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Delignifiering under sulfat koket innefattar både kemisk nedbrytning och fysisk upplösning av lignin, för vilket närvaron av oorganiska salter, oorganiska anjoner samt oorganiska katjoner (sammantaget benämnda som "Non-process elements", NPEs på engelska) kan ha inverkan på delignifieringens hastighet. Tidigare studier har funnit att ved med högt kalciuminnehåll är svårdelignifierad och att kalcium har potentiell inverkan på ligninlöslighet och kappatal. Att avlägsna kalcium från ved är svårt, men vissa studier har visat att detta kan motverka ovannämnda2(4)inverkan och öka delignifieringen. Denna studie har studerat effekten av kalcium under delignifieringen på fyra prover av Eucalyptus dunnii tagna från olika marktyper, åldrar, kalciumhalt samt geografisk plats (i Uruguay). Målet har varit att undersöka kalciumets inverkan under delignifieringen och dess effekt på massautbytet. Fyra satser av vardera vedmat erial kokades i stålautoklaver med följande parametrar: 18 % effektiv alkali, 35 % sulfiditet, 1 h impregnering vid 110 °C, 2,75 h, 3 h, 3,25 h respektive 3,5 h koktider (för vardera sats) vid 145 °C. Provet med den högsta kalciumhalten om 4668 mg/kg kunde dock inte delignifieras, vare sig vid dessa kokparametrar eller vid en temperaturökning till 155 °C och en resulterande H-faktor på 735 enheter – motsvarande 7 h koktid vid 145 °C – och analyserades inte vidare i studien. Resultaten visar på en negativ effekt från kalcium avseende både delignifieringshastighet och utbyte: Eucalyptus med en lägre kalciumhalt på 705 mg/kg gav massa med kappatal 13 efter kokning, medan eucalyptus med 1500 mg/kg kalcium efter samma kokning gav massa med kappatal 17. Motsvarande utbyte för dessa massor var 48 % för provet med lägre kalciumhalt och 46 % för provet med högre kalciumhalt. Kvantifiering av modifierat kappa och uronsyror bekräftade att ovannämnda effekter inte berodde på inverkan från hexennuronsyra i massan. / Delignification during sulphate cooking involves both chemical degradation and physical solubilization of lignin where the presence of non-process elements (NPEs), inorganic salts, anions or cations in the process could affect the rate of delignification. Previous studies also indicate that wood with higher calcium content is challenging to delignify which would affect the lignin solubility and increase kappa number. Besides, the removal of calcium from Eucalyptus is difficult. However, some study suggests that removal of calcium before the process increases the rate of delignification. This work studies the effect of calcium in four Eucalyptus dunnii samples of different soil type, age, different calcium content and Uruguayan geographical areas during the delignification process. The aim is to study the influence of calcium during the delignification in kraft cooking and its effects on pulp yield in Eucalyptus dunnii. Four batches of each material were cooked in a steel autoclaves with the following parameters: 18% effective alkali, 35% sulphidity, 1 h impregnation at 110 ° C, 2.75 h, 3 h, 3.25 h and 3.5 h cooking times, respectively (for each batch) at 145 ° C. Besides, sample with Ca-4668 mg/kg were not able to defibrate at common cooking conditions and even after altering the cooking conditions to higher temperature 155℃, H-Factor to be 735 (cooking time of 7 hours) and were not analyzed further in the study. Results suggest that there is a detrimental influence of calcium on delignification during the kraft cooking process, and it also affects the pulp yield in Eucalyptus dunnii. Eucalyptus with a lower calcium content of 705 mg / kg gave pulp with kappa number 13 after cooking, while eucalyptus at 1500 mg / kg calcium after the same cooking time gave pulp with kappa number 17. Corresponding yield for these pulps were 48% for the lower calcium sample and 46% for the higher sample calcium content. A slower rate of delignification with higher kappa number and lower overall pulp yield are the results of higher calcium content in Eucalyptus dunnii. Quantification of modified kappa and uronic acids confirm that the effect of calcium on kappa is due to residual lignin and not by the presence of hexenuronic acids.

Today’s society strives to eliminate the carbon dioxide (CO2) emissions, which is the main greenhouse gas emitted through anthropogenic activities and contributes to climate change. In this project utilization of CO2 emissions from waste to energy plants to carbohydrates via photocatalytic reduction with water and further carbon coupling reactions is investigated. Two routes for the synthesis of carbohydrates have been investigated. Both methods use photocatalytic reduction of carbon dioxide to methanol and then proceed via different steps to produce carbohydrates or their precursors. The first route uses aldol condensation as the main method for the formation of carbon-carbon bonds and the second route is based on the formose reaction that uses formaldehyde as a reactant. The waste incineration plant selected for this study was the one located in Kil, Sweden. This plant processes 15590 tons of waste per year and emits 16366.5 tons of carbon dioxide per year. In order to separate carbon dioxide from the flue gas stream, MEA absorption was chosen as the best option due to its high efficiency. The presented processes have negative carbon dioxide emissions due to the fact that they convert of 16.4% of the waste incineration CO2 emissions into useful products and do not generate any emissions of their own. The aldol condensation pathway exhibits an efficiency of 1.3% when considering only food industry products and 2.5% when including other products that are useful to manufacture solvents, lubricants, or pharmaceuticals. The total amount of food industry products obtained is 3.9 kg/h with the energy requirements being was 159550 kJ/kgproduct. The formose reaction route yields 15.4 kg/h of only food industry products, mainly glucose, and exhibits an efficiency of 5%. The power requirements equal to 90099 kJ/kgproduct. The formose route was found to have higher yield and efficiency, and to be more energy consuming but also more energy efficient. Economic data was difficult to find due to the fact that photocatalytic processes are not commercial yet. / Dagens samhälle strävar efter att eliminera koldioxidutsläppen (CO2), som är den viktigaste växthusgasen som släpps ut genom antropogena aktiviteter och påverkar klimat. Den här projekten undersöker användning av koldioxidutsläpp från avfall till energianläggningar till produktion av kolhydrater via fotokatalytisk reduktion med vatten och ytterligare kolkopplingsreaktioner. Projekten utforskar två vägar för syntes av kolhydrater. Båda metoderna använda fotokatalytisk reduktion av koldioxid till metanol. Kolhydrater eller deras ursprungsmaterial syntetiseras via olika steg nedströms den fotokatalitiska processen. Den första vägen använder aldolkondensation som huvudmetod av kol-kolbindningar och den andra vägen baseras på formosreaktionen som använder formaldehyd som reaktant. Den avfallsförbränningsanläggning som valts ut för denna studie var den i Kil, Värmland, Sverige. Denna anläggning behandlar 15590 ton avfall per år och släpper ut 16366,5 ton koldioxid per år. För att separera koldioxid från rökgasströmmen valdes MEA-absorption som det bästa alternativet på grund av dess höga effektivitet. De presenterade processerna har negativa koldioxidutsläpp på grund av att de omvandlar 16,4% av koldioxid från avfallsförbränning till användbara produkter och inte genererar  egna utsläpp. Aldolkondensationsvägen uppvisar en effektivitet på 1,3% om man endast beaktar livsmedelsindustrins produkter och 2,5% om man gör andra produkter som är användbara för att tillverka lösningsmedel, smörjmedel eller läkemedel. Den totala mängden av livsmedelsprodukter är 3,9 kg / h och energibehovet är lika med 159550 kJ / kg produkt. Formosreaktionsvägen ger 15,4 kg / h av livsmedelsindustrin produkt, huvudsakligen glukos, och uppvisar en effektivitet på 5%. Effektkraven är lika med 90099 kJ / kg produkt. Formosvägen visade sig ha högre utbyte och effektivitet och vara mer energikrävande men också mer energieffektiv. Ekonomiska data var svåra att hitta på grund av att fotokatalytiska processorn ännu inte är kommersiell.

The oxidation of simple benzene derivatives by a mutant of Pseudomonas putida, called 39-D, produces cis-arenediols (1). The diols are enantiomerically pure and can be used as synthons for the preparation of a variety of interesting compounds because of their stereochemistry and the special array of functional groups. See: Figure 1 cis -Toluenedio] (2) served as a chiral intermediate in an efficient synthesis of enone (3). which has been used to attain prostaglandin Fra and Neplanocin A. The same diol (2) was transformed into both enantiomers of a terpene synthon (4). See: Figures 2, 3, 4 Oxidative functionalization of cis-chlorobenzenediol (5) afforded intermediates suitable for transformation into L-erythrose (6), conduritol C (7), dihydroconduritol C (8) and aminoconduntol F-4 (9). See: Figures 5, 6, 7, 8 The application of this versatile synthetic protocol culminated in an approach to kifunensine (10), an important glycosidase inhibitor, which was approached according to the following retrosynthetic analysis: See: Figures 10, 11, 12, 5, 14, 13 A detailed study of the nucleophilic opening of epoxide 13 was carried out in order to better understand the parameters of the diastereoselective functionalization of arenediols. Details are provided for the oxidative functionalization of chlorobenzenediol (5), the key compound in all of the projects discussed. / Ph. D.

Degradation kinetics of carbohydrate fraction of commercial concentrate feeds for weaned calves, heifers, lactating and dry dairy cattle / Variations in composition and disappearance of nutrients in dairy cattle feeds are dictated by ingredients, methods of processing, storage while milk production levels depend on the animal, environmental factors and largely on pools of available carbohydrates, proteins, vitamins and minerals in the concentrate feeds. There is a wide variety of concentrates for dairy cattle on the formal and informal markets and dairy farmers need to be astute in selecting feeds appropriate for specific production periods and animals to sustain their businesses. Composition of nutrients displayed on concentrate containers is however inadequate for in-depth assessment of products. This study determined nutrient composition, rumen dry matter disappearance and microbial colonization on residual substrate on commercial concentrate feeds and simulated total mixed rations for dairy calves, heifers, lactating and dry cows based on common feeding guidelines. Equivalent feeds for each herd group were obtained from three suppliers in the formal markets in Gauteng province of South Africa, making a total of twelve. An analysis of the data on container labels for the herd groups displayed similar feed values, as also reflected on the recommendation Tables of Act 36: Feeds and Fertilizer bill 1947 of South Africa. / Agriculture, Animal Health and Human Ecology / M.Sc. (Agriculture)

Die Umsetzung des Park-Nucleotids zu Lipid I in der bakteriellen Zellwandbiosynthese wird durch das Enzym MraY katalysiert. Dieses Enzym ist ein interessantes, bisher ungenutztes Target für neuartige Antibiotika. In der vorliegenden Dissertation wurde das fluoreszenzmarkierte Park-Nucleotid, welches für MraY-Assays geeignet ist, totalsynthetisch dargestellt. Die Synthese konnte ausgehend von kommerziell erhältlichem N-Acetylglucosamin in 14 Stufen mit einer Gesamtausbeute von 4 % erfolgreich durchgeführt werden. Dabei wurden einige Schritte auf Basis einer literaturbekannten Synthese gründlich optimiert und neue Wege zur Darstellung des Peptids und anschließender Kupplung mit einem Kohlenhydrat Baustein gefunden. Im Zuge dieser neuen Syntheseroute wurde die Uridindiphosphat-N-Acetylmuraminsäure, als Substrat für MurC-Assays, synthetisiert. Dies gelang in einer achtstufigen Synthese ausgehend von der geschützten N-Acetylmuraminsäure in einer Gesamtausbeute von 15 %. Die Muraymycine, eine Klasse von natürlichen Nucleosid-Antibiotika, inhibieren das Enzym MraY effizient. In dieser Dissertation wurde der Grundstein für die Synthese möglichst vielfältiger vereinfachter Muraymycin Analoga gelegt, welche potentielle Inhibitoren für MraY darstellen. Die Harnstoffpeptidseitenkette wurde variiert, um den Einfluss dieses Strukturbausteins auf die Inhibitor-Aktivität intensiver untersuchen zu können. Der Ersatz der anspruchsvoll zu synthetisierenden Aminosäure Epicapreomycidin durch die kommerziell erhältlichen Aminosäuren L-Lysin, L-Ornithin, L-Arginin, L-Alanin und L-Methionin konnte die Synthese der Harnstoffpeptidkette stark vereinfachen. Des Weiteren wurde durch eine stereospezifische Synthese die geschützte 2S,3S-Diaminohexansäure dargestellt, um das in den natürlichen Muraymycinen enthaltene L-Hydroxyleucin, welches häufig mit einer Fettsäure verestert ist, zu ersetzten. Dieses sollte durch den Austausch einer Esterbindung durch eine Amidbindung zu einer Stabilisierung der Muraymycin Derivate führen. Unter Verwendung des in dieser Dissertation beschriebenen Lysin-haltigen Harnstoffpeptids wurden vor kurzen vereinfachte Muraymycin-Analoga synthetisiert und IC50 Werte mittels eines fluoreszenzbasierten MraY-Assays bestimmt. Diese stark vereinfachten Verbindungen weisen bereits gute Inhibitor Aktivitäten auf. Durch die Kombination der verschiedenen, in dieser Arbeit synthetisierten Harnstoffpeptide und Aminosäuren mit unterschiedlichen Uridinderivaten kann zukünftig eine große Anzahl diverser potentieller Inhibitoren dargestellt werden.

In the early 1990’s, a lot of work was focused on extending the kraft cook to a low lignin content (low kappa number). The driving force was the need to further reduce the environmental impact of the bleaching, as less delignification work would be needed there. However, the delignification during the residual phase of a kraft cook is very slow and, due to its poor selectivity, it is a limiting factor for the lignin removal. If the amount of lignin reacting according to the residual phase could be reduced, it would be possible to improve the selectivity of the kraft cook. In the work described in this thesis, special attention has been given to the activation energy of the slowly reacting residual phase of a kraft cook on softwood raw material and to the influence of different cooking parameters on the amount of the residual phase lignin. The activation energy of the residual phase delignification of the kraft cook was shown to be higher than that of the bulk phase delignification. In order to decrease the amount of residual phase lignin, it was essential to have a high concentration of hydrogen sulphide ions when cooking with a low hydroxide concentration. It was also important to avoid a high sodium ion concentration when cooking with low hydroxide and low hydrogen sulphide ion concentrations. Furthermore, it was demonstrated that dissolved wood components had a positive effect on the delignification rate in the bulk phase of a kraft cook. The influence of different cooking parameters in the extended softwood kraft process on the bleachability (i.e. the ease with which the pulps can be bleached to a target brightness) of the manufactured pulp was also investigated. If variations in bleachability were seen, an attempt would also be made to find chemical reasons to explain the differences. It was difficult to establish clear relationships between the chemical structures of the residual lignin and the bleachability of the pulp. However, it was seen that the higher the content of β-aryl ether structures in the residual lignin after cooking, the better was the QPQP*-bleachability. In the middle/end of the 1990’s, the focus moved from extended cooking to efficient utilisation of the wood raw material, e.g. by interrupting the kraft cook at higher kappa number levels and choosing appropriate cooking conditions to maximise the cooking yield. A high cooking yield often leads to a somewhat higher hexenuronic acid (HexA) content of the pulp at a given kappa number. Therefore additional attention was devoted to how the HexA content and carbohydrate composition were affected, e.g. by a set of cooking parameters. Performing these studies it was also important to investigate the effects of a low HexA (after cooking) strategy on such vital factors as the cooking yield, the bleachability and the yellowing characteristics of the pulp obtained. It proved to be difficult to significantly reduce the HexA content in a kraft pulp by altering the cooking conditions for both softwood and the hardwood Eucalyptus Globulus. A reduction in HexA content can be achieved by extending the cook to lower kappa numbers, or by using a high hydroxide concentration, a low hydrogen sulphide concentration or a high sodium ion concentration. However, neither of these strategies is attractive for industrial implementation since they would result in an extensive loss of yield, viscosity and strength. / <p>QC 20100825</p>

Depuis les révolutions industrielles des années 1700 et 1800, et pendant l'industrialisation des siècles les suivant, une accumulation de composés polluants a eu lieu dans l'atmosphère, principalement due à la combustion de matières fossiles comme le charbon et le pétrole. Outre les polluants directement émis comme les oxydes de souffre et d'azote, des polluants secondaires comme l'ozone se sont accumulés. Aujourd'hui, l'ozone est le troisième gaz responsable du réchauffement climatique, mais est également dangereux pour la santé humaine et responsable de dommages sur la végétation. Depuis les années cinquante, les effets de l'ozone sur les plantes et les réponses de ces dernières ont été étudiés de façon ciblée. Aujourd'hui, avec l'apparition de techniques permettant l'étude globale du transcriptome ou du protéome, il est possible d'aborder le problème d'une façon non biaisée, permettant des études plus complètes du stress. Dans le cadre de ce travail, une étude protéomique des effets de l'ozone sur les processus foliaires du peuplier a été proposée. Cette technique, complétée par des approches biochimiques, physiologiques, et des observations morphologiques, a permis de confirmer certains résultats d'études ciblées, mais également d'émettre des nouvelles hypothèses sur les mécanismes d'action de l'ozone sur le métabolisme du peuplier. En parallèle, l'étude du stress a aussi permis d'éclaircir les changements du métabolisme lors de la croissance de feuilles en conditions de stress et en conditions normales. Dans les pages de ce document, les procédures, résultats et conclusions de ce travail seront présentés en détail / After the industrial revolution of the 1700s and 1800s, and the subsequent industrialization, many pollutants have accumulated in the atmosphere, mainly due to the use of coal and fossil fuels. Besides the primary pollutants such as nitrogen oxides and sulfur oxides, secondary oxides such as ozone started to accumulate. Nowadays, ozone is the third gas involved in global climate change, but is also a major health risk for humans, and induces considerable damage to vegetation. Starting in the 50s, ozone research was based on targeted studies. Nowadays, with the advent of global techniques such as transcriptomics and proteomics, new results can be produced in an unbiased way. In the thesis presented here, a proteomic study of the effects of ozone on poplar leaf processes was carried out. With the help of this technique, complemented with biochemical and physiological approaches and with morphological observations, it was possible to confirm previous results, but also to elaborate new hypotheses concerning the effects of ozone on poplar leaf metabolism. In parallel, studying the stress also allowed to clarify some of the changes that occur in metabolism during leaf development, under stress conditions and under control conditions. In this document, the procedures, results and conclusions obtained during this study are presented in detail