twenty one strains of micro organism from Scandinavian soil had been isolated that could utilize lignin as only carbon source and 11 strains of them were identified. Different types of technical lignins were used.5 faster growing strains were cultivated in shaking flask cultures with ligninosulfonate as sole carbon source,and lignin appeared to be consumed after several days while mycelia was observed accumulated.Cell free filtrates of the 5 faster growing strains could lower the apparent molecular weights of lignosulphonates and the culture filtrate of one strain could cleave the lignin model compound with.The significances of the results are discussed.

  • 6.
    Ek, Monica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Chirat, Christine
    Fogelstrom, Linda
    Iversen, Tommy
    Li, Dongfang
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Norström, Emelie
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Ytbehandlingsteknik.
    Sixta, Herbert
    Testova, Lidia
    Toivari, Terhi
    Wawro, Dariusz
    WOBAMA: wood based materials and fuels2014Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 48, nr 9-10, s. 773-779Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    WOBAMA - Wood Based Materials and Fuels is a biorefinery oriented scientific research project supported by Wood Wisdom-Net Research Programme and ERA-NET Bioenergy. In this project, the wood based raw materials were converted to a range of value added products through unconventional techniques. So far, many demonstrators have been prepared, such as the dissolving pulps with high cellulose content, the regenerated cellulose films with high tenacity, the hydrophobic materials based on cellulose and birch bark suberin, as well as the adhesives based on polysaccharides.

  • 7. Ekblad, C.
    et al.
    Pettersson, B.
    Zhang, J.
    Jernberg, S.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Enzymatic-mechanical pulping of bast fibers from flax and hemp2005Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 39, nr 02-jan, s. 95-103Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A technique for pulping of bast fibers of flax (Linum usitatissimum) and hemp (Cannabis sativa), based on treatment with cellulolytic and pectinolytic enzymes has been developed. Initially the bast fibers were mechanically separated from shieves and subjected to washing with diluted acid, followed by enzyme treatment, an alkaline hydrogen peroxide bleaching step that also inactivated the enzymes, and finally beating in a laboratory beater. Brightness, dewatering and strength of handsheets were comparable with the traditionally-made pulps. Fibers not treated with enzymes could not be beaten. The main pulping effect is related to cellulases, but the presence of pectinases influenced both brightness and strength properties.

  • 8.
    Henriksson, Gunnar
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Träkemi och massateknologi.
    Ljunggren, S.
    Migrating electron holes in lignin during wood biosynthesis and biodegradation - A hypothesis2005Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 39, nr 04-mar, s. 189-200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An unsolved question in biodegradation is how ligninases can oxidize the lignin structures that are located so deep inside the compact woody cell walls, that they are inaccessible for the enzyme, due to sterical restrictions. One explanation may be that ligninases generate small diffusible agents, redox mediators, that in turn perform lignin oxidation. Parts of the cell wall structure may nevertheless be too compact even for these, and some enzymes seem to interact directly with the lignin. The present paper discusses the hypothesis that the enzymatically generated aromatic radicals in lignin can oxidize other aromatic structures within the polymer. A chain-reaction may be therefore created, that allows the electron-holes to migrate, probably facilitated by some flexibility of the lignin. Thus, the eventual depolymerization of lignin may possibly occur far apart from the initial oxidation site. The migrating electron hole theory might be also applied on lignin biosynthesis.

  • 9.
    Krusa, Martin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Lennholm, Helena
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Pre-treatment of cellulose by cellobiose dehydrogenase increases the degradation rate by hydrolytic cellulases2007Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 41, nr 2-3, s. 105-111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellobiose dehydrogenase (CDH) is an extra-cellular flavocytochrome with unknown biological function, produced by various wood degrading fungi. In the presence of Fe(III) and cellobiose, CDH produces hydroxyl radicals through a Fenton-type reaction. Treatment of cellulose with CDH, cellobiose, hydrogen peroxide and ferriacetate decreased cellulose's polymerization degree and increased its degradability for different functional types of hydrolytic cellulases, except for an exo-enzyme working from the reducing end. This suggests a biological role for CDH in fungal cellulose degradation, possibly by activating the cellulose for hydrolytic cellulases by depolymerization and disturbance of the hydrogen bonding pattern in cellulose.

  • 10.
    Lennholm, Helena
    et al.
    KTH, Skolan för industriell teknik och management (ITM).
    Henriksson, Gunnar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Kruså, Martin
    Pre-treatment of cellulose be cellobiose dehydrogenase increases the degradation rate by hydrolytic cellulase2007Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 41, nr 2-3, s. 105-111Artikel i tidskrift (Refereegranskat)
  • 11. Ondaral, Sedat
    et al.
    Usta, Mustafa
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Gumusderelioglu, Menemse
    Ondaral, Meryem
    FIXATION OF DISSOLVED AND COLLOIDAL SUBSTANCES ON FIBERS AND SILICON OXIDE SURFACES USING WATER SOLUBLE CROSSLINKED CATIONIC POLYMERS2008Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 42, nr 1-3, s. 61-69Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The efficiency of water soluble crosslinked cationic polymers (CCP) in the fixation of dissolved and colloidal substances (DCS) onto fibers was investigated. Two different types of CCP were synthesized by dispersion polymerization of acrylamide (AAm) and diallyldimethylammonium chloride (DADMAC), with N,N'-methylene-bis-acrylamide (MBA) as a crosslinker. Relative turbidity, zeta potential and average diameter of the colloidal particles were determined to monitor their performance in DCS fixation. The results indicated that both polymers were able to fix a maximum amount of DCS particles onto fibers around a zero zeta potential, most probably clue to a patch-type flocculation mechanism. The conclusion reached was that flocculation was significant while the particles still had a negative zeta potential. The aggregation mechanism of a fiber-free DCS suspension occurred as Charge neutralisation, changed, by the addition of 10 mM NaCl to a patch-type mechanism. The CCPI consumption necessary to attain a maximum DCS removal was lower than the CCP2 consumption, as ascribed to the higher charge density and higher molecular mass of this polymer. The experiments performed on a quartz crystal microbalance equipment with dissipation (QCM-D) showed that the adsorbed charge and layer thickness of the polymers significantly affected fixation of the DCS particles onto the pre-adsorbed polymer layers on the SiO2 surface.

  • 12. Rognes, H.
    et al.
    Gellerstedt, Göran
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Henriksson, Gunnar
    KTH, Tidigare Institutioner                               , Pappers- och massateknik.
    Optimization of flax fiber separation by leaching2000Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 34, nr 04-mar, s. 331-340Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The abilities of four chelators to separate bast fibers of non-retted oilseed flax from each other and the core and cuticle have been investigated at different pH level. EDTAand DTPA separate fibers efficiency at pH 10. Addition of a strong detergent (Sodium dodecyl sulphate, SDS) or sodium chloride further increased the fiber separation and so delignifying compounds hydrogen peroxide and sodium sulfite. A mixture of EDTA, SDS and hydrogen peroxide gave a complete fiber separation within 2 h at 70 degrees and pH 10. The fibers in the woody core of the flax straw did not separate under these conditions. The mechanistic background to fiber separation is discussed.

  • 13.
    Stevanic Srndovic, Jasna
    et al.
    STFI-Packforsk.
    Salmén, Lennart
    STFI-Packforsk.
    The primary cell wall studied by dynamic 2D FT-IR: Interaction among components in Norway spruce (Picea abies)2006Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 40, nr 9-10, s. 761-767Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Knowledge on the interactions among the wood polymers, viz. cellulose, hemicellulose, pectin, lignin and protein, in the outer fibre wall layers is essential for understanding fibre separation in thermomechanical and chemithermomechanical pulping processes. For this reason, dynamic two-dimensional Fourier Transform Infra-Red (2D FT-IR) spectroscopy was applied to examine the interaction of these components in the primary cell wall of spruce fibres. Sheets made of an enriched primary cell wall material were used for studying the viscoelastic response to loading. The dynamic 2D correlation FT-IR spectra indicated the existence of strong interactions between lignin and protein, as well as among pectin, xyloglucan and cellulose, in the primary cell wall. This is in contrast to the picture for the secondary cell wall, in which cellulose-glucomannan and xylan-lignin interactions are prevailing.

  • 14.
    Tavast, Daniel
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Brännvall, Elisabeth
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Lindström, Mikael E.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Henriksson, Gunnar
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Selectiveness and efficiency of combined peracetic acid and chlorine dioxide bleaching stage for kraft pulp in removing hexeuronic acid2011Ingår i: Cellulose Chemistry and Technology, ISSN 0576-9787, Vol. 45, nr 1-2, s. 89-95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Combined peracetic acid and chlorine dioxide bleaching stages of unbleached and oxygen delignified hardwood and softwood kraft pulps were compared with conventional chlorine dioxide and peracetic acid stages as to kappa number and viscosity reduction, selectivity and reduction of hexenuronic acid content. The combined stages were more efficient in kappa number reduction than those with only chlorine dioxide. Part of the increased kappa number reduction was due to an improved degradation of hexenuronic acid. The stages where chlorine dioxide was added before the peracetic acid (DT) showed a higher selectivity than those in which the chemicals were added simultaneously (D+T); in turn, the latter were more efficient than the "pure" chlorine dioxide (D, D-0) and peracetic acid stages (T). However, peracetic acid and chlorine dioxide seemed to react with each other, leading to the degradation of both bleaching chemicals. The mechanisms and practical implementation of these bleaching sequences are discussed.

1 - 14 av 14
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