Dissertations / Theses on the topic 'Fonctionnalisation enzymatique'
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Baig, Muhammad. "Extraction de composant de biomasse lignocellulosique oléagineuse en milieu eau et CO2 subcritique et fonctionnalisation enzymatique." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20215/document.
This work addresses the integrated biorefining concept (extraction, fractionation, separation of compounds from biomass prior to further transformation) by developing discrete units with the ultimate objective of coupling them to enable a continuous flow configuration. Due to the complexity of solid, there is a need for a sustainable and environmentally friendly pre-treatment technology. Sub-critical water has been used as a solvent for extracting natural compounds in addition to hydrolysis. This work investigated the hydrolysis of carbohydrates (rice bran) and triacylglycerols (TAG; sunflower oil) chosen as models. The attribute of subcritical water (ion product and dielectric constant) in continuous flow reactors built for the purpose, allowed almost quantitative hydrolysis of hemicellulose and TAG. The effect of adding CO2 and therefore carbonic acid was positive on the hydrolysis of hemicellulose. Further, free fatty acids were transformed to ethyl esters using lipase within continuous flow super critical CO2 resulting in 95% yield. The hydrolysis and esterification reaction kinetics were studied. To address the complex interplay between multiple processing parameters response surface methodologies (RSM) were developed. Using the empirical data the models were successfully validated, therefore showing the utility of the RSM to assist process development. The important question of solubility of extractible in subcritical water was also addressed, through the development of a prediction method, validated with experimental data. In summary this work shows the possibility of applying the innovative Integrated Biorefining concept under continuous flow conditions -instead of the current application under batch conditions- for producing valuable compounds
Adam, Aurélie. "Auto-assemblage de la gomme d'acacia modifiée par voie enzymatique." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0306.
The appearance of order from disorder has always fascinated us, especially self-assemblies. Indeed, they allow the spontaneous formation of particles in suspension (colloidal particles) without any energy input. Most studies to induce self-assembly are based on chemical techniques, often using organic solvents or toxic compounds.The originality of the Biomolecular Engineering Laboratory (LIBio) lies in the formulation of innovative vectors whose constituents are derived from renewable agro-resources. One of the research axes of the laboratory is thus focused on the modification of natural polysaccharides in order to bring them new functional properties. Here, in order to move towards a greener chemistry, the original approach of functionalization by enzymatic way of polysaccharides developed at LIBio is implemented to modify the Acacia gum in order to confer self-assembly properties. This modification is based on the use of an enzyme allowing the oxidation of phenolic compounds. The oxidation products then formed ester bonds with Acacia gum to modify the arabinogalactan peptide and arabinogalactan protein fractions. The oxidation products being hydrophobic modified the behavior of the gum by making it less hydrophilic and less hygroscopic. Thus in aqueous medium, at concentrations where the native Acacia gum is soluble, the modified Acacia gum forms monodisperse spherical particles. It is then necessary to determine which method is the most suitable to define the critical aggregation concentration of these assemblies. In particular, a new technique has been used: micro-scale thermophoresis. In the last part of this work it is a question of studying the influence of physicochemical parameters on the assembly. Indeed, the assemblies are formed thanks to the weak links between the sub-units of modified Acacia gum. These interactions depend on parameters such as ionic strength, pH or temperature
Enaud, Estelle. "Fonctionnalisation enzymatique de composés phénoliques : synthèses d'esters aromatiques de flavonoi͏̈des glycosylés catalysées par la lipase B de Candida antarctica." Vandoeuvre-les-Nancy, INPL, 2004. http://docnum.univ-lorraine.fr/public/INPL_T_2004_ENAUD_E.pdf.
Aljawish, Abdulhadi. "Fonctionnalisation enzymatique de chitosane par des composés phénoliques : évaluation des propriétés biologiques et physico-chimiques de ces nouveaux biopolymères." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0089/document.
Oxidation of ferulic acid and its ester (ethyl ferulate) by Myceliophtora thermophila laccase has been studied in aqueous medium under mild experimental conditions (30°C and pH 7.5) as a green process to synthesize natural neo-molecules. Enzymatic oxidation led to colored and colorless intermediaries for ferulic acid and ethyl ferulate, respectively. Additionally, ethyl ferulate was oxidized faster than ferulic acid. This procedure has led to dimeric major products with MM = 443 g/mol and MM = 386 g/mol for ethyl ferulate and ferulic acid, respectively. New synthesized molecules demonstrated important antioxidants properties with weak antibacterial and cytotoxic properties. With insoluble chitosan particles in the reaction medium, laccase was protected from inhibition due to oxidation products and the polymerization degree of these products was checked. In addition, the oxidation products reacted with the free NH2 groups forming covalent bonds of Schiff base type (C=N) at C-2 region. The majority of the oxidation products grafted onto chitosan was of dimeric form. This procedure led to colored and colorless chitosans by ferulic acid and ethyl ferulate, respectively, with new properties due to grafting of phenolic compounds. These chitosan derivatives presented interesting functional properties such as antioxidant, physico-chemical (thermal stability) and biological (cell adhesion) as well as the preservation of antibacterial properties of native chitosan
Nesterenko, Alla. "Etude et fonctionnalisation de protéines végétales en vue de leur application en microencapsulation." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0148/document.
Proteins extracted from vegetables are relatively low-cost, non-toxic, biocompatible and biodegradable raw materials. They represent a good alternative to animal-based proteins and petroleum-extracted polymers. In this study, proteins derived from soybean and sunflower seeds were used as wall materials for microencapsulation of hydrophobic (-tocopherol) or hydrophilic (ascorbic acid) active material by spray-drying technique. Soybean proteins are widely used in food and non-food applications, especially in microencapsulation. They were studied in this work as wall material of reference. Sunflower proteins are not actually used in industrial application, but only in the form of oil-cake for animal feeding. That’s why new ways of valorization of this agricultural by-product should be investigated. Several proteins’ modifications such as enzymatic hydrolysis, acylation, cross-linking and cationization were studied in order to improve encapsulating properties of wall material. In the context of green chemistry, all the modifications and preparations were performed without use of organic solvents and chemical catalysts. The effect of protein chemical and enzymatic modifications, and process parameters (homogenization pressure, wall/core ratio and protein concentration) on different characteristics of liquid preparations and microparticles (viscosity, emulsion droplet size, microparticle size and morphology) and on parameters related to the spray-drying process (yield and efficiency of microencapsulation) was particularly investigated in this study. The obtained results confirmed that sunflower proteins are quite suitable as encapsulating agent and provide the microencapsulation efficiencies significantly higher compared to those obtained with soy proteins
Karaki, Nadine. "Impact de la fonctionnalisation enzymatique de la pectine par des composés phénoliques sur la structure et les propriétés physicochimiques du polymère." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0205/document.
This dissertation concerns the functionalization of the citrus pectin with phenolic compounds. A first strategy consisted in grafting the products issued from the oxidation of ferulic acid (FA), in aqueous medium (pH 7,5, 30 ° C), in the presence of the laccase of Myceliophthora thermophila (pectin F). The main objectives were to demonstrate the covalent grafting of exogenous phenols onto the polysaccharide, to collect information about the structure and the properties of the modified polymer and to compare them with the characteristics of the native one. A second strategy of functionalization was applied, based on the adsorption of FA oxidation products onto the pectin (pectin POX). Whatever the functionalization pathway, biochemical analyses showed the incorporation of phenolic compounds into the pectin. The structure and the properties of the modified pectins depended on the type of modification undergone by the polysaccharide (covalent grafting or adsorption). Structural analyses suggested that the covalent grafting of phenols involved the carboxyl groups of the pectin (ester bound) on which FA oligomers were bound. The properties of native and modified pectins (POX and F) were studied and compared aiming to highlight the changes brought by functionalization. The study of the thermal properties of pectin POX and F suggested less organized and less compact structures compared to the native one. The antioxidant activity of the modified pectins was improved whereas their hygroscopic character was decreased because of the incorporation of hydrophobic phenolic compounds. As the native pectin, the pectins POX and F presented a shear-thinning profile. However, the viscosity and the gelation rate measured for the pectin F were significantly decreased, compared with those obtained for the native pectin. The pectin POX presented an intermediate behavior. Preliminary results of assemblies demonstrated the possibility to associate the native or modified pectin to another polysaccharide, the chitosan, leading to microparticles capable to encapsulate an active ingredient such as the curcumin
Meline, Thomas. "Synthèse enzymatique d’esters de sucres à partir du son de blé et applications." Thesis, Reims, 2017. http://www.theses.fr/2017REIMS026.
Lignocellulosic biomass is at the center of biorefinery development. This development is achieved by the fractionation of the main components of lignocellulosic biomass (cellulose and hemicelluloses) in order to produce biofuels, molecules of interest and agromaterials.This PhD thesis had the objective to study the transformation of wheat bran xylanes into pentose based surfactants. A two steps system was studied, a first step of enzymatic hydrolysis of wheat bran with hemicellulases (to produce xylose and arabinose) and a second step of sugar acylation catalyzed by a lipase to produce pentoses based surfactants.The PhD thesis mainly focused on the transesterification of D- xylose and L-arabinose (pure or obtained from wheat bran hydrolysate) by the immobilized lipase N435 with vinyllaurate. Several parameters were studied. Lauryl mono- and diesters of D- xylose and L-arabinose were produced by the lipase and their structures were elucidated. Physico-chemical properties of the original and newly produced pentoses based esters were investigated and shown the surfactant potential of these molecules. A preliminary approach was also developed to study the enzymatic synthesis of lauryl xylo-oligosaccharides esters by the lipase N435. Our results showed that such a production is possible but is less efficient than with monosaccharides. The production by transesterification of xylo-oligosaccharides with the lipase N435 needs to be optimized as well as the purification and the characterization of lauryl xylo-oligosaccharides esters
Alves, Da Costa Cardoso Ligia. "Identification de facteurs opératoires influents en vue d'une production microbienne optimale de torularhodine et de sa fonctionnalisation enzymatique, à partir d'études cinétiques." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL082N/document.
The aim of this work was to determine the optimum of an original carotenoid, the torularhodin, produced by Sporobolomyces ruberrimus, in batch culture. A very interesting characteristic of this strain is its ability to consume raw glycerol as a carbon and energy source for microbial growth and carotenoid production. In the fist part of this study, the identification of operating parameters that have an influence on the optimum torularhodin production, was achieved. Experimental assays reinforced by a statistical study allowed to identify temperature, dissolved oxygen pressure and oleic acid supplementation, as the major parameters of influence, and then the integration of these data was performed for the construction of a multiobjective optimization based on a multicriteria experimental design. The establishment of a mathematical model of a second degree polynomial type was developed for the prediction of the values of µmax and of the torularhodin concentration reported to biomass. In the last part, considering that torularhodin has an important antioxidant property and it exhibits a free carboxyl acid function which can be used as acyl agent, a study of its structure modifying by an enzymatic way as a stabilization pattern was started. The experimental conditions of lysine acylation by the lipase B of Candida antarctica were determined using a model carotenoid, the bixin. The resulting product of the synthesis of bixin derivative was purified and showed an antiradical activity of 2.5 times higher than that of bixin. This result showed the ability of the acylation reaction of peptides with this kind of carotenoids
Tibaldi, Alexandra. "Developpement de transistors organiques à grille électrolytique pour la caractérisation in-situ de processus de fonctionnalisation de surface : application au suivi d'une cinétique enzymatique." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC084/document.
This work deals with the realisation and study of Electrolyte-Gated Organic FieldEffect Transistors (EGOFETs). These field-effect transistors have the peculiarity of operating in the presence of an electrolyte and at very low voltages. The EGOFETs architecture has been adapted so that its electrical characteristics are mostly controlled by the structure and composition of the gate/electrolyte interface. This property has been used for the transduction of physico-chemical events located on the surface of the transistor gate. Based on the electrical signal variation of the EGOFETs, the kinetics of alkylthiols self-assembly on Au gate can be characterised. This example hightlights the potentiality of EGOFETs for in-situ and real-time study of various surface functionalisation phenomena. This property has been applied to the monitoring of in-situ production of an alkylthiol, the thiocholine, by an enzyme, the acetylcholinesterase (AChE). In the presence of its substrate, AChE generates thiocholine. The addition of enzyme to an EGOFET device containing its substrate in the electrolyte causes a variation in the drain current correlated to the amount of enzyme present. The device allowed the determination of AChE over the pM range, with a limit of detection of 2 pM. This analytical capability offers an alternative to the current reading devices of enzyme immunoassays
Abbas, Abdennour. "Fabrication et fonctionnalisation de bioMEMS par plasma froid pour l’Analyse de la biocatalyse en spectroscopie téraHertz." Electronic Thesis or Diss., Lille 1, 2009. http://www.theses.fr/2009LIL10050.
The applications of miniaturized devices are no longer limited to electronic industry. Today, a new kind of microsystems called BioMEMS (Bio-MicroElectroMechanical Systems) are spreading in different fields, including biomedical, environmental and food industry applications. Recurring challenges are focusing on enabling processes for smaller, cost-effective, high-functionality devices, with more sensitivity and suitability for industrial scale development. This highly interdisciplinary thesis work attempts to provide new solutions to meet some of the needs mentioned above. It reports the fabrication, functionalization, and applications of a BioMEMS for enzyme reaction monitoring. First, we have developed a PECVD (plasma enhanced chemical vapor deposition) process for the surface functionalization by plasma polymerized allylamine. Films with high amine density and enhanced stability in aqueous environment were obtained. The amine functions were then used for enzymes immobilization. The covalently bonded trypsin molecules were extensively characterized and kinetic parameters determined using several microscopic and spectroscopic methods. Finally, both optimized processes were applied to the biofunctionalization of a TeraHertz (THz)-based BioMEMS. THz spectroscopy is the only non-invasive analytic method able to monitor molecular events at the picosecond timescale by probing low binding energies directly. It is used here for sensing a biocatalysis reaction inside the bioMEMS microchannels. Sub-THz measurements (0.06-0.11 THz) showed that combining microfluidic microsystems technology with THz detection could be a promising alternative for label-free real-time detection of biological interactions at the microscale. Additionally, we have developed a new microchannel fabrication process using direct plasma polymerization of TMDS (TetraMethylDiSiloxane) on micropatterned surfaces. This achievement demonstrates that cold plasma processes could be used not only for functionalization purposes or surface treatment but for the 3D microfabrication as well. This highly reduces processing time and manual handling steps, which is of a great importance for further industrial scale production
Abbas, Abdennour. "Fabrication et fonctionnalisation de bioMEMS par plasma froid pour l’Analyse de la biocatalyse en spectroscopie téraHertz." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10050/document.
The applications of miniaturized devices are no longer limited to electronic industry. Today, a new kind of microsystems called BioMEMS (Bio-MicroElectroMechanical Systems) are spreading in different fields, including biomedical, environmental and food industry applications. Recurring challenges are focusing on enabling processes for smaller, cost-effective, high-functionality devices, with more sensitivity and suitability for industrial scale development. This highly interdisciplinary thesis work attempts to provide new solutions to meet some of the needs mentioned above. It reports the fabrication, functionalization, and applications of a BioMEMS for enzyme reaction monitoring. First, we have developed a PECVD (plasma enhanced chemical vapor deposition) process for the surface functionalization by plasma polymerized allylamine. Films with high amine density and enhanced stability in aqueous environment were obtained. The amine functions were then used for enzymes immobilization. The covalently bonded trypsin molecules were extensively characterized and kinetic parameters determined using several microscopic and spectroscopic methods. Finally, both optimized processes were applied to the biofunctionalization of a TeraHertz (THz)-based BioMEMS. THz spectroscopy is the only non-invasive analytic method able to monitor molecular events at the picosecond timescale by probing low binding energies directly. It is used here for sensing a biocatalysis reaction inside the bioMEMS microchannels. Sub-THz measurements (0.06-0.11 THz) showed that combining microfluidic microsystems technology with THz detection could be a promising alternative for label-free real-time detection of biological interactions at the microscale. Additionally, we have developed a new microchannel fabrication process using direct plasma polymerization of TMDS (TetraMethylDiSiloxane) on micropatterned surfaces. This achievement demonstrates that cold plasma processes could be used not only for functionalization purposes or surface treatment but for the 3D microfabrication as well. This highly reduces processing time and manual handling steps, which is of a great importance for further industrial scale production
Maccow, Awilda. "A chemo-enzymatic approach to expand the chemical space of cellulose-derived materials : Application to eco-friendly dyeing of cellulosic fibers." Electronic Thesis or Diss., Toulouse, INSA, 2022. http://www.theses.fr/2022ISAT0054.
The extension of the chemical molecular space accessible from plant biomass by soft and clean methods is a timely topic that stimulates the scientific community in order to develop biobased products with low environmental impact and to widen the field of biomass exploitation. The functionalization of cellulose, the most abundant polysaccharide on the planet, and/or cello-oligosaccharides as described in this thesis is part of this approach. Our objective was to develop a chemo-enzymatic method involving the action of a mediator-assisted laccase to oxidize cello-oligosaccharides or cellulosic fibers, followed by reductive amination to graft amino compounds onto the cellulosic material. To this end, we first demonstrated the oxidation of cellobiose and methyl cellobiose using the laccase from Trametes versicolor and TEMPO as a mediator. Oxidation conditions were optimized with methyl cellobiose and applied to a cello-oligosaccharide mixture and cellopentaose. Using LC/MS analysis, we showed that a wide range of oxidized compounds is obtained and that the method is effective in producing acidic cello-oligosaccharides potentially of interest for the biomedical and nutraceutical fields. Then, we showed that the reactivity of oxidized cellopentaose with two aminated molecules, p-toluidine and rhodamine 123 (an aminated dye), allowed the binding of the amino compound to the oligosaccharides. Using LC/ MS and MS/MS techniques, we provided evidence for the presence of a strong, covalent amine bond between the dyes and cellopentaose, thus enlarging the chemical space accessible through this hybrid process. After completed this proof of concept, we attempted the dyeing of cotton threads. Cellulosic fibers are one of the main biosourced and biodegradable textile materials. However, chemical processing of textiles and especially the chemical methods used to covalently fix dyes are extremely polluting and harmful to health. Providing more eco-friendly alternatives is a challenge but of prime interest for a company like PILI, which was involved in the thesis project and is developing natural dyes using synthetic biology. Thus, the potential of the two-pot/two-step hybrid process was used to successfully graft p-Toluidine, rhodamine 123 and Acid Red 33 onto cotton thread. The covalent bond established between these dyes and the cotton fiber was proven for the first time. In addition, good homogeneity and wash-fastness were observed for acid Red 33 dyeing, demonstrating the robustness and applicability of the approach in real life. These original results have been patented. By testing other amino dyes, we also showed that the solubility, reactivity and structure of the aminated dye are important parameters to be addressed for dyeing optimization, which opens the way to the custom synthesis of new amino dyes suitable for this promising hybrid process
Eid, Georges. "Nouveaux dérivés lipophiles ou amphiphiles de composés phénoliques bio-sourcés à propriétés antioxydantes, anti-inflammatoires et/ ou anti-prolifératives." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0166.
The decrease in easily accessible petrochemical resources has given over the past ten years a growing interest in the use of raw materials of renewable origin. The primary wood processing industry generates large amounts of waste each year which are currently either recycled to other sectors such as paper mills or the panel industry, or used as a source of energy, and therefore to markets with low added value. The project is situated in this context of sustainable development, circular economy and valorization of co-products of the wood industry by the exploitation of secondary metabolites present in wood, such as phenolic compounds, and more precisely flavonoids, which are indeed of interest in various fields because of their biological activities.The objective of this work is to functionalize accessible and abundant compounds in order to obtain polyfunctional compounds with 2-in-1 properties and thus be able to simplify cosmetic formulations. Functionalization has been considered by two routes: chemical hemisynthesis and/or enzymatic catalysis.By chemical hemisynthesis we were able to obtain bi-modular compounds by combining a fatty acid and a non-glycosylated flavonoid, in this case we worked with catechin. Direct acylations on the phenolic hydroxyls of catechin have been studied and the regioselectivity has been demonstrated by NMR spectroscopy and confirmed by molecular modelling. We have also obtained tri-modular compounds by chemical hemisynthesis by combining different amino acids, as well as fatty acids of variable length with catechin. Three different trimodular structures have been synthesized.By enzymatic hemisynthesis we have synthesized tri-modular compounds, from glycosylated flavonoids, rutin and narignin, aiming for the grafting of fatty acids of different chain lengths but this time on the glycosidic part of the flavonoids. We have also synthesized penta-modular compounds resulting from the grafting of a dicarboxylic acid on naringin or rutin. These compounds comprise two flavonoid entities grafted on either side of the carbon chain of the diacid.At the end of these syntheses, the physico-chemical properties of the products were studied, in particular their solubility in water, their anti-radical properties but also the surfactant properties. Some biological activities have also been studied such as antiproliferative activity against CaCo2 cells. In order to understand the effect of the structure of the compounds on their antioxidant capacity, molecular modeling work has been undertaken; correlations between the antioxidant activity of compounds determined experimentally and chemical reactivity descriptors calculated in silico were sought
Letellier, Philippe. "Recherche d'inhibiteurs enzymatiques synthese et fonctionnalisation de mono et di pseudosaccharides derives du glucose : epoxydation, amination, episulfuration." Amiens, 1993. http://www.theses.fr/1993AMIES020.
Maupas, Hubert. "Développement d'immunocapteurs impédimétriques et de microcapteurs enzymatiques pour la détection d'espèces dans des milieux physiologiques." Ecully, Ecole centrale de Lyon, 1995. http://www.theses.fr/1995ECDL0021.
The first part deals with the development of immunological sensors for the detection of alphafetoprotein in serum. They are based on an electrical measurement related to the variation of the total electrochemical impedance inducted by the antigen-antibody interaction in a sensitive membrane containing anti-alphafetoprotein. The supports used were Si/SiO2 heterostructures and platinum electrodes. The second part is made of two studies dealing with enzymatic biosensors. The first of them deals with the removal of the influence of buffer concentration on the response of enzyme field effect transistors (ENFET) by using additional membranes. The second study deals with the measurement of creatinine in physiological samples. The microcalorimetric and the amperometric approaches are compared
Reuillard, Bertrand. "Elaboration de bioélectrodes à base de nanotubes de carbone pour la réalisation de biopiles enzymatiques Glucose/02." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI090/document.
This work focuses on the optimization of the electrical wiring of glucose oxidizing and dioxygen reducing enzymes on carbon nanotube (CNT) matrixes for glucose biofuel cells.In the first part, glucose oxidase (GOx) mediated electron transfer (MET) is optimized in nanostructured CNTs matrixes by mechanical compression of a CNTs/GOx composite containing 1,4-naphtoquinone as redox mediator. This bioanode was then combined with MCOs (laccase and tyrosinase) based biocathodes. The GOx-NQ/Lac biofuel cell was able to deliver a maximum power density of 1.5 mW.cm-2. The use of this biofuel cell in short/long time discharge and in storage has also been studied. The second part presents the preparation of another bioanode based on the indirect wiring of a NAD+-dependant glucose dehydrogenase (GDH-NAD+) as an alternative for glucose oxidation. The GDH-NAD+ has been combined with an NADH oxidation catalyst by two different techniques. The first one involves the encapsulation of the protein in the metallopolymer redox film, whereas the second one relies on the supramolecular modification of the CNTs by the molecular catalyst and the enzyme. Both bioanodes showed good catalytic properties toward glucose oxidation in presence of NAD+ with respectively 1.04 mA cm-2 and 6 mA cm-2. The latter has been combined with a BOD based biocathode to form a biofuel cell exhibiting maximum power densities of 140 µW cm-2. The last part of this work focuses on the design of a bienzymatic biocathode for O2 reduction. The DET of horseradish peroxidase (HRP) was first investigated and optimized by modification of the CNTs with pyrenes derivatives. The combination of the HRP with the GOx on the same electrode enables an efficient reduction of O2 in a 2-step process. The biocathode could exhibit maximum currents densities of 200 µA cm-2. This cathode along with the previous GDH bioanode formed a biofuel cell functional in physiological conditions and 10 mM NAD+ showing maximum power densities of 57 µW cm-2
Lalaoui, Noémie. "Réduction bioélectrocatalytique du dioxygène par des enzymes à cuivres connectées sur des électrodes nanostructurées et fonctionnalisées : intégration aux biopiles enzymatiques." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI110/document.
The reduction of oxygen is realized in nature by oxidoreductase enzymes. Currently, these highly specific and efficient proteins are considered as biocatalysts for the development of biofuel cells. In this context, optimizing the orientation and the connection of multicopper oxidase (MCOs) for the reduction of O2 on functionalized carbon nanotubes was studied. In the first part of this manuscript, direct electron transfer of laccase is assessed and optimized by the non-covalent functionalization of CNTs by various hydrophobic derivatives. Electrochemical modeling and molecular dynamics enabled the rationalization of the developed biocathodes efficiency. In a second approach, the specific modification by pyrene moieties of laccases surface modified by protein engineered has also been considered. Additionally, supramolecular functionalization of CNTs by modified graphene sheets and gold nanoparticles also helped to promote laccase connection. The second part presents the development of other types of biocathodes based on the direct connection of bilirubin oxidase. Several strategies of covalent and non-covalent CNTs functionalization have been considered. The different biocathodes developed by the supramolecular assembly of nanostructured materials and MCOs delivered current density of several mA cm-2 for oxygen reduction. These new bioelectrodes combined with a bioanode which catalyzes the glucose oxidation have enabled the development of glucose/O2 enzymatic biofuel cells; delivering maximum power densities from 250 µW cm-2 to 750 µW cm-2 depending on the experimental conditions. Finally a hyperthermophilic hydrogenase based bioanode was developed and associated with a bilirubin oxidase-based biocathode to form a new design of H2/O2 biofuel cell. Within this device, the gas diffusion biocathode directly reduces oxygen from the air, which eliminates the use of a separation membrane while protecting the hydrogenase from its deactivation in the presence oxygen. This new biofuel cell delivers a maximum power density of 750 µW cm-2
Yahia, Marei Abdelrahim Mohamed. "Bio(molecular) control of selective ion transport, gas separation and catalytic enzyme-based reactions using functionalized membranes." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS251/document.
Different research works have been described in this thesis. The research works can be summarized as the following. The first chapter deals with the identification of effective potent inhibitors for the human carbonic anhydrase I (hCAI) isozyme. Considering the pharmacological importance to find selective CA inhibitors (CAIs) and CA activators (CAAs), human carbonic anhydrase I (hCAI) has been subjected to a parallel screening of various constitutional dynamic libraries (CDL). In the second chapter, constitutional dynamic networks have been used in liquid and solid membrane systems as a carrier network for transporting lanthanides. The transport is based on the complexing ability of lanthanides metals (La+3, Lu+3, and Eu+3) with the functional polyether groups in the membrane materials. In the third chapter, the proposed approach consists in using supported ionic liquid membranes (SILMs) comprising two different carbonic anhydrase enzymes, the thermo-resistant SspCA enzyme and the Bovine-CA enzyme, which catalyze the reaction of reversible conversion of CO2 to bicarbonate, enhancing the driving force for CO2 transport. Membrane stability, CO2 and N2 permeability and (CO2/N2) ideal selectivity were determined for the membranes developed. In the fourth chapter, the research work consists in the synthesis and characterization of dense polymeric membranes for gas separation application. The gas permeability measurements for the synthesized polymeric membranes showed that the permeability of CO2 is higher than other used gases (N2 and CH4). In the last chapter, two different methods of PVDF membrane functionalization with a phosphotriesterase (PTE) enzyme have been developed to construct biocatalytic membrane reactor (BMR) for bioconversion and selective separation of paraoxon substrate. The first method employs reversible dispersion of magnetic nanoparticle immobilized with PTE using an external magnetic field on the surface of native PVDF membrane. On the contrary, the second method comprises chemical grafting of the PTE enzyme, after surface modification of the native PVDF membrane (DAMP-GA-Enzyme). Both methods of enzyme immobilization showed good efficiency and sensitivity towards the bioconversion of paraoxon substrate at different conditions applied in a biocatalytic membrane reactor (BMR).In general, the concepts developed in this thesis research work will help bring new tracks on the way to the development of a polymeric membrane for selective ion and gas separation but also for selective catalytic reaction under bio(molecular) control
Abbas, Abdennour. "Fabrication et Fonctionnalisation de BioMEMS par Plasma Froid pour l'Analyse de la Biocatalyse en Spectroscopie TeraHertz." Phd thesis, 2010. http://tel.archives-ouvertes.fr/tel-00453908.