L'objectif principal du travail effectué au cours de cette thèse était de développer, caractériser et analyser des matériaux originaux pour des réactions d'oxydation photosensibilisée. Une attention particulière a été accordée à la détermination des propriétés photophysiques des sensibilisateurs (PSs) et à l'effet induit par l'immobilisation sur un support inerte (silice). Les espèces réactives formées lors de l'irradiation ont été identifiées et analysées. La production d'oxygène singulet a été suivie par deux méthodes complémentaires. Les sensibilisateurs supportés ont été employés, sous la forme de monolithes ou de poudres, pour la photo-oxydation du diméthyl sulfure à l'interface gaz-solide et de l’-terpinène à l'interface liquide-solide. L'oxygène singulet est la principale espèce réactive de l’oxygène formée par les PSs sélectionnés; néanmoins, les produits de réaction ont été analysés afin de mettre en évidence d’autres mécanismes. / The main aim of the work carried out during this PhD project was to develop, characterize and analyze original materials for photosensitized oxidation reactions. Particular attention was paid to the determination of the photophysical properties of the selected photosensitizers (PSs) and the effect induced by the immobilization on an inert support (silica). The reactive species formed upon irradiation were identified and analyzed. Singlet oxygen production was monitored by two complementary methods. The solid-supported sensitizers were employed, in the form of either monoliths or powders, for the photooxidation of dimethyl sulfide at the gas-solid interface and of -terpinene at the liquid-solid interface. Singlet oxygen was the main reactive oxygen species formed by the selected PSs; nonetheless, the reaction products were analyzed and other possible mechanistic scenarios investigated.

Ces travaux portent principalement sur l’étude de trois plantes tinctoriales : la garance, le nerprun et la gaude. Ces végétaux ont fait l’objet de nombreuses cultures en Provence et constituaient la principale matière première en colorants rouges et jaunes pour les teinturiers et les artistes. Une optimisation des conditions d’extraction des colorants de la garance assistée par ultrasons a été effectuée en utilisant un modèle statistique. Ce procédé d’extraction simple, rapide et efficace, a été comparé à deux autres techniques utilisées conventionnellement. Une étude cytohistologique des racines de garance a permis d’examiner les effets apportés par les différents procédés d’extraction. Les cellules traduisent après extraction par ultrasons, de profondes déstructurations fournissant une explication au plus important rendement en colorant extraits en comparaison aux extractions classiques. Une étude fondamentale sur l’identification des colorants extraits à partir des fruits immatures d’espèces appartenant au genre Rhamnus a été effectuée. Une approche chromatographique utilisant la CLHP/UVVisible/ SM a permis d’identifier la partie flavonol. Elle présente principalement des composés glycosylés dont la partie rhamninoside est liée sur le flavonol en position 3 ou 4'. Des flavonols 3-O-acétyl-rhamninoside ont également été caractérisés et sont spécifiques de Rh. saxatilis. Les fruits matures renferment aussi des anthraquinones qui ont été séparées des flavonols et concentrées en utilisant l’Extraction sur Phase Solide (SPE). Après analyse par RMN, des dérivés rhamnoside et arabinoside acétylés de l’émodine, jamais décrits dans la littérature, ont été identifiés dont le 6-O-(3',4' diacétyl)-arabinopyranoside d’émodine et 6-O-(2',3',4'-triacétyl)- arabinopyranoside d’émodine présents seulement dans Rh. alaternus. Les colorants jaunes de la gaude (Reseda luteola) ont été analysés par électrophorèse capillaire. En comparaison avec la CLHP, un gain important de la durée d’analyse a été observé tout en conservant une séparation convenable. L’ensemble de ces résultats expérimentaux a pu être appliqué avec succès à l’étude de colorants extraits à partir d’objets et d’échantillons historiques provenant de collections muséales et comprenant notamment des indiennes du XIXème siècle. Enfin, des essais de teintures ont été réalisés, en collaboration avec la société Les Olivades dans le but de développer une gamme de tissus à base de colorants naturels / This work concerns the study of three tinctorial plants: madder, buckthorn and weld. These plant species produced many cultures in Provence and represented the principal raw material in red and yellow dyes for dyers and artists. An optimisation of extraction conditions for madder dyes, using ultrasounds, was carried out with a statistical model. This easy, fast and effective extraction process was compared with two other conventional techniques. A cytohistological study on madder roots permits to examine effects produced by the different extraction processes. Cells reveal, after ultrasonic extraction, profound structural alterations, explaining the high yield in extracted dyes in comparison with classical methods. A fundamental study on the dyes identification extracted from Rhamnus species green fruits was carried out. A chromatographic approach using HPLC-UV-MS permits to identify the flavonol fraction. It is mainly composed of glycosiled compounds where the rhamninosid part is linked in position 3 or 4’ on the flavonol nucleus. 3-O-acetyl-rhamninosid derivatives were also characterised and they are specific to Rh. saxatilis species. Ripe fruits contained anthraquinonic compounds that were separated from flavonols and concentrated using Solid Phase Extraction (SPE). After NMR analyse, acetyl rhamnosid and arabinosid derivatives of émodine, never described in the specialised literature, were identified as emodin-6-O-(3',4'-diacetyl)-arabinopyranosid and emodin-6-O-(2',3',4' triacetyl)-arabinopyranosid were only present in Rh. alaternus. Yellow dyes of weld (Reseda luteola) were analysed by capillary electrophoresis. In comparison with HPLC, a reduced run time was observed while preserving a suitable separation. These experimental results were successfully applied to the study of ancient samples belonging from museums and including “indiennes” of the XIXth century. Finally, dying tests were carried out, in collaboration with Les Olivades society, in the aim to develop textiles containing natural dyes

Cytomegalovirus (CMV) is a significant cause of mortality and morbidity in immunocompromised patients and an important cause of birth defects if acquired in utero. The licensed CMV antivirals, ganciclovir, cidofovir and foscarnet, all target the viral DNA polymerase. For each drug prolonged use is associated with significant toxicities and development of drug resistance. None are approved for use during pregnancy. Therefore, development of new anti-CMV drugs that target different pathways would be beneficial. All herpesviruses encode an alkaline nuclease. That genetic disruption of the CMV alkaline nuclease, UL98, reduces CMV replication by 1,000-fold suggests that UL98 may be a useful target for development of novel anti-CMV drugs. Moreover, using herpes simplex virus type 1 Hsiang and Ho found that the anthraquinone emodin inhibits activity of the viral alkaline nuclease, blocks viral replication in cell culture, and reduces viral pathogeneses in a mouse model (Brit. J. of Pharm., 2008). Earlier studies also showed that anthraquinone derivatives including emodin have anti-CMV activity (Barnard et al., Antiviral Research 1992 & 1995), although the mechanism of CMV inhibition has not been further studied. We therefore sought to confirm the anti-CMV activities of emodin and related anthraquinone derivatives, to characterize their mechanisms of action, and to determine specifically if they act through inhibition of UL98. Using a luciferase-based CMV yield reduction assay emodin inhibited CMV replication (IC50 = 4.9 μM); however, that the TD50 for cytotoxicity (determined using an luciferase-based cell viability assay) was only 2-fold higher suggested that emodin may act non-specifically. Two additional anthraquinone derivatives (acid blue 40 and alizarin violet R) inhibited CMV only at high concentrations (IC50 = 238; 265 μM) that were also cytotoxic. Atanyl blue PRL, however, exhibited anti-CMV activity (IC50 = 6.3 μM) with low cytotoxicity (TD50 = 216 μM). Thus, characterization of atanyl blue PRL (impact on gene expression, GFP expression, viral spread, infectivity, time of addition studies, and inhibition of UL98 nuclease activity) should be informative. Atanyl blue PRL appears to block immediate-early gene expression and reduce early and late gene expression. Atanyl blue PRL also blocked GFP expression, reduced viral spread, and also lowered the infectivity of CMV. Finally, atanyl blue PRL inhibits UL98 alkaline nuclease activity at an IC50 of 5.7 μM. This suggests that atanyl blue PRL may inhibit CMV through inhibition of UL98. Thus, atanyl blue PRL represents a novel class of anti-herpesvirals and provides a lead structure for structure based drug discovery.

Das Bodenbakterium Rhodococcus opacus 1CP ist für sein Potenzial bekannt, organische Schadstoffe abzubauen. In dieser Studie lag der Fokus auf zwei Genprodukten, den farbstoffabbauenden Peroxidasen DypA und DypB, welche unter Anwendung von Klonierungs- und Expressionsstrategien mit hohen spezifischen Aktivitäten in reiner Form gewonnen werden konnten. Eine umfassende biochemische Analyse zeigte, dass beide Enzyme in der Lage sind, Farbstoffe unterschiedlicher Klassen, insbesondere jedoch, die als schwer abbaubar geltenden Anthraquinone, strukturell anzugreifen. Damit stellen sie lohnenswerte enzymatische Systeme zum Abbau toxischer Farbstoffe beispielsweise in industriellen Abwässern dar.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-02T19:44:17Z No. of bitstreams: 1 taisarthurcorrea.pdf: 15535064 bytes, checksum: bc51d525d36c8791fdee90743f4d27c6 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-13T13:12:19Z (GMT) No. of bitstreams: 1 taisarthurcorrea.pdf: 15535064 bytes, checksum: bc51d525d36c8791fdee90743f4d27c6 (MD5) / Made available in DSpace on 2017-05-13T13:12:19Z (GMT). No. of bitstreams: 1 taisarthurcorrea.pdf: 15535064 bytes, checksum: bc51d525d36c8791fdee90743f4d27c6 (MD5) Previous issue date: 2014-01-31 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / As antraquinonas constituem uma importante classe de compostos orgânicos, devido a sua ocorrência na natureza e por serem versáteis na preparação de novos compostos bioativos. Tal fato pode ser confirmado pelo grande número de moléculas sintetizadas a cada ano pertencentes a essa classe, dando destaque aos compostos com atividade antitumoral, antiinflamatória e imunossupressora. Neste trabalho são descritas as sínteses de aminas, amidas, éteres e amino-álcoois a partir das antraquinonas 1,4-diaminoantraquinona, 1,4-diidroxiantraquinona e 1,5-diamino-4,8-diidroxiantraquinona, usando a mitoxantrona como composto protótipo. Duas séries foram obtidas por reação de O-alquilação da 1,4-diidroxiantraquinona com posterior substituição do grupo abandonador presente no grupo alquila ou mesmo dos grupos O-alquila ligados ao anel antraquinônico por diferentes aminas ou amino-álcoois. Uma terceira série de compostos foi obtida através da preparação de dois intermediários reativos “leucoquinizarim” e sua posterior condensação com diferentes amino-álcoois. As quarta e quinta séries tratam da síntese de diferentes compostos a partir da 1,4-diaminoantraquinona como monoamidas, diamidas e amino-álcoois, via condensação empregando reagentes de acoplamento, cloreto de acila e abertura de epóxido, respectivamente. Após a purificação e caracterização dos compostos através de métodos espectroscópicos usuais (RMN de 1H e de 13C, infravermelho e massas) suas propriedades citotóxicas, antiinflamatória e imunossupressora foram avaliadas in vitro e as substâncias mais ativas estão sendo avaliadas quanto a sua atividade frente à modulação da resposta imune in vivo no modelo de encefalomielite autoimune experimental (EAE). Em geral, as modificações estruturais propostas neste conjunto de moléculas apresentaram uma diminuição no processo inflamatório através da diminuição na produção de NO, que é uma melhoria quando comparado com a mitoxantrona, além de apresentarem inibição de mediadores inflamatórios (TNF-α e IL-1β), sugerindo um caráter imunossupressor. / Anthraquinone is an important class of organic compounds due to their common occurrence in nature, as well as being versatile in the preparation of novel bioactive compounds. This can be confirmed by the large number of molecules synthesized each year containing this group, emphasizing compounds with immunosuppressive, antitumor and anti-inflammatory activity. This work describes the synthesis of amines, amides, ethers and amino alcohols derived from anthraquinones such as 1,4-diaminoanthraquinone, 1,4-dihydroxianthraquinone and 1-5-dihydroxi-4,8-diaminoanthraquinone using mitoxantrone as a prototype compound. Two series were obtained by O-alkylation reaction of 1,4-dihydroxianthraquinona with subsequent replacement of the leaving group or the same group attached to the alkyl-anthraquinone ring with different amino alcohols or amines. A third series of compounds was obtained by preparing two reactive intermediate "leucoquinizarim" and subsequent condensation to various amino-alcohols. The fourth and fifth series reports the synthesis of different compounds from the 1,4-diaminoanthraquinones as monoamides, diamides and amino alcohols, via condensation with coupling reagents, acyl chloride and epoxide opening, respectively. After purification and characterization of the compounds though the usual spectroscopic methods (1H and 13C NMR, Infrared and mass spectra) their immunosuppressive, anti-inflammatory and cytotoxic properties were evaluated in vitro and the most active substances are being evaluated and check the action in the modulation of the in vivo immune response of experimental autoimmune encephalomyelitis (EAE). In general, structural modifications proposed in this set of molecules showed a decrease in inflammation by reducing the production of NO, which is an improvement compared to the mitoxantrone, besides presenting inhibition of inflammatory mediators (TNF-α and IL-1β), suggesting an immunosuppressive character.

There is an increased awareness of the textile dyeing and finishing sector’s high impact on the environment due to high water consumption, polluted wastewater, and inefficient use of energy. To reduce environmental impacts, researchers propose the use of dyes from natural sources. The purpose of using these is to impart new attributes to textiles without compromising on environmental sustainability. The attributes given to the textile can be color and/or other characteristics. A drawback however, is that the use of bio-sourced dyes is not free from environmental concerns. Thus, it becomes paramount to assess the environmental impacts from using them and improve the environmental profile, but studies on this topic are generally absent. The research presented in this thesis has included environmental impact assessment, using the life cycle assessment (LCA) tool, in the design process of a multifunctional polyester (PET) fabric using natural anthraquinones. By doing so an eco-design approach has been applied, with the intention to pave the way towards eco-sustainable bio-functionalization of textiles. The anthraquinones were obtained from the root extracts of the madder plant (Rubia tinctorum L.), referred to as madder dye. The research questions were therefore formulated related to the use of madder dye. Three research questions have been answered: (I) Can madder dye serve as a multifunctional species onto a PET woven fabric? (II) How does the environmental profile of the dyeing process of PET with madder dye look like, and how can it be improved? (III) What are the main challenges in using LCA to assess the environmental impacts of textile dyeing with plant-based dyes? It is concluded that there is a potential for the madder dye to serve as a multifunctional species onto PET. Based on the encouraging result, a recommendation for future work would be to focus on the durability of the functionalities presented and their improvement potential, both in exhaustion dyeing and pad-dyeing. LCA driven process optimization of the exhaustion dyeing enabled improvement in every impact category studied. However, several challenges have been identified which need to be overcome for the LCA to contribute to the sustainable use of multifunctional plant-based species in textile dyeing. The main challenges are the lack of available data at the research stage and the interdisciplinary nature of the research arena. It is envisaged that if these challenges are addressed, LCA can contribute towards sustainable bio-functionalization of textiles. / Le secteur de la teinture et de l’ennoblissement textile est de plus en plus conscient de son impact sur l’environnement dû principalement à la consommation élevée de l’eau et à sa pollution, et aux pertes d’énergie. Pour réduire ces impacts, les chercheurs proposent l’utilisation de molécules issues de ressources naturelles, pour traiter les textiles en limitant les impacts sur l’environnement. C’est le cas pour l’obtention de textiles colorés ou pour l’attribution de toute autre fonctionnalité. Cependant, il n’est pas évident que ces molécules bio-sourcées n’aient aucun impact sur l’environnement. On comprend l’importance d’évaluer les impacts de leur utilisation et d’améliorer leur profil environnemental. Or ce type d’étude est peu présent dans la littérature. La recherche présentée dans cette thèse comporte l’évaluation des impacts environnementaux en utilisant l’outil d’analyse du cycle de vie (ACV) pour la conception du traitement d’un tissu de polyester (PET) multifonctionnel avec des anthraquinones naturelles. La méthodologie d’éco conception que nous avons appliquée ouvre la voie à une bio-fonctionnalisation des textiles plus respectueuse de l’environnement. Les anthraquinones ont été obtenues par extraction des racines de plantes de garance et constituent le colorant appelé garance. Les trois questions principales abordées lors de ce travail de recherche sont formulées autour de l’utilisation de la garance : (I) Peut-on traiter les tissus de PET avec de la garance pour obtenir des propriétés multifonctionnelles ? (II) Quel est le profil environnemental du procédé de teinture du PET par la garance et comment l’améliorer ? (III) Quels sont les principaux challenges pour l’utilisation de l’ACV dans l’évaluation environnementale du traitement des textiles par des colorants naturels? Nous avons montré que la garance peut être utilisée pour conférer des propriétés multifonctionnelles au PET. Ensuite, nous avons pu orienter notre étude pour améliorer la durabilité des traitements par les procédés de fonctionnalisation à la fois par épuisement ou par foulardage. En s’appuyant sur l’ACV, l’optimisation de la teinture que nous avons réalisée réduit tous les impacts sur l’environnement. Cette étude nous permet d’identifier les challenges qui doivent être surmontés pour que l’ACV puisse contribuer à l’utilisation de bio-molécules pour la teinture des textiles dans le respect des principes de développement durable. Ils concernent le manque de données pour ces travaux de recherche et leur nature interdisciplinaire. Ainsi, en résolvant ces questions, on peut envisager aboutir à une bio- fonctionnalisation des textiles respectueuse de l’environnement. / Den höga miljöpåverkan från textilfärgning och efterbehandling, på grund av hög vattenförbrukning, dess förorening, och ineffektiv användning av energi, är idag välkänt. För att minska miljöpåverkan föreslår forskningsvärlden användning av färgämnen från naturliga resurser. Syftet med att använda dessa är att ge nya attribut till textilier utan att göra avkall på miljömässig hållbarhet. Attribut som ges kan vara färg och/eller andra egenskaper. En nackdel är dock att användningen av bio-baserade färgämnen är inte fri från att belasta miljön. Det blir därför av största betydelse att bedöma denna miljöpåverkan och förbättra miljöprofilen. Sådana studier är dock i allmänhet sällsynta. Studien som presenteras i denna avhandling har inkluderat miljöpåverkans- bedömning, med hjälp av livscykelanalys (LCA), i designprocessen av en multifunktionell polyester (PET) väv via naturliga antrakinoner. Genom att göra så har ett eko-design tillvägagångssätt använts, med avsikt att bana väg för miljömässigt hållbar bio-funktionalisering av textil. Antrakinonerna erhölls från rot extrakt av växten krapp (Rubia tinctorum L.), och hänvisas till som krapp färgämne. Frågeställningar var därför formulerade relaterat till användningen av krapp färgämne. Tre forskningsfrågor har besvarats: (I) Kan krapp färgämne verka multifunktionellt på en PET väv? (II) Hur ser miljöprofilen ut, från färgningsprocessen av PET med krapp färgämne, och hur kan den förbättras? (III) Vilka är de största utmaningarna med att använda LCA för att bedöma miljökonsekvenserna av textilfärgning med växtbaserade färgämnen? Det kan konkluderas att det finns potential för krapp färgämne att verka multifunktionellt på PET. Baserat på uppmuntrande resultat är en rekommendation för det framtida arbetet att fokusera på kvalitén hos de attribut som presenterats och deras förbättringspotential, både i färgning via färgbad och via foulard. LCA driven processoptimering av textilfärgningen förbättrade i varje miljöpåverkans- kategori som studerats. Emellertid har flera utmaningar identifierats som måste  övervinnas för att LCA skall kunna bidra till en hållbar användning av multifunktionella växtbaserade färgämnen för textil. De största utmaningarna är bristen på tillgängliga data i forskningsstadiet och den tvärvetenskapliga forskningsarenan. Det är tänkt att om dessa utmaningar bemästras kan LCA bidra till en hållbar bio-funktionalisering av textil. / <p>Disputationen kan följas via länk i sal U401b, Textilhögskolan, Högskolan i Borås</p> / Erasmus Mundus Joint Doctorate program: Sustainable Management and Design for Textiles

Anthraquinone (AQ) has been used in electron transfer studies in DNA. The focus of this dissertation is the synthesis of conjugates between AQ derivatives and 2’-deoxyadenosine (dA), which can be used to induce adenine oxidation in DNA. Different AQ derivatives were attached to dA via ethynyl or ethanyl linkers. If incorporated into DNA, these short linkers should enable regiocontrol for electron transfer from adenine within the DNA duplex structure. The challenge in working with anthraquinone-2’-deoxynucleosides conjugates is that they and their intermediates are insoluble in water and only sparingly soluble in most organic solvents. A strategy used to overcome this problem was the use of either tert-butyldiphenylsilyl (TBDPS) or 4’,4-dimethoxytrityl (DMTr) 5’-protected deoxynucleosides as starting materials. A water-soluble, ethynyl-linked AQ-dA conjugate with a 3’-benzyl hydrogen phosphate was synthesized using DMTr protection. The DMTr group was not stable to the hydrogenation required to make the ethanyl-linked AQ-dA conjugate with 3’-benzyl hydrogen phosphate. Hence the latter was synthesized starting with the TBDPS protecting group. Both of these syntheses were based on the Pd coupling between ethynylanthraquinone and 8-bromodeoxyadenosine derivatives. New conjugates between AQ and A, in which the AQ moieties have been modified with formyl, trifluoroacetyl and methyl ester groups as electron withdrawing substituents were also synthesized. The synthesis of these AQ-dA conjugates was based on Pd coupling between bromoanthraquinone and 8-ethynyldeoxyadenosine derivatives. This route avoided the use of ethynylanthraquinone derivatives that had extremely low solubility and photoinstability. Other anthraquinones with electron withdrawing groups (which should provide enhanced driving force to enable respective AQ derivative to oxidize adenine) were synthesized as models. Cyclic voltammetry showed that the conjugate with the two ester groups and ethynyl linker was the most easily reduced of the derivatives synthesized. Conjugates between AQ and dU were also synthesized. Those conjugates can potentially be used to oxidize guanine or adenine or they can be used as a deep trap for an electron in reduced DNA.

The three main components of wood, namely, cellulose, hemicellulose, and lignin, can be used in various areas. However, since lignin covalently crosslinks with wood polysaccharides creating networks that is an obstacle for extraction, direct extraction of different wood components in high yield is not an easy matter. One potential approach to overcome such obstacles is to treat the wood with specific enzymes that degrade the networks by specific catalysis. However, the structure of wood is so compact that the penetration of the wood fibers by large enzyme molecules is hindered. Thus, the pretreatment of wood prior to the application of enzymes is necessary, for “opening” the structure. One pretreatment method that was performed in this thesis is based on kraft pulping, which is a well-established and industrialized technique. For untreated wood, the wood fibers cannot be attacked by the enzymes. A relatively mild pretreatment was sufficient for wood polysaccharides hydrolyzed by a culture filtrate. A methanol-alkali mixture extraction was subsequently applied to the samples that were pretreated with two types of hemicellulases, Gamanase and Pulpzyme HC, respectively. The extraction yield increased after enzymatic treatment, and the polymers that were extracted from monocomponent enzyme-treated wood had a higher degree of polymerization. Experiments with in vitro prepared lignin polysaccharide networks suggested that the increased extraction was due to the enzymatic untying. However, the relatively large loss of hemicellulose, particularly including (galacto)glucomannan (GGM), represents a problem with this technique. To improve the carbohydrate yield, sodium borohydride (NaBH4), polysulfide and anthraquinone were used, which increased the yields from 76.6% to 89.6%, 81.3% and 80.0%, respectively, after extended impregnation (EI). The additives also increased the extraction yield from approximately 9 to 12% w/w wood. Gamanase treatment prior to the extraction increased the extraction yield to 14% w/w wood. Sodium dithionite (Na2S2O4) is an alternative reducing agent for the preservation of hemicelluloses because it is less expensive than metal hydrides and only contains sodium and sulfur, which will not introduce new elements to the recovery system. Moreover, Na2S2O4has the potential to be generated from black liquor. Na2S2O4 has some preservation effect on hemicelluloses, and the presence of Na2S2O4 also contributed to delignification. The extraction yield increased to approximately 15% w/w wood. Furthermore, Na2S2O4 has been applied in the kraft pulping process of spruce. The yield and viscosity increased, while the Klason lignin content and kappa number decreased, which represents a beneficial characteristic for kraft pulp. The brightness and tensile strength of the resulting sheets also improved. However, the direct addition of Na2S2O4 to white liquor led to greater reject content. This problem was solved by pre-impregnation with Na2S2O4 and/or mild steam explosion (STEX) prior to the kraft pulping process. Following Na2S2O4 pre-impregnation and mild STEX, the obtained kraft pulp had substantially better properties compared with the properties exhibited after direct addition of Na2S2O4 to the white liquor. The wood structure opening efficiency of mild STEX alone was also tested. The accessibility of the wood structure to enzymes was obtained even at very modest STEX conditions, according to a reducing sugar analysis, and was not observed in untreated wood chips, which were used as a reference. The mechanical effect of STEX appears to be of great importance at lower temperatures, and both chemical and mechanical effects occur at higher STEX temperatures. / <p>QC 20140903</p>

A local integrated pulp and paper Kraft mill had come under pressure from the local communities and mill personnel to reduce the odours that were perceived to be generated at the Farm Dams and irrigation farm situated adjacent to the mill. The typical odours associated with Kraft mills are due to the generation of four reduced sulphur compounds such as hydrogen sulphide (H2S), methyl-mercaptan (CH3SH), dimethyl-sulphide (CH3)2S and dimethyl-disulphide (CH3)2S2. These compounds are collectively referred to as Total Reduced Sulphur (TRS) components which are generated as a direct result of the Kraft pulping and chemical recovery process. These components can either be in the gaseous or aqueous phase depending on the characteristics of the effluent. Gaseous and aqueous TRS profiling of the mill indicated that hydrogen sulphide (H2S) was the main odour component generated and emitted from the Clarifiers and the Treated Effluent Transfer Sump (TETS) at the effluent treatment plant. The hydrogen sulphide (H2S) emission levels were affected by process upsets, sludge removal frequencies, chemical composition of the effluent, Sulphate Reducing Bacteria (SRB) activity, pH and temperature fluctuations. Treatment options such as pH control using slaked lime, dosing of biocides, addition of biomodifiers and/or a sulphate reduction inhibitor were investigated. The use of slaked lime, Ca(OH) 2, for pH control was not practical due to continuous pH fluctuations, increasing the pH would increase the scaling tendencies of the effluent and would also affect the soil cation-anion exchange properties of the irrigated farm land. The use of non-oxidising biocides was effective in reducing SRB activity between 99.2% and 99.8% at dosages between 4 mg/l and 25 mg/l. However, the use of biocides was not considered as a long term treatment option due to the various disadvantages such as the stability of the biocides at fluctuating pH and temperatures, half-life, environmental accumulation, toxicity and costs. The aqueous H2S level was reduced by 79% using different combinations of biomodifiers (nitrates, nitrites, molybdenum). Increasing the dosages of the biomodifiers (> 500mg/l) would be required to increase the reduction of H2S levels by more than 79%. The increased dosages would significantly increase the cost of the treatment programme. The accumulation of nitrates, nitrites and molybdenum could affect the soil texture, cation-anion exchange capacity, permeability, Sodium Absorption Ratio (SAR) and nutrient availability. A more environmentally friendly and cost effective treatment was found using sodium nitrate (biomodifier) together with AQ (sulphate reduction inhibitor). The continuous dosing of 50 mg/l sodium nitrate together with 4 mg/l AQ would be effective in reducing the average aqueous H2S levels (40 mg/l) by at least 92%. This treatment would also be compatible with aeration or oxidation procedures to further increase the removal of H2S to achieve an aqueous H2S level of <1 mg/l. Aeration or oxidation would also increase the dissolved oxygen and COD levels, increase the inhibition of SRB activity and oxidise any reduced sulphur. The dosing of sodium nitrate and AQ to control the generation of H2S is not patented in South Africa. It can, therefore, be used to treat the Kraft mill effluent without violating any intellectual property rights in South Africa. / Dissertation (MSc(Applied Science))--University of Pretoria, 2008. / Chemical Engineering / unrestricted

Das Bodenbakterium Rhodococcus opacus 1CP ist für sein Potenzial bekannt, organische Schadstoffe abzubauen. In dieser Studie lag der Fokus auf zwei Genprodukten, den farbstoffabbauenden Peroxidasen DypA und DypB, welche unter Anwendung von Klonierungs- und Expressionsstrategien mit hohen spezifischen Aktivitäten in reiner Form gewonnen werden konnten. Eine umfassende biochemische Analyse zeigte, dass beide Enzyme in der Lage sind, Farbstoffe unterschiedlicher Klassen, insbesondere jedoch, die als schwer abbaubar geltenden Anthraquinone, strukturell anzugreifen. Damit stellen sie lohnenswerte enzymatische Systeme zum Abbau toxischer Farbstoffe beispielsweise in industriellen Abwässern dar.