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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biotransformations of Turpentine Constituents : Oxygenation and Esterification

Lindmark-Henriksson, Marica January 2003 (has links)
This thesis describes methods to obtain value–addedcompounds from TMP-turpentine obtained from the spruce, Piceaabies. The methodology focuses on biotransformations using twoapproaches: an oxygenation approach (i.e. oxygenation ofterpene hydrocarbons by cell cultures) and an esterificationapproach (i.e. lipase-catalysed transesterification of vinylacetate with terpene alcohols, and a further fractionation ofthe TMP-turpentine). The main constituents of the turpentine, a-pinene, b-pineneand limonene, were subjected to a P. abies suspension culture.Allylic oxidation formed the major products for α-pineneand β-pinene, which were further oxidised to theirrespective aldehyde or ketone. One of the minor products froma-pinene, cis-verbenol, was not only transformed into verbenonebut also isomerised to trans-verbenol. Limonene gavelimonene-(1,2)-epoxide as the major product. Fractionation of monoterpenes is accomplished throughphysical separation methods, chromatography and distillation,and lipase-catalysed transesterification of vinyl acetate withterpene alcohols. The esters of myrtenol and trans-pinocarveolwere separated from the more slowly reacting alcohols such asborneol and carveol by use of a combination of the Mucor mieheilipase and Candida antarctica lipase A as catalysts.Furthermore, the non-reacting tertiary terpene alcohols wereseparated from the reacting alcohols in a single step byCandida antarctica lipase A. Lipase-catalysed (Candida antarctica lipase B andPseudomonas cepacia lipase) transesterification of vinylacetate with sterically hindered secondary alcoholsunexpectedly yielded hemiacetals or hemiacetal esters. Thereaction conditions required to obtain these side products havebeen studied. <b>Keywords:</b>Picea abies, Pinaceae, Essential oilscomposition; Terpene alcohol; Hemiacetal; Hemiacetal ester,TMP-turpentine; Monoterpene; α-Pinene; β-Pinene;Limonene; Verbenol; Pinocarveol; Borneol; Myrtenol; Suspensioncell culture; Biotransformation; Lipase-catalysed; Oxidation;Allylic oxidation; Transesterification; Autoxidation;Separation.
2

Biotransformations of Turpentine Constituents : Oxygenation and Esterification

Lindmark-Henriksson, Marica January 2003 (has links)
<p>This thesis describes methods to obtain value–addedcompounds from TMP-turpentine obtained from the spruce, Piceaabies. The methodology focuses on biotransformations using twoapproaches: an oxygenation approach (i.e. oxygenation ofterpene hydrocarbons by cell cultures) and an esterificationapproach (i.e. lipase-catalysed transesterification of vinylacetate with terpene alcohols, and a further fractionation ofthe TMP-turpentine).</p><p>The main constituents of the turpentine, a-pinene, b-pineneand limonene, were subjected to a P. abies suspension culture.Allylic oxidation formed the major products for α-pineneand β-pinene, which were further oxidised to theirrespective aldehyde or ketone. One of the minor products froma-pinene, cis-verbenol, was not only transformed into verbenonebut also isomerised to trans-verbenol. Limonene gavelimonene-(1,2)-epoxide as the major product.</p><p>Fractionation of monoterpenes is accomplished throughphysical separation methods, chromatography and distillation,and lipase-catalysed transesterification of vinyl acetate withterpene alcohols. The esters of myrtenol and trans-pinocarveolwere separated from the more slowly reacting alcohols such asborneol and carveol by use of a combination of the Mucor mieheilipase and Candida antarctica lipase A as catalysts.Furthermore, the non-reacting tertiary terpene alcohols wereseparated from the reacting alcohols in a single step byCandida antarctica lipase A.</p><p>Lipase-catalysed (Candida antarctica lipase B andPseudomonas cepacia lipase) transesterification of vinylacetate with sterically hindered secondary alcoholsunexpectedly yielded hemiacetals or hemiacetal esters. Thereaction conditions required to obtain these side products havebeen studied.</p><p><b>Keywords:</b>Picea abies, Pinaceae, Essential oilscomposition; Terpene alcohol; Hemiacetal; Hemiacetal ester,TMP-turpentine; Monoterpene; α-Pinene; β-Pinene;Limonene; Verbenol; Pinocarveol; Borneol; Myrtenol; Suspensioncell culture; Biotransformation; Lipase-catalysed; Oxidation;Allylic oxidation; Transesterification; Autoxidation;Separation.</p>
3

Réponse biologique de cellules animales à des contraintes hydrodynamiques : simulation numérique, expérimentation et modélisation en bioréacteurs de laboratoire / Biological response of animal cell to hydrodynamic stresses : numerical simulation, experimentation and modelling in bench-scale bioreactors

Barbouche, Naziha 13 November 2008 (has links)
La réponse globale de cellules animales à des contraintes hydrodynamiques lors de leur culture en suspension dans des réacteurs agités a été étudiée grâce à une approche intégrative couplant les outils du génie biochimique à ceux de la mécanique des fluides numérique. En premier lieu, la description de l’hydrodynamique moyenne et locale de deux systèmes de culture agités de laboratoire, spinner et bioréacteur, a été réalisée. Puis, l'étude des cinétiques macroscopiques de cellules CHO cultivées en suspension, en milieu sans sérum et sans protéine, a été réalisée avec différentes vitesses d’agitation, pour évaluer l'impact de l'agitation sur les vitesses de croissance et de mort cellulaires, ainsi que de consommation des substrats et de production des métabolites et de l'interféron-gamma recombinant. Des caractérisations supplémentaires des cellules (apoptose, protéines intracellulaires) et de l'interféron ont également été réalisées. Les effets de l'intensification de l'agitation ont été représentés avec plusieurs corrélations globales reliant : (i) en milieu contenant du pluronic, l'intégrale des cellules viables au nombre de Reynolds, et la proportion de cellules lysées à la valeur moyenne de l'énergie de dissipation, <[epsilon]? (ii) en milieu sans pluronic, les vitesses spécifiques de croissance et de mort cellulaires à <[epsilon]. De plus, l'analyse par CFD de la distribution spatio-temporelle des contraintes indique que la lyse cellulaire, observée dans le réacteur aux conditions extrêmes d'agitation, serait plutôt liée à des valeurs locales très élevées de [epsilon], ainsi qu’à la fréquence d'exposition des cellules dans ces zones énergétiques. Un modèle hydro-cinétique original, couplant l’hydrodynamique locale aux cinétiques cellulaires de croissance et de mort, et basé sur l’intermittence de la turbulence permet la prédiction de la lyse massive observée en réacteur sous certaines conditions. Pour confirmer le fait que les effets liés à l'intensification de l'agitation sont bien le résultat d'une augmentation des contraintes hydrodynamiques, et non d'une amélioration du transfert d'oxygène, ce dernier a été mesuré et modélisé par couplage avec une simulation numérique de type Volume Of Fluid , concluant en une absence de limitation d'oxygène. Enfin, la conception, le dimensionnement et la caractérisation hydrodynamique d'un réacteur innovant de type Couette-Taylor, sont proposées pour la mise en œuvre de cultures perfusées dans un environnement hydrodynamique mieux contrôlé / The global response of animal cells to hydrodynamic stress when cultivated in suspension in stirred tank reactors was studied. To do this, an integrative approach coupling biochemical engineering and fluid mechanics tools were used. First, the description of the global and local hydrodynamics of two bench-scale agitated reactors, a spinner flask and a bioreactor, was carried out. Then, macroscopic kinetics of CHO cells cultivated in a serum and protein-free medium were obtained at various agitation rates, in order to evaluate the impact of agitation on cellular growth and death, as well as substrates consumption and metabolites and recombining IFN-[gamma] production. IFN-[gamma] and cells physiological state were more precisely characterised by glycosylation, apoptosis state and intracellular proteins measurements. The effects of the agitation increase were represented by several global correlations that related: (i) in a medium containing Pluronic F68, the Integral of the Viable Cells Density to the Reynolds number, and the proportion of lysed cells with the average value of energy dissipation rate <[epsilon]? (ii) in a medium without pluronic, specific cell growth and death rates to <[epsilon]. Moreover, CFD analysis of the stress distribution indicated that the cellular lysis observed in the bioreactor at the highest agitation rate, would be related to very high local values of [epsilon], and to the exposure frequency of the cells in these energetic zones. An original hydro-kinetic model based on the intermittency of turbulence and coupling the local hydrodynamics with cell growth and death kinetics, allowed the prediction of the massive cell lysis observed in the bioreactor under some mixing conditions. To decouple shear stress effects from oxygen transfer improvement, the oxygen transfer coefficient was experimentally measured and modelled using a Volume Of Fluid numerical simulation. Our results indicated the absence of an oxygen limitation, which confirmed that this cell response resulted from the hydrodynamic stress increase alone. Lastly, an innovative continuous and perfused Couette-Taylor reactor, allowing a better-controlled hydrodynamic environment was designed and sized. Its hydrodynamic description was carried out using CFD calculations

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