Les procédés de transformation de biomasse lignocellulosique en bioéthanol de seconde génération sont actuellement des sujets de recherche très répandus mais ne sont toujours pas compétitifs avec ceux de la première génération. Les facteurs clés limitants sont : l’efficacité et les coûts du prétraitement, les rendements de l’hydrolyse enzymatique, et la co-fermentation C5-C6. Un procédé continu de déconstruction de la matière végétale, compactant un prétraitement thermo-mécano-chimique utilisant un agent alcalin avec une introduction d’enzymes en extrusion bi-vis, appelé bioextrusion, est développé dans cette étude. Il permet de préparer la matière cellulosique à un haut taux de matière sèche (>20%), à une saccharification et une fermentation pouvant être simultanées (SSF). Le traitement continu peut extraire une grande part des hémicelluloses (jusqu’à 97%) et des lignines (>50%) et améliorer l’accessibilité de la cellulose tout en initiant sa dépolymérisation par des cocktails enzymatiques pendant la bioextrusion. Plusieurs matières premières (Résidu de maïs doux, Bagasse d’agave bleue, Résidu d’huilerie de palme, Paille d’orge, Résidu d’Eucalyptus, Sarments de vigne et Bagasse de canne à sucre) ont été caractérisées et leurs comportements vis-à-vis du procédé ont été comparés. L’évolution de la composition de ces matières à travers le procédé et leur hydrolysabilité ont été étudiées. Suite au traitement, une augmentation du rendement de saccharification dans un réacteur (24h de temps de réaction à 20% de consistance) a été obtenue pour ces matières (jusqu’à 85% des C6 théoriques et 70% des C5-C6 théoriques). Les rendements de fermentation non optimisés atteignent un maximum de 85% théorique des sucres C6 convertis, 65% théorique des C5-C6 convertis, et une concentration d’éthanol de 15g/100g extrudat sec. Le procédé de production d’éthanol dans son ensemble (avec addition de l’énergie de la valorisation des coproduits) atteint un ratio « énergie consommée/produite » de 0.5-0.6. Le nouveau procédé présente ainsi les avantages de minimiser la consommation d’énergie par l’application de faibles températures, de minimiser la consommation d’eau par l’utilisation de faibles ratios liquide/solide, de ne pas produire d’inhibiteurs de fermentation et d’être rapide, compact, continu et adaptable sur différentes biomasses. / Lignocellulosic biomass transformation processes in order to produce second generation bioethanol are actually widely studied all around the world but still not yet competitive compare to the first generation. The limiting key factors of the different processes are: the pre-treatment efficiency and costs, the enzymatic hydrolysis yields, and the co-fermentation C5-C6. A continuous plant matter deconstruction process, compacting a thermo-mechanico-chemical pre-treatment using alkali solution with an enzymes injection in twin-screw extruder, called bioextrusion, is developed in this study. It allows preparing the cellulosic material at a high dry matter content (>20%), to a possible simultaneous saccharification and fermentation (SSF). This continuous treatment may extract a big part of hemicelluloses (until 97%) and lignin (>50%) and configures cellulose to a better accessibility and a start of its depolymerisation by enzymes cocktail during the bioextrusion. Several raw matters (Sweet Corn Cob and Spathe, Blue Agave Bagass, Oil Palm Empty Fruit Bunch, Barley Straw, Eucalyptus Residue, Grape Pruning Residue and Sugarcane Bagass) have been characterized and theirs behaviours toward to the process were compared. Evolutions of these matters compositions throughout the process and their hydrolysability have been studied. Further to the treatment, an improvement of the saccharification yields in reactor (24h reaction time at 20% consistency) has been obtained on these matters (until 85% of theoretical C6 and 70% of theoretical C5-C6). The not optimized fermentation yields reach a maximum of 85% of theoretical converted C6 sugars, 65% of theoretical converted C5-C6 sugars, and an ethanol concentration of 15g/100g dry matter extrudate. The whole ethanol production process (with addition of energy from the recovery of the by-products) is achieved with a “consumed/produced energy” ratio of 0.5-0.6. The new process presents the advantages to minimize the energy consumption by operating low temperatures, to minimize water consumption by working at low liquid/solid ratio, to not produce fermentation ‘s inhibitors and to be quick, compact, continuous and adaptable to different biomasses.

As two of the most abundant natural polymers, chitin and lignin not only play critical roles in fungal and plant cell walls but are also important functional materials and promising feedstocks for a variety of chemicals. This study investigated the interactions of chitin and lignin thin films with several other molecules via a quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). Interactions between chitin and family 18 chitinases are vital for understanding bacterial invasion of fungi and human defense against fungal infection. Regenerated chitin (RChitin) thin films were prepared via chemical conversion and spin-coating. Changes in their mass and viscoelasticity were monitored by a QCM-D in real time during incubation with family 18 chitinases. The optimal temperature for the activity of chitinases on surfaces was lower than bulk solution studies in the literature. Family 18 chitinases showed greater activity on dissolved chitin oligosaccharides while family 19 chitinases showed greater activity on RChitin films, which was attributed to chitin-binding domains in family 19 chitinases. Catechyl lignin (C-lignin) is a promising substrate for lignin valorization. Films of C-lignin were synthesized via adsorbed horseradish peroxidase-catalyzed dehydrogenative polymerization (DHP) of caffeyl alcohol (C-alcohol), and degraded through Fenton chemistry with all processes observed by a QCM-D and AFM. The synthetic rate and yield for C-DHP films was lower than DHP films made from coniferyl alcohol (G-alcohol) and p-coumaryl alcohol (H-alcohol). The C-DHP film underwent complete Fenton mediated degradation in contrast to the G-DHP and H-DHP films regardless of their thicknesses. Conventional lignin suffers from recalcitrance to degradation. Copolymer lignin films were synthesized through surface-initiated copolymerization of C and G or C, G and H monolignols. As the concentration of C-alcohol increased, the percentage degradation of the synthesized DHP copolymer films increased. Almost all the CG-DHP or CGH-DHP films were degraded when the percentage of the C-alcohol in the polymerization feed was ≥ 75% and ≥ 60% for CG-DHP and CGH-DHP, respectively. / Doctor of Philosophy / Natural polymers are widely considered as an alternative to fossil fuels for the production of biofuels, biochemicals, and biomaterials. The features of their biodegradability, biocompatibility, and sustainability can significantly alleviate concerns about environmental pollution and energy security. The surfaces of natural polymers are critical to their properties and applications. This dissertation focuses on the study of interfacial behaviors occurring at two of the most abundant natural polymers, chitin and lignin, via surface analysis techniques, a quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). When an endosymbiont bacteria enter a fungal host, they secrete chitinases to soften and loosen the chitin layer in the fungal cell wall. Small chitin fragments will be released from digestion of the chitin layer of the fungal cell wall by chitinases in humans suffering from fungal infections. In order to fully understand the interactions between the fungal chitin layer and chitinases, a chitin thin film was fabricated to mimic the chitin layer, and the changes of the chitin film in mass, viscoelasticity, and morphology during treatment with family 18 chitinases were studied at various temperatures and pH using a QCM-D and AFM. Family 19 chitinases produced greater degradation of chitin thin films than family 18 chitinases, even though the family 18 chitinases had greater activity in solution. Greater surface activity for family 19 chitinases were attributed to chitin-binding domains in their chemical structure that are absent in family 18 chitinases. Millions of tons of lignin are produced in the lignocellulosic biorefinery and are discarded every year due to their recalcitrance to degradation as a result of their heterogeneous and complex structure. A newly discovered lignin, catechyl lignin (C-lignin), has potential for enhancing degradation on account of its simple linear structure. In this dissertation, C-lignin thin films were synthesized on gold-coated QCM-D sensor surfaces via surface-initiated dehydrogenative polymerization of caffeyl alcohol (C-alcohol). Their enzymatic and chemical degradation was investigated. It was found that the C-lignin films underwent complete chelator-mediated Fenton degradation in contrast to conventional lignin films. Although the C-lignin promises to be an ideal substrate for lignin valorization, its narrow distribution in nature severely limits its wide application. In view of this limitation, some people are trying to incorporate C units into conventional lignin through genetically engineered plants. This dissertation demonstrates the successful copolymerization of C-alcohol with conventional monolignols and the improved degradation of the synthesized C unit-containing copolymer lignin films relative to conventional lignin films. The results are expected to inform the design of lignocellulosic biomass for greater utilization.

During this project, photocatalytic material, nano sized titanium dioxide, was introduced into poly (lactic acid) to produce functional surface capable of self-cleaning property. Samples containing 0%, 5%, 10%, 15% and 20% titanium dioxide were prepared and etched with proteinase K to expose the nano particles on the surface. It was shown that the nano titanium dioxide could dispersed in the polymer matrix pretty well, it was also found that the nano particles affected the thermal and mechanical properties of the polymer matrix differently , due to difference in concentrations of nano filler. The self-cleaning property was evaluated by decolouration of stains caused by coffee and red wine, also by detecting degradation of methylene blue via a UV-vis spectrophotometer. By measuring changes in absorbance of light at 664nm wavelength after a maximum of 24h UV irradiation, it was possible to measure the degradation property of the samples. / Program: Masterutbildning i textilteknik

Polymere Nanopartikel sind ein vielversprechender Ansatz für die Diagnose und Therapie von Krankheiten. Sie ermöglichen den Einsatz von schwerlöslichen oder instabilen Wirkstoffen. Ein weiterer Vorteil ist die Möglichkeit das Targetings, durch gezielte Modifikationen des Nanopartikels wird der Wirkstoff zum Zielort transportiert und kann dort in der gewünschten Form freigesetzt werden; dadurch könnten bei erhöhter Wirksamkeit die Nebenwirkungen von Medikamenten reduziert werden. Ziel dieser Arbeit war die Untersuchung von physikalischen und biochemischen Eigenschaften von Nanopartikeln bestehend aus einem abbaustabilen Polystyren- Kern und einer biologisch abbaubaren Schale aus Polybutylcyanoacrylat. Es werden Methoden beschrieben, um die Größe, Struktur und den Abbau dieser Wirkstoffträger zu untersuchen. Die untersuchten Nanopartikel zeigen RAYLEIGH-Streuung, sowohl Größe als auch Abbau können durch Messung des Absorptionsspektrums bestimmt werden. Weiterhin konnten diese Eigenschaften mit Hilfe von dynamischer und statischer Lichtstreuung sowie Neutronenkleinwinkelstreuung untersucht werden. Bei letzterer Methode konnte gezeigt werden, dass die Schale größtenteils abgebaut werden kann, während der Kern intakt bleibt. In einem weiteren Teil der Arbeit wurde die Überwindung der Blut-Hirn-Schranke durch polymere Nanopartikel untersucht. Dabei wurde der fluoreszierende Thioflavine als Modellwirkstoffe eingesetzt. Das Durchdringen der Blut-Hirn-Schranke konnte nur mit Nanopartikeln erreicht werden, an deren Oberfläche ein Apolipoprotein E-Peptid gekoppelt war. Es konnte gezeigt werden, das die Nanopartikelschale im Gehirn abgebaut wird, der Wirkstoff freigesetzt wird und an Amyloid β, einem Marker der Alzheimer-Krankheit, bindet.

Une série d'homopolymères tels que poly(L-lactide) (PLLA), poly(triméthylène carbonate) (PTMC), poly (e-caprolactone) (PCL) et les copolymers ont été synthétisés par polymérisation par ouverture de cycles de monomère appropriés en utilisant du zinc lactate ou octanoate d'étain comme catalyseur. Leurs propriétés thermiques, dégradation hydrolytique, dégradation enzymatique, propriétés mécaniques et comportement à mémoire de forme ont été étudiées à l'aide de DSC, RMN, SEC, ESEM, DMA et machine à traction Instron. Les copolymères de triméthylène carbonate et DL-lactide (PTDLA) peuvent être dégradés non seulement par simple hydrolyse, mais aussi par la protéinase K. Le copolymère PTDLA composé de 50/50 TMC/LA est très élastique, Tg servant de température de transition entre les formes temporaire et permanente. Le PTMC ne peut pas être dégradé par simple hydrolyse ou par la protéinase K, mais peut être dégradé par les lipases de Candida Antarctica et Hog Pancreas. La biocompatibilité des PLLA, PTMC, PCL, PTLLA, PTDLA et PTCA a été évaluée par des expériences d'hémolyse, adhésion des plaquettes, MTT et culture cellulaire. Les résultats montrent des tous les polymères présentent très bonnes propriétés hémolytiques et anti-coagulantes, bonne adhésion, propagation et prolifération des cellules. / A series of homopolymers such as poly(L-lactide) (PLLA), poly(trimethylene carbonate) (PTMC), poly(e-caprolactone) (PCL) and various copolymers were synthesized by ring opening polymerization of appropriate monomer feeds using zinc lactate or stannous octoate as catalyst. Their thermal properties, hydrolytic degradation, enzymatic degradation, mechanical properties and shape memory behavior were investigated by using DSC, NMR, SEC, ESEM, DMA and Instron tensile instrument. Among the various polymers, copolymers of trimethylene carbonate and DL-lactide (PTDLA) can be degraded not only by pure hydrolysis, but also by proteinase K. PTDLA composed of the same TMC and LA contents is highly elastic, Tg acting as the switch temperature between temporary and permanent shapes. PTMC cannot be degraded by pure hydrolysis or by proteinase K, but can be degraded by lipases from Candida Antarctica or Hog Pancreas. The biocompatibility of PLLA, PTMC, PCL, PTLLA, PTDLA and PTCA was evaluated from haemolysis experiments, platelet adhesion, MTT assay and cell culture. The results showed that all the polymers present outstanding haemolytic and anti-coagulant properties, and good cellular adhesion, spreading and proliferation.

Natural polymers from renewable resources have attracted increasing interest as candidates for renewable energy and functional materials. In this work, the interactions between natural polymer thin films and biomacromolecules were studied via surface analysis techniques, such as a quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR) and atomic force microscopy (AFM). Chitinase activity on regenerated chitin (RChitin) films was studied by QCM-D and AFM. The optimal temperature and pH for chitinase activity on surfaces determined by QCM-D and AFM were consistent with bulk solution studies in the literature. Results from QCM-D also indicated that chitinase showed higher activity on fully acetylated chitin than highly deacetylated chitosan. Nanocrystalline chitin (Chitin NC) thin films were prepared by spincoating a nanocrystalline chitin colloidal suspension onto solid surfaces. Solvent exchange experiments via QCM-D with H2O/D2O revealed that Chitin NC films had more water than RChitin films of similar thickness. Results from QCM-D demonstrated that Chitin NC films had high bovine serum albumin loading capacity, and chitinase not only degraded, but also caused swelling of the chitin nanocrystals. Adsorption of human serum albumin (HSA) and fibrinogen (HFN) onto bare gold, regenerated cellulose (RC) and RChitin thin films was studied by SPR and QCM-D. Studies by SPR indicated that HSA and HFN formed close-packed monolayers on gold surfaces and sub-monolayers on polysaccharide surfaces, and the adsorption affinity of HSA for polysaccharide surfaces was greater than that of HFN. Results from QCM-D and SPR showed that the protein layers on polysaccharide surfaces had more associated water than proteins on gold surfaces. The dehydrogenative polymerization of monolignols catalyzed by physically immobilized horseradish peroxidase was investigated using QCM-D and AFM. Results from QCM-D and AFM showed that coniferyl and p-coumaryl alcohol underwent polymerization directly, whereas sinapyl alcohol required the addition of a nucleophile for polymerization. Studies by QCM-D and AFM also indicated that the surface-initiated polymerization was greatly affected by the support surface, monolignol concentration, hydrogen peroxide concentration and temperature. Thin films of dehydrogenative polymer (DHP), kraft (KL), organosolv (OL) and milled wood (MWL) lignins were used to study the enzymatic degradation of lignin mediated by lignin peroxidase (LiP) and manganese peroxidase (MnP). Results from QCM-D showed that the initial rates for degradation catalyzed by LiP increased in the order: KL < OL < MWL < guaiacyl DHP (G-DHP) < p-hydroxyphenyl DHP (H-DHP). In contrast, manganese peroxidase only degraded DHP films with a faster initial rate for G-DHP than H-DHP. Adsorption of hemicelluloses onto KL, OL and MWL thin films was studied by QCM-D and SPR. Results from QCM-D showed that hemicelluloses with different structures displayed very different adsorption behavior. Adsorption isotherms from QCM-D and SPR indicated that xyloglucan possessed stronger affinity for KL and OL films than MWL films. Data from QCM-D and SPR revealed that xyloglucan formed less hydrated layers on lignin surfaces compared to RC surfaces, and the adsorbed xyloglucan layers on different lignin films had similar percentages of coupled water. / Ph. D.

Cette thèse s’est articulée autour de l’élaboration de revêtements surfaciques à base de polymères et de composants naturels. Dans un premier projet, des surfaces mécano-sensibles pour des applications de libération de molécules bioactives ont été élaborées. Des films de multicouches polyélectrolytes constitués d'une strate « réservoir » permettant le chargement d’une molécule bioactive, le paclitaxel, et d'une strate « barrière » mécano-sensible recouvrant ce réservoir et confinant le paclitaxel ont été élaborés. Lors de la mise sous étirement du film, la barrière est rendue perméable vis-à-vis d'une enzyme présente dans le surnageant. Cette enzyme induit ensuite la dégradation enzymatique du « réservoir » et la libération du paclitaxel. Dans un second projet, des substrats cellulaires nourriciers ont été réalisés à partir de films minces de gélatine réticulés mimant la matrice extracellulaire. Ces films peuvent être chargés: 1) en facteurs de croissance, ce qui permet de s'affranchir ensuite de l'ajout de ces molécules dans le milieu de culture; 2) en nanoparticules afin de moduler les propriétés mécaniques des films; 3) en agents antimicrobiens pour assurer une stérilité de la culture cellulaire. Ainsi, ces substrats aux propriétés biochimiques et biophysiques modulables permettent un contrôle précis du microenvironnement cellulaire. / This PhD work is about designing surface coatings with polymers and natural compounds. In the first project, mechanosensitive surfaces have been developed for drug release applications. Polyelectrolyte multilayer films have been designed with i) one reservoir strata for the loading of a bioactive molecule, paclitaxel, and ii) one mechanosensitive barrier strata on top of the reservoir to confine the molecule. When a mechanical stretch is applied on the structure, the barrier becomes permeable and enables the diffusion of an enzyme within the film.This enzyme degrades the reservoir strata and triggers the release of paclitaxel. In a second project, ECM-mimicking feeder substrate has been developed with crosslinked gelatin thin films. These films can be loaded with: i) growth factors to prevent any further addition of these compounds in the culture medium; ii) nanoparticles to modulate mechanical properties of the substrate; iii) antimicrobial agents to ensure sterility during cell culture experiments. Finally, these substrates have some biochemical and biophysical tunable properties that enable the precise control of cell microenvironment.

Polymere Nanopartikel sind ein vielversprechender Ansatz für die Diagnose und Therapie von Krankheiten. Sie ermöglichen den Einsatz von schwerlöslichen oder instabilen Wirkstoffen. Ein weiterer Vorteil ist die Möglichkeit das Targetings, durch gezielte Modifikationen des Nanopartikels wird der Wirkstoff zum Zielort transportiert und kann dort in der gewünschten Form freigesetzt werden; dadurch könnten bei erhöhter Wirksamkeit die Nebenwirkungen von Medikamenten reduziert werden. Ziel dieser Arbeit war die Untersuchung von physikalischen und biochemischen Eigenschaften von Nanopartikeln bestehend aus einem abbaustabilen Polystyren- Kern und einer biologisch abbaubaren Schale aus Polybutylcyanoacrylat. Es werden Methoden beschrieben, um die Größe, Struktur und den Abbau dieser Wirkstoffträger zu untersuchen. Die untersuchten Nanopartikel zeigen RAYLEIGH-Streuung, sowohl Größe als auch Abbau können durch Messung des Absorptionsspektrums bestimmt werden. Weiterhin konnten diese Eigenschaften mit Hilfe von dynamischer und statischer Lichtstreuung sowie Neutronenkleinwinkelstreuung untersucht werden. Bei letzterer Methode konnte gezeigt werden, dass die Schale größtenteils abgebaut werden kann, während der Kern intakt bleibt. In einem weiteren Teil der Arbeit wurde die Überwindung der Blut-Hirn-Schranke durch polymere Nanopartikel untersucht. Dabei wurde der fluoreszierende Thioflavine als Modellwirkstoffe eingesetzt. Das Durchdringen der Blut-Hirn-Schranke konnte nur mit Nanopartikeln erreicht werden, an deren Oberfläche ein Apolipoprotein E-Peptid gekoppelt war. Es konnte gezeigt werden, das die Nanopartikelschale im Gehirn abgebaut wird, der Wirkstoff freigesetzt wird und an Amyloid β, einem Marker der Alzheimer-Krankheit, bindet.