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  • 401.
    Winestrand, Sandra
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Larsson, Simona
    Riga Technical University, Faculty of Civil Engineering, Latvia.
    Cassland, Pierre
    Applied Microbiology, Lund University/Lund Institute of Technology.
    Nilvebrant, Nils-Olof
    Karlstad University, Faculty of Technology and Science.
    Jönsson, Leif J.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Effects of ionic substances in bleaching filtrates and of lignosulfonates on the activity of oxalate oxidase from barley2011In: Engineering in Life Sciences, ISSN 1618-0240, E-ISSN 1618-2863, Vol. 11, no 3, p. 245-252Article in journal (Refereed)
    Abstract [en]

    The effects of ionic substances in seven industrial filtrates from kraft pulping, mechanical pulping, and sulfite pulping on the activity of oxalate oxidase from barley were investigated by pre-treatment of the filtrates with ion-exchange resins prior to enzymatic degradation of the oxalic acid in the filtrates. The pre-treatment resulted in increased oxalic acid degradation rates in all filtrates, except for one that was obtained from sulfite pulping. The possibility that lignosulfonates, which were present in the filtrate from sulfite pulping, could affect oxalate oxidase was investigated in a separate set of experiments involving four different preparations of lignosulfonates. At a lignosulfonate concentration of 50 mg/mL and a pH of 3.8, only 2-16% of the activity of oxalate oxidase remained. The results show the effects of anionic and cationic substances in bleaching filtrates on oxalate oxidase and indicate that there is an interaction between the enzyme, which has a positive net charge at pH 3.8, and the polymeric anionic lignosulfonates.

  • 402.
    Winestrand, Sandra
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Latha Gandla, Madhavi
    Department of Chemistry, Umeå University.
    Hong, Feng
    College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, China.
    Chen, Qi Zhi
    College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, China.
    Jönsson, Leif J.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Oxalate decarboxylase of Trametes versicolor: biochemical characterization and performance in bleaching filtrates from the pulp and paper industry2012In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 87, no 11, p. 1600-1606Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Oxalate decarboxylase (ODC) from acid-induced cultures of the white-rot fungus Trametes versicolor was purified and characterized with respect to its biochemical properties and the possibility to utilize the enzyme for treatment of process water with the intention to prevent problems with calcium-oxalate scaling in the pulp and paper industry. RESULTS: Purified T. versicolor ODC was identified by tandem mass spectrometry. As estimated by using SDS-PAGE, the molecular mass was 69 kDa, and 60 kDa after deglycosylation with N-glycosidase F. The pH optimum was 2.5 and the temperature optimum was 4045 degrees C. The effects of ten potential inhibitors in industrial filtrates were examined. The enzyme was sensitive to low concentrations (0.1 mmol L-1) of chlorite and sulfite. T. versicolor ODC exhibited activity in 16 filtrates collected from mechanical pulping and kraft pulping. It had higher activity than ODC from Aspergillus niger in all of the filtrates and higher activity than oxalate oxidase from barley in all filtrates except two. CONCLUSIONS: The investigation shows basic biochemical properties of T. versicolor ODC and indicates that the enzyme may be useful for treatment of industrial filtrates under acidic conditions. Copyright (c) 2012 Society of Chemical Industry

  • 403.
    Winestrand, Sandra
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Nilvebrant, Nils-Olof
    Karlstad University, Faculty of Technology and Science.
    The Effects of Oxyanions on the Activity of Oxalate Oxidase2009In: The Open Enzyme Inhibition Journal, ISSN 1874-9402, Vol. 2, p. 36-40Article in journal (Refereed)
  • 404. Zhen, Y.
    et al.
    Quian, J.
    Follmann, K.
    Hayward, T.
    Nilsson, Thomas
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Dahn, M.
    Hilmi, Y.
    Hamer, A.
    Hosler, J. P.
    Fergusson-Miller, S.
    Overexpression and purification of cytochrome c oxidase fromRhodobacter1998In: Protein Expression and Purification 13, 326-336Article in journal (Refereed)
  • 405.
    Åsberg, Dennis
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Enmark, Martin
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Fornstedt, Torgny
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    An Experimental and Theoretical investigation on Mobile PhaseEffects on Competitive Adsorption Isotherms in Preparative LC2012Conference paper (Refereed)
    Abstract [en]

    This poster serves as background information to the corresponding lecture. Mobile phase gradients have been used in LC since the 1950s and are still an important programming technique in both analytical and preparative LC. Improving the resolution, and thereby making the separation of complex samples possible, and reducing the separation time, which increases the productivity, are the two main advantages of gradient elution. The modelling of band profiles and the optimization of preparative separations has largely been studied under isocratic conditions. The shape of the gradient and the behaviour of the solutes are often determined experimentally with scarce knowledge about the underlying physicochemical equations. This "trial and error" approach results in time consuming and, possibly, expensive experiments. The goal of this work is to investigate the dependence of the adsorption behaviour on the mobile phase composition in reversed phase LC. By knowing the adsorption isotherm as a function of the concentrations of both the solute and the strong organic modifier, the band profiles are modelled under gradient elution conditions.Our aim is to make it possible to use modelling tools so one can optimize a separation and especially the gradient shape. Recent studies have shown that a significant improvement in productivity can be achieved if the gradient shapes are designed carefully [1,2].In this study we discuss how to obtain the adsorption isotherm data experimentally for two substances using the perturbation peak method. The substances which are investigated are cyclohexanone and cycloheptanone on a Kromasil C18-column with methanol-water as the mobile phase. The fitting of the nonlinear experimental data to appropriate theoretical isotherm models will also be discussed.For practical reasons, we will also be looking at how different key parameters, e.g. the column hold-up time, the column efficiency, the retention factor and the equilibrium constant, change with the mobile phase composition.With the experimentally determined adsorption isotherm as a basis, we will simulate overloaded band profiles under gradient elution conditions and compare the simulated results with experimentally obtained band profiles.A contribution from the Fundamental Separation Science Group www.separationscience.se

  • 406.
    Ņsberg, Dennis
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Enmark, Martin
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Samuelsson, Jörgen
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Fornstedt, Torgny
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Modelling of Overloaded Gradient Elution in Reversed-Phase Liquid Chromatography2012Conference paper (Refereed)
    Abstract [en]

    Mobile phase gradients have been used in LC since the 1950s and are still an important programming technique in both analytical and preparative LC. Improving the resolution, and thereby making the separation of complex samples possible - and thus reducing the separation time which increases the productivity- are the two main advantages of gradient elution. The modelling of band profiles and the optimization of preparative separations has largely been studied under isocratic conditions. The shape of the gradient and the behaviour of the solutes are often determined experimentally with scarce knowledge about the underlying physicochemical equations. This “trial and error” approach results in time consuming and, possibly, expensive experiments. The goal of this work is to investigate the dependence of the adsorption behaviour on the mobile phase composition in reversed phase LC. By knowing the adsorption isotherm as a function of the concentrations of both the solute and the strong organic modifier, the band profiles can be modelled under gradient elution conditions. Our aim is to make it possible to use modelling tools for a more reliable computer-assisted optimization, accounting for the gradient shape. Recent studies have shown that a significant improvement in productivity can be achieved if the gradient shapes are designed carefully [1,2]. In this presentation we will discuss how to obtain the adsorption isotherm data experimentally for two substances using the perturbation peak method. The substances investigated are cyclohexanone and cycloheptanone on a system comprising of a Kromasil C18-column and methanol-water as mobile phase. The fitting of the nonlinear experimental data to appropriate theoretical isotherm models will also be discussed. For practical reasons, we will also be looking at how different key parameters, e.g. the column hold-up time, the column efficiency, the retention factor and the equilibrium constant, change with the mobile phase composition. With the experimentally determined adsorption isotherm as a basis, we will simulate overloaded band profiles under gradient elution conditions and compare the simulated results with experimentally obtained band profiles. A contribution from the Fundamental Separation Science Group www.separationscience.se

  • 407. Öhman, M.
    et al.
    Wan, H.
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Hamberg, M.
    Separation of Divinyl Ether Fatty Acid Isomers by Micellar Electrokinetic Chromatography,2001In: Electrophoresis, 22 (2001) 1163-1169Article in journal (Refereed)
  • 408.
    Öhman, Marcus
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Blomberg, L.G.
    Bonded dimethylacrylamide as a permanent coating for capillary electrophoresis2001In: J. Chromatogr. A, 924 (2001) 59-70Article in journal (Refereed)
  • 409.
    Öhman, Marcus
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Wan, Hong
    Hamberg, Mats
    Blomberg, Lars G
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Separation of conjugated linoleic acid isomers and parinaric fatty acid isomers by capillary electrophoresis2002In: Journal of separation scienceArticle in journal (Refereed)
  • 410.
    Öhman, Marcus
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Wan, Hong
    Hamberg, Mats
    Blomberg, Lars G.
    Separation of divinyl ether fatty acid isomers by micellar electrokinetic chromatography2001In: ElectrophoresisArticle in journal (Refereed)
  • 411.
    Ölund, David
    Karlstad University, Faculty of Technology and Science, Department of Chemistry and Biomedical Sciences.
    Konstruktion av reporterplasmider innehållande möjliga promotorregioner för kloratreduktas respektive kloritdismutas från Ideonella dechloratans2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Ideonella dechloratans is one of several isolated strains of bacteria with the ability to use chlorate in its metabolism in an anaerobic environment. This can be utilized by, for example, the paper industry where chlorate is an environmentally dangerous pollutant after chlorine dioxine bleaching. 

       Chlorate and perchlorate have been found to have negative effects in humans, animals and plants which give rise to a need for more research on improved purification methods. If the gene regulation of the enzymes that handle the breakdown of chlorate, chlorate reductase and chlorite dismutase, could be improved to work in an aerobic environment then both the purification and cost efficiency could improve.

       By inserting the promoter regions for chlorate reductase and chlorite dismutase in a broad-host-range reporterplasmid, pQlacZ-1, they can be evaluated in several different conditions and different strains of gram-negative bacteria.

       Through double cleaving of pQlacZ-1 with BamHI and EcoRI, PCR products of Clrp and Cldp from Ideonella dechloratans have been ligated into E. coli, XL-1 Blue.

       Gel extraction was found to be the most efficient method of purification before ligation but further screening needs to be performed on the transformants to ensure the efficiency of the method.

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