Yes / Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phenols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating conditions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive potentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly catalyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

Yes / Platinum complexes are the most widely used anticancer drugs; however, new generations of agents are needed. The organoiridium(III) complex [(η5-Cpxbiph)Ir(phpy)(Cl)] (1-Cl), which contains π-bonded biphenyltetramethylcyclopentadienyl (Cpxbiph) and C^N-chelated phenylpyridine (phpy) ligands, undergoes rapid hydrolysis of the chlorido ligand. In contrast, the pyridine complex [(η5-Cpxbiph)Ir(phpy)(py)]+ (1-py) aquates slowly, and is more potent (in nanomolar amounts) than both 1-Cl and cisplatin towards a wide range of cancer cells. The pyridine ligand protects 1-py from rapid reaction with intracellular glutathione. The high potency of 1-py correlates with its ability to increase substantially the level of reactive oxygen species (ROS) in cancer cells. The unprecedented ability of these iridium complexes to generate H2O2 by catalytic hydride transfer from the coenzyme NADH to oxygen is demonstrated. Such organoiridium complexes are promising as a new generation of anticancer drugs for effective oxidant therapy. / We thank the ERC (247450), SNSF (PA00P2_145308 for N.P.E.B.), IAS (for I.R.C.), BBSRC (for J.M.H.), Science City (AWM and ERDF), and the EPSRC for support, and Prof. Timothy Bugg and members of EC COST Action CM1105 for stimulating discussions. We also thank Professor Pat Unwin, Mike Snowden, and Rob Lazenby for their help with the electrochemical experiments and the National Cancer Institute for NCI-60 human tumor cell panel screening.

Microbial fuel cell (MFC) technology is a renewable energy source that employs microorganisms as biocatalysts to degrade substrates into electrons and protons, and then transfer the electrons to the anode electrode. Electron transfer rates by microorganisms depend on many factors as well as on their diverse electron transfer mechanisms. The present study compared cytochromes, flavoproteins, electron transfer complexes, redoxins and other extracellular membrane proteins that have direct involvement in electron transfer mechanisms in Escherichia coli str. K-12 MG1655, Rhodopseudomonas pulastris DX-1 and Shewanella oneidensis MR-1. Escherichia coli str. The results showed that K-12 MG1655 had a more diverse range of extracellular proteins for electron transfer mechanisms compared to Rhodopseudomonas pulastris DX-1 and Shewanella oneidensis MR-1. Escherichia coli str. K-12 MG1655 expressed more flavoproteins, redoxin and electron transfer complex related proteins that had direct involvement in electron transfer mechanisms compared to two other bacterial species indicating that it may be able to transfer more electrons when employed in MFC technique. Escherichia coli str. K-12 MG1655 expressed 16 cytochromes, 9 flavoproteins, 6 redoxins, 6 electron transport complexes, 1 hypothetical and 1 oxidoreductase proteins. On the other hand, Rhodopseudomonas pulastris DX-1 and Shewanella oneidensis MR-1 expressed 26 and 35 cytochromes proteins. But these two bacterial species expressed less flavoproteins and redoxin related proteins and they didn’t express any electron transport complexes or hypothetical and oxidoreductase related proteins for electron transfer. STRING and SMART results suggested that the identified proteins transferred electrons either by connecting with other types of identified proteins in the constructed gene network or independently by taking part in oxidation-reduction reaction, metal ion reduction reaction or by their FMN binding activities.

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24668号 / 農博第2551号 / 新制||農||1099(附属図書館) / 学位論文||R5||N5449(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 小川 順, 教授 栗原 達夫, 教授 伊福 健太郎 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

No description available.

Este trabalho teve como objetivo sintetizar e caracterizar uma matriz híbrida estável de poli(estireno-co-divinilbenzeno) magnetizado pela adição de magnetita (Fe3O4) e avaliar seu potencial como suporte para a imobilização de lipases. A matriz híbrida foi sintetizado pela técnica de polimerização em suspensão utilizando dos monômeros de estireno e divinilbenzeno e ao qual foram adicionadas partículas de magnetita preparadas por coprecipitação dos íons Fe+2 e Fe+3. A caracterização foi realizada pelas técnicas de microscopia eletrônica de varredura (MEV), espectroscopia na região do infravermelho por transformada de Fourier (FTIR), difratometria de raios-X (DRX) e magnetização de amostra vibrante (VSM), comparando os materiais magnetizados e não magnetizados. Os biocatalisadores foram preparados pela imobilização da lipase de Candida rugosa (LCR) e lipase PS Burkholderia cepacia (LPS) via adsorção física e foram caracterizados em função da influência de pH e temperatura na atividade hidrolítica, parâmetros cinéticos, estabilidade térmica, estabilidade operacional e estabilidade de estocagem. O derivado de LCR foi aplicado em reações de esterificação e o derivado de LPS em reações de transesterificação. Os resultados obtidos pelas análises de FTIR, DRX e VSM confirmaram que a magnetita foi incorporada ao polímero, gerando atração das partículas por um campo magnético externo. A caracterização bioquímica indicou forte influência do pH na atividade hidrolítica, apresentando ponto ótimo próximo a 8,0 tanto para as lipases livres quanto imobilizadas. Os biocatalisadores magnetizados preparados apresentaram bom desempenho em todos os aspectos, o derivado da lipase de Candida rugosa alcançou conversões entre 89-94% nas reações de esterificação, revelando tempo de meia vida de t1/2=52 dias na estabilidade operacional. O derivado de Burkholderia cepacia atingiu rendimentos próximos a 80% nas reações de transesterificação com t1/2=40 dias. A imobilização aumentou a estabilidade térmica das lipases em 50 vezes no caso da LCR e em 2,3 vezes para a LPS. Estes resultados indicam que o material híbrido magnetizado sintetizado possui grande potencial para ser utilizado como suporte na imobilização de enzimas com aplicação em reações de interesse industrial. / This study aimed to synthesize and characterize a stable hybrid matrix of poly (styrene-codivinylbenzene) magnetized by the addition of magnetite (Fe3O4) and evaluate its potential for application in the immobilization of lipases, by characterization of the prepared biocatalysts. The support was synthesized by the suspension polymerization technique by applying styrene and divinylbenzene monomers and adding magnetite particles synthesized by co-precipitation of Fe + 2 and Fe + 3. The characterization of the material was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetization (VSM), by comparison of the magnetized and the not magnetized particles. The biocatalysts were prepared by immobilization of lipase from Candida rugosa (CRL) and lipase from Burkholderia cepacia (Lipase PS) via physical adsorption and they were characterized according to the influence of pH and temperature on the hydrolytic activity, kinetic parameters, thermal stability, operational stability and storage stability. The CRL derivative was applied in esterification reactions and the lipase PS derivative was applied in transesterification reactions. The results obtained by the analysis FTIR, XRD and VSM confirmed the magnetite was successfully incorporated into the polymer and generated the atraction for an external magnetic field. Biochemical characterization indicated a strong influence of pH on the hydrolytic activity, showing better results on pH around 8,0 for free and both immobilized lipases. The magnetized biocatalysts prepared had good performance in all respects, derivative from Candida rugosa lipase reached 89-94% conversion in esterification reactions showing half-life of operational stability t1 / 2 = 52 days. The immobilized lipase from Burkholderia cepacia reached yields close to 80% in transesterification reactions presenting t1/2 = 40 days. Immobilization increased the thermal stability of lipase by 50 times in the case of CRL and 2,3 times for Lipase PS. These results indicate that the magnetized hybrid material synthesized has great potential to be used as a support for the immobilization of enzymes for use in reactions of industrial interest.

Este trabalho teve como objetivo sintetizar e caracterizar uma matriz híbrida estável de poli(estireno-co-divinilbenzeno) magnetizado pela adição de magnetita (Fe3O4) e avaliar seu potencial como suporte para a imobilização de lipases. A matriz híbrida foi sintetizado pela técnica de polimerização em suspensão utilizando dos monômeros de estireno e divinilbenzeno e ao qual foram adicionadas partículas de magnetita preparadas por coprecipitação dos íons Fe+2 e Fe+3. A caracterização foi realizada pelas técnicas de microscopia eletrônica de varredura (MEV), espectroscopia na região do infravermelho por transformada de Fourier (FTIR), difratometria de raios-X (DRX) e magnetização de amostra vibrante (VSM), comparando os materiais magnetizados e não magnetizados. Os biocatalisadores foram preparados pela imobilização da lipase de Candida rugosa (LCR) e lipase PS Burkholderia cepacia (LPS) via adsorção física e foram caracterizados em função da influência de pH e temperatura na atividade hidrolítica, parâmetros cinéticos, estabilidade térmica, estabilidade operacional e estabilidade de estocagem. O derivado de LCR foi aplicado em reações de esterificação e o derivado de LPS em reações de transesterificação. Os resultados obtidos pelas análises de FTIR, DRX e VSM confirmaram que a magnetita foi incorporada ao polímero, gerando atração das partículas por um campo magnético externo. A caracterização bioquímica indicou forte influência do pH na atividade hidrolítica, apresentando ponto ótimo próximo a 8,0 tanto para as lipases livres quanto imobilizadas. Os biocatalisadores magnetizados preparados apresentaram bom desempenho em todos os aspectos, o derivado da lipase de Candida rugosa alcançou conversões entre 89-94% nas reações de esterificação, revelando tempo de meia vida de t1/2=52 dias na estabilidade operacional. O derivado de Burkholderia cepacia atingiu rendimentos próximos a 80% nas reações de transesterificação com t1/2=40 dias. A imobilização aumentou a estabilidade térmica das lipases em 50 vezes no caso da LCR e em 2,3 vezes para a LPS. Estes resultados indicam que o material híbrido magnetizado sintetizado possui grande potencial para ser utilizado como suporte na imobilização de enzimas com aplicação em reações de interesse industrial. / This study aimed to synthesize and characterize a stable hybrid matrix of poly (styrene-codivinylbenzene) magnetized by the addition of magnetite (Fe3O4) and evaluate its potential for application in the immobilization of lipases, by characterization of the prepared biocatalysts. The support was synthesized by the suspension polymerization technique by applying styrene and divinylbenzene monomers and adding magnetite particles synthesized by co-precipitation of Fe + 2 and Fe + 3. The characterization of the material was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetization (VSM), by comparison of the magnetized and the not magnetized particles. The biocatalysts were prepared by immobilization of lipase from Candida rugosa (CRL) and lipase from Burkholderia cepacia (Lipase PS) via physical adsorption and they were characterized according to the influence of pH and temperature on the hydrolytic activity, kinetic parameters, thermal stability, operational stability and storage stability. The CRL derivative was applied in esterification reactions and the lipase PS derivative was applied in transesterification reactions. The results obtained by the analysis FTIR, XRD and VSM confirmed the magnetite was successfully incorporated into the polymer and generated the atraction for an external magnetic field. Biochemical characterization indicated a strong influence of pH on the hydrolytic activity, showing better results on pH around 8,0 for free and both immobilized lipases. The magnetized biocatalysts prepared had good performance in all respects, derivative from Candida rugosa lipase reached 89-94% conversion in esterification reactions showing half-life of operational stability t1 / 2 = 52 days. The immobilized lipase from Burkholderia cepacia reached yields close to 80% in transesterification reactions presenting t1/2 = 40 days. Immobilization increased the thermal stability of lipase by 50 times in the case of CRL and 2,3 times for Lipase PS. These results indicate that the magnetized hybrid material synthesized has great potential to be used as a support for the immobilization of enzymes for use in reactions of industrial interest.

Made available in DSpace on 2015-04-22T22:17:32Z (GMT). No. of bitstreams: 1 DISSERTACAO-IZABELLE PINTO.pdf: 1098514 bytes, checksum: 770a915e1472a52e0bb9eb26759a1fea (MD5) Previous issue date: 2010-09-26 / Fundação de Amparo à Pesquisa do Estado do Amazonas / The cupuassu plant (Theobroma grandiflorum (Willdenow ex Sprengel) Schumann) is widespread in the wild or cultivated form throughout the north of Brazil. The fruit contains an average of 32 seeds per fruit, corresponding 20% to 30% of the fruit, but they are usually discarded, although they can be used to produce a kind of chocolate called "cupulate", using the same process of cocoa (Theobroma cacao L.), except the step to remove the pulp until obtain the fermented and dried seeds, because they belong to the same genus. Fermentation of cocoa and cupuaçu beans involves microbial processes and the action of enzymes that act on the physical, chemical and biochemical reactions responsible for developing the precursors of the flavor and taste of chocolate. Among these changes can be noted the hydrolysis of proteins to form peptides and amino acids and the hydrolysis of sucrose on glucose and fructose. The products of these reactions during roasting, by means of the Maillard reaction, contribute to the formation of the flavor of chocolate. Due to lack of information about the action of enzymes in fermented cupuassu seeds, the objective of this study was to determine the enzymes present during the different stages of fermentation of cupusassu seeds (Theobroma grandiflorum (Willdenow ex Sprengel) Schumann) and also analyze variations in temperature, pH and acidity during the process and establish the relationship with the production of these enzymes during fermentation. The fermentation of cupuassu beans was carried in wooden boxes with a capacity of 25 kg for a period of 7 days, according to the recommendations proposed by Venturieri (1988). The seeds, every 24 hours, were removed from the surface, middle and bottom of the boxes for the determination of pH and acidity and to make acetone powder which was used as a source of enzymes. It was detected the presence of amylase, cellulase, invertase, pectinesterases, polygalacturonase, peroxidase, polyphenol oxidases, proteases and lipases. The maximum temperature of cupuassu seeds was 46.7 º C after 72 h of fermentation. The mean pH and acidity were inversely proportional with the pH ranged from 3.92, on zero time, to 6.32 after 168 h of fermentation and the average acidity ranged from 17.29 to 4.89 meq NaOH / 100 g of dry seed. All the enzymes, except protease, showed maximum enzyme activity in the first 72 hours of fermentation, coinciding with the anaerobic phase of fermentation, where temperatures ranged from 35 to 47 °C and pH varied from 4.2 to 4.6. There was a correlation between the enzymatic activity of alpha-amylase, beta-amylase, peroxidase and polygalacturonase with the fermentation time and also with the pH and acidity measured during the 7 days of fermentation cupuassu beans. The temperature did not exert any influence on the activity of these enzymes. The Invertase and pectniesterase were influenced only by the fermentation temperature. The other parameters had no effect on enzyme activity of these enzymes. The incubation time, pH, temperature and acidity measured during the 168 hours of cupuassu seeds fermentation had no significative influence on the enzymatic activity of cellulase, lipase, protease and polyphenoloxidase. / O cupuaçuzeiro (Theobroma grandiflorum (Willdenow ex Sprengel) Schumann) se encontra disseminado, em estado silvestre ou cultivado, por toda a região Norte. O fruto contém em média 32 sementes por fruto e estas correspondem de 20 a 30% do fruto, porém são geralmente descartadas, apesar de poderem ser usadas na fabricação de um tipo de chocolate, denominado cupulate , seguindo-se o mesmo processo do cacau (Theobroma cacao L.), pois pertencem ao mesmo gênero, excetuando-se a etapa de despolpamento, até obtenção das sementes fermentadas e secas. A fermentação das sementes de cacau e cupuaçu envolve processos microbianos e ação de enzimas que atuam nas reações físico-químicas e bioquímicas responsáveis pelo desenvolvimento dos precursores do sabor e aroma do chocolate. Dentre estas modificações pode-se ressaltar a hidrólise de proteínas formando peptídeos e aminoácidos e a hidrólise da sacarose em glicose e frutose. Os produtos destas reações durante a torrefação, por meio da reação de Maillard, contribuem para a formação do flavor do chocolate. Devido à ausência de informações sobre a ação de enzimas em sementes de cupuaçu fermentadas, este estudo teve como objetivo determinar as enzimas presentes durante as diferentes fases de fermentação das sementes do cupuaçu (Theobroma grandiflorum (Willdenow ex Sprengel) Schumann) e, também, analisar as variações de temperatura, pH e acidez durante o processo, estabelecendo uma relação com a produção dessas enzimas durante a fermentação. A fermentação das sementes de cupuaçu foi realizada em caixas de madeira com capacidade de 25kg por um período de 7 dias, de acordo com as recomendações propostas por Venturieri (1988). As sementes, a cada 24h, foram retiradas da superfície, meio e fundo das caixas, para a determinação de pH e acidez e produção do pó cetônico que foi utilizado como fonte de enzimas, tendo sido detectadas a presença de amilases, celulases, invertases, pectinesterases, poligalacturonases, peroxidases, polifenoloxidases, proteases e lipases. Durante a fermentação, a temperatura máxima foi registrada nas 72 h de fermentação, os comportamentos do pH e da acidez foram inversamente proporcionais, tendo o pH aumentado de 3,92 no tempo zero para 6,32 nas 168 h de processo fermentativo, e a acidez baixou de 17,29 para 4,89 meq de NaOH/100 g de semente seca. A celulase e a poligalacturonase tiveram atividade máxima nas 48 h de fermentação com aumento de 57 % e 13 % da atividade inicial. A pectinesterase não teve variações significativas da atividade. A ação da invertase variou conforme a temperatura, apresentando média de maior atividade nas 72 h de processo fermentativo. Com relação às amilases, obteve-se perfis diferentes, sendo que a a-amilase mostrou-se inativa a partir de 96 h de fermentação enquanto que a b-amilase foi ativa durante todo o processo. As proteases revelaram dois picos de atividade, nas 24 e 120 h, podendo significar a presença de dois tipos de enzimas proteolíticas. As polifenoloxidases e as peroxidases tiveram maior atividade com 24 h de fermentação e apresentaram atividades médias inferiores às encontradas em fermentações com sementes de cacau. A lipase apresentou maior média de atividade com 72 h de fermentação.

No description available.

Une attention croissante est portée aux cascades multi enzymatiques pour l’élaboration de procédés de synthèse plus efficaces. Cependant, le contrôle de l’expression hétérologue de plusieurs gènes dans un même hôte s’avère difficile et peut mener à un déséquilibre du flux réactionnel. Pour exploiter au mieux les avantages d’une cascade in vivo, il est nécessaire d’ajuster les activités de chaque étape, et de construire des catalyseurs cellulaires capables de programmer la stœchiométrie des enzymes. Nous avons développé dans ce projet une approche originale pour moduler le ratio de deux enzymes in cellulo en jouant sur le nombre de copies de plasmides par cellule (PCN). Nous avons choisi comme modèle un système autosuffisant associant une Alcool Déshydrogénase (ADH) et une Baeyer-Villiger MonoOxygenase (BVMO), NADP(H)-dépendantes. Plusieurs plasmides recombinants portant les deux gènes ont été conçus et combinés dans E. coli. Les souches de co-expression construites ont été comparées en termes de PCN, de production d’enzymes et d’activité. Nous avons montré l’importance d’un choix judicieux de la combinaison de plasmides ainsi que l’existence d’une corrélation entre ratios d’enzymes et activité. Nos biocatalyseurs s’étendent sur une gamme allant du système inactif à un système affichant un TTN d’environ 6000. Ce système a permis la synthèse de lactones d’intérêt industriel, la dihydrocoumarine et la caprolactone, à partir d’indanol et de cyclohexanol. Enfin, sur ce modèle de combinaison de plasmides, trois nouveaux biocatalyseurs cellulaires, associant l’ADH à diverses BVMOs, ont été créés afin d’élargir la gamme d’esters et de lactones synthétisables à partir d’alcools. / Growing attention is paid to multienzymatic cascades to develop more efficient synthetic processes. However, in in cellulo process, the control of the simultaneous heterologous expression of several genes in the same host is often difficult and can lead to imbalances in the reaction flow. To exploit the benefits of cascades, activities of each step have to be adjusted and thus, cellular biocatalysts capable of programming enzymes stoichiometry have to be constructed. In this work, to modulate the stoichiometry of two enzymes in vivo, we developed an original approach based on the copy number per cell of plasmids (PCN) used as vectors. The PCN is regulated in bacteria by three main mechanisms leading, according to the replicon, to low, medium or high PCN. As proof of concept, we chose a self-sufficient system combining an Alcohol Dehydrogenase (ADH) and a Baeyer-Villiger MonoOxygenase (BVMO), both NADP(H)-dependent. Several recombinant plasmids harboring both genes were designed and combined in E. coli. Coexpression strains constructed were compared in terms of PCN, enzyme production and activity. We showed the importance of a judicious choice of plasmids combination and the existence of a correlation between enzymes ratios and activity. Our biocatalysts ranged from an inactive system to a system with a TTN of about 6000. This system allowed the synthesis of lactones of industrial interest, dihydrocoumarin and caprolactone, via double oxidation of indanol and cyclohexanol. Finally, based on this plasmids combination model, three new cellular biocatalysts combining ADH with various BVMOs were designed to broaden the range of esters and lactones synthesizable from alcohols.