Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(Sorption in polymer). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Queens University

1. Craig, Tom. Strategies for Enhanced Bioproduction of Benzaldehyde Using Pichia Pastoris in a Solid-Liquid Partitioning Bioreactor and Integrated Product Removal by In Situ Pervaporation .

Degree: Chemical Engineering, 2013, Queens University

Benzaldehyde (BZA), a biologically derived high-value molecule used in the flavour and fragrance industry for its characteristic almond-like aroma, has also found use in nutraceutical, pharmaceutical, cosmetics, agrochemical, and dye applications. Although, nature-identical BZA is most commonly produced by chemical synthesis, biologically derived BZA, whether by plant material extraction or via microbial biocatalysts, commands much higher prices. The bioproduction of high value molecules has often been characterized by low titers as results of substrate and product inhibition. The current work examined a variety of process strategies and the implementation of a solid-liquid bioreactor partitioning system with continuous integrated pervaporation to enhance the bioproduction of BZA using Pichia pastoris. Previous work on two-phase partitioning bioreactors (TPPBs) for the biotransformation of BZA using Pichia pastoris has had limitations due to long fermentation times and unutilized substrate in the immiscible polymer phase, contributing to complications for product purification. To reduce fermentation times, a mixed methanol/glycerol feeding strategy was employed and reduced the time required for high-density fermentation by 3.5 fold over previous studies. Additionally, because BZA and not the substrate benzyl alcohol (BA) had been found to be significantly inhibitory to the biotransformation reaction, a polymer selection strategy based on the ratio of partition coefficients (PCs) for the two target molecules was implemented. Using the polymer Kraton D1102K, with a PC ratio of 14.9 (BZA:BA), generated a 3.4 fold increase in BZA produced (14.4 g vs. 4.2 g) relative to single phase operation at more than double the volumetric productivity (97 mg L-1 h-1 vs. 41 mg L-1 h-1). This work also confirmed that the solute(s) of interest were taken up by polymers via absorption, not adsorption. BZA and BA cell growth inhibition experiments showed that these compounds are toxic to cells and it was their accumulation rather than low enzyme levels or energy (ATP) depletion that caused a reduction in the biotransformation rate. For this reason, the final strategy employed to enhance the bioproduction of benzaldehyde involved in situ product removal by pervaporation using polymer (Hytrel 3078) fabricated into tubing by DuPont, Canada. This aspect was initiated by first characterizing the custom-fabricated tubing in terms BZA and BA fluxes. The tubing was then integrated into an in situ pervaporation biotransformation and was shown to be effective at continuous product separation, using 87.4% less polymer by mass in comparison to polymer beads in conventional TPPB operation, and improved overall volumetric productivity by 214% (245.9 mg L-1 h-1 vs. 115.0 mg L-1 h-1) over previous work producing BZA.

Subjects/Keywords: Two Phase Partitioning Bioreactor ; In Situ Pervaporation ; Benzaldehyde ; In Situ Product Removal ; Flavour and Fragrance ; Pichia Pastoris ; Polymer Sorption ; Whole-Cell Biotransformation

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Craig, T. (2013). Strategies for Enhanced Bioproduction of Benzaldehyde Using Pichia Pastoris in a Solid-Liquid Partitioning Bioreactor and Integrated Product Removal by In Situ Pervaporation . (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/8346

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Craig, Tom. “Strategies for Enhanced Bioproduction of Benzaldehyde Using Pichia Pastoris in a Solid-Liquid Partitioning Bioreactor and Integrated Product Removal by In Situ Pervaporation .” 2013. Thesis, Queens University. Accessed May 07, 2021. http://hdl.handle.net/1974/8346.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Craig, Tom. “Strategies for Enhanced Bioproduction of Benzaldehyde Using Pichia Pastoris in a Solid-Liquid Partitioning Bioreactor and Integrated Product Removal by In Situ Pervaporation .” 2013. Web. 07 May 2021.

Vancouver:

Craig T. Strategies for Enhanced Bioproduction of Benzaldehyde Using Pichia Pastoris in a Solid-Liquid Partitioning Bioreactor and Integrated Product Removal by In Situ Pervaporation . [Internet] [Thesis]. Queens University; 2013. [cited 2021 May 07]. Available from: http://hdl.handle.net/1974/8346.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Craig T. Strategies for Enhanced Bioproduction of Benzaldehyde Using Pichia Pastoris in a Solid-Liquid Partitioning Bioreactor and Integrated Product Removal by In Situ Pervaporation . [Thesis]. Queens University; 2013. Available from: http://hdl.handle.net/1974/8346

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Champeau, Mathilde. Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants : Imprégnation par voie CO2 supercritique pour préparer des implants polymère à libération contrôlée de principes actifs.

Degree: Docteur es, Polymères, 2014, Bordeaux; Université de Liège

Le procédé d’imprégnation par voie CO2 supercritique est une solution prometteuse pour préparer des implants polymère à libération contrôlée de médicaments.Ce travail a permis de comprendre l’influence des paramètres gouvernant ce procédé et de préciser dans quelle mesure ce procédé peut être utilisé pour préparer des implants polymères chargés en médicament. Pour ce faire, nous avons combiné les informations obtenues grâce aux techniques classiques de caractérisation de polymères et à un dispositif que nous avons développé basé sur la micro-spectroscopie FTIR haute pression in situ.Dans cette étude, des fils de suture de PLLA, PP and PET ont été imprégné avec deux anti-inflammatoires (aspirine et kétoprofène).Tout d’abord, l’évolution du comportement des systèmes binaires médicament/CO2 (solubilité et spéciation) et polymère/CO2 (quantité de CO2 adsorbé, gonflement de la matrice, évolution de la microstructure et des propriétés de tension du polymère) a été déterminé en fonction de la pression et de la température. Ensuite, le procédé d’imprégnation a été étudié. L’influence des conditions expérimentales sur le taux d’imprégnation a été déterminée et expliquée par la quantité de CO2 adsorbé, le gonflement de la matrice, la solubilité du médicament, l’évolution de la microstructure du polymère et aussi l’affinité médicament/polymère. La matrice de PLLA a pu être plus largement imprégnée (jusqu’à 32%) que celles de PP et PET (5% max). Enfin, l’influence des conditions d’imprégnation et de dépressurisation sur le relargage a été démontrée sur le système PLLA/Kétoprofène, la durée de relargage variant de 3jours à 3mois.

The scCO2 impregnation process is a promising alternative to other manufacturing process to prepare drug-eluting polymer implants.This work enabled to rationalize the influence of the key parameters governing this process and to determine in which extent this process can be used to prepare drug-eluting implants. We have combined the information obtained with traditional polymer characterization techniques and a newly characterization set-up we have developed that is based on in situ FTIR micro-spectroscopy. We have worked on the impregnation of sutures made of PLLA, PP and PET with two anti-inflammatory drugs namely ketoprofen and aspirin.Firstly, the thermodynamic behaviors of the systems drug/CO2 (solubility and speciation of the drug) and polymer/CO2 (CO2 sorption, polymer swelling, evolution of the polymer microstructure and of the tensile properties) were studied as a function of pressure and temperature. Then, the scCO2 impregnation process was investigated. The impact of the operational conditions on the drug loading (contact time, pressure, temperature and depressurization conditions) was explored and accounted regarding to the CO2 sorption, the2swelling, the drug solubility as well as the changes in the polymer microstructure with the experimental conditions and the presence of the drug. The drug/polymer affinity was also explored. The tensile properties of the impregnated fibers were also…

Advisors/Committee Members: Tassaing, Thierry (thesis director), Howdle, Steven (thesis director), Boury, Frank (thesis director).

Subjects/Keywords: CO2 supercritique; Imprégnation; Implants en polymère; Libération contrôlée de médicament,; Micro-spectroscopie FTIR haute pression; Adsorption de CO2; Gonflement; Taux d’imprégnation,; Suture; Anti-inflammatoire; Supercritical CO2; Impregnation; Drug-eluting polymer implants; In situ FTIR micro-spectroscopy; CO2 sorption; Polymer swelling; Drug loading; Suture; Anti-inflammatory; Drug release

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Champeau, M. (2014). Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants : Imprégnation par voie CO2 supercritique pour préparer des implants polymère à libération contrôlée de principes actifs. (Doctoral Dissertation). Bordeaux; Université de Liège. Retrieved from http://www.theses.fr/2014BORD0205

Chicago Manual of Style (16th Edition):

Champeau, Mathilde. “Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants : Imprégnation par voie CO2 supercritique pour préparer des implants polymère à libération contrôlée de principes actifs.” 2014. Doctoral Dissertation, Bordeaux; Université de Liège. Accessed May 07, 2021. http://www.theses.fr/2014BORD0205.

MLA Handbook (7th Edition):

Champeau, Mathilde. “Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants : Imprégnation par voie CO2 supercritique pour préparer des implants polymère à libération contrôlée de principes actifs.” 2014. Web. 07 May 2021.

Vancouver:

Champeau M. Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants : Imprégnation par voie CO2 supercritique pour préparer des implants polymère à libération contrôlée de principes actifs. [Internet] [Doctoral dissertation]. Bordeaux; Université de Liège; 2014. [cited 2021 May 07]. Available from: http://www.theses.fr/2014BORD0205.

Council of Science Editors:

Champeau M. Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants : Imprégnation par voie CO2 supercritique pour préparer des implants polymère à libération contrôlée de principes actifs. [Doctoral Dissertation]. Bordeaux; Université de Liège; 2014. Available from: http://www.theses.fr/2014BORD0205


North Carolina State University

3. Hussain, Yazan Ahed. Supercritical CO2 Aided Processing of Thin Polymer Films Studied Using the Quartz Crystal Microbalance.

Degree: PhD, Chemical Engineering, 2006, North Carolina State University

Fundamental and applied aspects of the interactions between carbon dioxide (CO₂) and different polymer systems were investigated to demonstrate the effect and performance of CO₂ during polymer processing. From a fundamental perspective, the sorption of CO₂ into a non-soluble polymer and its dependence on the different system variables were examined. Another fundamental study investigated the dissolution of a fluorinated polymer in CO₂ at different conditions. Finally, the application of supercritical CO₂ for the impregnation of additives into two different polymers was evaluated. In all these studies, the quartz crystal microbalance (QCM) was used as the primary analytical technique. In the first part of this work, the sorption of CO₂ into poly(methyl methacrylate), PMMA, was investigated. The effect of several parameters, including pressure, temperature, film thickness, and polymer state, on the equilibrium and kinetics of the sorption process was studied. The uptake isotherms of CO₂ into PMMA were estimated from the QCM frequency change. This uptake was found to decrease with temperature and to depend on the film thickness. The presence of hysteresis in the sorption-desorpotion isotherms clearly marked the glass transition which was found to be in good agreement with previously reported values. This glass transition also affected the sorption kinetic. In the glassy state, two-stage sorption curves were observed, whereas in the rubbery stage, Fickian diffusion was evident. The results from this study were utilized to examine the reliability of Sauerbrey equation for mass calculation. By measuring the change in QCM resistance, it was found that both the thickness and the amount of CO₂ dissolved in the polymer can affect the QCM response. However, it was demonstrated that Sauerbrey equation was still applicable for films up to ˜1 μm thick. In the next part, the dissolution of poly(dihydroperfluorooctyl methacrylate-r-tetrahydropyranyl methacrylate); PFOMA, a copolymer was studied. The dissolution process consisted of two stages: CO₂ sorption and polymer dissolution. The measured frequency was utilized to determine mass changes for both processes. In the sorption stage, the solubility of CO₂ into PFOMA was measured at different temperatures and pressures. The solubility was found to depend on both the CO₂ density and the temperature. Polymer dissolution started at pressures between 1100 and 1600 psi, depending on the temperature. The dissolution rate was found to increase as the CO₂ density increases, but has a possible dependence on the temperature. Finally, the fraction of undissolved polymer after 1 hour of CO₂ exposure was estimated. This fraction increased linearly from 20 to more than 90% with CO₂ density. The last part in this work examined the impregnation of ibuprofen (IBU) into two biocompatible polymers: PMMA and poly(vinyl pyrrolidone), PVP. For PMMA, the amount of impregnated IBU decreased as the CO₂ density increased. The solubility parameter approach provided a possible explanation for this behavior… Advisors/Committee Members: Christine Grant, Committee Chair (advisor), Ruben Carbonell, Committee Member (advisor), Saad Khan, Committee Member (advisor), Richard Spontak, Committee Member (advisor).

Subjects/Keywords: Sorption in polymer; Polymer dissolution; Supercritical fluids; Carbon dioxide; QCM; CO<; sub>; 2<; /sub>;

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hussain, Y. A. (2006). Supercritical CO2 Aided Processing of Thin Polymer Films Studied Using the Quartz Crystal Microbalance. (Doctoral Dissertation). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/3450

Chicago Manual of Style (16th Edition):

Hussain, Yazan Ahed. “Supercritical CO2 Aided Processing of Thin Polymer Films Studied Using the Quartz Crystal Microbalance.” 2006. Doctoral Dissertation, North Carolina State University. Accessed May 07, 2021. http://www.lib.ncsu.edu/resolver/1840.16/3450.

MLA Handbook (7th Edition):

Hussain, Yazan Ahed. “Supercritical CO2 Aided Processing of Thin Polymer Films Studied Using the Quartz Crystal Microbalance.” 2006. Web. 07 May 2021.

Vancouver:

Hussain YA. Supercritical CO2 Aided Processing of Thin Polymer Films Studied Using the Quartz Crystal Microbalance. [Internet] [Doctoral dissertation]. North Carolina State University; 2006. [cited 2021 May 07]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/3450.

Council of Science Editors:

Hussain YA. Supercritical CO2 Aided Processing of Thin Polymer Films Studied Using the Quartz Crystal Microbalance. [Doctoral Dissertation]. North Carolina State University; 2006. Available from: http://www.lib.ncsu.edu/resolver/1840.16/3450

.