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  • 1.
    Agarwal, Parminder
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Effect of polymeric additives on calcium carbonate crystallization as monitored by nephelometry2004Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 4, nr 3, s. 479-483Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of polymaleimide polymers on calcium carbonate crystallization was studied using nephelometry. Induction time and percent growth inhibition were determined for polymeric additives from the nephelometric data. The polymaleimide synthesized by KOH-initiated polymerization exhibited the greatest growth inhibition and longest nucleation time among the polymers investigated. Raman spectroscopy was used to determine the calcium carbonate polymorph formed in the presence of these polymeric additives.

  • 2.
    Agarwal, Parminder
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    In situ monitoring of calcium carbonate polymorphs during batch crystallization in the presence of polymeric additives using Raman spectroscopy2003Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 3, nr 6, s. 941-946Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Polycarboxylic acids are well-known to affect calcium carbonate crystallization. Agarwal et al. (Ind. Eng. Chem. Res. 2003, in press) reported previously the synthesis of polymaleimide by a variety of techniques and initiators. In the present work, the effect of these polymers on calcium carbonate crystallization was studied by a variety of techniques. Crystallization experiments were carried out in a 1-L LABMAX automated batch reactor, and the concentration of calcium in solution was determined in real time. Raman spectroscopy was used to determine the relative amount of various calcium carbonate polymorphs as the crystallization occurred. However, Raman spectroscopy is a scattering technique, which may make it surface selective, and therefore results from solids may not be representative of bulk of sample. X-ray diffraction (XRD) was used to compare the results obtained by Raman spectroscopy. Peak intensity ratios were used for both Raman spectroscopy and XRD for calibration and measurement purposes. The results obtained by these two techniques for final percent vaterite for calcium carbonate crystallization in the presence of polymeric additives were in agreement within 2%. Therefore, use of Raman spectroscopy for in situ measurement of polymorph composition during calcium carbonate crystallization appears accurate. Scanning electron microscopy (SEM) data were useful in understanding the crystal morphology and to determine crystal size.

  • 3.
    Agarwal, Parminder
    et al.
    Michigan State University.
    Yu, Qiuyue
    Michigan State University.
    Harant, Adam
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Synthesis and characterization of polymaleimide2003Inngår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 42, nr 13, s. 2881-2884Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Simplified syntheses of polymaleimide employing anionic polymerization (from the melt and from solution) and metal compound-alcohol initiators such as PbO, SnO, tin bis(2-ethyl hexanoate) in the presence of tert-butyl benzyl alcohol are presented. The resulting polymers contain a combination of C-N- and C-C-connected monomers. Preliminary structures of the polymers were determined using NMR spectroscopy. The ratio of C-N- and C-C-connected monomers was determined, and the percentage of C-N-connected monomer units was found to vary from 40 to 80%, with the higher percentage resulting from anionic polymerization. The molecular weights of the polymers, as determined by gel permeation chromatography (GPC) with aqueous mobile phase and sodium polyacrylates standards, ranged between 1100 and 4200 for anionic polymerization and were about 11 500 for metal oxide-alcohol initiated polymerization. Solution-phase properties of the polymaleimides were evaluated by calcium chelation and precipitation inhibition studies. On the basis of the measured properties of these polymers, they are proposed as biodegradable, low-impact detergent additives to substitute currently used compounds.

  • 4. Andersson, Christian
    et al.
    Helmerius, Jonas
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Effects of neutralising agent, organic acids, and osmolarity on succinic acid production by Escherichia coli AFP1842008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Using a low-cost medium Escherichia coli AFP184 has previously been reported to produce succinic acid with volumetric productivities close to 3 g L-1 h-1. At a total organic acid concentration of 30 g L-1 the productivity decreased drastically resulting in final succinate concentrations of 40 g L-1. The economical viability of biochemical succinic acid production would benefit from higher final succinic acid concentrations and volumetric productivities maintained at >2.5 g L-1 h-1 for an extended period of time. In the present work the effects of osmolarity and neutralising agent (NH4OH, KOH, NaOH, K2CO3, and Na2CO3) on succinic acid production by AFP184 were investigated. Highest concentration of succinic acid was obtained with Na2CO3, 75 g L-1. It was also found that the osmolarity resulting from succinate production and subsequent base addition, only marginally affected the productivity per viable cell. Organic acid inhibition due to the produced succinic acid on the other hand significantly reduced succinic acid productivity per viable cell. When using NH4OH productivity completely ceased at approximately 40 g L-1. Volumetric productivities remained at 2.5 g L-1 h-1 for 5 to 10 hours longer when using K- or Na-bases than when using NH4OH. However, loss of cell viability occurred, and together with the acid inhibition decreased the volumetric productivities. In this study it was demonstrated that by altering the neutralising agent it was possible to increase the period of high volumetric productivity in the anaerobic phase and improve the final succinic acid concentration by almost 100 %

  • 5. Andersson, Christian
    et al.
    Helmerius, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Berglund, Kris
    Rova, Ulrika
    Inhibition of succinic acid production in metabolically engineered Escherichia Coli by neutralizing agent, organic acids, and osmolarity2009Inngår i: Biotechnology progress (Print), ISSN 8756-7938, E-ISSN 1520-6033, Vol. 25, nr 1, s. 116-123Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The economical viability of biochemical succinic acid production is a result of many processing parameters including final succinic acid concentration, recovery of succinate, and the volumetric productivity. Maintaining volumetric productivities >2.5 g L-1 h(-1) is important if production of succinic acid from. renewable resources should be competitive. In this work, the effects of organic acids, osmolarity, and neutralizing agent (NH4OH, KOH, NaOH, K2CO3, and Na2CO3) on the fermentative succinic acid production by Escherichia coli AFP184 were investigated. The highest concentration of succinic acid, 77 g L-1. was obtained with Na2O3. In general, irrespective of the base used, succinic acid productivity per viable cell was significantly reduced as the concentration of the produced acid increased. Increased osmolarity resulting from base addition during succinate production only marginally affected the productivity per viable cell. Addition of the osmoprotectant glycine betaine to cultures resulted in an increased aerobic growth rate and anaerobic glucose consumption rate, but decreased succinic acid yield. When using NH4OH productivity completely ceased at a succinic acid concentration of similar to 40 g L-1. Volumetric productivities remained at 2.5 g L-1 h(-1) for tip to 10 h longer when K- or Na-bases where used instead of NH4OH. The decrease in cellular succinic acid productivity observed during the anaerobic phase was found to be due to increased organic acid concentrations rather than medium osmolarity.

  • 6. Andersson, Christian
    et al.
    Hodge, David
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Effect of different carbon sources on the production of succinic acid using metabolically engineered Escherichia coli2007Inngår i: Biotechnology progress (Print), ISSN 8756-7938, E-ISSN 1520-6033, Vol. 23, nr 2, s. 381-388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Succinic acid (SA) is an important platform molecule in the synthesis of a number of commodity and specialty chemicals. In the present work, dual-phase batch fermentations with the E. coli strain AFP184 were performed using a medium suited for large-scale industrial production of SA. The ability of the strain to ferment different sugars was investigated. The sugars studied were sucrose, glucose, fructose, xylose, and equal mixtures of glucose and fructose and glucose and xylose at a total initial sugar concentration of 100 g L-1. AFP184 was able to utilize all sugars and sugar combinations except sucrose for biomass generation and succinate production. For sucrose as a substrate no succinic acid was produced and none of the sucrose was metabolized. The succinic acid yield from glucose (0.83 g succinic acid per gram glucose consumed anaerobically) was higher than the yield from fructose (0.66 g g-1). When using xylose as a carbon source, a yield of 0.50 g g-1 was obtained. In the mixed-sugar fermentations no catabolite repression was detected. Mixtures of glucose and xylose resulted in higher yields (0.60 g g-1) than use of xylose alone. Fermenting glucose mixed with fructose gave a lower yield (0.58 g g-1) than fructose used as the sole carbon source. The reason is an increased pyruvate production. The pyruvate concentration decreased later in the fermentation. Final succinic acid concentrations were in the range of 25-40 g L-1. Acetic and pyruvic acid were the only other products detected and accumulated to concentrations of 2.7-6.7 and 0-2.7 g L-1. Production of succinic acid decreased when organic acid concentrations reached approximately 30 g L-1. This study demonstrates that E. coli strain AFP184 is able to produce succinic acid in a low cost medium from a variety of sugars with only small amounts of byproducts formed.

  • 7. Andersson, Christian
    et al.
    Petrova, Ekaterina
    Luleå tekniska universitet.
    Berglund, Kris
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Maintaining high anaerobic succinic acid productivity by product removal2010Inngår i: Bioprocess and biosystems engineering (Print), ISSN 1615-7591, E-ISSN 1615-7605, Vol. 33, nr 6, s. 711-718Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During dual-phase fermentations using Escherichia coli engineered for succinic acid production, the productivity and viable cell concentration decrease as the concentration of succinic acid increases. The effects of succinic acid on the fermentation kinetics, yield, and cell viability were investigated by resuspending cells in fresh media after selected fermentation times. The cellular succinic acid productivity could be restored, but cell viability continuously decreased throughout the fermentations by up to 80% and subsequently the volumetric productivity was reduced. Omitting complex nutrients in the resuspension media had no significant effect on cellular succinate productivity and yield, although the viable cell concentration and thus the volumetric productivity was reduced by approximately 20%. By resuspending the cells, the amount of succinate produced during a 100-h fermentation was increased by more than 60%. The results demonstrate that by product removal succinic acid productivity can be maintained at high levels for extended periods of time.

  • 8.
    Andersson, Christian
    et al.
    Luleå tekniska universitet.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Process for producing succinic acid from sucrosePatent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    A process for hydrolyzing sucrose to glucose and fructose using succinic acid is described. The hydrolysate can be used to produce purified glucose and/or fructose or can be used as a carbon source for fermentations to produce various chemicals including succinic acid.

  • 9.
    Andraous, Johnny I.
    et al.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Claus, Michael J
    Department of Agricultural Engineering, Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Lindemann, Deirdre J.
    Department of Chemistry, Michigan State University.
    Effect of liquefaction enzymes on methanol concentration of distilled fruit spirits2004Inngår i: American Journal of Enology and Viticulture, ISSN 0002-9254, E-ISSN 1943-7749, Vol. 55, nr 2, s. 199-201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Liquefaction enzymes are often used during fermentation of fruit mashes to improve the yield of ethanol and the ability to pump the mash. The liquefaction enzymes hydrolyze pectin, but in addition to the desired pectin hydrolysis activity, the enzymes also have pectinesterase activity which hydrolyzes the methyl ester in pectin resulting in methanol formation. Fermentations of various apple varieties and Bartlett pears were conducted using liquefaction enzymes. The resulting distilled products contained concentrations of methanol above the legal limit of 280 mg/100 mL of 40% ethanol, with the observed methanol concentrations in a range between 320 and 656 mg/100 mL of 40% ethanol. In contrast to the undesired increase in methanol concentration, the enzymes provide only a marginal increase in ethanol yield. The results indicate that liquefaction enzymes should be used with caution for pomace fruit and that methanol monitoring should be implemented if these enzymes are used for commercial products.

  • 10.
    Bauer, Fredric
    et al.
    Lund University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hulteberg, Christian
    Lund University.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mesfun, Sennai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nilsson, Robert
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Wännström, Sune
    SP Technical Research Institute of Sweden.
    Comparative system analysis of carbon preserving fermentations for biofuels production2013Rapport (Fagfellevurdert)
  • 11.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Succinic acid from xylan: fermentations using mixed sugar feedstocks2008Inngår i: NWBC 2008: 2008 Nordic Wood Biorefinery conference : 11-14 March, 2008 : City Conference Centre, Stockholm, Sweden : proceedings, Stockholm: STFI-Packforsk , 2008, s. 121-124Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The next generation of cost effective, economically viable biorefinery scenarios requires the development and deployment of higher valued added products whose production can be integrated into a forest biorefinery. We present preliminary results for the production of one such product, succinic acid, from mixed sugars streams including glucose and xylose, as would be present from the hydrolysis of xylan. Examples are presented for the base laboratory case, softwood hydrolysis streams, and hardwood extracts

  • 12.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Andersson, Christian
    Luleå tekniska universitet.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Process for the production of succinic acidPatent (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    A process for the production of succinic acid can comprise supplying a media with E. coli AFP 184 and a high sugar concentration under aerobic conditions, then converting the media to aerobic conditions. Such a process can be useful when performed in conjunction with the production of ethanol in a biorefmery .

  • 13.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Falcon, Javier A
    Departments of Chemistry, Chemical Engineering & Materials Science and Agricultural Engineering, Michigan State University, East Lansing, Michigan.
    In situ monitoring of antisolvent addition crystallization with principal components analysis of Raman spectra2004Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 4, nr 3, s. 457-463Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fiber optic Raman spectroscopy was used for in situ monitoring of antisolvent addition crystallization of progesterone. Raman spectral features of the solute and the antisolvent were subjected to principal components analysis (PCA) to attempt to obtain information that is not readily apparent from the raw spectral data. For the system utilized, PCA was able to distinguish spectral features from the solute in solution, the solute crystals, and the antisolvent. Furthermore, PCA was capable of detecting subtle changes in the spectral data (as the addition of antisolvent progressed) that could be used as a warning for the onset of crystallization. The current study demonstrates the advantages that can be gained by combining PCA with Raman spectroscopy for monitoring crystallizations in situ.

  • 14. Berglund, Kris
    et al.
    Larson, M.A.
    Iowa State University.
    Modeling of growth rate dispersion of citric acid monohydrate in continuous crystallizers1984Inngår i: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 30, nr 2, s. 280-287Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A mathematical model for prediction of the crystal size distribution from a continuous crystallizer is presented. The kinetic data used for the model were obtained from batch contact nucleation experiments with citric acid monohydrate. In these experiments, the distribution of growth rates as well as the initial size distribution were estimated. Results from the model indicate that the excess number of crystals usually present at small sizes in continuous crystallizers is due to growth rate dispersion (where crystals of the same size may have different growth rates) and not size dependent growth.

  • 15. Berglund, Kris
    et al.
    Larson, Maurice A.
    Growth of contact nuclei of citric acid monohydrate1982Inngår i: Nucleation, growth, and impurity effects in crystallization process engineering / [ed] Mary Anne Farrell Epstein, American Institute of Chemical Engineers, 1982, s. 9-13Konferansepaper (Fagfellevurdert)
  • 16.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Fermentative Upgrading of Xylose2009Inngår i: NWBC-2009: The 2nd Nordic wood biorefinery conference : Finlandia Hall, Helsinki, Finland, September 2-4, 2009 : Proceedings-Posters / [ed] Annemari Kuokka-Ihalainen., Helsinki: KCL Re-inventing paper , 2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Chemical pulp mills such as Kraft, soda, or sulfite mills are current examples of biorefineries that can convert lignocellulosic biomass into energy, pulp or cellulose derivatives, and tall oil.  While existing viscose pulps use a hemicellulose extraction to generate soluble sugars for ethanol production, in general there still exists a large potential for other more profitable applications of the biomass (Fig. 1), i.e. the mill needs to present a widespread product portfolio.  The biofuels under development from fermentation that will be discussed are the diesel fuel oxygenates dibutyl succinate and diethyl succinate to be used for reduced particulate emissions and fossil fuel replacement for diesel engines and butanol for Otto engines.  It's important to stress that succinic acid, butanol and ethanol, needed for the production of the diesel additives and gasoline replacement will be produced from renewable resources and hence replacing products currently produced from non-renewable fossil sources.  Since wood will be used, there will be no issue of competing with raw material used for food production.  Besides biofuel production, succinic acid and butanol, can be used directly or further refined into numerous different products classified as green chemicals.

  • 17.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Fermentation-Based Building Blocks for Renewable Resource-Based Surfactants2010Inngår i: Surfactants from renewable resources, Chichester: John Wiley & Sons Ltd , 2010, s. 127-141Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    'new' top-ranked building blocks; Citric acid recovery from fermentation broths and CaCO3 precipitation; Citric, acetic and lactic acid - top three industrial carboxylic acids; Fermentation-based building blocks for renewable resource-based surfactants; Fermentation-based building blocks for surfactants; Filamentous fungi, Aspergillus niger and Candida yeast strains; New fermentation-based building blocks; Organic acid metabolites - as hydrophilic moiety; Sulfonates - largest market share of anionic surfactants; Sulfosuccinate class of surfactants

  • 18.
    Bonturi, Nemailla
    et al.
    Department of Materials and Bioprocess Engineering, School of Chemical Engineering, State University of Campinas.
    Matsakas, Leonidas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Nilsson, Robert
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Christakopoulos, Paul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Miranda, Everson Alves
    Department of Materials and Bioprocess Engineering, School of Chemical Engineering, State University of Campinas.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Single Cell Oil Producing Yeasts Lipomyces starkeyi and Rhodosporidium toruloides: Selection of Extraction Strategies and Biodiesel Property Prediction2015Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, nr 6, s. 5040-5052Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single cell oils (SCOs) are considered potential raw material for the production of biodiesel. Rhodosporidium sp. and Lipomyces sp. are good candidates for SCO production. Lipid extractability differs according to yeast species and literature on the most suitable method for each oleaginous yeast species is scarce. This work aimed to investigate the efficiency of the most cited strategies for extracting lipids from intact and pretreated cells of Rhodosporidium toruloides and Lipomyces starkeyi. Lipid extractions were conducted using hexane or combinations of chloroform and methanol. The Folch method resulted in the highest lipid yields for both yeasts (42% for R. toruloides and 48% for L. starkeyi). Also, this method eliminates the cell pretreatment step. The Bligh and Dyer method underestimated the lipid content in the tested strains (25% for R. toruloides and 34% for L. starkeyi). Lipid extractability increased after acid pretreatment for the Pedersen, hexane, and Bligh and Dyer methods. For R. toruloides unexpected fatty acid methyl esters (FAME) composition were found for some lipid extraction strategies tested. Therefore, this work provides useful information for analytical and process development aiming at biodiesel production from the SCO of these two yeast species.

  • 19.
    Bowman, Lawrence E.
    et al.
    Michigan State University.
    Berglund, Kris
    Nocera, Daniel G.
    Michigan State University.
    A single photon timing instrument that covers a broad temporal range in the reversed timing configuration1993Inngår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 64, nr 2, s. 338-341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A versatile single-photon timing instrument based on the reversed timing configuration has been constructed. Unlike similar instruments, the apparatus described here is capable of recording a broad range of excited-state decay times owing to a switched fiber optic delay. This allows the user to readily collect time-resolved luminescence data over a variable time window in the reversed-timing configuration. With proper adjustment of the appropriate components, one can acquire a luminescence decay over a variable time range from less than 1 ns to nearly 1 μs. The full width at half-maximum of the instrument response function is 42 ps. The utility of a switched fiber optic delay is discussed and the device's construction is described.

  • 20.
    Cerreta, M.K.
    et al.
    Michigan State University.
    Berglund, Kris
    Contact nuclei formation in aqueous dextrose solutions1990Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 102, nr 4, s. 869-876Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A laser Raman microprobe was used in situ to observe the growth of alpha dextrose monohydrate on alpha anhydrous dextrose crystals. The Raman spectra indicate growth of the monohydrate below 28.1°C, but the presence of only the anhydrous form above 40.5°C. Contact nucleation experiments with parent anhydrous crystals yielded only monohydrate nuclei below 28.1°C, while contacts in solutions between 34.5 and 41.0°C produced both crystalline forms, and contacts in solutions above 43.5°C produced only anhydrous nuclei. The inability of the monohydrate to grow on anhydrous crystals in the same solution that forms the two crystalline phases with a single contact precludes a simple attrition mechanism of nuclei formation. For the same reason, the hypothetical mechanism involving parent crystal stabilization of pre-crystalline clusters, allowing the clusters to grow into nuclei, is also contradicted. A third, mechanism, which may be a combination of the two, is believed to apply.

  • 21.
    Cerreta, M.K.
    et al.
    Iowa State University.
    Berglund, Kris
    Raman spectroscopic studies of the structure of supersaturated ammonium dihydrogen phosphate solutions1984Inngår i: Industrial crystallization 84: proceedings of the 9th Symposium on industrial crystallization, the Hague, the Netherlands, September 25-28, 1984 / [ed] S.J. Jančić; E.J. de Jong, Amsterdam: Elsevier, 1984, s. 233-236Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Raman spectroscopic studies of quiescent under and supersaturated ammonium dihydrogen phosphate (ADP) aqueous solutions were performed on the nu //1 (totally symmetric or breathing mode) and nu //3 (symmetric twist) H//2PO//4 OVER BAR bands as well as for the nu //1 band of solid ADP and solid diammonium hydrogen phosphate (DHP). The splitting of the non-degenerate ADP nu //1 band in concentrated solution is interpreted in terms of a well-ordered quasi-crystalline solution structure. Increases in nu //1 half-width at half-height support this view.

  • 22.
    Cerreta, M.K.
    et al.
    Michigan State University.
    Berglund, Kris
    The structure of aqueous solutions of some dihydrogen orthophosphates by laser Raman spectroscopy1987Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 84, nr 4, s. 577-588Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Powdered crystals and pure, aqueous solutions of ammonium, sodium, and potassium dihydrogen orthophosphates in concentrations ranging from 0.01M to supersaturated were investigated at 30°C using laser Raman spectroscopy between 700 and 1350 cm-1. With increasing solute concentration, the peak position of the 875 cm-1 P-(OH)2 symmetric strech band increased. Extreme asymmetry in the 1075 cm-1 P=O2 symmetric stretch band developed to lower energy. The integrated intensity ratio of the 875 cm-1 band to the 1075 cm-1 band envelope remained constant. These observations are consistent with anion-anion association via hydrogen bonds. Deconvolution of the spectral bands showed only 40% and 20% of the phosphates exist as monomers in saturated potassium and ammonium solutions, respectively, and that anion association does not cease at the dimer. The spectra provided no evidence of quasi-crystalline entities in solution. The necessary breaking and reforming of hydrogen bonds during the growth process can explain rapid z-direction growth, growth activation energy, and the rate-limiting surface growth mechanism.

  • 23.
    Chakraborty, Reena
    et al.
    Michigan State University.
    Berglund, Kris
    Steady state fluorescence spectroscopy of pyranine as a trace extrinsic probe to study structure in aqueous sugar solutions1992Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 125, nr 1-2, s. 81-96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The steady state fluorescence behavior of pyranine has been monitored in aqueous solutions of sucrose, glucose, fructose, and lactose. In each case it is possible to use the ratio of peak intensities at 440 and 511 nm (the PIR) as an indicator of the degree of supersaturation of the sugar solutions. We observed both bulk water and water of solvation in all solutions examined, regardless of degree of sapersaturation. In each case the amounts of bulk water and water of solvation per molecule of sugar appear to be nearly equal at saturation. We did not observe any evidence of solvent exclusive clusters in any of the systems we studied

  • 24.
    Chakraborty, Reena
    et al.
    Michigan State University.
    Berglund, Kris
    Use of pyranine as a trace fluorescent probe to study structure in aqueous sucrose solutions1991Inngår i: Particle design via crystallization / [ed] Ramu Ramanarayanan, Washington, DC: American Institute of Chemical Engineers, 1991, s. 114-123Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Emission spectroscopy using pyranine as a trace fluorescent probe was evaluated as a means of studying solution structure in aqueous sucrose solutions. Spectra of pyranine doped sucrose solutions of 0-70 wt% were obtained, indicating two microenvironments. The peak intensity ratio (defined as the ratio of peak intensities at 440 nm and 511 nm) was observed to be a very sensitive function of the water content in supersaturated solutions. The two microenvironments were designated as bulk water and that near the solvated sucrose molecules. Calculations yielded six water molecules of solvation per molecule of sucrose. This is in agreement with values in literature. The number of molecules of water per molecule of sucrose in the bulk water environment varies exponentially from 165 in a 10% solution to three for a 70% solution at 20 degrees C. These results indicate that this technique can be used successfully to measure water content in supersaturated solutions.

  • 25.
    Claus, Michael
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Fruit brandy production by batch column distillation with reflux2005Inngår i: Journal of food process engineering, ISSN 0145-8876, E-ISSN 1745-4530, Vol. 28, nr 1, s. 53-67Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The relationship between the operating parameters of batch fruit spirits column stills with reflux and the congener (trace compounds that provide flavors and aromas) concentrations in resulting fruit spirits has not been widely studied. Congener concentrations were determined in three different collection fractions, or "cuts," during batch distillation. Acetaldehyde and ethyl acetate were found in higher concentrations in the head cut, first overhead fraction, of the distillation and have lower boiling points relative to ethanol. 1-Propanol and isoamyl alcohol (isopentanol) were present in higher concentrations in the tail cut, third or final fraction, of the distillation and have boiling points that are higher than ethanol. Methanol has a unique concentration profile as it has higher concentrations in both the head and tail cuts, but a lower concentration in the heart cut, the middle fraction which is the desired product of the distillation. Methanol was of particular interest because the distillate must adhere to governmental regulations that limit its concentration in the product. Operating-condition parameters that were studied include the number of trays used in the distillation as well as the use of a "catalytic converter," a high surface, copper-packing material thought to catalyze formation of cyanide-containing compounds allowing them to be separated from the distillate. The effect of the number of trays used in a distillation on the concentration of ethanol and the congeners, methanol, acetaldehyde, ethyl acetate, 1-propanol and isoamyl alcohol in the final distilled spirits product is presented. An additional result of acetaldehyde production at the copper surface of the catalytic converter was also discovered in the analysis of the data.

  • 26.
    Claus, Michael J.
    et al.
    Department of Chemistry, Adrian College.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Defining still parameters using Chemcad batch distillation model for modeling fruit spirits distillations2009Inngår i: Journal of food process engineering, ISSN 0145-8876, E-ISSN 1745-4530, Vol. 32, nr 6, s. 881-892Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fruit spirits production has always been and continues to be heavily dependent upon the sensory evaluation of the distillate by the distiller. Sensory fatigue can lead to many problems of analysis for the distiller during production. As such, it is desirable to have a method of analysis that is not heavily dependent upon the senses of the distiller. Modeling of the distillation process is difficult because of the number of components present in the fruit mash and distillate, as well as because of the constantly changing thermodynamic interactions present on each tray as a result of the batch distillation process. This paper identifies a method for identifying the still parameters needed to perform predictive modeling. This involves setting a distillate flow rate and reflux ratio, as well as time or volume cutoff frames of analysis. After identifying the still characteristics, it is possible to model the distillation using the CHEMCAD batch distillation program.

  • 27. Dulebohn, Joel I.
    et al.
    Haefner, Steven C.
    Berglund, Kris
    Dunbar, Kim R.
    Reversible carbon monoxide addition to sol-gel derived composite films containing a cationic rhodium(I) complex: towards the development of a new class of molecule-based carbon monoxide sensors1992Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 4, nr 3, s. 506-508Artikkel i tidsskrift (Fagfellevurdert)
  • 28.
    Dunuwila, D.D.
    et al.
    Michigan State University.
    Berglund, Kris
    ATR FTIR spectroscopy for in situ measurement of supersaturation1997Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 179, nr 1-2, s. 185-193Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The current contribution establishes the technical feasibility of Attenuated Total Reflection (ATR) Fourier transform infrared (FTIR) spectroscopy for the in situ measurement of supersaturation in crystallization processes. The approach was inspired by recent advancements in ATR spectroscopy by way of various light transfer systems for remote sensing and by the increasing availability of ATR configurations well suited for remote, in situ measurements. The feasibility of the technique was investigated using a DIPPER-210® immersion probe manufactured by Axiom Analytical, Inc. Initial experiments conducted using aqueous maleic acid proved that ATR FTIR spectroscopy can be successfully employed to measure supersaturation, solubility and the metastable limit, in situ, with sufficient accuracy and precision.

  • 29.
    Dunuwila, Dilum D.
    et al.
    Michigan State University.
    Carroll, Leslie B.
    Michigan State University.
    Berglund, Kris
    An investigation of the applicability of attenuated total reflection infrared spectroscopy for measurement of solubility and supersaturation of aqueous citric acid solutions1994Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 137, nr 3-4, s. 561-568Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Currently applied methods for measurement of solubility and supersaturation based on viscometry, refractometry, interferometry and density require the separation of phases prior to measurement. ATR (attenuated total reflection) infrared spectroscopy provides a unique configuration in which the infrared spectrum of a liquid phase can be obtained in a slurry without phase separation. The applicability of the technique was investigated using a micro Circle® open boat cell equipped with a ZnSe (zinc selenide) ATR rod. Experiments conducted with aqueous citric acid proved that ATR infrared spectroscopy can be successfully employed to determine solubility and supersaturation.

  • 30.
    Dunuwila, Dilum D.
    et al.
    Michigan State University.
    Gagliardi, Charles D.
    Michigan State University.
    Berglund, Kris
    Application of controlled hydrolysis of titanium(IV) isopropoxide to produce sol-gel-derived thin films1994Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 6, nr 9, s. 1556-1562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A variety of porous optically transparent titanium carboxylate films that can be supported on silicate glass substrates have been developed. These films were made by spin casting polymeric solutions of titanium carboxylates processed using sol-gel techniques. The stability and the quality of these films have been qualitatively correlated to the extent of control of hydrolysis exerted by carboxylate modification of the precursor titanium(IV) isopropoxide. A series of carboxylic acids ranging from acetic acid to myristic acid has been used, and their effects on film quality and stability are presented.

  • 31.
    Dunuwila, Dilum D.
    et al.
    Michigan State University.
    Torgerson, B. A.
    Michigan State University.
    Chang, C. K.
    Michigan State University.
    Berglund, Kris
    Sol-gel derived titanium carboxylate thin films for optical detection of analytes1994Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 66, nr 17, s. 2739-2744Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The feasibility of using a sol-gel derived titanium carboxylate thin film, which can be supported on glass, for the fabrication of optical test strips was investigated using a model probe/ analyte combination. The porous films, being optically transparent and baring the capability to host probe molecules, provided an excellent system to investigate the possibility of making optical test strips. A colorimetric reagent, an iron(III) porpohyrin, was chosen as the probe molecule to detect free cyanide ion concentrations in aqueous solutions. Entrapment of the porphyrin in the film was accomplished by direct dissolution of the porphyrin in the sol-gel solutions. Chemically induced structural modifications of the polymer were carried out to stabilize the encapsulated metalloporphyrin within the sol-gel derived matrix. The syntheses of this model analyte detection system and its response are presented. An optical parameter reflective of the chemical changes that occur in the system was selected as the measurement tool; its response asymptotically increased over the cyanide ion concentration range of 40-25 000 ppm.

  • 32.
    Elankovan, P.
    et al.
    Michigan State University.
    Berglund, Kris
    Contact nucleation from aqueous dextrose solutions1987Inngår i: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 33, nr 11, s. 1844-1849Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Contact nucleation studies were performed with the dextrose-water system. Under some conditions two crystallographic phases were formed, which were identified in situ using a laser Raman microprobe. In addition, the growth of the contact nuclei was monitored in situ using photomicroscopy. The results are discussed in the context of contact nucleation and growth models.

  • 33.
    Elankovan, P.
    et al.
    Michigan State University.
    Berglund, Kris
    Technique for obtaining Raman spectra of contact nuclei In Situ1986Inngår i: Applied Spectroscopy, ISSN 0003-7028, E-ISSN 1943-3530, Vol. 40, nr 5, s. 712-714Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Secondary nucleation, the formation of new crystals due to the prior presence of other growing crystals, is the primary source of new particles in most industrial crystallizers. Of the various types of secondary nucleation possible, contact nucleation, wherein a disturbance of a growing crystal surface results in nuclei, is thought to be the most prevalent.

  • 34.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Growth promotive conditions for enhanced eritadenine production during submerged cultivation of Lentinus edodes2012Inngår i: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 87, nr 7, s. 903-907Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Mycelium of the medicinal mushroom shiitake, Lentinus edodes, is a potential source for production of the blood cholesterol reducing compound eritadenine. To increase the mycelial biomass and in turn the production of eritadenine, a potential growth promoting substance in the form of a water extract of distillers dried grains with solubles (DDGS) was added to the culture media. Results: The hot water extract of DDGS was shown to considerably increase the growth of shiitake mycelia in bioreactor cultivations; the mycelial yield was 2-3 times higher than in the control, and the highest final biomass concentration obtained was 3.4 g L -1. Further, by using shake flask cultures as inoculums the bioreactor cultivation time could be reduced by 1 week for some of the experiments. The highest final titer of eritadenine in the present study was 25.1 mg L -1, which was about 2 times higher than in the control, and was also obtained when a water extract of DDGS was added to the culture medium. Conclusion: It was demonstrated that a water extract of DDGS promoted the growth of shiitake mycelia in bioreactor cultivations, along with enhanced eritadenine production

  • 35.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Hodge, David
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Production of the bioactive compound eritadenine by submerged cultivation of shiitake (Lentinus edodes) mycelia2008Inngår i: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 56, nr 8, s. 2609-2612Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fruit bodies and mycelia of shiitake mushroom (Lentinus edodes) have been shown to contain the cholesterol-reducing compound eritadenine, 2(R),3(R)-dihydroxy-4-(9-adenyl)butyric acid. In the search for a production method for eritadenine, shiitake mycelia were investigated in the present study. The mycelia were cultivated both in shake flasks and in bioreactors, to investigate the effects of pH, stirring rate, and reactor type on the production and distribution of eritadenine. Both the biomass and the culture broth were examined for their eritadenine content. In the shake flasks, the final concentration of eritadenine was 1.76 mg/L and eritadenine was equally distributed between the mycelia and the growth media. In the bioreactors, the shiitake mycelia were found to contain eritadenine in relatively low levels, whereas the majority, 90.6-98.9%, was detected in the growth media. Applying a stirring rate of 250 rpm during bioreactor cultivation resulted in the highest eritadenine concentrations: 10.23 mg/L when the pH was uncontrolled and 9.59 mg/L when the pH was controlled at 5.7. Reducing the stirring rate to 50 rpm resulted in a decreased eritadenine concentration, both at pH 5.7 (5.25 mg/L) and when pH was not controlled (5.50 mg/L). The mycelia in the shake flask cultures appeared as macroscopic aggregates, whereas mycelia cultivated in bioreactors grew more as freely dispersed filaments. This study demonstrates for the first time the extra- and intracellular distribution of eritadenine produced by shiitake mycelial culture and the influence of reactor conditions on the mycelial morphology and eritadenine concentrations.

  • 36.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Solid state characterization of sodium eritadenate2011Inngår i: American Journal of Analytical Chemistry, ISSN 2156-8251, E-ISSN 2156-8278, Vol. 2, nr 2, s. 164-173Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Knowledge of the solid state is of great importance in the development of a new active pharmaceutical ingredient, since the solid form often dictates the properties and performance of the drug. In the present study, solid state characteristics of the sodium salt of the candidate cholesterol reducing compound eritadenine, 2(R), 3(R))-dihydroxy-4-(9-adenyl)-butanoic acid, were investigated. The compound was crystallized by slow cooling from water and various aqueous ethanol solutions, at different temperatures. Further, the compound solution was subjected to lyophilization and to high vacuum drying. The resulting solids were screened for polymorphism by micro Raman spectroscopy (λex = 830 nm) and the crystallinity was investigated by X-ray powder diffraction. Further, thermal analysis was applied to study possible occurrence of solvates or hydrates. Solids obtained from slow cooling showed crystallinity, whereas rapid cooling gave rise to more amorphous solids. Analysis of difference spectra of the Raman data for solids obtained from slow cooling of solution revealed subtle differences in the structures between crystals derived from pure water and crystals derived from aqueous ethanol solutions. Finally, from the thermal analysis it was deduced that crystals obtained from pure water were stoichiometrically dihydrates whereas crystals obtained from aqueous ethanol solutions were 2.5 hydrates; this formation of different hydrates were supported by the Raman difference analysis.

  • 37.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Raman analysis of synthetic eritadenine2008Inngår i: Journal of Raman Spectroscopy, ISSN 0377-0486, E-ISSN 1097-4555, Vol. 39, nr 10, s. 1464-1468Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eritadenine, 2(R),3(R)-dihydroxy-4-(9-adenyl)-butyric acid, is a cholesterol-reducing compound naturally occurring in the shitake mushroom (Lentinus edodes). To identify the unknown Raman spectrum of this compound, pure synthetic eritadenine was examined and the vibrational modes were assigned by following the synthesis pathway. This was accomplished by comparing the known spectra of the starting compounds adenine and D-ribose with the spectra of a synthesis intermediate, methyl 5-(6-Aminopurin-9H-9-yl)-2,3-O-isopropylidene-5-deoxy-β-D-ribofuranoside (MAIR) and eritadenine. In the Raman spectrum of eritadenine, a distinctive vibrational mode at 773 cm-1 was detected and ascribed to vibrations in the carbon chain, ν(C--C). A Raman line that arose at 1212 cm-1, both in the Raman spectrum of MAIR and eritadenine, was also assigned to ν(C--C). Additional Raman lines detected at 1526 and at 1583 cm-1 in the Raman spectrum of MAIR and eritadenine were assigned to ν(N--C) and a deformation of the purine ring structure. In these cases the vibrational modes are due to the linkage between adenine and the ribofuranoside moiety for MAIR, and between adenine and the carbon chain for eritadenine. This link is also the cause for the disappearance of adenine specific Raman lines in the spectrum of both MAIR and eritadenine. Several vibrations observed in the spectrum of D-ribose were not observed in the Raman spectrum of eritadenine due to the absence of the ribose ring structure. In the Raman spectrum of MAIR some of the D-ribose specific Raman lines disappeared due to the introduction of methyl and isopropylidene moieties to the ribose unit. With the approach presented in this study the so far unknown Raman spectrum of eritadenine could be successfully identified and is presented here for the first time.

  • 38.
    Enman, Josefine
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Berglund, Kris A.
    Quantification of the bioactive compound eritadenine in selected strains of shiitake mushroom (Lentinus edodes)2007Inngår i: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 55, nr 4, s. 1177-1180Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cardiovascular disease is one of the most common causes of death in the Western world, and a high level of blood cholesterol is considered a risk factor. The edible fungus, shiitake mushroom (Lentinus edodes), contains the hypocholesterolemic agent eritadenine, 2(R),3(R)-dihydroxy-4-(9-adenyl)-butyric acid. This study was conducted to quantify the amount of the cholesterol reducing agent eritadenine in shiitake mushrooms, in search of a potential natural medicine against blood cholesterol. The amounts of eritadenine in the fruit bodies of four different shiitake mushrooms, Le-1, Le-2, Le-A, and Le-B, were investigated in this study. To achieve this goal, methanol extraction was used to recover as much as possible of the hypocholesterolemic agent from the fungal cells. In addition, enzymes that degrade the fungal cell walls were also used to elucidate if the extraction could be further enhanced. To analyze the target compound, a reliable and reproducible HPLC method for separation, identification, and quantification of eritadenine was developed. The shiitake strains under investigation exhibit up to 10 times higher levels of eritadenine than previously reported for other shiitake strains. Further, pretreating the mushrooms with hydrolytic enzymes before methanol extraction resulted in an insignificant increase in the amount of eritadenine released. These results indicate the potential for delivery of therapeutic amounts of eritadenine from the ingestion of extracts or dried concentrates of shiitake mushroom strains.

  • 39.
    Falcon, Javier A.
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Monitoring of antisolvent addition crystallization with Raman spectroscopy2003Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 3, nr 6, s. 947-952Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fiber optic Raman spectroscopy was used for in situ monitoring of antisolvent addition crystallization of cortisone acetate. Raman spectral features of the solvent, the antisolvent, and the solute were monitored to measure the relative concentration of the components. Different rates of antisolvent addition were monitored and the resulting solid-state form was characterized using Raman spectroscopy and DSC. Raman spectroscopy was used to monitor dehydration during storage of the product crystals. The current study demonstrates the advantages of using Raman spectroscopy to monitor the solution phase during crystallization and simultaneously monitoring the solid-state form.

  • 40.
    Feng, Lili
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    ATR-FTIR for determining optimal cooling curves for batch crystallization of succinic acid2002Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 2, nr 5, s. 449-452Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The temperature profile applied during batch cooling crystallization affects the supersaturation level, which in turn affects the crystal size distribution. It is possible, in principle, to calculate the optimal cooling profile; however, the nucleation and growth kinetics are rarely known to the degree of accuracy necessary for this calculation. The current study demonstrates an alternative approach to determination of the optimal cooling profile without any prior knowledge of kinetic data or subsequent modeling. An attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer was used to monitor the supersaturation level during batch cooling crystallization. The ATR-FTIR was interfaced to a LABMAX automatic reactor system that was used in a feedback mode to control the cooling rate so that the supersaturation level remained close to the solubility throughout the cooling process. The resulting temperature profile corresponds to the optimal operating conditions for the maximum in the mean crystal size.

  • 41.
    Glassner, David A.
    et al.
    National Renewable Energy Laboratory, Golden, Colorado.
    Elankovan, Ponnam
    Michigan Biotechnology Institute, Lansing.
    Beacom, Daniel R.
    Michigan Biotechnology Institute, Lansing.
    Berglund, Kris
    Purification process for succinic acid produced by fermentation1995Inngår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 51, nr 1, s. 73-82Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Succinic acid is a versatile four-carbon dicarboxylic acid. It can be used commerically as an intermediate chemical for the manufacture of 1,4-butanediol, maleic anhydride, and many other chemicals. Succinic acid can be produced by the fermentation of carbohydrates. A complete process for the production and purification of succinic acid from carbohydrates has been developed. The process includes fermentation, desalting electrodialysis, water-splitting electrodialysis, and crystallization to produce a pure crystalline succinic acid. This article will present experimental work performed in the development of this process.

  • 42.
    Graiver, D.
    et al.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Dacomba, R.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Khawali, M.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Jaros, Adam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Narayan, R.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Steel-corrosion inhibitors derived from soybean oil2012Inngår i: Journal of the American Oil Chemists Society, ISSN 0003-021X, E-ISSN 1558-9331, Vol. 89, nr 10, s. 1895-1903Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soybean oil derivatives containing a Schiff-base (SOS-B) were prepared and evaluated as microbial corrosion inhibitors against sulfate-reducing bacteria using the gram-positive Desulfosporosinus orientis bacteria as a representative bacterium. These SOS-B compounds were also found to be excellent inhibitors against acidic corrosion of carbon steel. These soybean oil derivatives were prepared by ozonation of soybean oil to yield aldehyde functional intermediates which were then reacted with benzylamine to produce a mixture of imine functional triglycerides and linear compounds. The structure of these soy-based derivatives was confirmed by FTIR and NMR. It was found that the addition of these SOS-B compounds to D. orientis culture provided a complete inhibition of this bacterium. Furthermore, almost no corrosion of carbon steel panels was observed when the panels were aged in 2N HCl solution containing 10 ppm of these SOS-B compounds

  • 43.
    Hartel, R.W.
    et al.
    Michigan State University.
    Berglund, Kris
    Precipitation kinetics of the titanium isopropoxide hydrolysis reaction1986Inngår i: Better ceramics through chemistry II: symposium held April 15-19, 1986, Palo Alto, California, U.S.A. / [ed] C. Jeffrey Brinker, Materials Research Society, 1986, s. 633-640Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The precipitation product of the titanium isopropoxide (TiPT) hydrolysis reaction was followed using photon correlation spectroscopy. This technique followed the mean size of the precipitate as the reaction progressed as well as giving an indication of the number of particles being produced. From this analysis, the induction time for the onset of nucleation, nucleation rate (or the rate of particle production) and mean growth rate were correlated with reactant concentrations. In the concentration ranges studied, the induction time was an inverse function of reactant concentrations. Both nucleation rate and average growth rate increase as reactant concentration increased, with the TiPT concentration being more important. This reaction was also followed using absorbance spectrophotometry in the 500 to 320 nm range. After mixing of the reactants, an absorbance peak was seen between 330 and 335 nm, depending on the conditions. This peak increased slowly during the induction period and then increased rapidly after the onset of nucleation due to increasing turbidity

  • 44. Hartel, R.W.
    et al.
    Berglund, Kris
    Gwynn, S.M.
    Schierholz, P.M.
    Murphy, V.G:
    Crystallization kinetics for the sucrose-water system1980Inngår i: Design, control and analysis of crystallization processes / [ed] Alan D. Randolph, American Institute of Chemical Engineers, 1980, s. 65-72Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Crystallization kinetics for the sucrose-water system were studied in a continuous MSMPR cooling crystallizer. Growth and nucleation rates were derived from the measured size distributions using the population balance equation. In the region of higher supersaturation, where secondary nucleation occurs, it appeared that growth was a linear function of supersaturation; whereas, nucleation was approximately 1. 5 order in supersaturation. Growth rates were lower for crystals smaller than about 60 mu m, although these too increased with supersaturation. The latter trends were observed in both the higher (nucleating) and lower (non-nucleating) supersaturation regions. Preliminary batch studies indicated that the rate of secondary nucleation was also a function of both the method of contact and the impact energy.

  • 45. Helmerius, Jonas
    et al.
    Walter, Jonas Vinblad von
    Smurfit Kappa Kraftliner AB.
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Production of value added chemicals from xylan extraction in a Kraft pulp mill and the effect on pulp quality2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In the Kraft process hemicelluloses are lost in the cooking procedure to the black liquor stream, which is subsequently burnt in the recovery boiler to recover cooking chemicals and to produce steam and energy. Hemicelluloses have a low heating value compared to lignin and therefore recovery of hemicelluloses at an earlier stage of the Kraft process followed by biochemical conversionintohighvalue-conversion intohighvalue-into high value-added products might offer a muchbettereconomicopportunity.much better economic opportunityIn collaboration with the research and development department of Smurfit Kappa Kraftliner AB, Piteå, Sweden, alkali and water extractions of birch wood were performed under conditions compatible with the Kraft process, at different times, temperatures and alkali charges. The extraction conditions were set in a range suitable with the current pulp process at Smurfit Kappa Kraftliner. TherequirementsforprocessThe requirements for process configurations, based on either hot water or alkali extraction were also explored. ThexylanyieldsfromdifferentextractiontrialswereThe xylan yields from different extraction trials were measured and the chips from those extraction trials were cooked, refined and turned into sheets of paper. The effects on paper quality were compared with a reference pulp made from the same wooden chips. Recovered xylans from water extracted birch wood chips were subjected to secondary hydrolysis, enzymatic or sulphuricacid.sulphuric acidDetoxification of the hydrolysate with active carbon and regulation of pH were performed before fermentation. FermentationofthexyloseFermentation of the xylose hydrolysate to succinic acid was demonstrated by the use of thethe succinic acid producer Escherichia coli AFP184.

  • 46. Helmerius, Jonas
    et al.
    Walter, Jonas Vinblad von
    Smurfit Kappa Kraftliner AB.
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Hodge, David
    Production of value added chemicals from xylan extraction in a Kraft pulp mill and the effect on pulp quality2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    In the Kraft process hemicelluloses are lost in the cooking procedure to the black liquor stream, which is subsequently burnt in the recovery boiler to recover cooking chemicals and to produce steam and energy. Hemicelluloses have a low heating value compared to lignin and therefore recovery of hemicelluloses at an earlier stage of the Kraft process followed by biochemical conversion into high value-added products might offer a much better economic opportunity. In collaboration with the research and development department of Smurfit Kappa Kraftliner AB, Piteå, Sweden, alkali and water extractions of birch wood were performed under conditions compatible with the Kraft process, at different times, temperatures and alkali charges. The extraction conditions were set in a range suitable with the current pulp process at Smurfit Kappa Kraftliner. The requirements for process configurations, based on either hot water or alkali extraction were also explored. The xylan yields from different extraction trials were measured and the chips from those extraction trials were cooked, refined and turned into sheets of paper. The effects on paper quality were compared with a reference pulp made from the same wooden chips. Recovered xylans from water extracted birch wood chips were subjected to secondary hydrolysis, enzymatic or sulphuric acid. Detoxification of the hydrolysate with active carbon and regulation of pH were performed before fermentation. Fermentation of the xylose hydrolysate to succinic acid was demonstrated by the use of the succinic acid producer Escherichia coli AFP184.

  • 47.
    Helmerius, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Walter, Jonas Vinblad von
    Luleå tekniska universitet.
    Rova, Ulrika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Berglund, Kris
    Hodge, David B.
    Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing.
    Impact of hemicellulose pre-extraction for bioconversion on birch Kraft pulp properties2010Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 101, nr 15, s. 5996-6005Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The combination of hemicellulose extraction with chemical pulping processes is one approach to generate a sugar feedstock amenable to biochemical transformation to fuels and chemicals. Extractions of hemicellulose from silver birch (Betula pendula) wood chips using either water or Kraft white liquor (NaOH, Na2S, and Na2CO3) were performed under conditions compatible with Kraft pulping, using times ranging between 20 and 90 min, temperatures of 130-160 °C, and effective alkali (EA) charges of 0-7%. The chips from select extractions were subjected to subsequent Kraft pulping and the refined pulps were made into handsheets. Several metrics for handsheet strength properties were compared with a reference pulp made without an extraction step. This study demonstrated that white liquor can be utilized to extract xylan from birch wood chips prior to Kraft cooking without decreasing the pulp yield and paper strength properties, while simultaneously impregnating cooking alkali into the wood chips. However, for the alkaline conditions tested extractions above pH 10 resulted in low concentrations of xylan. Water extractions resulted in the highest final concentrations of xylan; yielding a liquor without the presence of toxic or inhibitory inorganics and minimal soluble aromatics that we demonstrate can be successfully enzymatically hydrolyzed to monomeric xylose and fermented to succinic acid. However, water extractions were found to negatively impact some pulp properties including decreases in compression strength, bursting strength, tensile strength, and tensile stiffness while exhibiting minimal impact on elongation and slight improvement in tearing strength index.

  • 48. Hodge, David
    et al.
    Andersson, Christian
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Rova, Ulrika
    Detoxification requirements for bioconversion of softwood dilute acid hydrolyzates to succinic acid2009Inngår i: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 44, nr 5, s. 309-316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work an Escherichia coli metabolically engineered to ferment lignocellulosic biomass sugars to succinic acid was tested for growth and fermentation of detoxified softwood dilute sulfuric acid hydrolyzates, and the minimum detoxification requirements were investigated with activated carbon and/or overliming treatments. Detoxified hydrolyzates supported fast growth and complete fermentation of all hydrolyzate sugars to succinate at yields comparable to pure sugar, while untreated hydrolyzates were unable to support either growth or fermentation. Activated carbon treatment was able to remove significantly more HMF and phenolics than overliming. However, in some cases, overliming treatment was capable of generating a fermentable hydrolyzate where activated carbon treatment was not. The implications of this are that in addition to the known organic inhibitors, the changes in the inorganic content and/or composition due to overliming are significant to the hydrolyzate toxicity. It was also found that any HMF remaining after detoxification was completely metabolized during aerobic cell growth on the hydrolyzates that were capable of supporting growth.

  • 49. Hodge, David
    et al.
    Andersson, Christian
    Helmerius, Jonas
    Walter, J. Vinblad von
    Rova, Ulrika
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Succinic acid production from forest based raw materials2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Lignocellulosic biomass and particularly hemicellulose from the forest products industry represents a large reservoir of sugars with the potential to be converted to higher value products through bioprocessing. This presentation will cover several projects regarding the fractionation and conversion of lignocellulose to succinic acid, a potentially important platform molecule in the synthesis of a number of commodity and specialty chemicals. The first of these investigates the feasibility of integrating a hardwood hemicellulose sugar extraction step into a Kraft pulping process with the intention of utilizing the hemicellulose as a fermentation feedstock. The requirements on processing configurations for hemicellulose extraction and recovery are compared, and a number of experimental parameters affecting the extraction (alkali, temperature, time) are investigated. Pulp quality is an important property and hemicellulose extraction can result in negatively affect the strength of the paper, which is also investigated. The second portion of the work deals with the fermentation requirements for microbial conversion of dilute acid hydrolyzed softwood to succinic acid. In particular, activated carbon and overliming detoxifications were tested for the ability to remove fermentation inhibitors and improve the fermentability of the hydrolyzates.

  • 50.
    Hussmann, G.A.
    et al.
    Iowa State University.
    Larson, M.A.
    Iowa State University.
    Berglund, Kris
    Characterization of solution structure near the surface of a growing crystal by Raman spectroscopy1984Inngår i: Industrial crystallization 84: proceedings of the 9th Symposium on industrial crystallization, the Hague, the Netherlands, September 25-28, 1984 / [ed] S.J. Jančić; E.J. de Jong, Amsterdam: Elsevier, 1984, s. 21-26Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In situ structure analyses of the supersaturated aqueous NaNO//3 solution near a growing NaNO//3 crystal have been performed using micro Raman spectroscopy. It was observed that the relative concentrations of higher ordered species (contact-ion pairs, and ion aggregates) are diminished near the growing crystal, indicating that these species are dominant in the diffusion process when compared to free aquated ions or solvent-separated ions. There were no detectable differences between the spectra obtained for saturated and supersaturated solutions.

12 1 - 50 of 89
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