Establishing a commercial, lignocellulose-based, second-generation ethanol process has received several decades of attention by both researchers and industry. However, a fully economically viable process still remains a long-term goal. The main bottleneck to this achievement is the recalcitrance of lignocellulosic feedstocks, although there are several other factors, such as the huge investment required for second-generation ethanol facilities. An intelligent alternative solution discussed in this thesis is an integrated approach using firstgeneration ethanol plants for second-generation processes. Wheat is the major feedstock for first-generation ethanol in Europe; therefore, wheat-based lignocellulose waste, such as wheat straw, bran, and whole stillage fiber (a waste stream from first-generation wheat-based ethanol plants) was the primary focus of the integration model in this thesis. Since the major share of first-generation ethanol plant economics focuses on the animal feed DDGS (Distillers’ dried gains with solubles), the integration of lignocellulose should be designed in order to maintain DDGS quality. An ethanol-producing edible filamentous fungus, Neurospora intermedia, a potential protein source in DDGS, was considered for use as the fermenting microbe. The morphological and physiological aspects of this fungus were studied in the thesis, leading to the first report of fungal pellet development. An alternative approach of using dilute phosphoric acid to pretreat lignocellulose, as it does not negatively affect fungal growth or DDGS quality, was demonstrated in both the laboratory and on a 1m3 pilot scale. Furthermore, the process of hydrolysis of pretreated lignocelluloses and subsequent N. intermedia fermentation on lignocellulose hydrolysate was also optimized in the laboratory and scaled up to 1 m3 using an in-house pilot-scale airlift bioreactor. Fungal fermentation on acid-pretreated and enzyme-hydrolyzed wheat bran, straw and whole stillage fiber resulted in a final ethanol yield of 95%, 94% and 91% of the theoretical maximum based on the glucan content of the substrate, respectively. Integrating the first- and second-generation processes using thin stillage (a waste stream from first-generation wheat-based ethanol plants) enhanced the fungal growth on straw hydrolysate, avoiding the need for supplementing with extra nutrients. Based on the results obtained from this thesis work, a new model for integrated first- and second-generation ethanol using edible filamentous fungi processes that also adds value to animal feed (DDGS) was developed.

Concern for the environment and a need for more efficient energy generation have sparked a growing interest throughout the world in renewable fuels. In order to reduce emissions that negatively contribute to global warming, especially CO2, enormous efforts are being invested in technologies to reduce our impact on the environment. Biomass is an option that is considered CO2 friendly due to the consumption of CO2 upon growth. Co-firing biomass with coal offers economic advantages because of reduced capital costs as well as other positive impacts, such as NOx and SOx emission reductions. However, due to the large average particle size of biomass, issues arise such as poor flame stability and poor carbon burnout. Larger particles can also result in longer flames and different heat transfer characteristics. Oxygen enrichment is being investigated as a possible solution to mitigate these issues and enable co-firing in existing facilities. An Air Liquide designed burner was used in this work to explore the impact of oxygen enrichment on biomass flame characteristics, emissions, and burnout. Multiple biomass fuels were used (medium hardwood, fine hardwood, and straw) in conjunction with multiple burner configurations and operating conditions. Exhaust ash samples and exhaust NO were collected for various operating conditions and burner configurations. All operating parameters including O2 addition, swirl, and O2 location could be used to reduce LOI but whenever LOI was reduced, NO increased producing an NO-LOI trade-off. Starting with high LOI, various parameters such as O2 addition and increased swirl could be used to reduce LOI with only small increases of NO. As O2 or swirl increased further, small decreases in LOI were obtained only with large increases in NO. This behavior was captured through NO-LOI trade-off curves where a given configuration or operating condition was deemed better when the curve was shifted toward the origin. Global enrichment or O2 addition to the secondary stream and O2 addition to the primary stream produced better trade-off results than center O¬2 injection. Straw produced NO-LOI trade-off curves just as the wood particles but the curve was shifted further from the origin, likely due to the higher nitrogen content of the straw. Flame characterization results showed that small amounts of O2 in the center improved flame attachment and stability while increasing flame temperature and pyrolysis rates.

Cellulosic biomass-to-bioenergy systems can provide environmental and economic benefits to modern societies, reducing the dependence on fossil-fuels and greenhouse gas emissions while simultaneously improving rural economies. Corn (Zea mays L.) stover and wheat straw (Triticum aestivum L.) residues have particular promise given these crops are widely grown and their cellulosic fractions present a captured resource as a co-product of grain production. Annual systems also offer the ability to change crops rapidly in response to changing market demands. However, concerns exist about residue removal effects on soil health, greenhouse gases emissions and subsequent crop productivity. The carbon footprint and the crop yield productivity and soil health responses resulting from the removal of crop residues has been studied extensively over the last 20 years, but this research has been largely conducted in the Corn Belt. To investigate the impact of crop residue removal in the Mid-Atlantic USA, combinations of corn stover (0, 3.33, 6.66, 10 and 20 Mg ha-1) and wheat straw (0, 1.0, 2.0, and 3.0 Mgha-1) were soil applied in a corn-wheat/soybean (Glycine max L. Merr.) rotation in Virginia's Coastal Plain. Corn stover (0, 3.33, 6.66, 10 and 20 Mg ha-1) was applied in a continuous corn cropping system in the Ridge/Valley province. For each system, residues were applied following grain harvest over two production cycles. Each experiment was conducted as a randomized complete design with four replications. The highest rates of stover retention resulted in greater greenhouse gas emissions in year 1, but not year 2 of these studies and did not affect overall global warming potentials. Stover application also increased soil carbon but had little effect on other measures of soil quality. Stover K levels were greater with high rates of stover retention. Overall, these studies indicate little effect of residue removal or retention (above typical residue production rates) on subsequent crop production, greenhouse gas emissions, or soil health measures in the short term. This study is one of the first to assess residue removal in the Mid-Atlantic USA and is the first study to investigate the impacts that managing more than one crop residue in a multi-crop system. Longer-term research of this type may be warranted both to determine the consequences of residue management and to start building a regionally-specific body of knowledge about these practices. / Ph. D. / Over the last decade, strategic economic and environmental concerns have increased interest in the use of crop residues as sustainable, renewable sources for bioenergy and bio-products. Most of the work investigating the sustainability of residue removal has occurred in the US Corn Belt, where corn stover and wheat straw (the part of the plant that is not grain) supplies are abundant. Although the research data from the Corn Belt provide guarded optimism about residue harvest systems in the Midwest, it is not suitable to extrapolate these results to the South because of differences in soils, climate, and cropping systems. Cooler, humid conditions can sustain higher levels of soil organic matter, lessening but not eliminating concerns about stover removal. Current research from the Midwest region suggests routine stover harvest – within limits – can be sustainable. The development of new bioenergy and bioproduct industries in the Southeast region is leading to a growing expectation that regional cropping systems will supply the millions of tons of biomass needed for these new businesses. However, few data are available regarding sustainable crop residue harvest from the Southeast. Sustainable levels of residue removal may be quite low given regional soil and climatic conditions, and the effects of residue removal on soil health parameters and greenhouse gas emissions remain to be defined. The purpose of this project was to determine the amount of corn stover and wheat straw can sustainably be harvested from Virginia’s grain-based cropping systems without reducing plant productivity or soil quality or increasing GHG emissions. This research generated regionally relevant information on the impacts of crop residue removal to help determine whether harvesting wheat straw and corn stover can be a sustainable practice for the region’s cropping systems. In a first stage, short term impacts of residue removal on soil quality and greenhouse gases were measured in Blacksburg and New Kent, VA, over the period 2015-2017.

La méthanisation est un processus biologique de transformation des matières organiques libérant principalement du méthane et du dioxyde de carbone. Cette technologie connaît un essor important pour la production de biométhane, source d’énergie renouvelable. Elle présente cependant des rendements de dégradation faibles lorsque de la biomasse lignocellulosique est utilisée comme matière première. Pour optimiser son rendement, la paille de blé a été sélectionnée comme biomasse représentative et l’impact sur la méthanisation de chacune des fractions (extractibles, hémicelluloses, cellulose et lignine) a été évalué. Une biomasse de synthèse a été construiteà partir des constituants pures de la paille de blé afin d’évaluer l’impact des interactions lignine-holocellulose. Le potentiel de méthanisation de différentes molécules phénoliques,provenant de la dégradation de la lignine, a été déterminé. Elles inhibent la méthanisation à l’exception de trois d’entres elles qui présentent un rendement de méthanisation élevé : les acides vanillique, l’acide férulique et le syringaldéhyde. Différents prétraitements physique (le chauffage par échangeur thermique ou par irradiation aux micro-ondes ainsi que la sonication et le raffinage papetier) et chimique (la soude, l’ammoniaque et l’ozone) ont ensuite été sélectionnés, et leurs impacts sur lacomposition de la paille et sa méthanisation ont été mesurés. Les meilleurs rendements de méthanisation ont été obtenus suite à l’exposition aux micro-ondes en présence de soude. / Methanization or anaerobic digestion is a biological process to transform organicmatter into a gas mixture composed by a majority of methane and carbon dioxide. Thistechnology is developing rapidly for the production of biomethane as renewable energysource. However this biotechnological route has low performances when lignocellulosicbiomass is used as raw material.Wheat straw has been chosen as typical biomass and the role of each lignocellulosicfraction (extractives, cellulose, hemicelluloses and lignin) has been determined on theperformance of anaerobic digestion. A synthetic biomass has been built with different pureconstituents of the wheat straw to assess the impact of holocellulose-lignin interactions onmethanization. Then methane potential of various lignin degradation products (phenolicmolecules) has been studied. Majority of them have been shown an inhibitory effect butthree of them have been converted to methane: ferulic and vanillic acids andsyringaldehyde.Various physical pretreatments (heating, microwave irradiation, sonication andrefining) and chemical pretreatments (sodium hydroxide, ammonia and ozone) have beenselected to prepare the biomass to anaerobic digestion and their impacts on wheat strawcomposition have been evaluated. The best methanization yield has been obtained afterpretreatments by sodium hydroxide heating by microwave irradiation.

La méthanisation de la biomasse lignocellulosique est un des moyens les plus efficients pour la production d’énergie renouvelable. Cependant, la lignine présente dans cette biomasse est difficile à hydrolyser. Cette limite peut être surmontée grâce aux prétraitements. Parmi eux, les prétraitements peu couteux par pourritures blanches sont attrayants mais ils ont été peu appliqués pour la digestion anaérobie. La présente étude explore les prétraitements par pourritures blanches de la paille de blé afin d’en améliorer sa méthanisation. Tout d’abord, une étape de sélection a révélé l’efficacité de la souche Polyporus brumalis BRFM 985 puisque 43% de méthane supplémentaire ont été obtenus par gramme de matières volatiles par comparaison avec la paille témoin. En prenant en compte les pertes de matières occasionnées par le prétraitement, cela correspondait à 21 % d’amélioration par gramme de matière sèche initiale. De plus, il a été montré que l’addition de glucose durant le prétraitement limitait la délignification et donc la production de méthane du substrat. Puis, des échantillons prétraités furent obtenus lors d’un plan d’expérience visant à optimiser le prétraitement par P. brumalis BRFM 985 ; les paramètres du prétraitement testés étaient : la durée et la température de culture, l’humidité initiale du substrat et l’addition de métaux. Les surfaces de réponse de la production de méthane à partir de ces échantillons furent construites. La production optimale de méthane ne fut pas atteinte dans le domaine expérimental testé mais l’impact positif de l’addition de métaux fut démontré, ainsi que l’importance de choisir une durée de culture adaptée. Ensuite, l’usage de la technique de la pyrolyse-GC-MS pour évaluer l’efficacité du prétraitement fut étudié. Une estimation de la quantité de biomasse fongique avec cette méthode apparaît possible. Le ratio polysaccharides/lignine déterminé par py-GC-MS a permis de classer des échantillons prétraités selon leur biodégradabilité anaérobie. La digestion anaérobie en voie sèche (DAVS) de paille de blé prétraitée en réacteur pilote fut menée en batch avec recirculation des lixiviats. Durant le démarrage de la DAVS, un trop fort S/I mène à une accumulation d’acides gras volatils (AGV) et parfois à la défaillance de la DAVS. Néanmoins, de forts S/I permettent de traiter plus de substrat et augmentent la production de méthane par volume de réacteur. Avec la paille de blé, des S/I entre 2 et 3 (en matières volatiles) permettent un bon démarrage de la DAVS. Alors qu’un ratio AGV totaux/alcalinité inférieur à 0,6 correspond à des réacteurs stables en digestion anaérobie voie liquide ; cette limite semble mal adaptée à la DAVS. Il fut observé que la DAVS pouvait récupérer d’une phase d’acidification tant que le ratio AGV totaux/alcalinité était inférieur à 2 et que la concentration en AGV était inférieure à 10 g/L dans les lixiviats. Malgré une amélioration de la biodégradabilité et une phase de démarrage facilitée, le prétraitement fongique non optimisé ne permit pas d’améliorer la production de méthane après prise en compte des pertes de matière occasionnées par le prétraitement. / Anaerobic digestion of lignocellulosic biomass is one of the most efficient ways to produce renewable energy. However, lignin contained in this biomass is difficult to hydrolyze. This limitation can be overcome by pretreatments. Among them, low-cost white-rot fungi pretreatments seem attractive but were scarcely applied for anaerobic digestion. The current study investigates white-rot fungi pretreatments of wheat straw to improve its methane production. Firstly, a selection step has revealed the efficiency of Polyporus brumalis BRFM 985 since 43% more methane per gram of pretreated volatile solids were obtained compared to the control straw. Taking into account the dry weight loss occurring during the pretreatment, it still corresponded to 21% more methane per gram of initial total solids. Moreover, glucose addition during the pretreatment was shown to limit delignification and thus methane production from the substrate. Secondly, pretreated samples were obtained in an experiment device aiming to optimize the pretreatment with P. brumalis BRFM 985; tested pretreatments parameters were: culture duration, temperature, initial substrate moisture content and metals addition. Response surfaces of methane production from those samples were built. Optimum methane production was not reached in the experimental domain but the positive impact of metals addition was demonstrated, so as the importance to choose adequate culture duration. Then, the use of pyrolysis-GC-MS technic to access pretreatment efficiency was studied. Estimation of fungal biomass amount on wheat straw with this method appeared possible. Polysaccharides/lignin ratio determined with py-GC-MS allowed to classify some pretreated samples according to their anaerobic degradability. Solid State Anaerobic Digestion (SSAD) of wheat straw pretreated in pilot-reactor was carried out in batch with leachate recycle. During SSAD start-up phase, too high Substrate/Inoculum (S/I) ratio leads to Volatile Fatty Acid (VFA) accumulation and sometimes to reactor failure but with high S/I more substrate can be treated and methane production per reactor volume increases. With wheat straw, S/I between 2 and 3 (Volatile Solid basis) allow a successful start-up in SSAD. Whereas Total VFA/alkalinity ratio under 0.6 corresponds to stable wet anaerobic digestion; this limit seems not well adapted to SSAD. It was observed that SSAD reactors were able to recover from acidification phase when Total VFA/alkalinity was lower than 2 and with VFA concentrations inferior to 10 g/L in leachate. Despite the improvement of biodegradability and the facilitation of start-up phase, non-optimized fungal pretreatment did not improve methane production after taking into account mass losses occurring during the pretreatment.

Abstract Plant fibres are an important part of modern daily life. The most obvious consumer products manufactured from them are paper, cardboard and the fibreboards used in the construction and furniture industries. Plants producing a woody stem are the most widely used raw materials for these fibre products but fibres originating from other plants, i.e. non-wood fibres, are used too. One of the most promising potential non-wood fibre resource categories is that of grasses, of which the cereals are the most important plants grown worldwide. A huge amount of straw is generated as an agricultural by-product annually, but the amount used as an industrial raw material is low because it contains components that are detrimental either to processability or to product quality. The purpose of pulp fractionation is to divide pulp into fractions with distinct properties. Industrially feasible fractionation methods are pressure screening, hydrocyclone fractionation and flotation. In pressure screening, separation is based on a mechanical barrier and particles are fractionated according to their dimensions, while a hydrocyclone fractionates particles according to their density and specific surface area and flotation fractionates particles according to their surface chemistry. These methods are traditionally used for removing impurities from pulp but numerous reports on pulp fractionation can also be found. Previous fractionation experiments were performed using wood-based pulps, whereas no previous studies are available concerning the fractionation of pulps manufactured using grasses. The aim of the present work was to determine whether it is possible to fractionate wheat straw pulp by methods that are feasible on an industrial scale. The experimental part was concerned with wheat straw pulp fractionation by pressure screening, hydrocyclone fractionation and flotation. The results show that all these fractionation methods were able to divide the wheat straw pulp into fractions with different cell properties and cell types, e.g. distinct cell lengths, cell wall thicknesses or surface chemistries. Likewise, fractionation can be used to remove detrimental components or to optimize pulp properties according to their end use or to optimize pulp processing sequences. Due to the uniform structure of grasses, it is likely that the results can be generalized to other grasses than that employed here. / Tiivistelmä Kasvisoluja sisältävät tuotteet ovat laajalti mukana ihmisten jokapäiväisessä elämässä. Kaikista näkyvimpiä tuotteita ovat paperi- ja kartonkituotteet sekä rakennus- ja huonekaluteollisuuden käyttämät kuitulevyt. Perinteisesti kasvikuidut näihin tuotteisiin on saatu puuvartisista kasveista, mutta raaka-aineena käytetään muitakin kasveja, niin kutsuttuja non-wood kasveja. Yksi potentiaalinen kasviryhmä teollisuuden raaka-aineeksi ovat heinäkasvit. Muun muassa tärkeimmät viljakasvit ovat heinäkasveja, ja maatalouden sivutuotteina syntyy korsimateriaalia maailmanlaajuisesti huomattava määrä. Heinäkasvien teollinen hyödyntäminen on kuitenkin vähäistä sillä ne sisältävät komponentteja, jotka haittaavat materiaalin prosessointia tai ovat lopputuotteen ominaisuuksia heikentäviä. Kuitususpension fraktioinnin tarkoituksena on jakaa suspensio kahteen tai useampaan jakeeseen, joiden kuituominaisuudet tai solukoostumus ovat erilaiset. Teollisesti käytettävissä olevia fraktiointilaitteita ovat painelajitin, hydrosykloni ja flotaatio: painelajittimessa erottuminen perustuu mekaaniseen esteeseen ja partikkelit erottuvat pääasiassa partikkelin dimensioiden perusteella, hydrosyklonissa erottuminen tapahtuu partikkelien tiheyden ja ominaispinta-alan mukaan kun taas flotaatiolla voidaan erottaa pintakemialtaan erilaisia partikkeleita. Näitä laitteita on perinteisesti käytetty epäpuhtauksien poistamiseen kuitususpensiosta, mutta laitteiden käyttöä puusta valmistettujen massojen fraktiointiin on tutkittu laajasti. Heinäkasveista valmistettujen massojen fraktiointiin näitä menetelmiä ei ole sovellettu. Tämän tutkimuksen tarkoituksena oli selvittää vehnämassan sisältämien solujen fraktiointia teollisuuden käyttöön soveltuvilla menetelmillä. Työn kokeellisessa osassa fraktiointiin vehnäsellua painelajittimella, hydrosyklonilla ja flotaatiolla. Työn tulokset osoittavat, että kaikki tutkitut fraktiointimenetelmät pystyvät jakamaan vehnämassan jakeisiin, joilla on erilaiset solujen ominaisuudet sekä solukoostumukset. Fraktioinnin avulla on mahdollista tuottaa jakeita, joiden kuitupituudet, seinämäpaksuudet sekä pintakemia eroavat. Näin ollen massasta voidaan poistaa jokin haitallinen solujae, tai vaihtoehtoisesti fraktiointia voidaan käyttää optimoitaessa massan ominaisuuksia lopputuotteen ominaisuuksien parantamiseksi, tai optimoitaessa massan prosessointia. Koska heinäkasvit ovat rakenteeltaan samanlaisia, ovat tulokset hyvin todennäköisesti yleistettävissä muidenkin heinäkasvien fraktiointiin.

Abstract New methods are being sought for the production of chemicals, fuels and energy from renewable biomass. Lignocellulosic biomass consists mainly of cellulose, hemicellulose and lignin. Cellulose and hemicellulose can be converted to their building blocks, i.e. sugars, via hydrolysis. This thesis is focused on glucose production from cellulose by dilute acid hydrolysis. Acid hydrolysis has the drawback of limited glucose yields, but it has the potential to become a short-term solution for biochemical production. During acid hydrolysis, the cellulose chain is split into glucose, which undergoes further decomposition reactions to hydroxymethylfurfural, levulinic acid, formic acid and by-products like insoluble humins. The present thesis aims to increase our knowledge on complicated acid-catalysed hydrolysis of cellulose. Glucose decomposition and cellulose hydrolysis were studied independently in laboratory experiments. Kinetic modelling was used as a tool to evaluate the results. The effect of the hydrogen ion on the reactions was evaluated using formic or sulphuric acid as a catalyst. This thesis provides new knowledge of cellulose hydrolysis and glucose decomposition in formic acid, a novel catalyst for high-temperature dilute acid hydrolysis. Glucose yields from cellulose hydrolysed in formic or in sulphuric acid were comparable, indicating that a weak organic acid could function as a cellulose hydrolysis catalyst. Biomass fibres in the form of wheat straw pulp were hydrolysed more selectively to glucose than a model component, microcrystalline cellulose, using formic acid. Glucose decomposition took place similarly in formic and sulphuric acid when the temperature dependence of the hydrogen ion concentration was taken into account, but a significant difference was found between the reaction rates of cellulose hydrolysis in formic acid and in sulphuric acid. The observations can be explained by changes in the cellulose hydrolysis mechanism. Thus, it is proposed in this thesis that side-reactions from cellulose to non-glucose compounds have a more significant role in the system than has earlier been understood. / Tiivistelmä Uusia menetelmiä etsitään kemikaalien, polttoaineiden ja energian valmistamiseen uusiutuvasta biomassasta. Eräs biomassa, ns. lignoselluloosa, koostuu pääasiassa selluloosasta, hemiselluloosasta ja ligniinistä. Selluloosa ja hemiselluloosa voidaan muuttaa hydrolyysin avulla niiden rakennuspalikoikseen eli sokereiksi. Tämä väitöskirja keskittyy glukoosin tuottamiseen selluloosasta laimean happohydrolyysin menetelmällä. Happohydrolyysi kärsii rajoittuneesta glukoosin saannosta, mutta sillä on potentiaalia tulla lyhyen aikavälin ratkaisuksi biokemikaalien tuotannossa. Happohydrolyysin aikana selluloosaketju pilkkoutuu glukoosiksi, joka reagoi edelleen hajoamisreaktioiden kautta hydroksimetyylifurfuraaliksi, levuliini- ja muurahaishapoiksi ja kiinteäksi sivutuotteeksi. Tämän tutkimuksen tavoitteena on kasvattaa ymmärrystämme monimutkaisesta happokatalysoidusta selluloosan hydrolyysistä. Glukoosin hajoamista ja selluloosan hydrolyysiä tutkittiin erikseen laboratoriokokein. Kineettistä mallinnusta käytettiin työkaluna arvioimaan tuloksia. Vety-ionien vaikutus reaktioihin arvioitiin käyttämällä muurahais- ja rikkihappoja katalyytteinä. Tämä väitöskirja antaa uutta tietoa selluloosan hydrolyysistä ja glukoosin hajoamisreaktioista muurahaishapossa, joka on uusi katalyytti korkean lämpötilan laimean hapon hydrolyysissä. Glukoosisaannot muurahaishappo-hydrolysoidusta selluloosasta olivat vertailukelpoisia vastaaviin rikkihappo-hydrolyysi saantoihin. Tämä viittaa siihen, että heikko orgaaninen happo voisi toimia selluloosahydrolyysin katalyyttinä. Kun katalyyttinä käytettiin muurahaishappoa, vehnän oljesta tehdyt kuidut hydrolysoituivat selektiivisemmin glukoosiksi kuin mallikomponenttina toimineen mikrokiteisen selluloosan. Kun vetyionikonsentraation lämpötilariippuvuus otettiin huomioon, glukoosi hajosi samalla tavalla sekä muurahais- että rikkihappokatalyytissä, mutta merkittävä ero havaittiin selluloosahydrolyysin reaktionopeudessa. Havainnot voidaan selittää selluloosahydrolyysin mekanismissa tapahtuvilla muutoksilla. Väitöskirjassa esitetään, että sivureaktioilla selluloosasta ei-glukoosi-tuotteiksi on merkittävä vaikutus systeemiin.

Le développement des bioraffineries lignocellulosiques représente une alternative durable aux ressources fossiles pour produire des biocarburants et constitue un enjeu majeur dans le contexte énergétique et environnemental mondial actuel. La production de bioénergies de deuxième génération nécessite obligatoirement un prétraitement physique, chimique, physicochimique ou biologique de la biomasse végétale. Cette première étape a pour objectif de déstructurer la matrice lignocellulosique afin d’améliorer les étapes suivantes d’hydrolyse enzymatique, tant pour la production de méthane que de sucres simples fermentescibles, issus à la fois des fractions cellulosiques et hémicellulosiques, pour la production de bioéthanol. Les travaux réalisés dans le cadre de cette thèse ont eu pour objectif d’explorer la biodiversité des champignons filamenteux afin de sélectionner des souches performantes pour la Fermentation en Milieu Solide (FMS) de deux biomasses lignocellulosiques modèles (paille de blé et miscanthus) afin de faciliter leur conversion énergétique. Dans un premier temps, une nouvelle procédure originale de criblage moyen débit en FMS en microplaques « deep-well » a été mise au point et a permis de cribler 176 souches fongiques issues de la collection du Centre de Ressources CIRM-CF pour leur efficacité à prétraiter de la paille de blé. Les meilleures d’entre elles, 63 souches, ont également été criblées sur de la paille de miscanthus. Ce crible a permis de mettre en évidence plusieurs champignons d’intérêt dont les plus prometteurs ont été étudiés dans un second temps à l’échelle de bioréacteurs en colonnes de 250 ml. / The development of lignocellulosic biorefineries represents a sustainable alternative to fossil fuels and constitutes a major challenge in the energy context and current global environment. Second generation bioenergy production necessarily requires a physical pre-treatment of plant biomass either chemical, physicochemical or biological. This first step aims at deconstructing the lignocellulosic matrix to improve the subsequent step of enzymatic hydrolysis, even for the production of methane or simple fermentable sugars from both cellulosic and hemicellulosic fractions for bioethanol production. The work carried out during this thesis aimed to explore the biodiversity of filamentous fungi to select efficient strains for the solid state fermentation (SSF) of two lignocellulosic biomass models (miscanthus and wheat straw) to facilitate their conversion to bioenergy.In a first part, a new original procedure of SSF screening using "deep-well" microplates was developed and was used to screen 176 fungal strains from the collection of the CIRM-CF Resource Centre for their effectiveness in wheat straw pretreatment. The best of them, 63 strains were also screened on miscanthus straw. This screening has enabled to highlight several fungi of interest, among them, the five most promising on wheat straw were studied in a second time to 250 ml bioreactor columns (three of these strains were also performing on miscanthus). The performances of the strains have been analyzed more finely considering critical criteria for evaluating the whole bioprocess such as the mass yields, the holocellulose preservation and the net yields of carbohydrates conversion.

La pyrolyse rapide de différents types de celluloses, lignines, xylanes ainsi que de mélanges synthétiques obtenus à partir de ces composés modèles et aussi de deux biomasses réelles (bois de bouleau et paille de blé), est étudiée dans un four à image. Les vitesses de perte de masse pour les composés modèles étudiés sont très différentes, de manière générale la plus grande vitesse de perte de masse est observée pour la cellulose, suivie du xylane et de la lignine. La lignine se distingue par un temps de début de réaction plus petit que celui observé pour le xylane et la cellulose. Pour un temps donné, le rendement en charbon est plus grand pour la lignine que pour le xylane. La formation de charbon à partir de la cellulose est marginale. La cellulose microgranulaire produit en majorité des vapeurs et très peu de gaz. La cellulose extraite du bois de bouleau montre un comportement intermédiaire entre le comportement de la cellulose microgranulaire et les lignines. Le xylane se distingue par une vitesse de formation de gaz supérieure à celles des vapeurs. Les mélanges synthétiques à partir des trois composés modèles montrent un comportement intermédiaire. Le bois de bouleau est plus réactif que la paille de blé et son comportement peut être comparé à celui de la cellulose extraite du bois de bouleau en ce qui concerne les vitesses de perte de masse et de formation de vapeurs. Une corrélation simple se basant sur l’addition pondérée des vitesses de formation des produits est établie et les résultats obtenus sont comparés aux résultats expérimentaux. Il s’avère que les inorganiques jouent un rôle important lors de la pyrolyse : le comportement de la paille de blé, une biomasse riche en inorganiques, ne peut pas être décrit par de telles corrélations. Des écarts moins significatifs entre les valeurs obtenues par les corrélations théoriques et celles provenant des résultats expérimentaux sont observés pour les mélanges synthétiques et le bois de bouleau. En conclusion, l’hypothèse d’une corrélation simple, appelée loi prévisionnelle, ne semble pas être justifiée sur les vitesses de formation de produits. Un modèle est alors développé qui permet de décrire le comportement pyrolytique à l’aide de courbes non linéaires pour la perte de masse et la production des produits. A l’exception de la paille de blé, de nouvelles lois prévisionnelles additives peuvent alors être déterminées de manière très satisfaisante au regard de la précision des mesures expérimentales / The fast pyrolysis of different types of celluloses, lignins, xylanes as well as different mixtures of these basic compounds and two real biomasses (birch wood and wheat straw) has been studied in an image furnace. The mass loss rates of each of the studied model compounds are very different, but usually higher for cellulose than xylane and higher for xylane than lignins. Lignins begin to react before xylane and cellulose. For a given pyrolysis time, lignins produce more char than xylane. Char formation from cellulose remains insignificant, close to zero. Microgranular cellulose gives mainly rise to vapours and very little gas is formed. Cellulose extracted from birch wood shows an intermediate behaviour between microgranular cellulose and lignins. Production rates of gases are higher than those of vapours for xylan. Regarding the mixtures of these three compounds, an intermediate behaviour can be observed. Birch wood is more reactive than wheat straw. Its pyrolytic behaviour is similar with that of cellulose extracted from birch wood with regard to concerning mass loss rates and vapours formation. A simple additive correlation relying on mass loss rates and products formations rates is elaborated and the results compared to the experimental values. It appears that inorganics play an important role in biomass pyrolysis : the pyrolytic behaviour of wheat straw, a biomass which is rich in inorganics, cannot be described by simple additive correlations. Less significant gaps between expected rates obtained by the correlations and the observed rates obtained by the experiments are found for synthetic mixtures and birch wood. In conclusion, the hypothesis of linear correlations cannot be supported for representing the products formations rates. A complete mathematical model is then developed revealing a non-linear behaviour of the variations of mass losses and products formations. Except for wheat straw, new additive correlations are then determined. The agreement with the experimental results is very satisfying with regard to the measurements accuracies

<p>Истраживање у оквиру докторске дисертације обухвата анализу могућности производње и примене биокомпозитних термоизолационих плоча заснованих на нуспроизводима пољопривредне производње и мицелијума гљиве буковаче као везивног средства. Циљеви истраживања су развој методе за производњу биокомпозитних термоизолационих материјала и утврђивање морфолошких, физичко-хемијских, механичких и хигротермичких својстава биокомпозита. У складу са резултатима истраживања и закључцима да је могуће произвести и користити биокомпозитни термоизолациони материјал заснован на биомаси и мицелијуму гљива изведена је анализа енергетске ефикасности и животног циклуса материјала. Резултати истраживања представљају значајну полазну основу за производњу и даље унапређење биокомпозитних термоизолационих материјала у грађевинарству, са позитивном оценом мицелијума гљива као везивног средства.</p> / <p>Istraživanje u okviru doktorske disertacije obuhvata analizu mogućnosti proizvodnje i primene biokompozitnih termoizolacionih ploča zasnovanih na nusproizvodima poljoprivredne proizvodnje i micelijuma gljive bukovače kao vezivnog sredstva. Ciljevi istraživanja su razvoj metode za proizvodnju biokompozitnih termoizolacionih materijala i utvrđivanje morfoloških, fizičko-hemijskih, mehaničkih i higrotermičkih svojstava biokompozita. U skladu sa rezultatima istraživanja i zaključcima da je moguće proizvesti i koristiti biokompozitni termoizolacioni materijal zasnovan na biomasi i micelijumu gljiva izvedena je analiza energetske efikasnosti i životnog ciklusa materijala. Rezultati istraživanja predstavljaju značajnu polaznu osnovu za proizvodnju i dalje unapređenje biokompozitnih termoizolacionih materijala u građevinarstvu, sa pozitivnom ocenom micelijuma gljiva kao vezivnog sredstva.</p> / <p>Research in the thesis is focused on development and utilisation of<br />biocomposite thermal insulation panels based on agricultural biomass and<br />oyster mushroom mycelium as a binding agent. The goals of the research are<br />development of production method of biocomposite thermal insulation panels<br />and determination of morphological, physical-chemical, mechanical and<br />hygrothermal properties of the biocomposite. Energy efficiency and life cycle<br />assessment were conducted in accordance with the research results and<br />conclusions that it is possible to manufacture and use the biocomposite<br />thermal insulation panels based on biomass and mushroom mycelium. The<br />research results represent significant starting point for manufacturing and<br />further improvement of biocomposite thermal insulation panels used in civil<br />engineering and confirm the use of mycelium as a binding agent.</p>