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.

Made available in DSpace on 2015-03-26T13:51:43Z (GMT). No. of bitstreams: 1 01 - capa_abstract.pdf: 74835 bytes, checksum: 716f5bf894e92efbf5c4b42ff95351ad (MD5) Previous issue date: 2008-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The increase in world population demands ever more food and consumer goods, with a consequent increase in the production of agroindustrial residues natives from logging, alcohol fuel plants and industries for beneficiary eligibility of agricultural products. Several studies have demonstrated the potential of white rot fungi to decompose of lignocellulosic substrates, but the use of such residues in ruminant diets has not been properly examined. The objective of this study was to determine the chemical composition and in vitro digestibility of agroindustrial residues (eucalyptus bark, sawdust, sugarcane bagasse, corn kernels, coffee bark, coconut fiber and lump of cotton) inoculated with white rot fungi (Pleurotus ostreatus and Lentinula edodes), and determine the activity of cellulase, xylanase and laccase in ruminal fluid incubated in vitro with corn kernels or sugarcane bagasse ground at different particle sizes. When the residues were treated with L. edodes the content of CP in eucalyptus bark increased 91 % and 78 % in the treatments added with rice bran or urea, respectively. The content of ADL decreased 70% in fructified sawdust added with rice bran compared to the controls. The NDF of sugarcane bagasse decreased 5 % when added with rice bran and 21 % when added with urea. When the residues were treated with P. ostreatus the levels of CEL and ADL of eucalyptus bark decreased 22 % and 137 %, respectively. With sawdust, the concentrations of NDF and ADF decreased 19 % and 27 %, respectively, after fruit body formation. The EE increased 402 % in sugarcane bagasse treated with P. ostreatus. With corn kernels, the content of ash increased 130 % compared to controls in the treatment showing fruit body formation. There was a reduction of 60 % in the LDA content of coffee barks after fructification. Fungus fructification in the coconut fiber reduced the levels of LDA and CEL in 25 % and 20 %, respectively. There were no significant differences between treatments for CP, ADF, CEL, HEM and ADL contents in the lump of cotton. However, there was significant difference in IVDMD between the enriched fructified substrates treated with L. edodes. An average increase 111 % and 98 % was observed for the fructified fungus added with rice bran or urea, respectively, compared to controls. The biggest increase in IVDMD after fructification in residues treated with P. ostreatus was obtained for the eucalyptus bark (200 %), followed by corn kernels (67 %) and sugar cane bagasse (13 %). The highest cellulase activity in corn kernels residues was obtained when using particles with a diameter of 0.6 mm. The xylanase activity was higher than the activity of cellulase for all treatments and sizes of particles tested. The particle size of 0.6 mm in the inoculated treatment yielded maximum xylanase activity after 48 hours of incubation (118.17 U/mL). The activity of cellulase in sugarcane bagasse was superior for all treatments and particle sizes when compared to corn kernels residues. The highest activity of xylanase (78.89 U/mL) in the fructified sugarcane bagasse was obtained after 48 hours of incubation and particles size of 0.6 mm. The changes in chemical composition and IVDMD showed that L. edodes (UFV 73) and P. ostreatus (PLO 06) could improve the nutritional quality of ruminant rations by increasing the content of CP and IVDMD and reducing the levels of NDF, ADF and ADL of agroindustrial residues, allowing its use in ruminant rations. / O aumento da população mundial demanda cada vez mais alimentos e bens de consumo, com conseqüente aumento na produção de resíduos agroindustriais oriundos de madeireiras, usinas de álcool combustível e indústrias de beneficiamento de produtos agrícolas. Diversos estudos têm demonstrado o potencial de fungos da podridão branca em decompor substratos ligninocelulósicos, mas a utilização desses resíduos na alimentação de ruminantes ainda tem sido pouco explorada. O objetivo deste trabalho foi determinar a composição bromatológica e a digestibilidade in vitro de resíduos agroindustriais (casca de eucalipto, serragem de eucalipto, bagaço de cana-de-açúcar, sabugo de milho, casca de café, fibra de coco e casca de caroço de algodão desengordurado) inoculados com fungos causadores da podridão branca (Pleurotus ostreatus e Lentinula edodes), assim como determinar a atividade enzimática de celulase, xilanase e lacase em três diferentes tamanhos de partículas dos resíduos sabugo de milho e bagaço de cana-de-açúcar incubados com líquido ruminal in vitro, visando avaliar o potencial hidrolítico das comunidades microbianas do rúmen. Quando os resíduos foram tratados com L. edodes o teor de PB do resíduo casca de eucalipto aumentou 91 % e 78 % no tratamento enriquecido com farelo de arroz e uréia, respectivamente. O teor de LDA diminuiu 70 % na serragem de eucalipto frutificada e enriquecida com farelo de arroz comparada ao controle. A FDN do resíduo bagaço de cana diminuiu 5 % quando enriquecido com farelo e 21 % quando enriquecido com uréia. Quando os resíduos foram tratados com P. ostreatus os teores de CEL e LDA da casca de eucalipto diminuíram 22 % e 137 %, respectivamente, após o tratamento. Na serragem de eucalipto as concentrações de FDN e FDA diminuíram 19 % e 27 % no tratamento frutificado, respectivamente. O EE aumentou 402 % no tratamento frutificado no bagaço. No sabugo o conteúdo de cinzas aumentou 130 % no tratamento frutificado em relação ao controle. Houve redução de 60 % no teor de LDA da casca de café após a frutificação. A frutificação fúngica reduziu os teores de LDA e CEL em 25 % e 20 %, respectivamente na fibra de coco. Não houve diferenças significativas entre os tratamentos para os teores de PB, FDA, CEL, HEM e LDA no resíduo casca de caroço de algodão desengordurado. Houve diferença significativa na DIVMS entre os enriquecimentos dos resíduos tratados com L. edodes, tendo sido observado aumento médio de 111 % e 98 % quando frutificado e adicionado de farelo de arroz e uréia, respectivamente, em relação ao controle O maior incremento de DIVMS no tratamento frutificado nos resíduos tratados com P. ostreatus foi obtido para a casca de eucalipto (200 %), sabugo de milho (67 %) e bagaço de cana-de-açúcar (13 %). As maiores atividades de celulase no resíduo sabugo de milho foram obtidas quando se utilizou partículas com 0,6 mm de diâmetro. A atividade de xilanase foi maior quando comparada à atividade de celulase em todos os tratamentos e tamanhos de partículas testados. O tamanho de partícula 0,6 mm no tratamento inoculado foi o que apresentou atividade máxima de xilanase após 48 horas de incubação (118,17 U/mL). A atividade de celulase no resíduo bagaço de cana-de-açúcar foi superior em todos os tratamentos e tamanhos de partículas quando comparado ao resíduo sabugo de milho. O tamanho de partícula 0,6 mm apresentou as maiores concentrações de xilanase no bagaço de cana-de-açúcar, tendo sido observado valor máximo após 48 horas de incubação de 78,89 U/mL no tratamento frutificado. As mudanças na composição química e na DIVMS indicam que L. edodes (UFV 73) e P. ostreatus (PLO 06) melhoram o valor nutricional dos resíduos tratados, aumentando o teor de PB e DIVMS e reduzindo os teores de FDN, FDA e LDA dos resíduos agroindustriais, com possibilidade de utilização na alimentação de ruminantes.

Wastewater from the textile industry is difficult to treat effectively due to the prevalent use and wide variety of synthetic dyes that are resistant to conventional treatment methods. White-rot fungi, such as Trametes versicolor, have been found to be effective in decolorizing many of these synthetic dyes and current research is focusing on their application to wastewater treatment. Although numerous studies have been conducted on the ability of both living and nonliving Trametes versicolor to separately decolorize textile dyes, no studies were found to have investigated the use of a mixture of live and dead fungus for decolorization. This study explored potential interactions between live and dead, autoclaved Trametes versicolor biomass in a mixed system by utilizing a series of batch tests with two structurally different synthetic textile dyes. Samples were analyzed by spectrophotometer and compared with controls to determine the effect of any interactions on decolorization. The results of this study indicate that an interaction between living and nonliving biomass occurred that affected the specific dye removal for both Reactive Blue 19, an anthraquinone textile dye, and Reactive Orange 16, an azo textile dye. This interaction was seen to improve the specific dye removal during the first 10-46 hours of experimentation but then diminish the specific dye removal after this period. This effect could be due to hydrophobins, which are surface-active proteins excreted by live fungi that may alter hydrophobicity. Additionally, the presence of adsorptive dead biomass could affect dye contact with degrading enzymes released from the live fungus. By expanding current knowledge of the interactions that take place in a fungal bioreactor and their effect on textile dye decolorization, this research aims to inspire more effective and less costly bioreactor designs for the treatment of textile wastewater.

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The remediation of persistent chlorinated aromatic compounds has become a priority of great relevance due to the teratogenic, carcinogenic and endocrine-disrupting properties of these xenobiotics. The use of biological methodologies for the clean-up of contaminated sites, collectively referred to as "bioremediation", has been gaining an increasing interest in recent years because it represents an effective, cost-competitive and environmentally friendly alternative to the physico-chemical and thermal treatments. In this respect, "white rot" fungi, an ecological subgroup of filamentous fungi, display features that make them excellent candidates to design an effective remediation technology ("mycoremediation"). In spite of this, fungi have not been widely exploited for their metabolic capabilities and the mechanism by which they are able to degrade the aforementioned pollutants has not been fully elucidated yet. Within this frame, the present Ph.D thesis was aimed at: i) assessing the efficiency of different mycoremediation strategies for the clean-up of a polychlorinated biphenyl (PCBs)-contaminated soil; ii) understanding the fungal degradation pathways of polychlorinated biphenyls and their major metabolites, namely chlorobenzoic acids (CBAs) and hydroxylated polychlorinated biphenyls (OH-PCBs). i)...

Dans les écosystèmes forestiers, la décomposition du bois est un processus majeur, notamment impliqué dans le cycle du carbone et des nutriments. Les champignons basidiomycètes saprotrophes, incluant les pourritures blanches, sont les principaux agents de cette décomposition dans les forêts tempérées. Bien que peu étudiées, des communautés bactériennes sont également présentes dans le bois en décomposition et cohabitent avec ces communautés fongiques. L'impact des interactions bactéries-champignons sur le fonctionnement d'une niche écologique a été décrit dans de nombreux environnements. Cependant, leur rôle dans le processus de décomposition du bois n'a été que très peu investigué. A partir d'expériences en microcosme et en utilisant une approche non cultivable, il a été démontré que la présence du champignon Phanerochaete chrysosporium influençait significativement la structure et la diversité des communautés bactériennes associées au processus de décomposition du hêtre (Fagus sylvatica). Par une approche cultivable, cet effet mycosphère a été confirmé, se traduisant par une augmentation de la densité des communautés bactériennes en présence du champignon ainsi que par une modification de la diversité fonctionnelle de ces communautés. Enfin, une approche polyphasique a été développée, combinant l'analyse des propriétés physico-chimiques du bois et des activités enzymatiques extracellulaires. Les résultats de cette expérience ont révélé que l'association de P. chrysosporium avec une communauté bactérienne issue de la mycosphère de ce dernier aboutissait à une dégradation plus importante du matériau bois par rapport à la dégradation par le champignon seul, démontrant pour la première fois des interactions bactéries-champignons synergiques dans le bois en décomposition / Wood decomposition is an important process in forest ecosystems in terms of their carbon and nutrient cycles. In temperate forests, saprotrophic basidiomycetes such as white-rot fungi are the main wood decomposers. While they have been less studied, bacterial communities also colonise decaying wood and coexist with these fungal communities. Although the impact of bacterial-fungal interactions on niche functioning has been highlighted in a wide range of environments, little is known about their role in wood decay. Based on microcosm experiments and using a culture-independent approach, we showed that the presence of the white-rot fungus Phanerochaete chrysosporium significantly modified the structure and diversity of the bacterial communities associated with the degradation of beech wood (Fagus sylvatica). Using a culture-dependent approach, it was confirmed that in the presence of the fungus the mycosphere effect resulted in increased bacterial abundance and modified the functional diversity of the fungal-associated bacterial communities. Lastly, a polyphasic approach simultaneously analysing wood physicochemical properties and extracellular enzyme activities was developed. This approach revealed that P. chrysosporium associated with a bacterial community isolated from its mycosphere was more efficient in degrading wood compared to the fungus on its own, highlighting for the first time synergistic bacterial-fungal interactions in decaying wood

La bioconversion en méthane de biomasses lignocellulosiques est l’une des alternatives les plus prometteuses pour la production de méthane issu de la digestion anaérobie. Toutefois, les biomasses lignocellulosiques présentent des caractéristiques bio-physico-chimiques très variables en raison leur composition biochimique et de l’organisation structurale très diverses. Par ailleurs, leur faible biodégradabilité en conditions anaérobie nécessite de les prétraiter avant méthanisation pour optimiser la production de méthane. Ce travail vise à évaluer l’influence des caractéristiques d’une large gamme de substrats lignocellulosiques sur leur biodégradabilité anaérobie et les corrélations entre leurs caractéristiques bio-physico-chimiques et le potentiel biométhanogène, et d’étudier les effets du prétraitement fongique en présence de Ceriporiopsis subvermispora sur le potentiel biométhanogène de biomasses lignocellulosiques sélectionnées dans la présente étude et de caractériser les changements de leurs caractéristiques après le prétraitement fongique. La caractérisation de 36 biomasses lignocellulosiques représentatives d’une large gamme de gisements potentiellement mobilisables a permis de mettre en évidence les corrélations linéaires entre le potentiel biométhanogène des biomasses et certaines de leur caractéristiques bio-physico-chimiques, dont la teneur en lignine et la demande biochimique en oxygène. Les biomasses sylvicoles et agricoles ont montré des caractéristiques distinctes de la biodégradabilité aérobie et anaérobie. Les résultats de prétraitement fongique sur les 5 biomasses ont permis de mettre en évidence que le champignon de pourriture blanche Ceriporiopsis subvermispora réagit distinctement selon la biomasse prétraitée. Pour certaines biomasses, le prétraitement fongique conduit à augmenter significativement la production de méthane et la vitesse de bioconversion en méthane. Cette espèce présente la capacité de dégrader sélectivement la lignine sur certaines biomasses et, sur d’autres, celle de dégrader de manière non-sélective des polysaccharides et des lignines. De plus, pour les deux souches de Ceriporiopsis subvermispora testées, des métabolismes différents ont été mis en évidence sur une même biomasse. Les résultats de compositions et ceux de l’analyse structurale des biomasses (initiales, autoclavées, contrôles, et prétraitées par Ceriporiopsis subvermispora) ont montré que leur structure peut être modifiée sans toutefois observer une transformation significative de leur composition biochimique. / Bioconversion to methane lignocellulosic biomass is one of the most promising alternatives for the production of methane from anaerobic digestion. However, lignocellulosic biomass has various bio-physicochemical characteristics due to their biochemical composition and diverse structural organization. Moreover, their low biodegradability in anaerobic condition requires pretreatment before methanation to optimize methane production. This work aims to evaluate the influence of the characteristics of a wide range of lignocellulosic substrates on their anaerobic biodegradability and correlations between their bio-physical-chemical characteristics and biomethane potential, and study the effects of fungal pretreatment in the presence of Ceriporiopsis subvermispora on the biogas potential of lignocellulosic biomass selected in this study and characterize their changes of their characteristics before and after the fungal pretreatment. The characterization of 36 representative lignocellulosic biomass of a wide range of potentially mobilized deposits allowed to highlight the linear correlations between biomethane potential of biomass and some of their bio-physical-chemical characteristics, of which the lignin content and biochemical oxygen demand. The forest and agricultural biomass exhibited distinct characteristics of the aerobic and anaerobic biodegradability. The results of fungal pretreatment of the 5 biomass indicated that the white rot fungus Ceriporiopsis subvermispora reacts distinctly depending on the pretreated biomass. For some biomass, fungal pretreatment leads to significant increase of methane production and the bioconversion rate of methane. This species presents the ability to selectively degrade lignin on some biomasses, in others, the ability to non-selectively degrade polysaccharides and lignins. In addition, for both strains of Ceriporiopsis subvermispora tested, different metabolisms were highlighted on the same biomass. The results of compositions and those of the structural analysis of biomass (initials, autoclaved, controls, and pretreated with Ceriporiopsis subvermispora) showed that their structure can be modified without observing a significant transformation of their biochemical composition.

This diploma thesis focuses on the determination of sulfonamide antibiotics especially the possibility of elimination of these substances from the aquatic ecosystem. Nowadays, environmental contamination of the pharmaceuticals and their residues is a serious concern. Main sources of this contamination are wastewater treatment plants (WWTPs), where these compounds are not effectively removed by contemporary conventional technology. For this reason, new methods are being developed and tested that could eliminate the number of contaminants entering the environment in this way. There is a possibility to use the potential of the enzymatic system of wood-decay fungi, especially white rot fungi. Six representatives of sulfonamide antibiotics were selected and isolated from the aquatic matrix via solid phase extraction. The final identification and quantification method was high performance liquid chromatography with mass spectrometric detection. Monitoring of the concentration level of selected sulfonamide antibiotics at the inflow and effluent at the Brno-Modřice WWTP was carried out weekly. Moreover, the effectiveness of elimination of selected antibiotics from the aquatic ecosystem by the use of Trametes versicolor wood-decay fungi cultured on a suitable carrier was verified.

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