Orientador: Paulo Mazzafera / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-22T15:58:19Z (GMT). No. of bitstreams: 1 Sobczak_JullyanaCristinaMagalhaesSilvaMoura_D.pdf: 7349939 bytes, checksum: 6eb326ffabf9657fb56fa2027dc9ae6a (MD5) Previous issue date: 2013 / Resumo: A lignina é um complexo composto fenólico vegetal cujas propriedades lhe permitem desempenhar suas funções, as quais são, principalmente, suporte mecânico dos tecidos vegetais e condução eficiente de seiva no xilema. Atualmente, a lignina é intensamente estudada, pois sua característica hidrofóbica, altamente resistente à degradação química e enzimática, a torna indesejável durante a produção do papel e biocombustíveis. Assim, diversos estudos estão sendo conduzidos com o objetivo de se entender a biossíntese de lignina, de modo a reduzir o conteúdo ou alterar a reatividade da lignina em plantas utilizadas nestes processos. Pelo presente trabalho foi estudada a lignificação em espécies de eucaliptos utilizados para a produção de papel, utilizando-se tratamentos de baixa temperatura e estresse hídrico como moduladores da lignificação. Foram feitas análises bioquímicas da lignina e estudos da expressão de genes de sua rota biossintética, em duas regiões distintas do caule (ápice e base caulinar), em plantas submetidas aos estresses e em plantas controle. Feito isto, buscou-se relacionar a expressão dos genes analisados com as alterações bioquímicas observadas, com ênfase nas alterações que poderiam ser benéficas do ponto de vista da produção do papel. Foi observado que em híbridos urograndis P42 (Eucalyptus urophylla S. T. Blake x Eucalyptus grandis Hill ex-Maiden), a redução da expressão de LACA8, CAD2 e 4CL0 e o aumento da expressão de POX8.1 e CCR1 podem estar relacionados com as respostas bioquímicas benéficas observadas, isto é, aumento de coniferaldeído, lignina solúvel e digestibilidade da celulose. Em Eucalyptus globulus Labill, análises de plantas submetidas à seca indicaram que a redução da expressão de LACA0 e CCR1, e o aumento da expressão de POX4 e HCT1, podem estar relacionados com o aumento da digestibilidade da celulose. Além disso, uma expressão reduzida de LACA1, LACA6 e DIRI0 podem estar relacionadas com a redução no total de lignina e coniferaldeído. Adicionalmente, em E. globulus, a análise de plantas expostas a frio indicou que a redução da expressão do gene CAD1 pode estar relacionada com o aumento da lignina solúvel. Finalmente, em híbridos uroglobulus (E. urophylla S. T. Blake x E. grandis Hill ex-Maiden) x (E. globulus), comparações das amostras de bases caulinares do ensaio de seca indicaram que a redução da expressão de DIRI0 pode estar relacionada com o aumento da lignina solúvel. Deste modo, este trabalho pode indicar alguns genes possivelmente relacionados com alterações da lignina que poderiam ser benéficas do ponto de vista da produção do papel e, eventualmente, desejáveis para a produção de biocombustíveis, embora este último caso não fosse o foco do trabalho / Abstract: Lignin is a complex plant phenolic compound whose properties allow it to perform its functions, which are mainly the mechanical support of plant tissues and efficient xylem sap conduction. Currently, lignin is intensively studied because its hydrophobic feature and high resistance to chemical and enzymatic degradation makes it undesirable for the production of paper and biofuels. Thus, several studies are being conducted with the goal of understanding the biosynthesis of lignin in order to reduce the content or change the reactivity of lignin in plants used in these processes. In this work, it was studied the lignification in Eucalyptus species used for paper production. Low temperature and water stress treatments were used as modulators of lignification. Biochemical analysis of lignin and gene expression studies were performed in two distinct regions of the stem (stem tips and bases) for plants exposed to stress and control plants. After this, the observed biochemical changes (preferentially those which could be beneficial to paper production) were related to results of gene expression. It was observed that in urograndis P42 hybrids (Eucalyptus urophylla S. T. Blake x Eucalyptus grandis Hill ex-Maiden), the reduction of the expression of LACA8, CAD2 and 4CL0 and the increased expression of POX8.1 and CCR1 may be related to the beneficial biochemical responses observed, that is, an increased coniferaldehyde, soluble lignin and cellulose digestibility. In Eucalyptus globulus Labill, analysis of plants submitted to drought treatments indicated that a reduced expression of LACA0 and CCR1, and an increased expression of POX4 and HCT1, may be related to increased digestibility of cellulose. Besides that, a reduced expression of LACA1, LACA6 and DIRI0 may be related to the reduction in total lignin and coniferaldehyde. Additionally, in E. globulus, analysis of plants exposed to cold indicated that the reduction of the expression in CAD1 may be related to the increase in soluble lignin. Finally, in uroglobulus hybrids (E. urophylla S. T. Blake x E. grandis Hill ex-Maiden) x (E. globulus), comparisons of stem bases of plants subjected to drought treatments indicated that reduced expression of DIRI0 may be associated with increased soluble lignin. In this way, this work indicates some genes possibly related to changes in lignin that could be beneficial for production of paper and possibly be desirable for the production of biofuels, although this latter case was not the focus of the work / Doutorado / Biologia Vegetal / Doutora em Biologia Vegetal

Orientador: Paulo Mazzafera / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T10:24:06Z (GMT). No. of bitstreams: 1 Cesarino_Igor_D.pdf: 8868735 bytes, checksum: c2f0579fef15f4e7a7a37e4b77a434f3 (MD5) Previous issue date: 2012 / Resumo: A lignina é um heteropolímero complexo depositado principalmente na parede celular secundária de tipos celulares especializados, conferindo força mecânica e rigidez para as plantas se manterem eretas e também proporcionando hidrofobicidade para que células condutoras transportem água e nutrientes por longas distâncias. Embora a lignina seja essencial para o desenvolvimento da planta, este polímero é o principal componente da parede celular responsável pela recalcitrância da biomassa vegetal, sendo que sua presença afeta negativamente o uso do material lignocelulósico para a produção de biocombustíveis e biomateriais. Diversas evidências suportam um papel para peroxidases e laccases no processo de polimerização da lignina. No entanto, identificar genes/isoformas relacionados(as) com o processo de polimerização de lignina e caracterizar seu mecanismo de ação estão entre as tarefas mais desafiadoras acerca do metabolismo deste polímero fenólico. Neste trabalho, uma abordagem técnica abrangente foi aplicada com o objetivo de se identificar potenciais candidatos envolvidos na oxidação dos monômeros de lignina. No capítulo I, atividade enzimática e o perfil proteômico de peroxidases de classe III foram analisados durante o desenvolvimento do colmo de cana-de-açúcar. No capítulo II, células em suspensão foram usadas como valiosa ferramenta para isolar e caracterizar peroxidases de classe III potencialmente envolvidas na polimerização de lignina. Finalmente, no capítulo III, a combinação de análises de co-expressão, expressão tecido/tipo celular específica e complementação de um mutante de Arabidopsis thaliana permitiu a caracterização de uma laccase fortemente relacionada com a polimerização de lignina em cana-de-açúcar. Acreditamos que estes foram os primeiros trabalhos a caracterizar peroxidases e laccases em cana-de-açúcar, além de terem contribuído para aumentar o conhecimento acerca do metabolismo de lignina nesta importante cultura dedicada à bioenergia / Abstract: Lignin is a complex heteropolymer deposited in the secondarily thickened walls of specialized plant cells to provide strength and rigidity for plants to stand upright and hydrophobicity to conducting cells for long-distance water transport. Although lignin is essential for plant growth and development, this phenolic polymer is the major plant cell wall component responsible for biomass recalcitrance and its presence negatively affects the use of ligriocellulose as a source for biofuels and bio-based materiais. Several evidences support the role of peroxidases and laccases in lignin polymerization. However, the identification and characterization of peroxidases/laccases involved in lignin polymerization is still a major bottleneck. Here, we carried out a comprehensive approach to identify candidate genes related to the combinatorial coupling of lignin monomers. ln chapter I, we analyzed the enzymatic activity and proteomic profile of class III peroxidases during sugarcane stem development. ln chapter II, suspension cell culture was used as a tool for the characterization of class III peroxidases potentially involved in lignin polymerization. Finally, in chapter III, we provide evidence for the role of a laccase gene in lignin biosynthesis in sugarcane, by using a combination of co-expression analysis, tissue-specific expression analysis and genetic complementation of an Arabidopsis thaliana mutant. To our knowledge, these are the first reports on the characterization of peroxidases and laccases in sugarcane, which might ultimately improve our understanding of the lignin metabolism in this important bioenergy crop / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

The wood-degrading basidiomycete, Phanerochaete chrysosporium, has been studied as a model organism in elucidating the mechanisms and pathways enabling this white-rot fungus to degrade recalcitrant lignin. These same mechanisms are implicated in the mineralisation of environmentally persistent, toxic phenolic chemicals. For this reason, P. chrysosporium has been exploited in a number of environmentally sound technologies, including the degradation of the indigestible lignin component in agricultural waste for the generation of digestible animal feedstocks or high sugar content raw materials for ethanol production; brightening processes in the pulp and paper industry; the detoxification and decolourisation of industrial effluents; and the bioremediation of hazardous waste sites. The improvement of these technologies is dependant on ongoing research involving strain selection, strain development using genetic engineering approaches and process development. Strain improvement using non-recombinant methods is beneficial in that it does not limit the inherent robustness observed amongst natural variants. In this research, through a breeding programme, ten P.chrysosporium sibling strains were screened for variable ligninase activities and pollutant degradation capabilities in order to further describe previously identified differences between these organisms. A conventional stationary liquid culture technique was effectively miniaturised from 10 ml flask cultures to a 96-well microtitre plate format, for the assessment of multigenic traits amongst sibling strains. Using the 96-well microtitre plate method, the relationships between P. chrysosporium growth kinetics, peroxidase production, pollutant sensitivity and pollutant degradation was explored. Significant correlations were primarily associated with P. chrysosporium growth [P < 0.05]. Percentage p-cresol removal and tannic acid tolerance were both correlated with a shorter lag phase in growth [tannic acid: r = 0.7698, P < 0.05; p-cresol: r = 0.7584, P < 0.05] and lower stationary phase biomass levels [tannic acid: r = 0.8177, P < 0.05; p-cresol: r = 0.7803, P < 0.05]. A significant correlation (linear relationship) was also detected between percentage Poly-R478 decolourisation and time of onset of MnP [r = 0.9689, P < 0.001]. No correlation was observed between dye decolourisation, p-cresol degradation, lignin degradation and lignin peroxidase (LiP) or manganese peroxidase (MnP) activities [P > 0.05]. These results imply that differences in the biosynthetic pathways for biomass accumulation in sibling strains play a significant role in the intraspecific variation observed in pollutant sensitivity, pollutant degradation, and enzyme production. Categorical analysis of intraspecific differences was assessed according to four criterions. These included growth, extracellular peroxidase activities, tolerance to toxic pollutants and the biodegradation of model pollutants. Sibling strains showing the most variable responses in three or more of the selective criterion were recommended for further studies. These strains include P. chrysosporium ME446, BS 2.52, BS 13, BS 17, BS 18, and BS 24. Interestingly, BS 2.52 (a dikaryotic strain generating from the crossing of two haploid progeny) showed significantly lower degradation capabilities than the wildtype parent strain ME446. The inherited variability observed between sibling strains is to be further explored through proteome and transcriptome analysis and genetic linkage studies aimed at describing the mechanisms or pathways conferring tolerance to or degradation of environmental pollutants. In examining fewer organisms at this next level, the number of replicates examined can be increased and thus the power of detection of experimental procedures improved, enabling the detection of multigenic traits amongst genetically related organisms. Growth was shown to play a significant role in the intraspecific differences detected in pollutant sensitivity and degradation between sibling strains. Little is known about the mechanism of growth and differentiation, or the role of differentiation in regulating the lignolytic activity in this organism. The membrane gradostat bioreactor and a unique plug-flow membrane bioreactor were evaluated as novel tools with which to further explore the relationship between secondary metabolism, pollutant degradation and biofilm development in sibling strains. High yield MnP production at levels as high as 1478.8 U.l-1 was achieved using a laboratory scale membrane gradostat bioreactor. Furthermore, extensive mycelial differentiation and tissue formation are reported for P. chrysosporium in both the membrane gradostat bioreactor and plug-flow membrane bioreactor. Intraspecific differences in the extent of this differentiation were observed in strains ME446, BS 13, BS 17 and BS 26 cultured using the membrane gradostat bioreactor, highlighting the potential of these techniques as a platform for future strain improvement strategies.

Doctor of Philosophy / Department of Grain Science and Industry / X. Susan Sun / Oilseed protein is a promising renewable source to be used as the replacement of petroleum-based materials for adhesion purpose, and it has drawn increasing attention since soy-based adhesives were developed for wood glues. However, soy protein comprises a portion of humans’ diets, thereby creating competition between utilization of soy protein for protein-based products or human food. Therefore, alternative bio-resources must be discovered. Proteins from camelina sativa provide such potential. Similar to other protein-based polymers, low mechanical strength and poor water resistance are the major drawbacks limiting camelina protein’s further applications. In this research, camelina protein (CP) was modified by unfolding, crosslinking, and co-polymerization treatment for improved flow-ability, adhesion properties and water resistance, which facilitates the industrialization of camelina as an alternative to soy-based adhesives. The physicochemical properties and microstructures of CP were also investigated. To increase the reactivity of CP adhesive, the first step is to denature the folded structure of native proteins. Camelina protein was extracted from defatted camelina meal through alkali solubilization and acid precipitation and modified with varying amount of NaHSO₃ (0-12% of the protein dry base) and Gdm.Cl (0-250% of the protein dry base). NaHSO₃ treatment broke the disulfide bonds of the CP and thus increased its free sulfhydryl content and surface hydrophobicity. As NaHSO₃ concentration increased, the viscosity, elastic modulus (G') and water resistant of NaHSO₃-modified camelina protein (SMCP) dispersion decreased, and the protein became hydrophobic. Gdm.Cl treatment broke the CPI’s hydrogen bonds but decreased their surface hydrophobicity. Similarly, viscosity, G', and water resistant of Gdm.Cl-modified camelina protein (GMCP) dispersions decreased as Gdm.Cl increased and protein became to aggregate. The reducing effect of NaHSO₃ was more obvious than Gdm.Cl to disrupt CPI’s intermolecular protein interaction but less obvious than Gdm.Cl to reduce the viscosity and water resistant. To further increase the CP’s water resistance, a coupling agent, Ethyl-3-(3-dimethyl-aminopropyl-1-carbodiimide) (EDC), was applied to stabilize the protein structure by crosslinking the free carboxyl groups and amino groups. The cross-linked CP exhibited increased molecular weight and particle size. Microstructures of modified CP also became rigid and condensed. Accordingly, CP’s increased intermolecular protein interaction resulted in its higher elastic modulus, viscosity and water resistance. The ultrasound pretreatment further increased the crosslink degree of CP, which resulted in protein’s increased aggregation behaviors and compact micro-structures. Consequently, the elastic modulus, viscosity, and water resistance of CP increased accordingly. Copolymerization with hydrophobic enhancers was also an effective method to improve CP’s water resistance. In this study, kraft lignin was oxidized by H₂O₂ and then copolymerized with CP as wood adhesives, which exhibited increased wet strength. In the presence of ultrasound irradiation, the H₂O₂-depolymerized kraft lignin exhibited reduced particle size, thermal stability and increased content of hydroxyl groups. Fluorescence spectroscopy analysis revealed that after coupling with pristine or de-polymerized lignin, CP exhibited increased hydrophobicity due to lignin’s increased reactivity with camelina protein. Accordingly, the water resistance of CP-based adhesives improved. In the optimized condition, when CP was copolymerized with ultrasound-induced oxidized lignin, it had increased wet shear adhesion strength from 0.28 MPa to 1.43 MPa, with wood panels passing the three-cycle water soaking test.

Ces travaux de thèse visent à valoriser la lignine, biopolymère aromatique le plus abondant sur terre. Pour cela, la dépolymérisation oxydante de la lignine par voie enzymatique a été explorée afin d’obtenir des synthons aromatiques fonctionnalisés. La laccase et le système laccase médiateur (LMS) ont été sélectionnés comme système enzymatique. Dans une première partie, les paramètres réactionnels (choix du médiateurs, température, co-solvant…) de fonctionnement optimal du LMS ont été déterminés notamment via l’utilisation de molécules modèles de lignine. Ces conditions optimales ont été directement appliquées pour l’oxydation d’une lignine organosolv issue d’une plante herbacée. Une étape de fractionnement organique a été conduite sur la lignine avant oxydation afin d’éliminer les populations à l’origine de réactions de couplage. La lignine a ensuite été oxydée par le LMS en milieu biphasique, puis traitée au peroxyde d’hydrogène. Ce procédé en trois étapes a permis de générer des composés aromatiques monomères à trimères (mis en évidence par chromatographies SEC, HPLC, GC et LC-MS) et a été appliqué avec succès à une seconde lignine issue de conifère. Dans les deux cas, des rendements élevés ont été constatés comparés à ceux obtenus dans la littérature. Après isolation, les composés aromatiques produits pourraient trouver des applications comme précurseurs dans les industries de la chimie fine et des polymères. / This work aims at valorizing lignin, the most abundant aromatic biopolymer on earth. For that purpose, an enzymatic approach for the oxidative depolymerization of lignin was investigated in order to obtain fine chemicals. Laccase and the laccase-mediator system (LMS) were selected for the enzymatic oxidation. In the first part, optimal conditions (type of mediator, temperature, co-solvent…) were determined especially by studying reactions on lignin model molecules. These conditions were applied for the oxidation of an organosolv grass lignin. Prior to the oxidation, an organic fractionation was conducted on the lignin in order to remove the population responsible for radical coupling. Then, the lignin was oxidized by the LMS in a biphasic medium followed by a mild hydrogen peroxide treatment. This three-step process allowed the production of monomeric to trimeric aromatic compounds (as shown by SEC, HPLC, GC and LC-MS) and was successfully applied to a different organosolv lignin coming from hardwood. High yield were obtained in both cases as compared with literature results. After isolation, the obtained aromatic molecules could be of interest as precursors for the fine chemistry and polymer industries.

Lignin is a major chemical component of plants and the second most abundant natural polymer after cellulose. The concerns and interests of agriculture and industry have stimulated the study of genes governing lignin content in plants in an effort to adapt plants to human purposes. Arabidopsis thaliana provides a convenient model for the study of the genes governing lignin content because of its short growth cycle, small plant size, and small completely sequenced genome. In order to identify the genes controlling lignin content in Arabidopsis accessions using Quantitative Trait Locus (QTL) analysis, a rapid micro-scale method of lignin determination is required. The acetyl bromide method has been modified to enable the rapid micro-scale determination of lignin content in Arabidopsis. Modifications included the use of a micro-ball mill, adoption of a modified rapid method of extraction, use of an ice-bath to stabilize solutions and reduction in solution volumes. The modified method was shown to be accurate and precise with values in agreement with those determined by the conventional method. The extinction coefficient for Arabidopsis lignin, dissolved using acetyl bromide, was determined to be 23.35 g-iLcm-1. This value is independent of the Arabidopsis accession, environmental growth conditions and is insensitive to syringyl/guaiacyl ratio. The modified acetyl bromide method was shown to be well correlated with the 72% sulfuric acid method once the latter had been corrected for protein contamination and acid-soluble lignin content (R² = 0.988, P < 0.0001). As determined by the newly developed acetyl bromide method and confirmed by the sulfuric acid method, lignin content in Arabidopsis was found to be a divergent property. Lignin content in Arabidopsis was found to be weekly correlated with growth rate among Arabidopsis accessions (R² = 0.48, P = 0.011). Lignin content was also found to be correlated with plant height among Arabidopsis accessions (R² = 0.491, P < 0.0001). / Forestry, Faculty of / Graduate

Cette thèse est dédiée à l'élaboration de matériaux poreux par polymérisation d'émulsion concentrées à partir de polymères issus de la biomasse. La méthodologie polyHIPE a été adaptée pour mettre en œuvre un sous-produit de l'industrie papetière : la liqueur noire Kraft. Des matériaux poreux et possédant une structure interne modulable par les paramètres d'émulsification, ont été obtenus. / This project is dedicated to the synthesis of porous materials from biopolymers via an emulsion-templated polymerisation. The polyHIPE synthesis was adaptated to the physico-chemical properties of the main by-product of the paper industry : the Kraft black liquor. Porous material was obtained and their morphological caracteristics can be modulated through the emulsification parameters.

No description available.

Macromolecular structures, such as lignin and cellulose, are important components of soil organic carbon, the major terrestrial global carbon pool. The degradation of these macromolecules, including lignin and cellulose, in plant-derived soil organic matter, is important to the global carbon cycle. In grasslands, saprotrophic (decomposer) fungi are major decomposers of such organic material. Some of these compounds, such as lignin are relatively resistant to decay by the microbial community if compared with other compound classes such as cellulose. In this work we investigate the involvement of fungi in the decomposition of both lignin and cellulose and look to link the decomposition processes observed in the field to those observed in a laboratory-controlled environment. The key findings of this work are:- Field based experiments in both tropical and temperate environments indicated that lignin can be degraded completely, most likely by white-rot fungi, as shown by the shifts in the [Ac/Al]S, [Ac/Al]G and [S/G] relative lignin decomposition state proxies. The results confirm that even in a very low carbon environment, fungi are able to completely degrade lignin over time. However, lignin is degraded much faster in tropical environments. Culturing experiments showed that it was possible to isolate a number of fungi present on the degraded wheat straw collected in the field, especially soft-rot fungi. When used in microcosm experiments using a range of organic substrates, the relative lignin decomposition state proxies indicated that Absidia cylindrospora and Trichoderma koningii are not able to completely degrade lignin but preferentially degrade cellulose. Cellulose degradation rates are much higher than those of lignin in degraded field samples over time, confirming previous work.

Orientador: Katia Tannous / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T02:38:53Z (GMT). No. of bitstreams: 1 Baroni_EricodeGodois_M.pdf: 4653492 bytes, checksum: abc40b6bb4cc970c83b082daf28c5195 (MD5) Previous issue date: 2015 / Resumo: Este trabalho tem como objetivo realizar o estudo cinético da pirólise do endocarpo do fruto do tucumã mediante termogravimetria em atmosfera de nitrogênio para análise da decomposição térmica, assim como a obtenção dos parâmetros cinéticos, aplicando modelos cinéticos globais e de reações independentes e paralelas. A energia de ativação, fator pré-exponencial e ordem de reação foram calculados utilizando dois conjuntos de experimentos. O primeiro, obtido de Nascimento (2012), utilizando taxas de aquecimento de 5°C/min a 20°C/min e diâmetro médio de 499 µm. O segundo conjunto de dados termogravimétricos foi obtido de modo a avaliar a influência do diâmetro de partícula (de 128,04 µm a 499,55 µm) considerando taxa de aquecimento de 10°C/min e da taxa de aquecimento (de 2,5°C/min a 15°C/min) com diâmetro médio de 128,04 µm. A partir do primeiro conjunto de dados, foram calculados os parâmetros cinéticos por meio de três modelos de reação isoconversionais global (Ozawa-Flynn-Wall, Coats-Redfern modificado e Friedman), em que foram calculadas energias de ativação entre 149 kJ/mol e 159 kJ/mol, fator pré-exponencial de aproximadamente 13 ?1-ns-1 e as ordens de reação de aproximadamente 6. A função de conversão foi definida como correspondente a um mecanismo reacional de n-ésima ordem, baseando-se em onze diferentes equações disponíveis na literatura. Para esse conjunto de dados, o modelo de reações independentes e paralelas (MRIP) foi aplicado considerando reações para hemicelulose, celulose e lignina. Adicionalmente, com o segundo conjunto de dados, o MRIP foi aplicado considerando três e quatro reações, em que foi considerada uma reação adicional associada às reações secundárias de decomposição. A aplicação do MRIP de três reações a partir de dados de Nascimento (2012), gerou desvios relativos próximos aos obtidos com os dados deste trabalho (~4% e ~3%, respectivamente). Entretanto, a aplicação do MRIP de quatro reações gerou desvios relativos ainda menores (~2%), em que energias de ativação, de aproximadamente 128 kJ/mol, 198 kJ/mol, 133 kJ/mol e 150 kJ/mol, foram estimadas para as reações de hemicelulose, celulose, lignina e reações secundárias, respectivamente. As ordens de reação para hemicelulose e celulose foram próximas à unidade, enquanto que para lignina e reações secundárias, variaram de 6 a 8. Com isso, concluiu-se que a aplicação do MRIP de quatro reações descreve favoravelmente o processo de decomposição térmica para cada taxa de aquecimento considerada. Como finalização do trabalho, avaliou-se a capacidade preditiva e descritiva, por meio de curvas simuladas da conversão em função da temperatura. O modelo simulado de quatro reações, utilizando os parâmetros cinéticos com três taxas de aquecimento (5°C/min, 7,5°C/min e 10°C/min), mostrou-se preditivo até a temperatura de 360°C para as taxas de aquecimento de 2,5°C e 15°C/min. Complementarmente, aplicando os parâmetros cinéticos médios com taxas de aquecimento de 2,5°C/min a 15°C/min, a capacidade descritiva demonstrou boa concordância entre dados experimentais e simulados para todo o intervalo de temperatura, denotando a habilidade do modelo em descrever o processo de decomposição do endocarpo do fruto de tucumã / Abstract: This work aims to perform a kinetic study of the pyrolysis of tucumã fruit endocarp by using thermogravimetry in nitrogen atmosphere to analyze the thermal decomposition and to estimate the kinetic parameters through global reaction models and independent parallel reaction models. The activation energy, pre-exponential factor, and reaction order were calculated using two sets of data. The first, obtained by Nascimento (2012), applying heating rates from 5°C/min to 20°C/min and mean diameter of 499 µm. The second thermogravimetry data set was obtained in order to evaluate the influence of the particle diameter (from 128,04 µm to 499,55 µm) considering heating rate of 10°C/min, and heating rates (from 2,5°C/min to 15°C/min) with mean diameter of 128,04 µm. Using the first data set, the kinetic parameters were calculated using three isoconversional global reaction models (Ozawa-Flynn-Wall, modified Coats-Redfern, and Friedman), in which were found activation energies between 149 kJ/mol and 159 kJ/mol, pre-exponential factor of about 13 ?1-ns-1 and reaction orders of about 6. The conversion function was defined, corresponding to an nth order reaction mechanism, based on eleven different equation available in the literature. For this data set, the independent parallel reaction model (IPRM) was applied considering reaction for hemicellulose, cellulose, and lignin. Additionally, with the second data set, the IPRM was applied considering three and four reactions, in which an additional reaction was associated to the secondary decomposition reactions. By the application of the three reactions IPRM from the data of Nascimento (2012), close relative deviations were obtained with the data from this work (~4% and ~3%, respectively). However, the application of the four reactions IPRM, relative deviations even lower were obtained (~2%), in which activation energies of about 128 kJ/mol, 198 kJ/mol, 133 kJ/mol, and 150 kJ/mol were estimated for the reactions hemicellulose, cellulose, lignin, and secondary reactions, respectively. The reaction orders for hemicellulose and cellulose were close to unit, while for lignin and secondary reactions varied from 6 to 8. Therewith, it was observed that the application of the four reactions IPRM describes favorably the thermal decomposition process for each heating rate considered. For this work¿s completion, the predictive and descriptive capacity were evaluated using simulated curves of conversion as a function of temperature. The four reactions simulated model using the kinetic parameters with three heating rates (5°C/min, 7,5°C/min, and 10°C/min) was predictive up to 360°C for the heating rates of 2,5°C/min and 15°C/min. Complementarily, using the mean kinetic parameters obtained at heating rates from 2,5°C/min to 15°C/min, the descriptive capacity showed a good agreement between experimental and simulated data for the whole temperature interval, denoting the model¿s ability in describing the decomposition process of tucumã fruit endocarp / Mestrado / Engenharia Química / Mestre em Engenharia Química