La biomasse végétale (source de carbone renouvelable) peut être utilisée pour fabriquer des carburants liquides et produits de base pour la chimie. Ainsi depuis environ une dizaine d'années, se développe le procédé APHDO (Aqueous Phase HydroDeOxygenation) de transformation directe en phase aqueuse de polyols d'origine lignocellulosique (comme le sorbitol) en alcanes valorisables (C5-C6). Ce procédé repose sur une catalyse hétérogène bifonctionnelle métal/acide et fait intervenir des ruptures compétitives de liaisons C-C et C-O. L'objectif de la thèse est de mettre au point des systèmes bimétalliques supportés actifs et sélectifs pour la transformation du sorbitol en hexane. La modification d'un catalyseur de référence Pt/SiO2-Al2O3 par ajout de Re, Ir, Pd, Rh et Ru est effectuée par trois techniques de synthèse : co-imprégnation, imprégnations successives et dépôt par réduction catalytique. Les performances des catalyseurs bimétalliques sont comparées à isoconversion de sorbitol à celles des catalyseurs monométalliques parents pour un test catalytique réalisé en autoclave, avec une solution aqueuse à 10% massique de sorbitol, à 240°C et 60 bar de pression totale sous H2. Les produits se répartissent en phase gaz (CO2, alcanes en C1-C6) et liquide (composés oxygénés). Le sorbitane et l'isosorbide sont majoritairement formés en phase liquide, le dernier étant un intermédiaire clé de la transformation du sorbitol dans cette étude. Les catalyseurs Pt-Ru/SiO2-Al2O3 s'avèrent les plus sélectifs pour la réaction, celui préparé par imprégnations successives conduisant à une plus forte proportion de C6 en phase gaz comparé aux deux monométalliques Pt/SiO2-Al2O3 et Ru/SiO2-Al2O3. / Plant Biomass (renewable source of carbon) can be used to make liquid fuels and basic products of chemistry. So, from about ten years, the APHDO (Aqueous Phase HydroDeOxygenation) process is developed for the direct transformation in aqueous phase of polyols from Biomass (such as sorbitol) into renewable alkanes (C5-C6). This process involves a metal/acid bifunctional heterogeneous catalysis and competitive C-O and C-C bond cleavages. The aim of the PhD work is to develop supported bimetallic systems active and selective for the transformation of sorbitol into hexane. The modification of a reference Pt/SiO2-Al2O3 catalyst by addition of Re, Ir, Pd, Rh and Ru is carried out by three synthesis methods: co-impregnation, successive impregnations and deposit by catalytic reduction. The performances of bimetallic catalysts are compared at sorbitol isoconversion to those of the parent monometallic catalysts for a catalytic test carried out in an autoclave with an aqueous solution of sorbitol (10 wt%) at 240°C and 60 bar total pressure under dihydrogen. The products are distributed in the gas phase (CO2, C1-C6 alkanes) and in the liquid phase (oxygenated compounds). Sorbitan and isosorbide are predominantly formed in the liquid phase, the latter being a key intermediate of sorbitol transformation in this study. Pt-Ru/SiO2-Al2O3 catalysts are the most selective for the reaction, the one prepared by successive impregnations leads to a higher proportion of C6 in gaseous phase compared to both monometallic Pt/SiO2-Al2O3 and Ru/SiO2-Al2O3 catalysts.

Este trabalho teve como objetivo estudar o potencial do uso de farelo obtido do resíduo da extração do pigmento de cúrcuma (Cúrcuma longa L.) na elaboração de filmes biodegradáveis. Primeiramente, foi conduzido um estudo da extração de corante de cúrcuma por método Soxhlet para simular o processo industrial, dessa forma, utilizaram-se dois tipos de solventes, etanol: isopropanol (1:1) e metanol: acetona (1:1). A partir das tortas foi feito um processo de moagem e peneiragem na tentativa de isolar o amido presente, apesar de não ter obtido sucesso, este processo permitiu obter diferentes frações de farelo de cúrcuma. As frações foram divididas em 80 (F1), 200 (F2), 270 (F3), 400 (F4) mesh e fração centrifugada (F5). A caracterização das tortas de cúrcuma e das frações consistiu em análise da composição centesimal, MEV, difração de raios X e FTIR. A partir destas frações foram elaborados filmes pela metodologia casting. Os filmes foram caracterizados por MEV, difração de raios X, FTIR, análise antioxidante, propriedades mecânicas, solubilidade em água, umidade e permeabilidade ao vapor de água. Os filmes feitos a partir das frações (metanol:acetona) apresentaram melhores propriedades mecânicas e de barreira do que os feitos a partir da frações (etanol:isopropanol), porém industrialmente o solvente utilizado para a extração do pigmento é o etanol:isopropanol. Assim, o filme elaborado a partir da fração FE2 (200 mesh) (etanol:isopropanol) foi o escolhido para realizar o estudo de otimização do processo de elaboração destes filmes por ter as melhores propriedades mecânicas e de barreira do que os filmes feitos a partir das frações FE3 e FE5 . Para o estudo da otimização foi desenvolvido um planejamento experimental 22 com quatro pontos axiais e três pontos centrais para estudar o efeito da temperatura de aquecimento (Ta) e do pH da solução filmogênica sobre as propriedades mecânicas, umidade, solubilidade e permeabilidade ao vapor de água dos filmes plastificados com glicerol (22 g de glicerol/100 g da fração) e sorbitol (30 g de sorbitol/100 g da fração). Os resultados foram avaliados utilizando a metodologia de superfície de resposta e análise de multi-resposta. As condições ótimas obtidas para obter filmes com melhores propriedades mecânicas e funcionais foram: T=84,7ºC e pH 8,3, para filmes com glicerol e T=87,6ºC e pH 8,5 para filmes com sorbitol. Os filmes com glicerol quando comparados com o sorbitol, apresentaram menor índice de cristalinidade, menor teor de curcuminóides pela análise por HPLC e DPPH. Os filmes de farelo de cúrcuma com sorbitol foram mais resistentes, pouco elongáveis e menos permeáveis ao vapor de água do que filmes elaborados com glicerol. / This work aimed to study the potential of the bran residue obtained from the extraction of the pigment from turmeric (Curcuma longa L.) in the preparation of biodegradable films. The extraction of the turmeric dye was conducted by Soxhlet procedure in orer to simulate the industrial process. Two types of solvents were employed ethanol isopropanol (1:1) and methanol acetone (1:1). The pies were crushed and sieved in an attempt to isolate the starch, but no success was achieved. However, this process yielded different fractions, which ensured better characterization of the material. The fractions were divided into 80 (F1), 200 (F2), 270 (F3) and 400 (F4) mesh subfractions and centrifuged (F5). The analysis of pies and turmeric fraction were characterized by chemical composition, SEM, XRD and spectroscopy. Films were prepared from these fractions by film casting methodology, and were characterized by SEM, X-ray diffraction and FTIR analysis; they were also analyzed in terms of their antioxidant, mechanical, water solubility, moisture permeability, and water vapor properties. The films prepared from fractions (methanol: acetone) showed better mechanical and barrier properties than those prepared from the fractions (ethanol: isopropanol), but industrially the solvent used for the extraction of pigment is ethanol: isopropanol. Thus, the film prepared from fractional FE2 (200 mesh) (ethanol: isopropanol) which have the best mechanical and barrier properties than the films prepared from fractions from FE3 and FE5, was chosen for the optimization of the preparation of these films. To this end, we developed an experimental design 22 with four axial points and three focal points, for evaluation of the effect of the heating temperature (Ta) and the filmogenic solution pH on the mechanical properties, moisture, solubility, and permeability to water vapor of the films plasticized with glycerol (22 g fraction glycerol/100 g) and sorbitol (30 g sorbitol/100 g fraction). Results were examined by using response surface methodology and analysis multi-response analysis. The optimum conditions for attainment of films with better mechanical properties and functional characteristics were: T = 84.7 º C and pH 8.3 for films with glycerol, and T = 87.6 ° C and pH 8.5 for films with sorbitol. Compared to films plasticized with sorbitol, the films containing glycerol, had lower crystallinity index, lower content of curcuminoids as verified by HPLC analysis and DPPH. The turmeric bran films plasticized with sorbitol were more resistant, less elongated, and slightly permeable to water vapor compared to films prepared with glycerol.

Abiotic stresses are responsible for limiting crop production worldwide. Among diverse abiotic stresses, drought and salinity are the most challenging. Plants under these conditions have diverse strategies for tolerating stress. Osmotic adjustment and osmoprotection occur in plants during salinity and drought stress through accumulation of compatible solutes to a high level without interfering with cellular metabolism. Polyols (sugar alcohols) including sorbitol and ribitol are one such class of compatible solutes. Using plants of wild-type (WT) and three genetically-modified lines of tomato (Solanum lycopersicum cv. ‘Ailsa Craig’), an empty vector line ‘TR22’, and 2 sdh anti-sense lines ‘TR45’, and ‘TR49’ designed to severely limit sorbitol metabolism, the objective of this work was to characterize the sorbitol cycle in tomato in response to abiotic stresses. Sorbitol and ribitol content, as well as the enzymatic activities, protein accumulation, and gene expression patterns of the key sorbitol cycle enzymes ALDOSE-6-PHOSPHATE REDUCTASE (A6PR), ALDOSE REDUCTASE (AR), and SORBITOL DEHYDROGENASE (SDH), were measured in mature leaves in response to drought stress by withholding water and by using polyethylene glycol as a root incubation solution to mimic drought stress, to salt stress by incubating roots in NaCl solution, and to incubation of roots in 100 mM sorbitol and ribitol. A6PR, not previously reported for tomato, and AR both exhibited increased activity correlated to sorbitol accumulation during the drought osmotic, and salt stresses, with SDH also increasing in WT and TR22 to metabolize sorbitol. The level of sorbitol accumulation was considerably lower than that of the common sugars glucose and fructose so was not enough to have a significant impact on tissue osmotic potential but could provide other important osmoprotective effects. Use of the sdh antisense lines indicated that SDH has the key role in sorbitol metabolism in tomato as well as a likely role in ribitol metabolism. Like sorbitol, ribitol also accumulated significantly more in the antisense lines during the stresses. Expression and/or activity of A6PR, AR, and SDH were also induced by the polyols, although it is not clear if the induction was due to a polyol signal, the osmotic effect of the incubation solution, or both. In addition, a unique post-abiotic stress phenotype was observed in the sdh anti-sense lines. After both drought and salt stresses and during a recovery phase after re-watering, the antisense lines failed to recover. This may have been due to their accumulation of ribitol. The sdh anti-sense lines were uniquely sensitive to ribitol but not sorbitol, with an apparent foliar and seed germination toxicity to ribitol. The determination that sorbitol, and perhaps ribitol as well, plays a role in abiotic responses in tomato provides a cornerstone for future studies examining how they impact tomato tolerance to abiotic stresses, and if their alteration could improve stress tolerance.

Supercritical fluids have unique properties which may make them ideal as reaction media for biotransformation or extractive solvents. Supercritical fluids are ideal for reducing diffusivity limitations over conventional fluids. Depending on the polarity of the fluid, a supercritical fluid can be similar to conventional organic solvents, but with few of the environmental drawbacks. The use of supercritical fluids in enzymatic research has the advantage of removing mass transport limitations so that they can act as a suitable solvent. In this study, four permeabilization techniques were compared: control, toluene, supercritical carbon dioxide, and freeze/thaw cycles. The model cell systems studied were Z. mobilis and E. coli. The cells were analyzed for lipid profiles, recovery of proteins and enzymatic activity. The use of supercritical carbon dioxide may not be the most effective of the treatments based on total protein or enzyme recovery since the greatest protein and enzyme recovery was with the freeze/thaw treatment. However, it can be selective in removing cofactors from Z. mobilis enabling sorbitol production and minimizing side reactions. In this application, supercritical carbon dioxide does show an advantage over the freeze/thaw treatment. Aspects of the mechanism of permeabilization were investigated based on the lipid profiles of the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM and AFM show changes of the cell surface morphology which indicate that the treatments affect the cellular surface. The use of supercritical carbon dioxide as a reaction medium was investigated. Minute quantities of sorbitol were produced when Z. mobilis and sugars were placed in a supercritical carbon dioxide environment over a period of 24 hours.

Supercritical fluids have unique properties which may make them ideal as reaction media for biotransformation or extractive solvents. Supercritical fluids are ideal for reducing diffusivity limitations over conventional fluids. Depending on the polarity of the fluid, a supercritical fluid can be similar to conventional organic solvents, but with few of the environmental drawbacks. The use of supercritical fluids in enzymatic research has the advantage of removing mass transport limitations so that they can act as a suitable solvent. In this study, four permeabilization techniques were compared: control, toluene, supercritical carbon dioxide, and freeze/thaw cycles. The model cell systems studied were Z. mobilis and E. coli. The cells were analyzed for lipid profiles, recovery of proteins and enzymatic activity. The use of supercritical carbon dioxide may not be the most effective of the treatments based on total protein or enzyme recovery since the greatest protein and enzyme recovery was with the freeze/thaw treatment. However, it can be selective in removing cofactors from Z. mobilis enabling sorbitol production and minimizing side reactions. In this application, supercritical carbon dioxide does show an advantage over the freeze/thaw treatment. Aspects of the mechanism of permeabilization were investigated based on the lipid profiles of the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM and AFM show changes of the cell surface morphology which indicate that the treatments affect the cellular surface. The use of supercritical carbon dioxide as a reaction medium was investigated. Minute quantities of sorbitol were produced when Z. mobilis and sugars were placed in a supercritical carbon dioxide environment over a period of 24 hours.

In this study, recombinant human growth hormone (rhGH) production by Pichia pastoris-Mut+ strain was improved by designing feeding strategies which were applied in the production phase of the bioreactor operations. During the bio-reactor experiments the cell growth, sorbitol and methanol consumptions, recom-binant hGH production, alcohol oxidase (AOX) activity, the by-products protease and organic acid concentrations were followed and analyzed. In this context, in the first part of the study, three bioreactor operations were designed and per-formed. In general, the designed strategies are fundamentally based on simulta-neous feeding of the two substrates starting at t=0 h of the production phase, i.e., batch-wise 50 gL-1sorbitol feeding, together with fed-batch methanol feeding with a specific growth rate of &mu / 0=0.03 h-1 or &mu / 0=0.04 h-1, and fed-batch sorbitol feeding with a specific growth rate of &mu / 0=0.025h-1 which was calculated based on the specific consumption rate qS=0.152 g g-1h-1 of sorbitol. Consequently, sorbitol concentration was kept constant at 50 gL-1 within t=0-15h of the production phase / where, sorbitol feeding was terminated at t=15h. Amongst, in the first strategy (SSM1), methanol was fed to the system with the specific growth rate of &mu / 0=0.03 h-1, and the H+ concentration (pH) in the bioreactor was kept constant at pH=5.0. In the second strategy (SSM2), pH was kept constant at 5.5 until t=24h of the induction phase (production phase), thereafter, was reduced to pH= 5.0 / where methanol was fed to the bioreactor with the specific growth rate of &mu / 0=0.03 h-1. In the third strategy (SSM3), methanol was fed with the specific growth rate of &mu / 0=0.04 h-1, and the pH in the bioreactor was kept constant at pH 5.0. The highest rhGH production and cell concentration were achieved in the first strategy SSM1 as CrhGH=640 mg L-1 and CX=105.3 g L-1, and the overall cell and product yields on total substrate were calculated as YX/S =0.21 g g-1 and YCrhGH/S =1.83 mg g-1. In the second part of this study the two-substrates sorbitol and methanol were fed simultaneously in a solution compose of 1.37 mol sorbitol and 6.21 mol methanol in 13.88 mol water, which is named as SM. In this strategy (SM), the two-substrate solution was fed to the medium with the specific growth rate of &mu / 0=0.03 h-1 on sorbitol until t=30h / thereafter, only methanol was fed to the bio-reactor with the specific growth rate of &mu / 0=0.03 h-1. The highest cell and rhGH concentrations obtained in SM were, respectively, Cx=104.7 g L-1 and CrhGH=124 mg L-1 / and the overall cell and product yields on the total substrate were calcu-lated as YX/S=0.21 g g-1 and YCrhGH/S=0.39 mg g-1. Although the highest cell con-centration obtained at SM is close to that of the SSM1, the rhGH concentration obtained at SM is 5.2-fold lower than that of the strategy SSM1.

The effects of AVG, an inhibitor of ethylene synthesis, in combination with MCP or heat treatment (HT) on quality traits of several apple cultivars after harvest (AH) or cold storage (ACS), and the involvement of ethylene in the regulation of SDH activity during the last weeks of fruit development were studied. AVG was applied to Royal Gala, Lodi, Senshu, Redchief Delicious and Red Fuji trees 4 weeks before normal harvest (H1). Control and AVG-treated (AVG) fruit were harvested at H1 and treated with MCP or air-heated. Fruit were ripened at room temperature (RT) AH or ACS. Some AVG fruit were harvested at H1 and 1 to 2 weeks after H1 (H2), or at H2 only. Ethylene production (EP), respiration rate (RR), firmness, starch index (SI), titratable acidity (TA), volatile production (VP) and AAT activity, among others, were measured AH and ACS. Peel and cortex of Gala were alcohol-fed and ester production quantified. EP and SDH presence and activity were measured at various harvest dates on control and AVG Lodi, Red Delicious and Fuji apples. AVG plus MCP was more effective in reducing HEP, RR, firmness and TA loss than either treatment alone; it did not provide further control on SI and did not repress Gala red skin color development more than AVG alone, though it consistently repressed VP. AVG plus HT was generally more effective than single treatments in reducing HEP, RR and firmness loss during storage. It was not different than the single treatments on TA, SI, and VP. The effect of AVG plus HT on fruit quality ACS was cultivar-dependent. AVG plus HT was not enough to maintain the quality of the earlyharvest cultivars, and it did not improve fruit quality of late-harvest cultivars. The effects of AVG plus MCP but not of AVG plus HT were evident at H2. Precursor availability was the major factor limiting VP, suggested by the low VP when RR was low, the increase in ester production in alcohol-fed samples, and the lack of correlation between AAT and ester production. SDH activity or expression was not affected by a reduction in ethylene production.

Two force fields, the GROMOS53A5/53A6 (united atom) and the AMBER95 (all atom) parameter sets, coupled with partial atomic charges derived from quantum mechanical calculations were evaluated for their ability to reproduce the known crystalline forms of the polyols mannitol and sorbitol. The force fields were evaluated using molecular dynamics simulations at 10 K (which is akin to potential energy minimization) with the simulation cell lengths and angles free to evolve. Both force fields performed relatively poorly, not being able to simultaneously reproduce all of the crystal structures within a 5% deviation level. The parameter sets were then systematically optimized using sensitivity analysis, and a revised AMBER95 set was found to reproduce the crystal structures with less than 5% deviation from experiment. The stability of the various crystalline forms for each of the parameter sets (original and revised) was then assessed in extended MD simulations at 298 K and 1 bar covering 1 ns simulation time. The AMBER95 parameter sets (original and revised) were found to be effective in reproducing the crystal structures in these more stringent tests. Remarkably, the performance of the original AMBER95 parameter set was found to be slightly better than that of the revised set in these simulations at 298 K. The results of this study suggest that, whenever feasible, one should include molecular simulations at elevated temperatures when optimizing parameters. / Dutch Top Institute Pharma

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Quimica. / Made available in DSpace on 2012-10-24T15:03:40Z (GMT). No. of bitstreams: 1 266669.pdf: 2251672 bytes, checksum: 4670a0dfd5caff713b421ebabbbe066c (MD5) / As condições severas do processo de purga empregado tradicionalmente em fibras celulósicas ocasionam um ataque generalizado, especificamente em tecidos 100% algodão, resultando em elevada perda de massa e diminuição da resistência das fibras. A substituição do processo de purga alcalina pela enzimática, além de permitir menor agressão química às fibras, devido à elevada especificidade das enzimas às substâncias que necessitam serem removidas como gorduras, proteínas, entre outras. Também possibilitam produtos acabados com melhores características de toque e resistência. Muitas enzimas já foram testadas para a remoção das substâncias hidrofóbicas das fibras, entretanto poucos são os estudos para a remoção dos fragmentos das cascas do capulho e gravetos presentes nas malhas produzidos por fios de algodão cardado. Neste trabalho foram avaliados a termoestabilidade do caldo bruto centrifugado de Bacillus pumilus CBMAI 0008 e a influência da interação entre a enzima e substâncias químicas frequentemente utilizadas no processamento têxtil tais como os agentes tensoativos, ácidos e bases utilizados para a correção de pH, a adição de polióis para a estabilização enzimática e também o efeito de inibição ou ativação da atividade enzimática na presença de íons que comporiam as fibras de algodão. Utilizou-se como parâmetro de comparação à preparação comercial Pulpzyme HC (Novozymes), que possui o mesmo tipo de atividade de endoxilanase. Os efeitos inibitórios decorrentes dos íons presentes na fibra de algodão poderiam impossibilitar a utilização da purga enzimática de substratos têxteis, especificamente malha de fio cardado 100% algodão. Dentre os reagentes testados, o KCl, NaCl and (NH4)2SO4 promoveram aumento na atividade quando utilizados na concentração de 5,0 mM. Dentre as diversas condições testadas constatou-se que o sorbitol 1,0 M, em tampão glicina-NaOH 0,01 M, com 5,0 g/L de umectante e 37,5 minutos de incubação são condições capazes de manter 62,94% da atividade inicial da enzima, e que o emulsificante não tem efeito significativo sobre a atividade da enzima. O agente umectante apresentou efeito significativo, provavelmente por ser composto por álcoois alifáticos. Os resultados da biopurga com xilanase mostraram que a enzima não apresentou o efeito desejado como agente de biopurga, considerando-se os padrões de qualidade exigidos pela indústria.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Quimica. / Made available in DSpace on 2012-10-23T12:03:07Z (GMT). No. of bitstreams: 1 244419.pdf: 4453366 bytes, checksum: 73a3c9da4be0dc42e984cc60b862f368 (MD5) / O objetivo geral deste estudo foi desenvolver e caracterizar filmes formados por blendas de gelatina, um polímero natural e poli(acrilamida-co-ácido acrílico), um polímero sintético, em diferentes proporções, combinando a biodegradabilidade da proteína e as propriedades mecânicas do componente sintético. Para promover uma melhora em algumas de suas propriedades, foi adicionado sorbitol como agente plastificante e hidrocloreto de 1-etil-3-(3-dimetilaminopropil) carbodiimida (EDC) como agente de reticulação. Estes filmes foram caracterizados quanto às suas propriedades térmicas (através de análise termogravimétrica - TGA, calorimetria diferencial de varredura - DSC e análise termomecânica - TMA), estruturais por espectroscopia de infravermelho com transformada de Fourier - FTIR e morfológicas através de microscopia eletrônica de varredura - MEV. As propriedades mecânicas (tensão de ruptura - TR, porcentagem de elongação - %E e módulo de Young - MY) foram também investigadas, assim como ensaios de absorção de vapores de água na umidade relativa de 98%. As análises de DSC e TMA indicaram miscibilidade entre os componentes, comprovada pela presença de uma única temperatura de transição vítrea e pela homogeneidade dos filmes formados. A adição de sorbitol nas blendas provocou uma pequena diminuição na estabilidade térmica dos filmes, na temperatura de transição vítrea, na tensão de ruptura e no módulo de Young, acompanhada de um aumento na elongação e na absorção de vapores de água. Os filmes reticulados apresentaram um grau máximo de reticulação de 70%. Este processo alterou também algumas das propriedades dos filmes, como temperatura de transição vítrea, tensão de ruptura e módulo de Young, para valores menores e aumentou consideravelmente a elongação dos filmes e a absorção a vapores de água, sugerindo que o processo de reticulação causou uma desestabilização na estrutura da gelatina. Características como baixa solubilidade em água e alta porcentagem de elongação são favoráveis a aplicação destes materiais como embalagens.