Neste trabalho, foi realizada a caracterização de ligninas de palha de cana-de-açúcar. O isolamento das ligninas se deu por acidólise branda e por polpação soda, precedida ou não por pré-tratamento com ácido diluído ou por explosão a vapor. A palha de cana e as ligninas foram caracterizadas por Cromatografia Líquida de Alta Eficiência (CLAE), Espectrometrias no Infravermelho (FT-IR) e no Ultravioleta (UV), por Ressonância Magnética Nuclear de Prótons (1H RMN), Cromatografia de Permeação em Gel (GPC), Análise Termogravimétrica (TGA) e Calorimétrica (DSC), Análise Elementar e de Poder Calorífico Superior (PCS). A lignina técnica isolada por acidólise branda apresentou fórmula C9Har2,31Hal4,14O1,27(OH)ph0,58(OH)al1,19(OCH3)1,11 e relação H:G:S de 1 : 3,22 : 3,68, com 20% de condensação e massa molar média de 1908 Da. A cinética de termodegradação dessa lignina em atmosfera inerte se deu com energia de ativação de 13,90 kJ.mol-1, constante pré-exponencial 0,4799 min-1 e 42% em massa de carvão residual. Foram determinados, ainda, o coeficiente de extinção a 280 nm de 26,03 L.g-1 e o Poder Calorífico Superior de 23,72 kJ.g-1. A partir das informações obtidas em todas as análises, foi proposta uma estrutura para esta lignina. A deslignificação via polpação soda mostrou-se eficiente na remoção de lignina da matriz e foi verificado que, durante o processo, ocorre o rompimento de ligações entre a lignina e carboidratos, entretanto, algumas dessas ligações não são rompidas e o resíduo do processo, denominado lignina, contêm cerca de 17% carboidratos. A lignina soda apresentou poder calorífico superior de 25,14 kJ.g-1, 36% em massa de carvão residual e cinética de termodegradação com energia de ativação de 12,73 kJ.mol-1 e k0=0,4195 min-1. Foi verificado que as polpas soda que sofreram pré-tratamentos apresentaram um menor teor de lignina e maior solubilização de hemiceluloses. Estes tratamentos se mostraram eficientes na hidrólise dos complexos lignina-carboidrato e a ligninas obtidas apresentaram os menores teores de carboidrato residual e características estruturais diferentes das demais, mostrando-se mais condensadas em função das reações que ocorrem em meio ácido. Os coeficientes de extinção a 280 nm foram iguais a 24,2 L.g-1 e 23,3 L.g-1, respectivamente para as ligninas de explosão a vapor e pré-tratamento ácido e suas fórmulas estruturais determinadas por 1H RMN foram, respectivamente, C9Har1,59Hal4,12O0,84(OH)ph0,61(OH)al0,88(OCH3)1,51 e C9Har2,12Hal4,23O1,64(OH)ph0,83(OH)al0,58(OCH3)1,10. / In this work, the characterisation of lignins of sugarcane straw was made. The lignins were isolated by moderate acidolysis and soda process, preceded or not by either diluted acid or steam explosion pretreatments. The sugarcane straw and the lignins were characterised by High Performance Liquid Chromatography (HPLC), Infrared (FT-IR) and Ultraviolet (UV) Spectrometry, Proton Nuclear Magnetic Resonance (H1-RMN), Gel Permeation Chromatography (GPC), Thermogravimetrica analysis (TGA) and Differential Scattering Calormietry (DSC), Elemental Analysis and Heat Power (HP). The technical lignin isolated by moderate acidolysis has the formula C9Har2.31Hal4.14O1.27(OH)ph0.58(OH)al1.19(OCH3)1.11, H:G:S ratio of 1 : 3.22 : 3.68, is 20% condensed and its avarage molecular weight is 1908 Da. The thermal degradation kinetics analysis of this lignin in inert atmosphere was carried out, the results obtained were: activation energy of 13.80 kJ.mol-1, pre-exponential constant of 0.4799 min-1 and 42% residual char. The extinction coefficient obtained at 280 nm was 26.03 L.g-1 and the heat power 23.72 kJ.g-1. A structure was proposed for this lignin based on all the information obtained from these analyses. The delignification via soda process was efficient at removing lignin; during the process, the breaking of bonds between the lignin and carbohydrates was noticed, nevertheless, some of these bonds were not broken and the process residue, hereinafter called lignin, contains about 17% carbohydrates. The soda lignin has heat power of 25.14 kJ.g-1, 36% residual char and the thermal degradation kinetics ocurred with activation energy of 12.73 kJ.mol-1 and k0=0.4195 min-1. It was found that pretreated soda pulps have a lower lignin content and higher solubilisation of complexes, the lignins obtained had the lowest residual carbohydrates contents and different structural features from the untreated ones, being more condensed due to the reactions that occur in acid medium. The extinction coefficients at 280 nm obtained are 24.2 L.g-1 and 23.3 L.g-1, the structural formulas determined by 1H RMN are C9Har1.59Hal4.12O0.84(OH)ph0.61(OH)al0.88(OCH3)1.51 and C9Har2.12Hal4.23O1.64(OH)ph0.83(OH)al0.58(OCH3)1.10 for the steam explosion and acid pretreatment lignins, respectively.

Ce projet de thèse est dédié à l’étude de l’intensification de l’extraction des polymères d’hémicelluloses à partir du bois d’épicéa par l’application de prétraitements physicochimiques : microondes (MO), décharges électriques de hautes tension (DEHT) et explosion à la vapeur (STEX). L’extraction des hémicelluloses est souvent réalisée par autohydrolyse ou par des traitements chimiques. Dans ce travail de thèse, nous avons étudié un procédé basé sur l’extraction des hémicelluloses en combinant des prétraitements physiques aux prétraitements chimiques et à l’autohydrolyse. Ce couplage a permis d’avoir des hémicelluloses avec des poids moléculaires moyens en masse (Mw) élevés allant jusqu’à 70 kDa, 66 kDa et 55 kDa lors des extractions en milieu basique par STEX, MO et DEHT respectivement. Les performances des prétraitements en termes de rendement d’extraction sont plus élevées que pour l’autohydrolyse seule pour les mêmes conditions de température et de temps d’extraction. La caractérisation des hémicelluloses extraites a révélé une sélectivité d’extraction en fonction du pH du milieu d’imprégnation. L’imprégnation en milieu neutre favorise la solubilisation des galactoglucomannanes (GGM) et l’imprégnation en milieu basique favorise la solubilisation des arabinoglucoronoxylanes (ARX). L’analyse du degré d’acétylation (DA) a montré que la STEX a permis d’extraire des acetyl-GGM avec des DA (~0,35) proches de celui des hémicelluloses à l’état natif. Les films élaborés à partir des hémicelluloses extraites présentent des barrières intéressantes vis à vis de l’oxygène (0,83 cm3.μm-1.jour-1.kPa au maximum) et du rayonnement UV. / This thesis project is specifically dedicated to the study of the intensification of the extraction of hemicellulose polymers from spruce wood by the application of physicochemical pretreatments: Microwave (MW), High Voltage Electrical Discharge (HVED) and Steam Explosion (STEX). Extraction of hemicelluloses is often carried out by an autohydrolysis or by chemical treatments. In this work, we have developed an original process for extracting hemicelluloses polymers by combining physical pretreatments (MW, HVED and STEX) with chemical pretreatments and autohydrolysis. This combination allowed us to recover hemicelluloses with average molecular weights (Mw) highs up to 70 kDa, 66 kDa and 55 kDa when STEX, MW and HVED were applied in basic medium respectively. The performance of the pretreatments in terms of extraction yield is higher than the autohydrolysis alone for the same extraction temperatures. The characterization of the extracted hemicelluloses revealed an extraction selectivity as a function of the pH of the medium of impregnation. Impregnation in neutral medium promotes the solubilization of galactoglucomannans (GGM) and impregnation in a basic medium promotes the solubilization of arabinoglucoronoxylans (ARX). The analysis of the degree of acetylation (AD) showed that STEX pretreatment allowed the extraction of acetyl-GGM with an AD of approximately 0.35 which is close to that in native hemicelluloses.The characterization of films made from extracted hemicelluloses showed that these films are good barrier to oxygen with oxygen permeability near to 0.83 cm3 μm-1 day-1 kPa-1 and to UV radiations.

The two main sources of biomass for energy generation are purpose-grown energy crops and waste materials. Energy crops, such as Miscanthus and short rotation woody crops (coppice), are cultivated mainly for energy purposes and are associated with the food vs. fuels debate, which is concerned with whether land should be used for fuel rather than food production. The use of residues from agriculture, such as barley, canola, oat and wheat straw, for energy generation circumvents the food vs. fuel dilemma and adds value to existing crops. In fact, these residues represent an abundant, inexpensive and readily available source of renewable lignocellulosic biomass. In order to reduce industrys operational cost as well as to meet the requirement of raw material for biofuel production, biomass must be processed and handled in an efficient manner. Due to its high moisture content, irregular shape and size, and low bulk density, biomass is very difficult to handle, transport, store, and utilize in its original form. Densification of biomass into durable compacts is an effective solution to these problems and it can reduce material waste. Upon densification, many agricultural biomass materials, especially those from straw and stover, result in a poorly formed pellets or compacts that are more often dusty, difficult to handle and costly to manufacture. This is caused by lack of complete understanding on the natural binding characteristics of the components that make up biomass. An integrated approach to postharvest processing (chopping, grinding and steam explosion), and feasibility study on lab-scale and pilot scale densification of non-treated and steam exploded barley, canola, oat and wheat straw was successfully established to develop baseline data and correlations, that assisted in performing overall specific energy analysis. A new procedure was developed to rapidly characterize the lignocellulosic composition of agricultural biomass using the Fourier Transform Infrared (FTIR) spectroscopy. In addition, baseline knowledge was created to determine the physical and frictional properties of non-treated and steam exploded agricultural biomass grinds. Particle size reduction of agricultural biomass was performed to increase the total surface area, pore size of the material and the number of contact points for inter-particle bonding in the compaction process. Predictive regression equations having higher R2 values were developed that could be used by biorefineries to perform economic feasibility of establishing a processing plant. Specific energy required by a hammer mill to grind non-treated and steam exploded barley, canola, oat and wheat straw showed a negative power correlation with hammer mill screen sizes. Rapid and cost effective quantification of lignocellulosic components (cellulose, hemicelluloses and lignin) of agricultural biomass (barley, canola, oat and wheat) is essential to determine the effect of various pre-treatments (such as steam explosion) on biomass used as feedstock for the biofuel industry. A novel procedure to quantitatively predict lignocellulosic components of non-treated and steam exploded barley, canola, oat and wheat straw was developed using Fourier Transformed Infrared (FTIR) spectroscopy. Regression equations having R2 values of 0.89, 0.99 and 0.98 were developed to predict the cellulose, hemicelluloses and lignin compounds of biomass, respectively. The average absolute difference in predicted and measured cellulose, hemicellulose and lignin in agricultural biomass was 7.5%, 2.5%, and 3.8%, respectively. Application of steam explosion pre-treatment on agricultural straw significantly altered the physical and frictional properties, which has direct significance on designing new and modifying existing bins, hoppers and feeders for handling and storage of straw for biofuel industry. As a result, regression equations were developed to enhance process efficiency by eliminating the need for experimental procedure while designing and manufacturing of new handling equipment. Compaction of low bulk density agricultural biomass is a critical and desirable operation for sustainable and economic availability of feedstock for the biofuel industry. A comprehensive study of the compression characteristics (density of pellet and total specific energy required for compression) of ground non-treated and steam exploded barley, canola, oat and wheat straw obtained from three hammer mill screen sizes of 6.4, 3.2 and 1.6 mm at 10% moisture content (wb) was conducted. Four preset pressures of 31.6, 63.2, 94.7 and 138.9 MPa, were applied using an Instron testing machine to compress samples in a cylindrical die. It was determined that the applied pressure (60.4%) was the most significant factor affecting pellet density followed by the application of steam explosion pre-treatment (39.4%). Similarly, the type of biomass (47.1%) is the most significant factor affecting durability followed by the application of pre-treatment (38.2%) and grind size (14.6%). Also, the applied pressure (58.3%) was the most significant factor affecting specific energy required to manufacture pellets followed by the biomass (15.3%), pre-treatment (13.3%) and grind size (13.2%), which had lower but similar effect affect on specific energy. In addition, correlations for pellet density and specific energy with applied pressure and hammer mill screen sizes having highest R2 values were developed. Higher grind sizes and lower applied pressures resulted in higher relaxations (lower pellet densities) during storage of pellets. Three compression models, namely: Jones model, Cooper-Eaton model, and Kawakita-Ludde model were considered to determine the pressure-volume and pressure-density relationship of non-treated and steam exploded straws. Kawakita-Ludde model provided the best fit to the experimental data having R2 values of 0.99 for non-treated straw and 1.00 for steam exploded biomass samples. The steam exploded straw had higher porosity than non-treated straw. In addition, the steam exploded straw was easier to compress since it had lower yield strength or failure stress values compared to non-treated straw. Pilot scale pelleting experiments were performed on non-treated, steam exploded and customized (adding steam exploded straw grinds in increments of 25% to non-treated straw) barley, canola, oat and wheat straw grinds obtained from 6.4, 3.2, 1.6 and 0.8 mm hammer mill screen sizes at 10% moisture content (wb). The pilot scale pellet mill produced pellets from ground non-treated straw at hammer mill screen sizes of 0.8 and 1.6 mm and customized samples having 25% steam exploded straw at 0.8 mm. It was observed that the pellet bulk density and particle density are positively correlated. The density and durability of agricultural straw pellets significantly increased with a decrease in hammer mill screen size from 1.6 mm to 0.8 mm. Interestingly, customization of agricultural straw by adding 25% of steam exploded straw by weight resulted in higher durability (> 80%) pellets but did not improve durability compared to non-treated straw pellets. In addition, durability of pellets was negatively correlated to pellet mill throughput and was positively correlated to specific energy consumption. Total specific energy required to form pellets increased with a decrease in hammer mill screen size from 1.6 to 0.8 mm and also the total specific energy significantly increased with customization of straw at 0.8 mm screen size. It has been determined that the net specific energy available for production of biofuel is a significant portion of original agricultural biomass energy (89-94%) for all agricultural biomass.

The two main sources of biomass for energy generation are purpose-grown energy crops and waste materials. Energy crops, such as Miscanthus and short rotation woody crops (coppice), are cultivated mainly for energy purposes and are associated with the food vs. fuels debate, which is concerned with whether land should be used for fuel rather than food production. The use of residues from agriculture, such as barley, canola, oat and wheat straw, for energy generation circumvents the food vs. fuel dilemma and adds value to existing crops. In fact, these residues represent an abundant, inexpensive and readily available source of renewable lignocellulosic biomass. In order to reduce industrys operational cost as well as to meet the requirement of raw material for biofuel production, biomass must be processed and handled in an efficient manner. Due to its high moisture content, irregular shape and size, and low bulk density, biomass is very difficult to handle, transport, store, and utilize in its original form. Densification of biomass into durable compacts is an effective solution to these problems and it can reduce material waste. Upon densification, many agricultural biomass materials, especially those from straw and stover, result in a poorly formed pellets or compacts that are more often dusty, difficult to handle and costly to manufacture. This is caused by lack of complete understanding on the natural binding characteristics of the components that make up biomass. An integrated approach to postharvest processing (chopping, grinding and steam explosion), and feasibility study on lab-scale and pilot scale densification of non-treated and steam exploded barley, canola, oat and wheat straw was successfully established to develop baseline data and correlations, that assisted in performing overall specific energy analysis. A new procedure was developed to rapidly characterize the lignocellulosic composition of agricultural biomass using the Fourier Transform Infrared (FTIR) spectroscopy. In addition, baseline knowledge was created to determine the physical and frictional properties of non-treated and steam exploded agricultural biomass grinds. Particle size reduction of agricultural biomass was performed to increase the total surface area, pore size of the material and the number of contact points for inter-particle bonding in the compaction process. Predictive regression equations having higher R2 values were developed that could be used by biorefineries to perform economic feasibility of establishing a processing plant. Specific energy required by a hammer mill to grind non-treated and steam exploded barley, canola, oat and wheat straw showed a negative power correlation with hammer mill screen sizes. Rapid and cost effective quantification of lignocellulosic components (cellulose, hemicelluloses and lignin) of agricultural biomass (barley, canola, oat and wheat) is essential to determine the effect of various pre-treatments (such as steam explosion) on biomass used as feedstock for the biofuel industry. A novel procedure to quantitatively predict lignocellulosic components of non-treated and steam exploded barley, canola, oat and wheat straw was developed using Fourier Transformed Infrared (FTIR) spectroscopy. Regression equations having R2 values of 0.89, 0.99 and 0.98 were developed to predict the cellulose, hemicelluloses and lignin compounds of biomass, respectively. The average absolute difference in predicted and measured cellulose, hemicellulose and lignin in agricultural biomass was 7.5%, 2.5%, and 3.8%, respectively. Application of steam explosion pre-treatment on agricultural straw significantly altered the physical and frictional properties, which has direct significance on designing new and modifying existing bins, hoppers and feeders for handling and storage of straw for biofuel industry. As a result, regression equations were developed to enhance process efficiency by eliminating the need for experimental procedure while designing and manufacturing of new handling equipment. Compaction of low bulk density agricultural biomass is a critical and desirable operation for sustainable and economic availability of feedstock for the biofuel industry. A comprehensive study of the compression characteristics (density of pellet and total specific energy required for compression) of ground non-treated and steam exploded barley, canola, oat and wheat straw obtained from three hammer mill screen sizes of 6.4, 3.2 and 1.6 mm at 10% moisture content (wb) was conducted. Four preset pressures of 31.6, 63.2, 94.7 and 138.9 MPa, were applied using an Instron testing machine to compress samples in a cylindrical die. It was determined that the applied pressure (60.4%) was the most significant factor affecting pellet density followed by the application of steam explosion pre-treatment (39.4%). Similarly, the type of biomass (47.1%) is the most significant factor affecting durability followed by the application of pre-treatment (38.2%) and grind size (14.6%). Also, the applied pressure (58.3%) was the most significant factor affecting specific energy required to manufacture pellets followed by the biomass (15.3%), pre-treatment (13.3%) and grind size (13.2%), which had lower but similar effect affect on specific energy. In addition, correlations for pellet density and specific energy with applied pressure and hammer mill screen sizes having highest R2 values were developed. Higher grind sizes and lower applied pressures resulted in higher relaxations (lower pellet densities) during storage of pellets. Three compression models, namely: Jones model, Cooper-Eaton model, and Kawakita-Ludde model were considered to determine the pressure-volume and pressure-density relationship of non-treated and steam exploded straws. Kawakita-Ludde model provided the best fit to the experimental data having R2 values of 0.99 for non-treated straw and 1.00 for steam exploded biomass samples. The steam exploded straw had higher porosity than non-treated straw. In addition, the steam exploded straw was easier to compress since it had lower yield strength or failure stress values compared to non-treated straw. Pilot scale pelleting experiments were performed on non-treated, steam exploded and customized (adding steam exploded straw grinds in increments of 25% to non-treated straw) barley, canola, oat and wheat straw grinds obtained from 6.4, 3.2, 1.6 and 0.8 mm hammer mill screen sizes at 10% moisture content (wb). The pilot scale pellet mill produced pellets from ground non-treated straw at hammer mill screen sizes of 0.8 and 1.6 mm and customized samples having 25% steam exploded straw at 0.8 mm. It was observed that the pellet bulk density and particle density are positively correlated. The density and durability of agricultural straw pellets significantly increased with a decrease in hammer mill screen size from 1.6 mm to 0.8 mm. Interestingly, customization of agricultural straw by adding 25% of steam exploded straw by weight resulted in higher durability (> 80%) pellets but did not improve durability compared to non-treated straw pellets. In addition, durability of pellets was negatively correlated to pellet mill throughput and was positively correlated to specific energy consumption. Total specific energy required to form pellets increased with a decrease in hammer mill screen size from 1.6 to 0.8 mm and also the total specific energy significantly increased with customization of straw at 0.8 mm screen size. It has been determined that the net specific energy available for production of biofuel is a significant portion of original agricultural biomass energy (89-94%) for all agricultural biomass.

Lignocellulosic biomass is composed of cellulose, hemicellulose, lignin and extraneous compounds (waxes, fats, gums, starches, alkaloids, resins, tannins, essential oils, silica, carbonates, oxalates, etc). The sugars within the complex carbohydrates (cellulose and hemicellulose) can be accessed for cellulosic bioethanol production through ethanologenic microorganisms. However, the composite nature of lignocellulosic biomass, particularly the lignin portion, presents resistance and recalcitrance to biological and chemical degradation during enzymatic hydrolysis/saccharification and the subsequent fermentation process. This leads to a very low conversion rate, which makes the process uneconomically feasible. Thus, biomass structure requires initial breakdown of the lignocellulosic matrix. In this study, two types of biomass pretreatment were applied on barley straw grind: radio-frequency (RF)-based dielectric heating technique using alkaline (NaOH) solution as a catalyst and steam explosion pretreatment at low severity factor. The pretreatment was applied on barley straw which was ground in hammer mill with a screen size of 1.6 mm, so as to enhance its accessibility and digestibility by enzymatic reaction during hydrolysis. Three levels of temperature (70, 80, and 90oC), five levels of ratio of biomass to 1% NaOH solution (1:4, 1:5, 1:6, 1:7, & 1:8), 1 h soaking time, and 20 min residence time were used for the radio frequency pretreatment. The following process and material variables were used for the steam explosion pretreatment: temperature (140-180oC), retention time (5-10 min), and 8-50% moisture content (w.b). The effect of both pretreatments was assessed through chemical composition analysis and densification of the pretreated and non-pretreated biomass samples. Results of this investigation show that lignocellulosic biomass absorbed more NaOH than water, because of the hydrophobic nature of lignin, which acts as an external crosslink binder on the biomass matrix and shields the hydrophilic structural carbohydrates (cellulose and hemicellulose). It was observed in the RF pretreatment that the use of NaOH solution and the ratio of biomass to NaOH solution played a major role, while temperature played a lesser role in the breakdown of the lignified matrix, as well as in the production of pellets with good physical quality. The heat provided by the RF is required to assist the alkaline solution in the deconstruction and disaggregation of lignocellulosic biomass matrix. The disruption and deconstruction of the lignified matrix is also associated with the dipole interaction, flip flop rotation, and friction generated between the electromagnetic charges from the RF and the ions and molecules from the NaOH solution and the biomass. The preserved cellulose from the raw sample (non-treated) was higher than that from the RF alkaline pretreated samples because of the initial degradation of the sugars during the pretreatment process. The same observation applies to hemicellulose. This implies that there is a trade-off between the breakdown of the biomass matrix/creating pores in the lignin and enhancing the accessibility and digestibility of the cellulose and hemicellulose. The use of dilute NaOH solution in biomass pretreatment showed that the higher the NaOH concentration, the lower was the acid insoluble lignin and the higher was the solubilized lignin moieties. The ratio of 1:6 at the four temperatures studied was determined to be the optimal. Based on the obtained data, it is predicted that this pretreatment will decrease the required amount and cost of enzymes by up to 64% compared to using non-treated biomass. However, the use of NaOH led to an increase in the ash content of biomass. The ash content increased with the decreasing ratio of biomass to NaOH solution. This problem of increased ash content can be addressed by washing the pretreated samples. RF assisted-alkaline pretreatment technique represents an easy to set-up and potentially affordable route for the bio-fuel industry, but this requires further energy analysis and economic validation, so as to investigate the significant high energy consumption during the RF-assisted alkaline pretreatment heating process. Data showed that in the steam explosion (SE) pretreatment, considerable thermal degradation of the energy potentials (cellulose and hemicellulose) with increasing acid soluble and insoluble lignin content occurred. The high degradation of the hemicellulose can be accounted for by its amorphous nature which is easily disrupted by external influences unlike the well-arranged crystalline cellulose. It is predicted that this pretreatment will decrease the required amount and cost of enzymes by up to 33% compared to using non-treated biomass.The carbon content of the solid SE product increased at higher temperature and longer residence time, while the hydrogen and oxygen content decreased. The RF alkaline and SE treatment combinations that resulted to optimum yield of cellulose and hemicellulose were selected and then enzymatically digested with a combined mixture of cellulase and β-glucosidase enzymes at 50oC for 96 h on a shaking incubator at 250 rev/min. The glucose in the hydrolyzed samples was subsequently quantified. The results obtained confirmed the effectiveness of the pretreatment processes. The average available percentage glucose yield that was released during the enzymatic hydrolysis for bioethanol production ranged from 78-96% for RF-alkaline pretreated and 30-50% for the SE pretreated barley straw depending on the treatment combination. While the non-treated sample has available average percentage glucose yield of just below 12%. The effects of both pretreatment methods (RF and SE) were further evaluated by pelletizing the pretreated and non-pretreated barley straw samples in a single pelleting unit. The physical characteristics (pellet density, tensile strength, durability rating, and dimensional stability) of the pellets were determined. The lower was the biomass:NaOH solution ratio, the better was the quality of the produced pellets. Washing of the RF-alkaline pretreated samples resulted in pellets with low quality. A biomass:NaOH solution ratio of 1:8 at the three levels of temperature (70, 80, and 90oC) studied are the RF optimum pretreatment conditions. The higher heating value (HHV) and the physical characteristics of the produced pellets increased with increasing temperature and residence time. The steam exploded samples pretreated at higher temperatures (180ºC) and retention time of 10 min resulted into pellets with good physical qualities. Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS) was further applied on the RF alkaline and SE samples in light of the need for rapid and easy quantification of biomass chemical components (cellulose, hemicellulose, and lignin). The results obtained show that the FTIR-PAS spectra can be rapidly used for the analysis and identification of the chemical composition of biofuel feedstock. Predictive models were developed for each of the biomass components in estimating their respective percentage chemical compositions.

Orientador: Roberto da Silva / Banca: Nei Pereira Júnior / Banca: Maurício Boscolo / Resumo: O aproveitamento de resíduos agrícolas e agro-industriais como fonte de energia pode se tornar uma alternativa viável. O alvo principal para esta empreitada, pela sua disponibilidade e proximidade das indústrias fermentativas é o bagaço de cana, que ainda retém 2/3 da energia presente na cana, é largamente disponível no Brasil e hoje é parcialmente rejeitado ou subaproveitado. Uma forma de aproveitamento que tem se mostrado bastante promissora refere-se ao uso dessa biomassa na produção do bioetanol. No presente trabalho, avaliou-se o perfil de produção enzimática dos fungos Thermoascus aurantiacus CBMAI 756, Thermomyces lanuginosus, Penicillium viridicatum RFC3 e Trichoderma reesei QM9414, através de fermentação em estado sólido em meio com bagaço de cana e farelo de trigo. Aplicou-se esses extratos enzimáticos na hidrólise de bagaço de cana submetido a diferentes pré-tratamentos térmicos: água quente, explosão a vapor, e água quente em combinação com HCl, H2SO4, H3PO4, H2O2 ou NaOH. Determinou-se os principais inibidores (furfural e 5-hidroximetilfurfural) e açúcares redutores (glicose, xilose, arabinose, galactose, xilobiose e celobiose) gerados no processo. O fungo T. aurantiacus foi o melhor produtor de enzimas celulolíticas (536,3 U/g de CMCase) e hemicelulolíticas (3419,2 U/g de xilanase), apresentando juntamente com o extrato enzimático de T. reesei os melhores rendimentos na sacarificação do bagaço. Os extratos enzimáticos foram mais eficientes na hidrólise do bagaço pré-tratado com NaOH e explosão a vapor com rendimentos de 3,87 e 1,21 mg/mL de açúcares redutores, respectivamente. A mistura dos extratos enzimáticos de T. aurantiacus e T. reesei aumentou em 31,4% a eficiência da hidrolise com o bagaço pré-tratado com explosão a vapor. A concentração dos extratos por precipitação por etanol foi eficiente para a maioria... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The utilization of agricultural and agro-industrial residues as energy source can become a viable alternative. The main target for this venture, for its availability and proximity to fermentation industries is the sugarcane bagasse, which still retains two thirds of the energy present in the cane, is widely available in Brazil and today is partly rejected or underused. One form of exploitation that has shown promising refers to the use of biomass in the production of bioethanol. In this study, we evaluated the profile of enzymatic production of fungi Thermoascus aurantiacus CBMAI 756, Thermomyces lanuginosus, Penicillium viridicatum RFC3 and Trichoderma reesei QM9414 through solid state fermentation in a medium with sugar cane bagasse and wheat bran. These enzymatic extracts were applied on the hydrolysis of sugarcane bagasse under different thermic pre-treatments: hot water, steam explosion, and hot water in combination with HCl, H2SO4, H3PO4, NaOH or H2O2. The main inhibitors (furfural and 5-hydroxymethylfurfural) and reducing sugars (glucose, xylose, arabinose, galactose, xilobiose and cellobiose) generated in the process were determined. The fungus T. aurantiacus was the best producer of cellulolytic (536.3 U/g CMCase) and hemicellulolytic enzymes (3419.2 U/g xylanase), exhibiting along the enzymatic extract from T. reesei the best yields in the saccharification of bagasse. The enzymatic extracts were more efficient in the hydrolysis of bagasse pretreated with NaOH and steam explosion with a yield of 3.87 and 1.21 mg/mL of reducing sugars, respectively. The mixture of enzyme extract of T. aurantiacus and T. reesei increased 31.4% the efficiency of hydrolysis with bagasse pre-treated with steam explosion. The concentration of the extracts by precipitation with ethanol was effective for most enzymatic activities and resulted in an increase of approximately 50% of hydrolysis... (Complete abstract click electronic access below) / Mestre

To develop anaerobic digestion (AD), innovative solutions to increase methane yields in existing AD processes are needed. In particular, the adoption of low energy pre-treatments to enhance biomass biodegradability is needed to provide efficient digestion processes increasing profitability. To obtain these features, hydrodynamic cavitation has been evaluated as an innovative solutions for AD of waste activated sludge (WAS), food waste (FW), macro algae and grass, in comparison with steam explosion (high energy pre-treatment). The effect of these two pre-treatments on the substrates, e.g. particle size distribution, soluble chemical oxygen demand (sCOD), biochemical methane potential (BMP) and biodegradability rate, have been evaluated. After two minutes of hydrodynamic cavitation (8 bar), the mean fine particle size decreased from 489- 1344 nm to 277- 381 nm (≤77% reduction) depending of the biomasses. Similar impacts were observed after ten minutes of steam explosion (210 °C, 30 bar) with a reduction in particle size between 40% and 70% for all the substrates treated.  In terms of BMP value, hydrodynamic cavitation caused significant increment only within the A. nodosum showing a post treatment increment of 44% compared to the untreated value, while similar values were obtained before and after treatment within the other tested substrates. In contrast, steam explosion allowed an increment for all treated samples, A. nodosum (+86%), grass (14%) and S. latissima (4%). However, greater impacts where observed with hydrodynamic cavitation than steam explosion when comparing the kinetic constant K. Overall, hydrodynamic cavitation appeared an efficient pre-treatment for AD capable to compete with the traditional steam explosion in terms om kinetics and providing a more efficient energy balance (+14%) as well as methane yield for A. nodosum. / Det behövs innovativa lösningar för att utveckla anaerob rötning i syfte att öka metangasutbytet från biogassubstrat. Beroende på substratets egenskaper, kan förbehandling möjliggöra sönderdelning av bakterieflockar, uppbrytning av cellväggar, elimination av inhiberande ämnen och frigörelse av intracellulära organiska ämnen, som alla kan leda till en förbättring av den biologiska nedbrytningen i rötningen. För att uppnå detta har den lågenergikrävande förebehandlingsmetoden hydrodynamisk kavitation prövats på biologiskt slam, matavfall, makroalger respektive gräs, i jämförelse med ångexplosion. Effekten på substraten av dessa två förbehandlingar har uppmäts genom att undersöka distribution av partikelstorlek, löst organiskt kol (sCOD), biometan potential (BMP) och nedbrytningshastigheten. Efter 2 minuters hydrodynamisk kavitation (8 bar) minskade partikelstorleken från 489- 1344 nm till 277- 281 nm (≤77 % reduktion) för de olika biomassorna. Liknande påverkan observerades efter tio minuters ångexplosion (210 °C, 30 bar) med en partikelstorlekreducering mellan 40 och 70 % för alla behandlade substrat. Efter behandling med hydrodynamisk kavitation, i jämförelse med obehandlad biomassa, ökade metanproduktionens hastighetskonstant (K) för matavfall (+65%), makroalgen S. latissima (+3%), gräs (+16 %) samtidigt som den minskade för A. nodosum (-17 %). Förbehandlingen med ångexplosion ökade hastighetskonstanten för S. latissima (+50 %) och A. nodosum (+65 %) medan den minskade för gräs (-37 %), i jämförelse med obehandlad biomassa. Vad gäller BMP värden, orsakade hydrodynamisk kavitation små variationer där endast A. nodosum visade en ökning efter behandling (+44 %) i jämförelse med obehandlad biomassa. Biomassa förbehandlade med ångexplosion visade en ökning för A .nodosum (+86 %), gräs (14 %) och S. latissima (4 %). Sammantaget visar hydrodynamisk kavitation potential som en effektiv behandling före rötning och kapabel att konkurrera med den traditionella ångexplosionen gällande kinetik och energibalans (+14%) samt metanutbytet för A. nodosum.