Dissertations / Theses on the topic 'Sugarcane bagasse'

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The world’s depleting fossil fuels and increasing greenhouse gas emissions have given rise to much research into renewable and cleaner energy. Biomass is unique in providing the only renewable source of fixed carbon. Agricultural residues such as Sugarcane Bagasse (SB) are feedstocks for ‘second generation fuels’ which means they do not compete with production of food crops. In South Africa approximately 6 million tons of raw SB is produced annually, most of which is combusted onsite for steam generation. In light of the current interest in bio-fuels and the poor utilization of SB as energy product in the sugar industry, alternative energy recovery processes should be investigated. This study looks into the thermochemical upgrading of SB by means of pyrolysis. Biomass pyrolysis is defined as the thermo-chemical decomposition of organic materials in the absence of oxygen or other reactants. Slow Pyrolysis (SP), Vacuum Pyrolysis (VP), and Fast Pyrolysis (FP) are studied in this thesis. Varying amounts of char and bio-oil are produced by the different processes, which both provide advantages to the sugar industry. Char can be combusted or gasified as an energy-dense fuel, used as bio-char fertilizer, or upgraded to activated carbon. High quality bio-oil can be combusted or gasified as a liquid energy-dense fuel, can be used as a chemical feedstock, and shows potential for upgrading to transport fuel quality. FP is the most modern of the pyrolysis technologies and is focused on oil production. In order to investigate this process a 1 kg/h FP unit was designed, constructed and commissioned. The new unit was tested and compared to two different FP processes at Forschungszentrum Karlsruhe (FZK) in Germany. As a means of investigating the devolatilization behaviour of SB a Thermogravimetric Analysis (TGA) study was conducted. To investigate the quality of products that can be obtained an experimental study was done on SP, VP, and FP. Three distinct mass loss stages were identified from TGA. The first stage, 25 to 110°C, is due to evaporation of moisture. Pyrolitic devolatilization was shown to start at 230°C. The final stage occurs at temperatures above 370°C and is associated with the cracking of heavier bonds and char formation. The optimal decomposition temperatures for hemicellulose and cellulose were identified as 290°C and 345°C, respectively. Lignin was found to decompose over the entire temperature range without a distinct peak. These results were confirmed by a previous study on TGA of bagasse. SP and VP of bagasse were studied in the same reactor to allow for accurate comparison. Both these processes were conducted at low heating rates (20°C/min) and were therefore focused on char production. Slow pyrolysis produced the highest char yield, and char calorific value. Vacuum pyrolysis produced the highest BET surface area chars (>300 m2/g) and bio-oil that contained significantly less water compared to SP bio-oil. The short vapour residence time in the VP process improved the quality of liquids. The mechanism for pore formation is improved at low pressure, thereby producing higher surface area chars. A trade-off exists between the yield of char and the quality thereof. FP at Stellenbosch University produced liquid yields up to 65 ± 3 wt% at the established optimal temperature of 500°C. The properties of the bio-oil from the newly designed unit compared well to bio-oil from the units at FZK. The char properties showed some variation for the different FP processes. At the optimal FP conditions 20 wt% extra bio-oil is produced compared to SP and VP. The FP bio-oil contained 20 wt% water and the calorific value was estimated at 18 ± 1 MJ/kg. The energy per volume of FP bio-oil was estimated to be at least 11 times more than dry SB. FP was found to be the most effective process for producing a single product with over 60% of the original biomass energy. The optimal productions of either high quality bio-oil or high surface area char were found to be application dependent.
AFRIKAANSE OPSOMMING: As gevolg van die uitputting van fossielbrandstofreserwes, en die toenemende vrystelling van kweekhuisgasse word daar tans wêreldwyd baie navorsing op hernubare en skoner energie gedoen. Biomassa is uniek as die enigste bron van hernubare vaste koolstof. Landbouafval soos Suikerriet Bagasse (SB) is grondstowwe vir ‘tweede generasie bio-brandstowwe’ wat nie die mark van voedselgewasse direk affekteer nie. In Suid Afrika word jaarliks ongeveer 6 miljoen ton SB geproduseer, waarvan die meeste by die suikermeulens verbrand word om stoom te genereer. Weens die huidige belangstelling in bio-brandstowwe en ondoeltreffende benutting van SB as energieproduk in die suikerindustrie moet alternatiewe energie-onginningsprosesse ondersoek word. Hierdie studie is op die termo-chemiese verwerking van SB deur middel van pirolise gefokus. Biomassa pirolise word gedefinieer as die termo-chemiese afbreking van organiese bio-materiaal in die afwesigheid van suurstof en ander reagense. Stadige Pirolise (SP), Vakuum Pirolise (VP), en Vinnige Pirolise word in hierdie tesis ondersoek. Die drie prosesse produseer veskillende hoeveelhede houtskool en bio-olie wat albei voordele bied vir die suikerindustrie. Houtskool kan as ‘n vaste energie-digte brandstof verbrand of vergas word, as bio-houtskoolkompos gebruik word, of kan verder tot geaktiveerde koolstof geprosesseer word. Hoë kwaliteit bio-olie kan verbrand of vergas word, kan as bron vir chemikalië gebruik word, en toon potensiaal om in die toekoms opgegradeer te kan word tot vervoerbrandstof kwaliteit. Vinnige pirolise is die mees moderne pirolise tegnologie en is op bio-olie produksie gefokus. Om die laasgenoemde proses te toets is ‘n 1 kg/h vinnige pirolise eenheid ontwerp, opgerig en in werking gestel. Die nuwe pirolise eenheid is getoets en vegelyk met twee verskillende vinnige pirolise eenhede by Forschungszentrum Karlsruhe (FZK) in Duitsland. Termo-Gravimetriese Analise (TGA) is gedoen om die ontvlugtigingskenmerke van SB te bestudeer. Eksperimentele werk is verrig om die kwaliteit van produkte van SP, VP, vinnige pirolise te vergelyk. Drie duidelike massaverlies fases van TGA is geïdentifiseer. Die eerste fase (25 – 110°C) is as gevolg van die verdamping van vog. Pirolitiese ontvlugtiging het begin by 230°C. Die finale fase (> 370°C) is met die kraking van swaar verbindings en die vorming van houtskool geassosieer. Die optimale afbrekingstemperatuur vir hemisellulose en sellulose is as 290°C en 345°C, respektiewelik, geïdentifiseer. Daar is gevind dat lignien stadig oor die twede en derde fases afgebreek word sonder ‘n duidelike optimale afbrekingstemperatuur. Die resultate is deur vorige navorsing op TGA van SB bevestig. SP en VP van bagasse is in dieselfde reaktor bestudeer, om ‘n akkurate vergelyking moontlik te maak. Beide prosesse was by lae verhittingstempo’s (20°C/min) ondersoek, wat gevolglik op houtskoolformasie gefokus is. SP het die hoogste houtskoolopbrengs, met die hoogste verbrandingsenergie, geproduseer. VP het hootskool met die hoogste BET oppervlakarea geproduseer, en die bio-olie was weens ‘n dramatiese afname in waterinhoud van beter gehalte. Die meganisme vir die vorming van ‘n poreuse struktuur word deur lae atmosferiese druk verbeter. Daar bestaan ‘n inverse verband tussen die kwantiteit en kwaliteit van die houtskool. Vinnige pirolise by die Universiteit van Stellenbosch het ‘n bio-olie opbrengs van 65 ± 3 massa% by ‘n vooraf vasgestelde optimale temperatuur van 500°C geproduseer. Die eienskappe van bio-olie wat deur die nuwe vinnige pirolise eenheid geproduseer is het goed ooreengestem met die bio-olie afkomstig van FZK se pirolise eenhede. Die houtskool eienskappe van die drie pirolise eenhede het enkele verskille getoon. By optimale toestande vir vinnige pirolise word daar 20 massa% meer bio-olie as by SP en VP geproduseer. Vinnige pirolise bio-olie het ‘n waterinhoud van 20 massa% en ‘n verbrandingswarmte van 18 ± 1 MJ/kg. Daar is gevind dat ten opsigte van droë SB die energie per enheidsvolume van bio-olie ongeveer 11 keer meer is. Vinnige pirolise is die mees doeltreffende proses vir die vervaardiging van ‘n produk wat meer as 60% van die oorspronklike biomassa energie bevat. Daar is gevind dat die optimale hoeveelhede van hoë kwaliteit bio-olie en hoë oppervlakarea houtskool doelafhanklik is.

Sugarcane is a major crop in many countries. It is the most abundant lignocellulosic material in tropical countries such as South Africa. It is one of the plants with the highest bioconversion efficiency. The sugarcane crop is able to efficiently fix solar energy, yielding some 55 tons of dry matter per hectare of land annually. After harvest, the crop produces sugar juice and bagasse. Sugarcane bagasse is a residue that results from the crushing of sugarcane in the sugar industry. It is a renewable feedstock that can be used for power generation and manufacturing cellulosic ethanol. As biomass, sugarcane bagasse holds promise as a fuel source since it can produce more than enough electricity and heat energy to supply the needs of a common sugar factory. However, in the sugarcane industry the bagasse is currently burnt inefficiently in boilers that provide the heating for the industry. This project seeks to investigate the possibility of gasifying sugarcane bagasse as an efficient conversion technology. The investigation is necessary because fuel properties govern the gasifier design and ultimately, the gasification efficiency. Proximate and ultimate analysis of sugarcane bagasse was conducted after which the results were used to conduct a computer simulation of the mass and energy balance during gasification. The kinetic investigation undertaken through the TGA and DTG analyses revealed the activation energy and pre – exponential factor which were obtained by the model – free Kissinger method of kinetic analysis and were found to be 181.51 kJ/mol and 3.1 × 103/min respectively. The heating value of sugarcane bagasse was also measured and found to be 17.8 MJ/kg, which was used in the calculation of the conversion efficiency of the gasification process. Fuel properties, including moisture content and gasifier operating parameters were varied in order to determine optimum gasifier operating conditions that results in maximum conversion efficiency. The highest conversion efficiency was achieved at low moisture content after computer simulation of the gasification process. Moisture content also affected the volume of CO and H2 as the former decreases with increasing moisture content while the latter increases with increasing moisture content, accelerating the water – gas reaction. Scanning electron microscope fitted to an Energy dispersive X – ray spectroscopy was also used in order to view the shape and size distribution as well as determine the elemental composition of sugarcane bagasse. The results obtained established that the fuel properties and gasification conditions affect the conversion efficiency. During computer simulation, it was established that smaller particle size resulted in higher conversion efficiency. The smaller throat diameter also resulted in higher conversion efficiency. The throat angle of 25° also resulted in higher conversion efficiency. The temperature of input air was also found to be one of the major determining factors in terms of conversion efficiency. The dissertation presents the proximate and ultimate analysis results as well as the kinetic analysis results. The SEM/EDX analysis as well as the computer simulation results of the gasification process is also presented. The major contribution of this project was on the investigation of the gasification characteristics of sugarcane bagasse and the utilization of these in the design of a laboratory scale sugarcane bagasse gasifier with enhanced conversion efficiency through computer simulation.

Universidade Federal do CearÃ
The present work aimed at the production of lignosulfonate, based in the lignin extracted from sugarcane bagasse-cane for using in phenolic resins. The extraction of lignin was carried out using the acetosolv process, which was optimised with a central composite design 22 to evaluate the effects of reaction time and temperature on the extraction yield, weight-average (M ̅w) and number-average (M ̅n) molecular weights, relative content of total hydroxyl, phenolic hydroxyl and methoxyl groups. The lignins obtained under conditions that maximized the extraction yield and showed better structural and thermal characteristics were sulfonated to obtain the lignosulfonates. The structural and thermal characteristics of the lignins and lignosulfonates were determined by FT-IR, GPC, 1H-NMR and 13C-NMR, DSC and TGA. The results show that the best extraction yield (64.5%) was obtained with 95% (w/w) of acetic acid, the addition of 0.1% HCl, at a temperature of 187 ÂC and reaction time of 40 min. However, with the same concentration of acetic acid and reaction time of 15 min at 187 ÂC, the extraction yield decreased to 55.6% Â 4.5%, without significant reduction. Furthermore, the increase in temperature of 187 ÂC to 205 ÂC was not enough to cause a significant increase in the relative content of hydroxyls and reduction of the relative content of methoxyl. These results show that the most appropriate conditions for adequate extraction of lignin for application in resins are: 95% (w/w) of acetic acid, addition of 0.1% of HCl, temperature of 187 ÂC and reaction time of 15 min. The acetosolv lignins showed p-hidroxifenila units as major constituent, higher thermal stability and higher purity than the commercial Kraft lignin. The glass transition temperature of the Kraft lignins was lower than that of the acetosolv lignin. This is due to the hydrophilic character and the presence of carbohydrates in the Kraft lignin. The lignosulfonates obtained in this study showed structural characteristics suitable for application in phenolic resins, because they showed high reactivity due to the greater presence of p-hidroxifenila units as major constituent, low molecular weights (40234878 g/mol), greater stability and greater purity compared to commercial sodium lignosulfonate. Therefore, lignosulfonates obtained in this work are more suitable for use in phenolic resins than commercial sodium lignosulfonate used for comparison.
O presente trabalho teve por objetivo a produÃÃo de lignossulfonato, a partir da lignina extraÃda do bagaÃo da cana-de-aÃÃcar para aplicaÃÃo em resinas fenÃlicas. Foi realizada a otimizaÃÃo da extraÃÃo da lignina do bagaÃo de cana-de-aÃÃcar utilizando o processo acetosolv. Para tanto, empregou-se um delineamento composto central 22 para analisar os efeitos do tempo de reaÃÃo e da temperatura no rendimento de extraÃÃo, massa molar ponderal mÃdia, massa molar numÃrica mÃdia, e conteÃdo relativo de hidroxilas totais, hidroxilas fenÃlicas e metoxilas. As ligninas obtidas nas condiÃÃes que maximizaram o rendimento de extraÃÃo e que mostraram melhores caracterÃsticas estruturais e tÃrmicas foram sulfonadas para obtenÃÃo dos lignossulfonatos. As caracterÃsticas estruturais e tÃrmicas das ligninas e dos lignossulfonatos foram determinadas por FT-IR, GPC, RMN-1H e 13C, TGA e DSC. Os resultados mostram que o melhor rendimento de extraÃÃo (64,5 % 4,2%) foi obtido com 95% (m/m) de Ãcido acÃtico, adiÃÃo de 0,1% de HCl, a uma temperatura de 187 C e tempo de reaÃÃo de 40 min. No entanto, com a mesma concentraÃÃo de soluÃÃo de Ãcido acÃtico e com tempo de reaÃÃo de 15 min a 187ÂC, o rendimento de extraÃÃo diminuiu para 55,6%  4,5%, nÃo sendo significativa esta reduÃÃo. AlÃm disto, a elevaÃÃo da temperatura de 187ÂC para 205ÂC nÃo foi suficiente para causar um aumento significativo no conteÃdo relativo de hidroxilas e reduÃÃo do conteÃdo relativo de metoxila. Esses resultados mostram que as condiÃÃes mais adequadas para extraÃÃo da lignina a ser aplicada em resinas sÃo: 95% (m/m) de Ãcido acÃtico, adiÃÃo de 0,1% de HCl, temperatura de 187 C e tempo de reaÃÃo de 15 min. As ligninas acetosolv apresentaram unidades p-hidroxifenila como constituinte majoritÃrio, maior estabilidade tÃrmica e maior pureza em relaÃÃo à lignina Kraft comercial. A temperatura de transiÃÃo vÃtrea da lignina Kraft foi menor do que à das ligninas acetosolv, devido à sua caracterÃstica hidrofÃlica e à presenÃa de carboidratos na lignina Kraft. Os lignossulfonatos obtidos no presente trabalho apresentaram caracterÃsticas estruturais adequadas para aplicaÃÃo em resinas fenÃlicas, pois mostraram alta reatividade devido a maior presenÃa de unidades p-hidroxifenila como constituinte majoritÃrio, baixas massas molares (4023 a 4878 g/mol), maior estabilidade e uma maior pureza em relaÃÃo ao lignossulfonato de sÃdio comercial. Portanto, os lignossulfonatos obtidos no presente trabalho sÃo mais adequados para aplicaÃÃo em resinas fenÃlicas do que o lignossulfonato de sÃdio comercial utilizado no presente trabalho.

Sugarcane is considered as the most abundant plant based crop grown in the tropics and part of the temperate climates. Its by-product, sugarcane bagasse, constitutes 30% of the total production. In the past, it was considered as waste material but contemporaries through innovative research projects over the years have found uses for it. Among these projects is soil reinforcement, which provides an alternative application to industrial by-products and natural fibres as a way of reducing their environmental footprints and contributing to sustainable geotechnics. Although bagasse morphological composition contains structural elements ideal for reinforcement and composite materials, it has received little research as a standalone reinforcement material. Because of this, a direct shear test was therefore initiated to establish the usefulness of using sugarcane bagasse as a soil reinforcement material by comparing the extent of shear strength and stiffness response due to its inclusion to unreinforced soil. Three different types of bagasse, fibre, millrun and pith, were added to unreinforced soil in percentage by weight content of 0.3 - 1.7. The bagasse was added to Klipheuwel sand, Cape Flats sand and Kaolin Clay at both dry and moist conditions. In addition, durability studies involving 12 cycles of wetting and drying, and soaking for a period of 14 days were constituted.

This work was stimulated by the fact that supplies of fossil fuels are finite, while there are abundant renewable forms of energy waiting to be tapped. The current fossil fuels store is reviewed before identifying usable forms of renewable energy which could replace or supplement fossil fuels. Bagasse - a solid byproduct in sugarcane milling - is then described in detail as a typical lignocellulosic waste which forms part of a larger class of renewable energy sources called biomass. The chemical and physical characteristics, as well as world-wide regions of production of bagasse are described. The research work therefore concerned itself with investigating various physical methods of conserving renewable energy by improving on the extraction efficiency of such energy from bagasse. The equipment used for carrying out the research work is described in detail in chapter two. The methods employed in carrying out the investigations are similarly described in the same chapter, detailing every step in the investigations, including any precautions which had to be taken. The crude results from the investigations are analysed in detail in chapter three so that fuel combustion, combustion oxygen demand, heat and mass balances for the process are considered. An analysis of the boiler system - the main equipment in the investigations - is also carried out in chapter three so that temperatures, gas flow patterns, particle elutriations and size distributions of the fuel in the system are established. Conclusions of the investigations are then drawn from the analyses of chapter three. As a prelude to the conclusion of the work, an industrial biomass survey carried out in Tanzania is analysed to show that bagasse is not the only lignocellulosic which is produced industrially, and that reasonable financial savings can be obtained from these other lignocellulosics. The work concludes by describing a few areas of related research interest for further investigation.

The research presented in this thesis was developed as part of DIBANET, an EC funded project aiming to develop an energetically self-sustainable process for the production of diesel miscible biofuels (i.e. ethyl levulinate) via acid hydrolysis of selected biomass feedstocks. Three thermal conversion technologies, pyrolysis, gasification and combustion, were evaluated in the present work with the aim of recovering the energy stored in the acid hydrolysis solid residue (AHR). Mainly consisting of lignin and humins, the AHR can contain up to 80% of the energy in the original feedstock. Pyrolysis of AHR proved unsatisfactory, so attention focussed on gasification and combustion with the aim of producing heat and/or power to supply the energy demanded by the ethyl levulinate production process. A thermal processing rig consisting on a Laminar Entrained Flow Reactor (LEFR) equipped with solid and liquid collection and online gas analysis systems was designed and built to explore pyrolysis, gasification and air-blown combustion of AHR. Maximum liquid yield for pyrolysis of AHR was 30wt% with volatile conversion of 80%. Gas yield for AHR gasification was 78wt%, with 8wt% tar yields and conversion of volatiles close to 100%. 90wt% of the AHR was transformed into gas by combustion, with volatile conversions above 90%. 5volO2%-95vol%N2 gasification resulted in a nitrogen diluted, low heating value gas (2MJ/m3). Steam and oxygen-blown gasification of AHR were additionally investigated in a batch gasifier at KTH in Sweden. Steam promoted the formation of hydrogen (25vol%) and methane (14vol%) improving the gas heating value to 10MJ/m3, below the typical for steam gasification due to equipment limitations. Arrhenius kinetic parameters were calculated using data collected with the LEFR to provide reaction rate information for process design and optimisation. Activation energy (EA) and pre-exponential factor (ko in s-1) for pyrolysis (EA=80kJ/mol, lnko=14), gasification (EA=69kJ/mol, lnko=13) and combustion (EA=42kJ/mol, lnko=8) were calculated after linearly fitting the data using the random pore model. Kinetic parameters for pyrolysis and combustion were also determined by dynamic thermogravimetric analysis (TGA), including studies of the original biomass feedstocks for comparison. Results obtained by differential and integral isoconversional methods for activation energy determination were compared. Activation energy calculated by the Vyazovkin method was 103-204kJ/mol for pyrolysis of untreated feedstocks and 185-387kJ/mol for AHRs. Combustion activation energy was 138-163kJ/mol for biomass and 119-158 for AHRs. The non-linear least squares method was used to determine reaction model and pre-exponential factor. Pyrolysis and combustion of biomass were best modelled by a combination of third order reaction and 3 dimensional diffusion models, while AHR decomposed following the third order reaction for pyrolysis and the 3 dimensional diffusion for combustion.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O bagaço da cana-de-açúcar é uma biomassa vegetal que possui muito potencial de uso devido aos seus três elementos estruturais: celulose, hemicelulose e lignina. Para servir como matéria prima na produção de insumos, o bagaço da cana-de-açúcar precisa passar por um processo de pré-tratamento. Nesse estudo, duas metodologias para o processo de pré-tratamento do bagaço da cana-de-açúcar foram utilizadas: a deslignização via peróxido de hidrogênio (H2O2) e via dióxido de carbono supercrítico (ScCO2). Para o estudo utilizando H2O2, foram desenvolvidos modelos a partir de planejamento experimental, Algoritmos Genéticos (GA, do inglês Genetic Algorithms), Redes Neurais Artificiais (RNA) e Neuro-Fuzzy (ANFIS). As variáveis independentes foram temperatura (25 – 60 graus Celsius), concentração de H2O2 (2 – 15 por cento m/v) e pH (10 – 13), tendo como resposta os teores de lignina residual e oxidada no processo, através de análises de FT-IR e análise pelo método de Klason. Para o estudo utilizando ScCO2 foram construídos modelos a partir de RNA e ANFIS. As variáveis estudadas no processo foram: temperatura (35 – 100 graus Celsius), pressão (75- 300 bar) e teor de etanol na solução de co-solvente (0 – 100 graus Celsius). De modo geral, para os dois processos, os modelos desenvolvidos consideram as variáveis independentes como sendo neurônios na camada de entrada e as variáveis dependentes como sendo neurônios na camada de saída. Todos os modelos neurais e ANFIS desenvolvidos neste trabalho foram avaliados pelo coeficiente de correlação e índices de erro (SSE, MSE e RMSE), além do número de parâmetros. Os resultados mostraram que, dentre estas estratégias estudadas, os modelos neurais se mostraram mais satisfatórios para predição das respostas do pré-tratamento com H2O2, já que se encaixa nos índices de performance estipulados. O mesmo ocorreu no modelo neural para predição do teor de lignina residual no pré-tratamento com ScCO2. Para cada modelo polinomial e neural desenvolvido, foi realizada a investigação das superfícies de respostas e das curvas de contorno. Com esse recurso, foi possível a identificação dos melhores pontos operacionais para os processos, visando a minimização dos teores de lignina residual e oxidada na biomassa.
Sugarcane bagasse is a plant biomass that has a great potential for use due to its three structural elements: cellulose, hemicellulose and lignin. To serve as raw material in the production of other products, sugarcane bagasse needs to undergo a pre-treatment process. In this study, two methodologies for the sugarcane bagasse pretreatment process were used: delignification via hydrogen peroxide (H2O2) and via supercritical carbon dioxide (ScCO2). The models for study the process with H2O2 were developed from experimental planning, Genetic Algorithms (GA), Artificial Neural Networks (ANN) and Neuro-Fuzzy (ANFIS). The independent variables were: temperature (25- 60 degrees Celsius), H2O2 concentration (2 - 15 percent m/v) and pH (10-13). The residual and oxidized lignin contents in the process were evaluated from FT-IR and Klason method analysis. The models for study the process with ScCO2 were developed from RNA and ANFIS. The variables studied in the process were: temperature (35-100 degrees Celsius), pressure (75-300 bar) and ethanol content in the aqueous solution of co-solvent (0-100 percent). In general, for the two processes, the developed models consider the independent variables to be neurons in the input layer and the dependent variables to be neurons in the output layer. All the neural and ANFIS models developed in this study were evaluated by the correlation coefficient and error indexes (SSE, MSE and RMSE), as well as the number of parameters. From the stipulated indices of performance, among the results obtained by the different strategies, the neural models were the most satisfactory for the prediction of pretreatment responses with H2O2. The same occurred in the neural model for prediction of the residual lignin content in the pre-treatment with ScCO2. Response surfaces and the contour curves were investigated for each polynomial and neural model developed. With this resource, it was possible to identify the best operational points for the processes, pointing at minimizing the residual and oxidized lignin contents in the biomass.

Sugarcane cultivation is a major source and sinks of greenhouse gas emissions (GHGs). In 2019, approximately 30.04 x 106 t of sugarcane was harvested from 364,428 ha of land. Of the total cane harvested, sugarcane bagasse (SB) and sugarcane trash (ST) accounted for 30.1% and 14.9%, respectively. Further, fossil fuel consumption in the transport of cane to mills was 29.15 ML and is equivalent to 221.5 Mt CO2-equivalent GHG emissions. Anaerobic digestion (AD) of sugar industry wastes for biomethane production and use as vehicle fuel (bioCNG) would reduce the fossil fuel consumption and the associated GHG emissions in cane transportation to mill. The study aims to optimize biogas production and upgrade the produced biogas to vehicle fuel. For that the study is divided into different objectives. To determine the substrate characteristic and suitable AD parameters viz biodegradability (Experiment I), particle size (Experiment II), acid/base thermal pretreatment (Experiment III), C:N ratio (Experiment IV), and trace nutrient supplementation (Experiment V), to generate the maximum methane yield from ST with respect to SB was designed as objective I. At first, chemical composition and methane yields of ST and SB were determined through bench-scale biochemical methane potential (BMP) tests (Experiment I). Buswell’s equation predicted a theoretical methane yield of 291.0 and 349.4 mL CH4 g-1VSadded for ST (C107.8H179.1O101.4N1S0.08) and SB (C86.7H134.3O64.9N1S0.07), respectively. The corresponding methane yields with Modified Dulong’s equation were 266.3 and 298.7 mL CH4 g-1VSadded, respectively. The calculated energy value was 14.1 MJ for ST and 12.6 MJ for SB. However, experimental methane yields obtained were 161.8 and 187.9 mL CH4 g-1VSadded for ST and SB, respectively. First-order kinetic model revealed that experimental data fitted well (R2 = 0.99) with the modelling data and the hydraulic rate constant (khyd) values of 0.04 and 0.06 day-1 were obtained for ST and SB, respectively. However, modified Gompertz model had a lag phase () of 2.1 and 1.7 day, for ST and SB, respectively indicating hydrolysis was the rate limiting step for the studied lignocellulosic feedstocks. Thus, the effect of mechanical (Experiment II)., thermal and chemical pretreatments (Experiment III) on chemical composition and methane yields of ST and SB were evaluated. The effect of particle size of <0.25, 0.25-0.50, 0.50-1 and 1-2 mm on chemical composition and methane yields were determined. Results showed that particle size reduction had a profound effect on methane yields, especially for SB than for ST. For ST, particle size of 1-2 mm showed an improvement in methane yields by 19.1% over control (161.8 mL CH4 g-1 VSadded). For SB, the increase in methane yields over control (189.7 mL CH4 g-1 VSadded) were by 23.6%, 20.3%, 18.1% and 6.4% respectively at particle sizes of 1-2, 0.5-1, 0.25-0.5, 0.13-0.25 mm, respectively. These results suggest that the optimal particle size for anaerobic digestion of ST and SB will be 1-2 mm for maximum methane yield. Further, mechanical pretreatment through milling did not solubilise hemi-cellulose and/or improve delignfication but improved the surface area of the holocellulose. Therefore, the effect of chemical catalysts (dilute NaOH, H2SO4, HNO3) with and without steam explosion on chemical composition and methane yields was evaluated (Experiment III). Pretreatment conditions used for the steam explosion were 130 °C for 5 minutes at acid/base concentration of 2.5% catalyst loading. Results showed that the studied pretreatments had a profound effect on chemical composition and methane yields of ST. On comparison to control, dilute H2SO4, followed by NaOH and HNO3 addition with steam explosion improved the methane yields of ST by 63.5%, 52.1% and 45.6%, respectively. Steam explosion alone also improved the methane yields of ST by 40% over control. Biomass composition analysis showed that dilute H2SO4, HNO3, NaOH and steam explosion alone had improved the glucan content by 13.7%, 11.7%, 9.3% and 3% respectively than control. Dilute H2SO4 pretreatment improved the glucan availability by 45.2% and hemicellulose (xylan and arabinan) solubilisation by 63.7%-66.9%. Lignin depolymerisation in pretreated ST was improved (16.7%) over untreated ST. In Experiment I, chemical composition of ST and SB showed that the studied substrates were deficit in trace elements and contained high carbon to nitrogen (C/N) ratio of 92.4and 146.5 respectively. Therefore, the effect of C/N ratios of 15:1, 20:1, 25:1, 30:1, 35:1 and 40:1 with urea addition on methane yields of ST and SB was investigated (Experiment IV). Results showed that methane yields improved by 13.6% and 11.3% for ST when the C/N ratio was at 20:1 and 25:1, respectively. The corresponding values for SB were 14.2% and 14.3% at 20:1 to 25:1 C/N ratio, respectively. Both these results indicate that the optimal C/N was 20-25:1 for AD of lignocellulosic residues such as ST and SB. On the other hand, the effect of trace nutrients nickel (Ni), cobalt (Co), molybdenum (Mo), manganese (Mn), copper (Cu) and zinc (Zn) on methane yields during AD of ST and SB (Experiment V) showed that trace elements supplementation influenced the methane yields and both substrates responded differently. With ST, methane yields of 68.1% and 68.7% increase over control were noticed with addition of Co and Mo, respectively. For SB, methane yields increased by 48.6%, 63.9% and 4.8% with Co, Mo and Mn dosing at 2, 3, 90 mg kg-1 respectively. All other TE addition resulted in lower methane yields than control or inhibited the biogas production at different stages of incubation. All the batch BMP tests were conducted in triplicates at inoculum to substrate (ISR) ratio of 2 in serum glass bottles with a working volume of 100 mL and incubated statically at 37 °C. All the results were analysed for variance using LSD and Dunnett-t test giving methane yield as dependent variable (p<0.05). Second objective was designed to study the effect of organic loading on process performance and methane yields in four lab-scale stainless reactors (10 L working volume) and operated at an initial organic loading rate (OLR) of 1.5 gVS L-1 d-1 with hydraulic retention times (HRT) of 35 days for 225 days. Reactors were fed with untreated ST (ST), untreated SB (SB), pretreated SB (TB) and pretreated ST (TT). Dilute H2SO4 followed by steam explosion (Experiment II) was used for pretreatment of ST and SB. OLR was increased in a stepwise manner from the initial rate of 1.5 to 2.5 and 3.5 gVS L-1 d-1. OLR was changed upon achieving steady-state condition and/or operating for 2 consecutive HRTs. Methane production rates and yields responded with increase in OLR from 1.5 to 2.5 gVS L-1 d-1. Mean methane yields of 138, 173, 248 and 252 ml g-1VSfed were obtained at an OLR 1.5 gVS L-1 d-1 in ST, SB, TT and TB reactors, respectively. Increase in OLR to 2.5 gVS L-1 d-1 showed decrease in methane yields. Mean methane yields obtained for TB, TT, SB and ST were 121, 148, 226, 236 ml g-1VSfed with a VS removal rate of 48.5, 51.4, 51.5 and 52.4%, respectively. Process parameters such as pH, total ammoniacal nitrogen (TAN) and total volatile fatty acids (TVFA) were shown to be stable and were 7.3-7.5, 0.36-0.54 g L-1 and 0.79-0.98 g L-1 respectively during operational OLR’s. Further increase in OLR from 2.5 to 3.5 gVS L-1 d-1 resulted in further decrease in methane yields and unstable AD process. At OLR 3.5 gVS L-1 d-1, methane yields were 119, 139, 189 and 199 ml g-1VSfed for substrates ST, SB, TT and TB respectively. TVFA accumulation was noticed (1.55-2.49 g L-1) , pH was 7.4-7.5 and lower methane concentration (50.5-51.9%). Residual methane production (RMP) test after each OLR indicated the process efficiency. At OLR 2.5 gVS L-1 d-1, TT and TB reactors had the lowest RMP (32.1% and 30.2% respectively) with relatively high VS removal compared with SB and ST reactors. These results indicate that steam explosion with dilute sulphuric acid improved the biodegradability and methane yields of ST and SB. The results obtained from the lab-scale reactors were used to design and optimise process performance and methane yields from pretreated sugarcane trash in pilot-scale reactors (date not presented). Third objective was designed to evaluate detailed biogas composition and to develop and optimise high pressure water scrubbing technology (HPWS). For that, the biogas composition, energy content, siloxanes and trace volatile organic compounds in biogas generated from lab-scale biogas reactors were determined and compared with the pilot-scale. Laboratory biogas samples were collected during the steady-state condition when the reactors were operated at an OLR of 2.5 gVS L-1 d-1. Results showed that biogas collected from ST, SB, TT and TB reactor had methane concentration of 52.3, 52.2, 52.7, 52.7 %, respectively. The corresponding lower calorific values (LCV) were 18.4, 18.1, 18.9 and 19.2 MJ m-3 respectively. The wobbe index values in the biogases were 18.3, 18.2, 18.7 and 19.0 MJ m-3, respectively. Volatile organic compounds were noticed in the biogas samples. Organic silicon compounds (siloxanes) were in the range of 0-0.4 mg m-3. The reduced sulphur compounds and benzene and toluene content in the biogases were in the range of 0.7-1.3 mg m-3 and 0.2-0.7 mg m-3, respectively. Among the studied siloxanes, the proportion of cyclic siloxane (D3:D4:D5) viz., hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) were noticed. The ratio of D3:D4:D5 in biogases produced from lab-reactors were 68.5:5.7: 22.4 for ST, 33.9:4.9: 60.1 for SB, 25:8.6:69.3 for TT and 14.8:3.7:81.8 for TB. Trimethylsilanol, linear siloxanes and decamethylcyclohexasiloxane (D6) content in the biogases were below the detection limits. Volatile organic compounds, reduced sulphur compounds and siloxanes cause environmental impact and affect biomethane quality for vehicle fuel use. Biogas composition from pilot-scale biogas reactors (1.2 m3 reactor with 0.8 m3 working volume) fed with steam exploded ST at an OLR of 1.5 kgVS m-3 d-1 and HRT of 35 d was analysed to optimise the process parameters to achieve the desired biomethane quality and evaluate the energy requirements of pilot-scale biogas upgrading unit (10 m3 h-1) for biogas upgrading and bottling. Results showed that the biogas had 54.1% CH4 and 39.7% CO2 and the produced biogas was upgraded to 96.7% biomethane purity by using high pressure water scrubbing process. Experimental data from the biogas upgrading process was used to optimise biogas upgrading by using Aspen Plus software. The influence of process parameters such as absorber column pressure, water to gas flow rate, temperature on biomethane purity and percentage of H2S and CO2 removal were evaluated. Experimental results showed that at liquid flow rate of 3 m3/hr, fluid temperature of 20°C, at absorption column pressure of 8 bar with 4 m random packing material with redistributor at 2 m with 25 mm plastic pall ring packing material; biogas can be upgraded to biomethane of 96.8% CH4, 2.9% CO2, < 1 ppm H2S. These model results were validated with software simulation.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

Over the last decade, Ionic Liquids (ILs) have been used for the dissolution and derivatization of isolated cellulose. This ability of ILs is now sought for their application in the selective dissolution of cellulose from lignocellulosic biomass, for the manufacture of cellulosic ethanol. However, there are significant knowledge gaps in the understanding of the chemistry of the interaction of biomass and ILs. While imidazolium ILs have been used successfully to dissolve both isolated crystalline cellulose and components of lignocellulosic biomass, phosphonium ILs have not been sufficiently explored for the use in dissolution of lignocellulosic biomass. This thesis reports on the study of the chemistry of sugarcane bagasse with phosphonium ILs. Qualitative and quantitative measurements of biomass components dissolved in the phosphonium ionic liquids (ILs), trihexyltetradecylphosphonium chloride ([P66614]Cl) and tributylmethylphosphonium methylsulphate ([P4441]MeSO4) are obtained using attenuated total reflectance-Fourier Transform Infra Red (FTIR). Absorption bands related to cellulose, hemicelluloses and lignin dissolution monitored in situ in biomass-IL mixtures indicate lignin dissolution in both ILs and some holocellulose dissolution in the hydrophilic [P4441]MeSO4. The kinetics of lignin dissolution reported here indicate that while dissolution in the hydrophobic IL [P66614]Cl appears to follow an accepted mechanism of acid catalysed β-aryl ether cleavage, dissolution in the hydrophilic IL [P4441]MeSO4 does not appear to follow this mechanism and may not be followed by condensation reactions (initiated by reactive ketones). The quantitative measurement of lignin dissolution in phosphonium ILs based on absorbance at 1510 cm-1 has demonstrated utility and greater precision than the conventional Klason lignin method. The cleavage of lignin β-aryl ether bonds in sugarcane bagasse by the ionic liquid [P66614]Cl, in the presence of catalytic amounts of mineral acid. (ca. 0.4 %). The delignification process of bagasse is studied over a range of temperatures (120 °C to 150 °C) by monitoring the production of β-ketones (indicative of cleavage of β-aryl ethers) using FTIR spectroscopy and by compositional analysis of the undissolved fractions. Maximum delignification is obtained at 150 °C, with 52 % of lignin removed from the original lignin content of bagasse. No delignification is observed in the absence of acid which suggests that the reaction is acid catalysed with the IL solubilising the lignin fragments. The rate of delignification was significantly higher at 150 °C, suggesting that crossing the glass transition temperature of lignin effects greater freedom of rotation about the propanoid carbon-carbon bonds and leads to increased cleavage of β-aryl ethers. An attempt has been made to propose a probable mechanism of delignifcation of bagasse with the phosphonuim IL. All polymeric components of bagasse, a lignocellulosic biomass, dissolve in the hydrophilic ionic liquid (IL) tributylmethylphosphonium methylsulfate ([P4441]MeSO4) with and without a catalytic amount of acid (H2SO4, ca. 0.4 %). The presence of acid significantly increases the extent of dissolution of bagasse in [P4441]MeSO4 (by ca. 2.5 times under conditions used here). The dissolved fractions can be partially recovered by the addition of an antisolvent (water) and are significantly enriched in lignin. Unlike acid catalysed dissolution in the hydrophobic IL tetradecyltrihexylphosphonium chloride there is little evidence of cleavage of β-aryl ether bonds of lignin dissolving in [P4441]MeSO4 (with and without acid), but this mechanism may play some role in the acid catalysed dissolution. The XRD of the undissolved fractions suggests that the IL may selectively dissolve the amorphous cellulose component, leaving behind crystalline material.

Dilute acid pretreatment is a process that is used to enhance ethanol yields in biofuel manufacturing by removing hemicelluloses from plant biomass. This thesis presents a new mathematical model of dilute acid pretreatment that can be used to predict hemicellulose yield profiles at the laboratory scale and inform further investigations at the industrial reactor scale. This work provides a framework for determining the optimal reaction conditions for acid pretreatment and thus has the potential to reduce the cost of commercial bioethanol production from 2nd generation lignocellulosic biomass feedstocks.

The thesis investigated biorefining of sugarcane bagasse into value-added products. A glycerol-based fractionation method was developed at laboratory and pilot scales to convert sugarcane bagasse into fermentable sugar and high-quality lignin. The fermentable sugar was used for microbial oil production with applications in biofuel, biochemical, food and feed industries. The generated lignin had physico-chemical properties suitable for biochemical and polymer production. The thesis proposes methods to generate new revenue streams for Australian sugarcane industry.

Lignocellulosic biomasses are an important source of chemical components such as cellulose, lignin and hemicelluloses, and can be used for a variety of purposes in both the pulp and paper and chemical conversion industries. Xylan, the main hemicellulose found in hardwood and grass plants, plays an important role during the pulping/pretreatment process reactions, including those used in 2nd generation bioethanol production. It may also play an important role in the production of certain novel materials. This thesis evaluates the composition of eucalyptus (Eucalyptus urophylla x Eucalyptus grandis), sugarcane bagasse and sugarcane straw, with a specific focus on the structure and properties of xylan. The chemical characterization of biomasses showed that sugarcane bagasse and straw contain larger amounts of extractives, ash and silica than eucalyptus. The large amount of silica leads to an overestimation of the Klason lignin content, if not corrected. By using a complete mass balance approach, sugarcane bagasse and straw were shown to contain smaller amounts of lignin (18.0% and 13.9%, respectively) than previously reported for these raw materials, and certainly a much smaller amount of lignin than was found in eucalyptus (27.4%). The hemicellulose content in sugarcane bagasse (28.7%) and straw (29.8%) was much higher than that in eucalyptus (20.3%). In order to investigate the structure of the xylan in greater detail, it was extracted with dimethyl sulfoxide from holocellulose, obtained by either peracetic acid or sodium chlorite delignification. The structure of the isolated xylans was confirmed by FTIR and 1H NMR analysis. In eucalyptus, the O-acetyl-(4-O-methylglucurono)xylan (MGX) was identified. This had a molar ratio of xylose units to branches of 4-O-methylglucuronic acid of 10:1.1 and a degree of acetylation of 0.39. All 4-O- methylglucuronic acid groups were attached to position O-2 of the xylose units, which had an acetyl group in position O-3. The acetyl groups were distributed in positions O-3 (64%), O-2 (26%) and O-2,3 (10%). The MGX had a molecular weight (Mw) of about 42 kDa. In bagasse and straw, arabinoxylan (AX) was identified. This had a molar ratio of xylose units to arabinosyl substitutions of 10:0.5 for bagasse and 10:0.6 for straw. A degree of acetylation was 0.29 and 0.08 for bagasse and straw, respectively. The arabinose units were attached preferentially to position O-3 in AX. In the xylan from bagasse, the acetyl groups were found in positions O-3 (60%), O-2 (13%) and O-2,3 (27%), while in the xylan from straw, the acetyl groups were distributed between positions O-3 (67%) and O-2 (33%). The AX had a molecular weight (Mw) of about 38 kDa and 30 kDa for bagasse and straw, respectively. The differences in the structure of xylan present in the various biomasses played an important role during hydrothermal pretreatment, which is often used as the first step in 2nd generation ethanol production. The varying amounts of uronic acid and acetyl groups resulted in different starting pH levels of liquor and, thus, affected the chemical transformation in the biomasses in different ways. The hydrothermal pretreatment resulted mostly in the removal and/or transformation of hemicelluloses, but also in the formation of a significant number of pseudo-lignin structures. In addition, in eucalyptus, pseudo-extractives structures were generated. The sugarcane straw showed the highest mass loss during the investigated pretreatment.

QC 20151023

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O etanol tem sido considerado um promissor biocombustível para substituir combustíveis fósseis. O uso estratégico de eucalipto, bagaço e palha de cana-de-açúcar em tecnologias de segunda geração para a produção de etanol foi estudada neste trabalho, usando vários processos de pré-tratamentos seguidos por sacarificação e fermentação simultâneas (SFS). No artigo I é apresentada a caracterização química de eucalipto, bagaço e palha de cana-de-açúcar antes e após os pré-tratamentos hidrotérmico (H 2 O), ácido diluído (4,5% H 2 SO 4 ) e alcalino (15% NaOH). Foi determinado que o significativo teor de sílica presente em bagaço e palha da cana-de- açúcar causaram superestimação da lignina Klason nessas biomassas. O novo método para reportar a composição química das biomassas, baseado no completo balanço de massas, foi sugerido e provou ser útil para avaliar ambas, matéria-prima e biomassa pré- tratada. A formação de pseudo-extrativos na madeira de eucalipto e pseudo-lignina no bagaço e na palha foi observada como resultado dos pré-tratamentos. O Artigo II apresenta a caracterização química e estrutural das xilanas isoladas a partir de eucalipto, bagaço e palha usando dois métodos, sendo eles: deslignificação com ácido peracético seguida por extração com dimetilsulfóxido e deslignificação com clorito de sódio seguida por extração com dimetilsulfóxido. A xilana obtida a partir do eucalipto foi identificada como do tipo O-acetil-4-O-metilglucuronoxilana, contendo 39 unidades de grupos acetilas e 11 ácidos 4-O-metilglucurônicos para cada 100 unidades de xilose na cadeia principal. Além disso, um ácido 4-O-metilglucurônico foi também substituído por uma unidade de galactosil terminal. A xilana obtida a partir de bagaço e palha foi do tipo arabinoxilana, que apresentou proporcionalmente 100 unidades de xiloses: 29 unidades de grupos acetilas: 5 unidades de arabinofuranosil para o bagaço e proporcionalmente 100 unidades de xiloses: 8 unidades de grupos acetilas: 6 unidades de arabinofuranosil para a palha. O Artigo III descreve o efeito dos pré-tratamentos hidrotérmico e ácido diluído (1,5%, 3,0% e 4,5% de H 2 SO 4 ) na composição química das biomassas e sua subsequente conversão em etanol. Observou-se que a redução no pH dos pré-tratamentos favoreceu a remoção de lignina e carboidratos. O eucalipto apresentou a maior produção de etanol após o pré-tratamento hidrotérmico, mas com rendimento relativamente baixo. Após os pré-tratamentos ácidos, bagaço e palha mostraram maiores produções de etanol que o eucalipto. O pré-tratamentos realizados com 4,5% de H 2 SO 4 foi o mais eficiente. O Artigo IV avalia o efeito da carga alcalina durante os pré-tratamentos alcalinos (5%, 10% e 15% NaOH) na composição química das biomassas e sua subsequente conversão em etanol. Observou-se que as maiores cargas alcalinas propiciaram as maiores remoções de lignina e carboidratos. Para pré- tratamentos alcalinos, o bagaço provou ser a biomassas mais promissora para produção de etanol. O pré-tratamento com 15% de NaOH foi o mais eficiente. O Artigo V apresenta a otimização do pré-tratamento de extração alcalina a frio (EAF) referente à temperatura (20oC, 30oC e 40oC), tempo de reação (10, 35 e 60 min.) e concentração de NaOH (70, 90 e 110 g L -1 ) com foco na remoção de xilanas das biomassas e subsequente conversão das biomassas deficientes em xilanas em etanol. As condições ótimas para a remoção de xilanas de madeira de eucalipto, bagaço e palha da cana-de- açúcar foram respectivamente: 40oC, 60 min. e 70 g L -1 de NaOH; 33oC, 60 min. e 110 g L -1 de NaOH; e 31oC, 55 min. e 110 g L -1 de NaOH. Nessas condições de pré- tratamentos, considerável quantidade de lignina também foi removida das biomassas. Para a madeira de eucalipto, a formação de pseudo-extrativos foi observada durante os pré-tratamentos de EAF. A palha da cana-de-açúcar pré-tratada por EAF foi a biomassa mais promissora para a produção de etanol de segunda geração. Para os pré-tratamentos de EAF, os maiores rendimentos em etanol foram obtidos para bagaço e palha da cana- de-açúcar que para a madeira de eucalipto. Em resumo, os resultados acumulados por essa tese de doutorado sugeriram que bagaço e palha são biomassas aplicáveis à produção de etanol de segunda geração. O uso dessas biomassas lignocelulósicas cria a possibilidade de integrar primeira e segunda plataformas para a produção de etanol, transformando resíduo em produto principal.
The ethanol has been considered a promising biofuel to replace fossil-based fuels. The strategic use of eucalyptus, sugarcane bagasse and sugarcane straw in second generation technology to ethanol production was investigated in this work, by performing various pretreatment processes followed by simultaneous saccharification and fermentation (SSF). In article I it is presented the chemical characterization of eucalyptus, sugarcane bagasse and straw before and after hydrothermal (H 2 O), diluted acid (4.5% H 2 SO 4 ) and alkaline (15% NaOH) pretreatments. It was determined that the significant amount of silica present in sugarcane bagasse and straw led to overestimation of Klason lignin of these biomasses. A novel approach to report the chemical composition of biomasses, based on the complete mass balance, was suggested and proved to be useful to assess both, raw materials and pretreated biomasses. The formation of pseudo-extractives in eucalyptus wood and pseudo-lignin in bagasse and straw as result of pretreatments was observed. Article II presents the chemical and structural characterization of xylans isolated from eucalyptus, bagasse and straw via two different methods, namely: peracetic acid delignification followed by dimethyl sulfoxide extraction and sodium chlorite delignification followed by dimethyl sulfoxide extraction. The xylan obtained from eucalyptus was identified as an O-acetyl-4-O-methylglucuronoxylan type, containing 39 acetyl groups units and 11 4-O-methylglucuronic acids per 100 units of xylose on the backbone. In addition, one 4-O-methylglucuronic acid was also substituted by one terminal galactosyl unit. The xylan obtained from bagasse and straw was an arabinoxylan type, which contained 100 xylose units: 29 acetyl groups units: 5 arabinofuranosyl units for bagasse, proporcionally, and 100 xylose units: 8 acetyl groups units: 6 arabinofuranosyl units for straw, proporcionally. Article III describes the effect of hydrothermal and diluted acid (1.5, 3.0 and 4.5% H 2 SO 4 ) pretreatments on the chemical composition of biomasses and their subsequent conversion into ethanol. It was observed that lowering pretreatment pH resulted in improved lignin and carbohydrates removal. The eucalyptus presented the highest ethanol production after hydrothermal pretreatment, but with relative low yield. After acid pretreatments, bagasse and straw showed higher ethanol productions then eucalyptus. The pretreatment performed at 4.5% H 2 SO 4 was the most efficient. Article IV assesses the effect of alkaline charge during alkaline (5, 10 and 15% NaOH) pretreatments on the chemical composition of biomasses and their subsequent conversion into ethanol. It was observed that higher alkaline charge provided the highest lignin and carbohydrates removal. For the alkaline pretreatments, the bagasse proved to be the most promising biomass for ethanol production. The pretreatment with 15% NaOH was the most efficient. Article V presents an optimization of the cold alkaline extraction (CAE) pretreatment regarding temperature (20oC, 30oC and 40oC), reaction time (10, 35 and 60 min) and NaOH concentration (70, 90 and 110 g L -1 ), focusing on xylan removal from biomasses and subsequent conversion of the xylan-depleted biomasses into ethanol. The optimal conditions for xylan removal from eucalyptus wood, sugarcane bagasse and sugarcane straw were, respectively: 40oC, 60 min and 70 g L -1 NaOH; 33oC, 60 min and 110 g L -1 NaOH; and 31oC, 55 min and 110 g L -1 NaOH. Under these pretreatments conditions, substantial amounts of lignin were also removed from the biomasses. For the eucalyptus wood, the formation of pseudo-extractives was observed during the CAE pretreatments. The sugarcane straw pretreated with CAE was the most promising biomass for production of second generation ethanol. For the CAE pretreatments, higher ethanol yields were achieved with sugarcane bagasse and straw in relation to eucalyptus wood. In summary, the results accumulated from this doctoral thesis suggested that bagasse and straw are suitable biomasses for production of second generation ethanol. The use of these lignocellulosic biomasses creates the possibility of integrating first and second platforms for ethanol production, which turns residues into main product.

付記する学位プログラム名: 京都大学大学院思修館
京都大学
新制・課程博士
博士(総合学術)
甲第23347号
総総博第20号
京都大学大学院総合生存学館総合生存学専攻
(主査)教授 山敷 庸亮, 教授 山本 貴士, 教授 寶 馨, 教授 齋藤 敬
学位規則第4条第1項該当
Doctor of Philosophy
Kyoto University
DFAM

New technologies, such as an efficient vapor-compression evaporator, a stationary lime kiln (SLK), and the MixAlco process, compelled us to re-evaluate methods for producing sugar from cane. These technologies allow more water and lime to be used, and they add more value to bagasse. Extracting and preserving the sugars, and lime pretreating the bagasse to enhance biodigestibility, all at the same time in a pile, was demonstrated to be unfeasible; therefore, sugar extraction must occur before lime treating the bagasse. Sugar extraction should occur countercurrently by lixiviation, where liquid moves in stages opposite to the soaked bagasse (megasse), which is conveyed by screw-press conveyors that gently squeeze the fiber in each stage, improving extraction. The performance of a pilot-scale screw-press conveyor was tested for dewatering capabilities and power consumption. The unoptimized equipment decreased megasse moisture from 96 to 89%. Simulation of the process suggested that eight stages are necessary to achieve 98% recovery from typical sugarcane. The cumulative power for the screw-press conveyor system was 17.0±2.1 hp•h/ton dry fiber. Thin raw juice preserved with lime for several months showed no sucrose degradation and no quality deterioration, except for reducing sugar destruction. The lime loading needed for 1-year preservation is 0.20 g Ca(OH)2/g sucrose. Shorter times require less lime. After preservation, the juice was carbonated and filtered, and the resulting sludge pelletized. Due to their high organic content, the pellets were too weak for calcination temperatures used in the SLK. The organics must be decreased prior to pelletization and sodium must be supplemented as a binding agent. Long-term lime pretreatment of bagasse showed two delignification phases: bulk (rapid) and residual (slow). These were modeled by two simultaneous first-order reactions. Treatments with air purging and higher temperatures (50 – 57oC) delignified more effectively, especially during the residual phase, thus yielding higher cellulase-enzyme digestibilities after 2 – 8 weeks of treatment. At temperatures > 60oC, pure oxygen purging is preferred. Fresh bagasse was of better quality than old bagasse. Treatment with NaOH yielded a larger bulk delignification phase than Ca(OH)2. Long-term lime pulping of bagasse was unsuitable for copy-quality paper, but it was appropriate for strawboard and other filler applications.

To reduce formaldehyde emissions and prevent deforestation, particle boards prepared from sodium hydroxide modified algae and sugarcane bagasse were used to study the effect of process parameters such as fine-filler ratio, algae-filler ratio, ambient storage times, and sodium hydroxide concentration on mechanical properties. P-test was conducted to test for significance of parameters on flexural modulus and flexural strength. Results showed that algae-filler ratio and ambient storage times have significant impact on mechanical properties, while fine-filler ratio showing significant impact on secant flexural modulus and sodium hydroxide concentration having impact only on tangent flexural modulus. Mechanical properties of particleboard composites made from sugarcane bagasse and spirulina algae were found to be comparable to conventional particle boards.

In the last few centuries the world-wide energy demand rose to a stage were traditional power-supply networks struggle to satisfy the necessary supply of energy. Consequently, humanity is still largely dependent on every energy source possible and primarily environmentally unfriendly sources such as coal, fossil-oils, nuclear etc. Governments world-wide finally realised that those recourses are limited and began to subsides renewable energy solutions such as solar and wind energy, but by neglecting the fact that those sources have problems to supply energy 24/7 to the customers. Pyrolysis from bio feedstock is one of the technologies which can not only produce oil and gas for generators as well as fertiliser, but also conquer another problem arising from modern society, garbage reduction. Pyrolysis does exist for many years now, but the technology has not often been employed due to high initial investments, maintenance, and other factors. Furthermore, most of the conducted pyrolysis laboratory experiments also focused on expensive setups, catalysts etc., which create potentially good results, but consequently the pyrolysis process continued of being unaffordable for private consumers and especially for smaller businesses, such as farmers. Several research projects focussed on the yield output, rather than the quality of the oil which could be used for power generation. As a result, the usage of the oil was not suitable for generators or even for storing, due to impurities as well as due to forming of aromatics which occur very often in the aim of maximising the yield output and causes wax deposits, which can cause severe damage in machines operated with fuel produced from this oil. In this research pyrolysis experiments were conducted with the focus on increasing the oil quality by changing the temperature parameters, with a setup which is as simple as possible in order to make the setup mainstream capable, but also with the possibility of upscaling in mind. Although there are numerous feedstocks to choose from, sugarcane bagasse was chosen to be the feedstock of this research. This feedstock appears to be ideal, as the consumption and therefore the sugarcane bagasse waste rose significantly in the last century. At first the simplistic test rig was designed to determine the most suitable heating ramps and finally to investigate maximum temperatures from 300⁰C up to 650⁰C, based on the literature review conducted. This returned an overall picture at what temperature the best possible oil output for this feedstock and simplistic set-up can be. After analysis of the different oil outputs, the temperature range was more refined and the ramp, which proved to be the best, was fixed. The final analysis is conducted in a narrowed temperature band of 450⁰C to 550⁰C and showed very promising results at 550⁰C not only in regard of a 11% increase of the higher heating value, which would mean that if a person consumes an average of 800kwh per year and everybody on this planet would use pyrolysis as a primary energy source, 38 million tonnes less of feedstock would be needed per year world-wide. Furthermore, storage capabilities of oil produced by 550⁰C showed an immense storage capability improvement, due to a very low amount of aromatics in comparison to temperatures above and below 550⁰C. Furthermore, the analysis was repeated four months after the experiments to observe any build-up of wax deposits from possible aromatics. The results were found to be exactly the same in regard to the HHV as well as the FTIR spectra of oil. Overall the research project proved that pyrolysis can be affordable, but also can produce good quality oil at the same time. Consequently, pyrolysis can play a vital role in the run for sustainable energy resources in the future.
Thesis (Masters)
Master of Philosophy (MPhil)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

O fungo filamentoso Trichoderma reesei é um dos principais fungos utilizados para a produção em larga escala de enzimas devido a sua grande capacidade de produção e secreção de holocelulases para aplicação em processos de sacarificação da biomassa vegetal lignocelulósica. Embora o T. reesei seja utilizado como um dos principais produtores de celulases a nível industrial, diversos processos e estudos são realizados com o objetivo de aprimorar o entendimento de todo o mecanismo de degradação de biomassa vegetal além de prover o aumento da eficiência tanto da produção quanto da atividade das celulases. No presente trabalho foi realizado a construção de uma linhagem mutante para o gene cel74a (codificando para uma xiloglucanase) e a caracterização funcional de CEL74A na regulação gênica de holocelulases durante o cultivo em bagaço de cana-de-açúcar. Os nossos resultados mostraram que deleção de cel74a possivelmente pode estar envolvida no sinergismo da regulação da expressão de holocelulases durante o cultivo em bagaço de cana-de-açúcar. A partir da análise do perfil de expressão gênica, foi possível observar a redução na expressão de todos os genes de celulases testados (cel7a, cel7b e cel6a) embora não tenha afetado a atividade enzimática, ao passo que as hemicelulases (xyn1 e xyn2) apresentaram aumento tanto na expressão quanto na atividade enzimática. Na linhagem ?cel74a, foi observado redução na liberação de glicose, xilose e galactose após a hidrólise de xiloglucano. Além disso, a atividade de CEL74A foi modulada na presença de cálcio e pode ser necessária para a atuação mais eficiente de outras enzimas envolvidas na degradação de xiloglucano. Desta forma, em T. reesei, CEL74A apresenta um papel importante tanto na regulação de genes holocelulolíticos quanto para a degradação eficiente de bagaço de cana-de-açúcar, contribuindo para a elucidação de mecanismos pelos quais este fungo utiliza para a utilização do bagaço de cana-de-açúcar como fonte de carbono
The filamentous fungus Trichoderma reesei is one of the main fungi used for the large-scale production of enzymes due to their great capacity of production and secretion of holocellulases for application in saccharification processes of lignocellulosic plant biomass. Although T. reesei is used as one of the main producers of cellulases at industrial level, several processes and studies are carried out with the aim of improving the understanding of the whole plant biomass degradation mechanism, as well as increasing the efficiency of both the production and cellulase activity. In the present work the construction of a mutant lineage for the cel74a gene (coding for a xyloglucanase) and the functional characterization of CEL74A in the gene regulation of holocellulases during the cultivation of sugarcane bagasse were carried out. Our results showed that deletion of cel74a may be involved in the regulation of holocellulase expression during sugarcane bagasse cultivation. From the analysis of the gene expression profile, it was possible to observe the reduction in the expression of all tested cellulase genes (cel7a, cel7b and cel6a), although it did not affect the enzymatic activity, whereas the hemicellulases (xyn1 and xyn2) presented increase in both expression and enzymatic activity. In the ?cel74a strain, a reduction in glucose, xylose and galactose release was observed after xyloglucan hydrolysis. In addition, the activity of CEL74A was modulated in the presence of calcium and may be required for the more efficient performance of other enzymes involved in the degradation of xyloglucan. Thus, in T. reesei, CEL74A plays an important role both in the regulation of holocellulolytic genes and in the efficient degradation of sugarcane bagasse, contributing to the elucidation of mechanisms by which this fungus uses for the use of sugarcane bagasse as source of carbon

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
Apresenta-se o estudo experimental do comportamento de um solo arenoso e de um solo argiloso, reforçado e não reforçado com cinza de bagaço de cana-deaçúcar e com cinza de casca de arroz, por meio da realização de ensaios de caracterização física e química e de ensaios de cisalhamento direto. Busca-se estabelecer padrões de comportamento que possam explicar a influência da adição das cinzas, relacionando-os com os parâmetros de resistência ao cisalhamento e de deformação do solo. Os ensaios foram realizados em amostras com teores que variaram entre 5-20 por cento. Por meio dos resultados obtidos, foi possível concluir que a inserção de cinza de bagaço de cana-de-açúcar, aos solos argiloso e arenoso em estudo, mostra-se viável, uma vez que resultaram em melhoria dos parâmetros de resistência ou não causaram alterações significativas. Para a cinza de casca de arroz, em misturas com solo arenoso, a aplicação não se mostrou viável, visto que, para ambos os teores de cinza, houve um decréscimo no ângulo de atrito e nenhum acréscimo de coesão. Nas misturas com solo argiloso, a aplicação da mesma cinza mostrou-se viável, haja vista que sua aplicação resultou em melhoria dos parâmetros de resistência. Quanto ao teor de cinza para as misturas com solo argiloso, verificou-se que o melhor comportamento obtido foi com o teor de 20 por cento, para as misturas com ambas as cinzas. Para as misturas com areia, como não houve um aumento proporcional da resistência com o aumento do teor das cinzas foi difícil determinar um teor ótimo de cinza a ser utilizado. Os resultados obtidos neste estudo, em geral, mostraram-se satisfatórios e cumpriram os objetivos iniciais propostos com relação à investigação do comportamento solo-cinza para utilização em obras geotécnicas.
This paper presents the experimental study of the behavior of a sandy soil and a clay soil, reinforced and unreinforced with sugarcane bagasse ash and rice husk ash, by performing physical and chemical characterization tests and direct shear tests. The aim is to establish patterns of behavior that may explain the influence of the addition of ashes, relating them to the shear strength parameters and soil deformation. The tests were carried out on samples with concentrations ranging from 5-20 percent. Through the results, it was possible to conclude that the inclusion of sugarcane bagasse ash, to clay and sandy soils under study, proves viable, since it resulted in improved strength parameters or did not cause significant alterations. For the rice husk ash in mixtures with sandy soil, the application was not feasible, since for both ash contents there was a decrease in the friction angle and no increase in the cohesion. In blends with clay soil, the application of the same ash proved to be feasible, given that its application resulted in improvement of resistance parameters. As for the ash content for mixtures containing clay soil, it was found that the best performance was obtained with 20 percent content for mixtures with both ashes. For mixtures with sand, as there was not a proportional increase in resistance with increasing content of ash it was difficult to determine an optimal ash content to be used. The results of this study generally were satisfactory and met the initial proposed objectives in relation to soil-ash behavioral research for use in geotechnical works.

The insight that the fossil fuel reserves are limited, together with concerns over security of supply (i.e. the oil crises), initiated the first raise of interest in biomass and all other renewable energy forms. However, the concern grew that global warming and the resulting climate change were enhanced by carbon dioxide (CO2) emissions resulting from fossil fuel consumption. Meanwhile, biomass energy is thought to account for 14–15% of total world energy consumption. Hence, the exploitation and utilization of biomass energy are effective and necessary for relieving the pressures caused by environmental pollution and fossil fuel shortage (Lv et al., 2010). Recently, extensive research aimed at converting biomass to useful energy have been carried out, especially pyrolysis and gasification, which are particularly suitable for the effective and efficient utilization of biomass. Sugarcane bagasse is the main byproduct of sugarcane mill, ready available at the production site so that it may be a suitable raw material for the production of biofuels, chemicals, and electricity. Among the methods that have been previously studied, is this particular study we explore thermochemical process, gasification. The properties of sugarcane bagasse relevant to gasification are briefly reviewed. The compositions of the bagasse as a fuel are variable, especially with respect to inorganic constituents important to the critical problems of sintering, fouling and slagging. Alkali and alkaline earth metals, in combination with other fuel elements such as silica and sulfur, are responsible for many undesirable reactions in a gasifier system.

Pretretament is an essential and expensive processing step for the manufacturing of ethanol from lignocellulosic raw materials. Ionic liquids are a new class of solvents that have the potential to be used as pretreatment agents. The attractive characteristics of ionic liquid pretreatment of lignocellulosics such as thermal stability, dissolution properties, fractionation potential, cellulose decrystallisation capacity and saccharification impact are investigated in this thesis. Dissolution of bagasse with 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) at high temperatures (110 �‹C to 160 �‹C) is investigated as a pretreatment process. Material balances are reported and used along with enzymatic saccharification data to identify optimum pretreatment conditions (150 �‹C for 90 min). At these conditions, the dissolved and reprecipitated material is enriched in cellulose, has a low crystallinity and the cellulose component is efficiently hydrolysed (93 %, 3 h, 15 FPU). At pretreatment temperatures < 150 �‹C, the undissolved material has only slightly lower crystallinity than the starting. At pretreatment temperatures . 150 �‹C, the undissolved material has low crystallinity and when combined with the dissolved material has a saccharification rate and extent similar to completely dissolved material (100 %, 3h, 15 FPU). Complete dissolution is not necessary to maximize saccharification efficiency at temperatures . 150 �‹C. Fermentation of [C4mim]Cl-pretreated, enzyme-saccharified bagasse to ethanol is successfully conducted (85 % molar glucose-to-ethanol conversion efficiency). As compared to standard dilute acid pretreatment, the optimised [C4mim]Cl pretreatment achieves substantially higher ethanol yields (79 % cf. 52 %) in less than half the processing time (pretreatment, saccharification, fermentation). Fractionation of bagasse partially dissolved in [C4mim]Cl to a polysaccharide rich and a lignin rich fraction is attempted using aqueous biphasic systems (ABSs) and single phase systems with preferential precipitation. ABSs of ILs and concentrated aqueous inorganic salt solutions are achievable (e.g. [C4mim]Cl with 200 g L-1 NaOH), albeit they exhibit a number of technical problems including phase convergence (which increases with increasing biomass loading) and deprotonation of imidazolium ILs (5 % - 8 % mol). Single phase fractionation systems comprising lignin solvents / cellulose antisolvents, viz. NaOH (2M) and acetone in water (1:1, volume basis), afford solids with, respectively, 40 % mass and 29 % mass less lignin than water precipitated solids. However, this delignification imparts little increase in saccharification rates and extents of these solids. An alternative single phase fractionation system is achieved simply by using water as an antisolvent. Regulating the water : IL ratio results in a solution that precipitates cellulose and maintains lignin in solution (0.5 water : IL mass ratio) in both [C4mim]Cl and 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc)). This water based fractionation is applied in three IL pretreatments on bagasse ([C4mim]Cl, 1-ethyl-3-methyl imidazolium chloride ([C2mim]Cl) and [C2mim]OAc). Lignin removal of 10 %, 50 % and 60 % mass respectively is achieved although only 0.3 %, 1.5 % and 11.7 % is recoverable even after ample water addition (3.5 water : IL mass ratio) and acidification (pH . 1). In addition the recovered lignin fraction contains 70 % mass hemicelluloses. The delignified, cellulose-rich bagasse recovered from these three ILs is exposed to enzyme saccharification. The saccharification (24 h, 15 FPU) of the cellulose mass in starting bagasse, achieved by these pretreatments rank as: [C2mim]OAc (83 %)>>[C2mim]Cl (53 %)=[C4mim]Cl(53%). Mass balance determinations accounted for 97 % of starting bagasse mass for the [C4mim]Cl pretreatment , 81 % for [C2mim]Cl and 79 %for [C2mim]OAc. For all three IL treatments, the remaining bagasse mass (not accounted for by mass balance determinations) is mainly (more than half) lignin that is not recoverable from the liquid fraction. After pretreatment, 100 % mass of both ions of all three ILs were recovered in the liquid fraction. Compositional characteristics of [C2mim]OAc treated solids such as low lignin, low acetyl group content and preservation of arabinosyl groups are opposite to those of chloride IL treated solids. The former biomass characteristics resemble those imparted by aqueous alkali pretreatment while the latter resemble those of aqueous acid pretreatments. The 100 % mass recovery of cellulose in [C2mim]OAc as opposed to 53 % mass recovery in [C2mim]Cl further demonstrates this since the cellulose glycosidic bonds are protected under alkali conditions. The alkyl chain length decrease in the imidazolium cation of these ILs imparts higher rates of dissolution and losses, and increases the severity of the treatment without changing the chemistry involved.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
O crescimento da demanda por energia elétrica e investimentos governamentais em fontes renováveis incentivam produtores do setor sucro-energético no país a buscar melhorias nos processos de suas usinas. Através do aumento da produção de vapor nas caldeiras de biomassa, que operam com ciclos Rankine, é possível gerar energia elétrica excedente para comercialização. O Brasil, um dos maiores produtores de cana-de-açúcar do mundo, gera resíduos derivados da cana com alto potencial energético. Os ciclos termodinâmicos híbridos têm sido utilizados em várias usinas de biomassa no exterior utilizando como combustíveis o gás natural e resíduos sólidos urbano (waste-to-energy). Como mostrado por diferentes autores, é possível, com estes ciclos, melhorar a eficiência térmica das usinas utilizando gases quentes da exaustão de uma turbina a gás operando com gás natural. A desvantagem é que o percentual de participação do gás natural de alguns ciclos híbridos pode ser alto, tornando estes projetos economicamente inviáveis. Neste trabalho será aplicado um ciclo híbrido adaptado para usinas de cana-de-açúcar brasileiras que queimam o bagaço em caldeiras de biomassa com reaquecimento externo. Os benefícios destes ciclos termodinâmicos incluem a melhoria de eficiência da planta, acarretando a maior geração de energia elétrica e aumento da quantidade de vapor de processo produzido para a mesma quantidade de bagaço queimado originalmente. Além da melhoria da eficiência térmica, o ciclo tem como uma de suas principais vantagens o fato de não depender de grandes quantidades de gás natural, reduzindo a possibilidade de prejuízos caso haja aumento do seu preço. Por último será mostrado que, embora haja a queima deste combustível fóssil, é possível reduzir as emissões específicas de CO2/kWh devido ao seu baixo consumo na usina aliado a elevada geração de energia elétrica.
The growing electric energy demand and government investments in renewable sources motivated sugar producers in Brazil to improve the thermal efficiencies of their sugarcane plants. For this reason, to generate excess electric energy and to sell it, has become an important and extra source of revenue. This country, one of the biggest sugarcane producers in the world, employs sugar waste, with high energetic potential, in boilers operated with Rankine cycles. Thermodynamic hybrid cycles have been in use in several biomass plants abroad, using natural gas and municipal solids waste as fuels. As shown by different authors, it is possible to increase the thermal efficiency of these plants by means of the heat recovery from hot exhaust gases of a gas turbine operating with natural gas. The main disadvantage of hybrid cycles, for some cases, is the high fraction of natural gas as fuel, making these specific plants economically unfeasible. In this work, a hybrid cycle concept is presented and studied, adapted for Brazilian sugar cane plants which burn bagasse in biomass boilers with reheating systems. The benefits of these thermodynamics cycles include a thermal efficiency improvement thus allowing more power generation and higher production of process steam, for the same amount of bagasse originally burned. Besides the higher thermal efficiency, the hybrid cycle presents the advantage of not depending on large natural gas consumption. This makes the plant s economic feasibility less dependent on fluctuations on natural gas prices. Furthermore, this study shows that, although a fossil fuel is burned, it is possible to reduce CO2/kWh specific emissions due to lower consumption of fossil fuels and to higher power generation.

This work focuses on the actions sought by the authorities to minimize global climate problems that are currently changing the conditions of survival of the planet to mitigate emissions of greenhouse gases (GHG) in the atmosphere. First, it is addressed the Framework Convention to start the discussions on climate changes, then the creation of the Kyoto Protocol, which came, giving nations the opportunity to act, minimizing damage to the environment, thus enabling that developing countries work together through the Clean Development Mechanism (CDM) in creating new and more efficient technologies, replacing the use of fossil fuels by renewable energy sources. The power source focus of this work is the residue of sugar cane bagasse that is more representative biomass of the Brazilian energy matrix. The sector chosen for the research was the sugar-alcohol, through the Usina Santa Candida placed within the State of Sao Paulo. It is shown through data comparison, the current Brazilian situation in the global scenario, both in world energy supply and in the composition of the energy matrix, showing that Brazil is in a privileged position about renewable energy use in comparison to the world, and is the third more significant country that reduces emissions of CO2, which shows its commitment to the Kyoto Protocol. By creating a scenario, it is evaluated the financial performance of Usina Santa Candida (SP), after the implementation of CDM. Scenario 1 shows the financial return without cogeneration system; scenario 2 shows the financial return after installation of cogeneration system; scenario 3 shows the financial return of cogeneration system installation associated to sale of grant guarantee; and the scenario 4 shows the financial return of cogeneration system installation associated to sale of grant guarantees and the receipt obtained with carbon credit market. Briefings for scenario analysis were generated through calculations of net present value (NPV), internal rate of return (IRR) and payback, to demonstrate the financial benefits after the adjustment to the clean development mechanism, demonstrating the gains from the sale of surplus power and the negotiations of certified emission reductions (CERs), the brief return of the investment payback, profitability by the board and monetary return for NPV. The result of the work shows that investment in compliance with the guidelines is very low compared to the financial return in the first auction of CERs, and added that the sale of surplus power, it becomes even more viable.
Este trabalho aborda as ações buscadas pelas autoridades mundiais para minimizar os problemas climáticos que atualmente estão mudando as condições de sobrevivência do planeta, mitigando as emissões de gases de efeito estufa (GEE) na atmosfera. Primeiramente, foi abordada a Convenção-Quadro como início das discussões sobre as mudanças do clima, posteriormente, a criação do Protocolo de Kyoto, que surgiu, dando às nações, a oportunidade para que ajam, minimizando os danos causados ao ambiente, possibilitando assim, que os países em desenvolvimento colaborem por meio do mecanismo de desenvolvimento limpo (MDL) na criação de novas e mais eficientes tecnologias, substituindo o uso de fontes de energia fósseis por fontes de energia renováveis. A fonte de energia foco desta pesquisa, o bagaço da cana-de-açúcar que é a biomassa mais representativa da matriz energética brasileira. O setor escolhido para a pesquisa foi o sucroalcooleiro, na Usina Santa Cândida situada no interior do Estado de São Paulo. É demonstrado, por meio de comparação de dados, a atual situação brasileira perante o mundo, tanto na oferta mundial de energia como na composição da matriz energética, mostrando que o Brasil está em uma posição privilegiada na utilização de energias renováveis em relação ao mundo, sendo o terceiro país que mais reduz as emissões de CO2, confirmando seu comprometimento com o Protocolo de Kyoto. Por meio da criação de cenários, foi possível avaliar o desempenho financeiro da Usina Santa Cândida (SP). O cenário 1 demonstra o retorno financeiro sem sistema de cogeração, o cenário 2 demonstra o retorno financeiro após a implementação de sistemas de cogeração, o cenário 3 demonstra o retorno financeiro do sistema de cogeração mais a venda das garantias contratuais, e por fim, o 4 cenário onde e demonstrado o retorno financeiro da implementação do sistema de cogeração mais a venda das garantias contratuais e ainda a receita obtida por meio da negociação dos créditos de carbono. As informações apuradas para análise dos cenários foram geradas a partir dos cálculos de Valor Presente Líquido (VPL), da Taxa Interna de Retorno (TIR) e do Payback para demonstrar os benefícios financeiros após a adequação ao mecanismo de desenvolvimento limpo, comprovando os ganhos obtidos com a venda de energia excedente e com as negociações dos Certificados de Redução de Emissão (RCEs), o retorno breve do investimento pelo payback, sua rentabilidade pela TIR e o retorno monetário pelo VPL. O resultado da pesquisa mostra que o investimento para a adequação às diretrizes é muito baixo se comparado com o retorno financeiro já no primeiro leilão das RCEs e que somado à venda de energia excedente, torna-se financeiramente ainda mais viável.

Lignocellulose, mostly from agricultural and forestry resources, is a potential renewable material for sustainable development of biorefineries. From previous studies, reducing sugar production through biological pretreatment involves two steps: solid-state fermentation (SSF) for delignification, followed by enzymatic hydrolysis by adding celluloytic enzymes (cellulase and xylanase etc.). In the process described in this thesis, the necessary enzymes are produced in-situ and the hydrolysis proceeds directly after the solid-state fermentation. Enzyme hydrolysis releases free amino nitrogen (FAN), reducing sugar and many other potential nutrients from the fermented materials. This method additionally avoids the need for removal of inhibitors compared with conventional chemical pretreatment processes. A range of solid-state fermentations were carried out to investigate the effect of washing procedure, particle size and nitrogen supplement on Trichoderma longibrachiatum growth. From these preliminary studies it was concluded that nitrogen supplementation is a crucial factor to improve significantly the fungi growth and production of feedstock using sugarcane bagasse as raw material. In order to evaluate the influence of environmental humidity on petri dish experiments, moist environments were investigated, with over 75% relative humidity to limit water evaporation from solid-state fermentation. The results showed that moist environments gave approximately 1.85 times the reducing sugar yield than dry environments. The process of simultaneous enzymatic hydrolysis of substrates and fungal autolysis were also studied. The degree of hydrolysis was affected by initial fermented solid to liquid ratio, temperature and pH range. The optimal conditions for subsequent hydrolysis of fermented solids were determined. The optimal solid to liquid ratio, 4% (w/w), temperature 50°C and pH 7 were established. The highest final reducing sugar, 8.9 g/L and FAN, 560 mg/L, were measured after 48 h. The fungal autolysis was identified by image analysis as well as by the consumption of nutrient and the release of free amino nitrogen and phosphorous. Solid state fermentation in a multi-layer tray bioreactor and a packed-bed bioreactor were also developed, with moist air supply for oxygen provision and heat removal. Fermented solids in the multi-layer bioreactor led to the highest subsequent hydrolysis yield on reducing sugar, FAN and Inorganic Phosphorous (IP), 222.85 mg/g, 11.56 mg/g and 19.9 mg/g, respectively. These series of fermentation experiments illustrate the feasibility for the application of consolidated bioprocessing, through simultaneous pretreatment and enzyme production as a more economic and environment-friendly process compared with those reported for chemical pretreatment followed by commercial enzyme process. A growth kinetic model regarding both growth and respiration is also proposed. Ethanol production was studied using the generic feedstock produced from sugarcane bagasse and soybean hulls. Total ethanol yield reached 0.31 mg g-1 (61.4% of theoretical yield) after 30 h of submerged fermentation. The result of subsequent fermentation has already shown the potential of the generic microbial feedstock to be used to produce varied products depending on the microorganism utilised.

This study investigated the chemical modification method by citric acid and its enhancement effect on the adsorption capacity of sugarcane bagasse (SB) for copper removal from aqueous solution. Characterization studies were performed by using Fourier transform infra red (FTIR), which showed the introduction of carboxylic group in the structure the modified sugarcane bagasse (MSB). Batch study revealed the influence of pH, time, initial concentration of metal ion on adsorption capacity. The data showed an extremely good fit to Langmuir isotherm model from which the maximum adsorption capacity estimated reached 28.17 mg/g at optimum pH 5.5. Fixed bed column study using the adsorbent MSB confirmed that the breakthrough curves of the adsorption processes were dependent on bed height, initial concentration and flow rate. Linear regression analysis of the data demonstrated that Yoon-Nelson kinetic models were appropriate to explain the breakthrough curves.
Nghiên cứu đã thực hiện biến tính hóa học vật liệu bã mía bằng acid citric và đánh giá khả năng hấp phụ ion Cu(II) trong nước của bã mía (SB) trước và sau biến tính axit citric. Khảo sát cấu trúc vật liệu thông qua phổ hồng ngoại FTIR cho thấy các nhóm chức carboxylic có khả năng hấp phụ kim loại xuất hiện trong vật liệu biến tính. Thí nghiệm mẻ đánh giá sự ảnh hưởng của pH, thời gian và nồng độ của vật liệu tự nhiên và biến tính đến khả năng hấp phụ ion Cu(II). Kết quả của thí nghiệm mẻ phù hợp với mô hình Langmuir với khả năng hấp phụ cực đại đạt 28,17 mg/g tại nồng độ pH tối ưu là 5,5. Kết quả thí nghiệm trên mô hình cột cho thấy đường cong thoát của quá trình hấp phụ của vật liệu biến tính và chưa biến tính phụ thuộc và chiều cao lớp vật liệu, nồng độ ion Cu(II) ban đầu và vận tốc dòng chảy qua cột. Các dữ liệu thu nhận được từ thực nghiệm phù hợp với mô hình động học Yoon-Nelson.

The rapid development of the bioethanol industry globally demonstrates the importance of bioethanol as an alternate energy source to the depleting fossil fuels. To decrease costs and avoid undue pressure on the global food supply, the renewable lignocelluloses appear to be a better substrate for bioethanol production compared to others being investigated. This study investigated the conversion of lignocellulosic material, sugarcane bagasse, to ethanol by the use of Zymomonas mobilis and Pichia stipitis. The investigation of fermentation characteristics of the two strains revealed that their performance on the ethanol production was closely related to the viable cell concentration in the medium. The increase of inoculum size to five fold resulted in an increase in the system co-efficiency to 2.2 fold and 5.2 fold respectively for Z. mobilis and P. stipitis. A theoretical value de (the cell instantaneous ethanol production rate) was introduced to describe the ethanol productivity based on biomass. System co-efficiency proved to be only affected by the viable cell concentration (xC) and de, regardless of ethanol re-assimilation. Immobilized culture of Z. mobilis and P. stipitis showed distinct differences in their characteristics. The bacterium acclimatized to the interior of gel beads; the biomass concentration within the beads increased greater than 10 fold during the reuse of the beads, resulting in an improved fermentation performance. The immobilized P. stipitis gave a similar system co-efficiency level of approximately 0.5 g/l/h under different culture conditions; cell growth in the medium was considerably more vigorous compared to that within the beads. P. stipitis sole-culture on the glucose/xylose medium with a high inoculum size showed a comparable fermentation efficiency with the best result of the co-culture processes. Fermentation of 50.0 g/l of sugar mixture (30.0 g/l glucose and 20.0 g/l xylose) was completed in 20 h with an ethanol yield of 0.44 g/g. No catabolite repression due to glucose was observed for the xylose assimilation. Co-culture of immobilized Z. mobilis and free cells of P. stipitis proved to be the best fermentation scheme on the glucose/xylose sugar mixture co-fermentation. The removal of Z. mobilis after the utilization of glucose improved the stability of the performance. The best result showed that 50.0 g/l sugars were fully converted to ethanol within 19 h, giving an ethanol yield of 0.49 g/g, which is 96% of the theoretical rate. When co-cultured, viable cells of Z. mobilis inhibited the cell activity of P. stipitis, and were capable of growing to high concentration levels without an appropriate carbon source. Acid and enzymatic hydrolysates of sugarcane bagasse showed similar fermentability, but the hydrolysate without overliming significantly inhibited both cell growth and ethanol production of P. stipitis. The co-culture process on the hydrolysate medium successfully utilized 53.56 g/l sugars (32.14 g/l glucose and 21.42 g/l xylose) in 26 h with a yield of 0.43 g/g; this value further increased to 0.49 g/g when ethanol peaked at 40 h. A high cell density proved to be an effective method to improve the system co-efficiency for ethanol production. For the fermentation processes on the sugar medium, results achieved in this study, 10.54 g/l/h for Z. mobilis free cell culture on glucose, 0.755 g/l/h for P. stipitis free cell culture on xylose, 1.092 g/l/h for P. stipites free cell culture on the glucose/xylose mixture and 1.277 g/l/h for glucose/xylose co-fermentation using co-culture, are higher than the best values reported in the literature in batch culture. In the fermentation of the hydrolysate, the system co-efficiency of 0.879 g/l/h achieved with co-culture is comparable to the best values reported for the fermentation of lignocellulosic hydrolysates.

Thesis (M.S. (Hons.))-- University of Western Sydney, 2008.
A thesis sumitted to the University of Western Sydney in fulfilment of the requirements for the degree of Masters of Science (Honours), School of Natural Sciences, College of Health and Science. Includes bibliography.

Lignocellulosics represent a renewable resource for producing fuels and chemicals as an alternative to fossil resources. This study utilised an organic acid catalyst and a co-solvent to develop an environmentally friendly processing technology for the production of levulinic acid and furfural from a waste material, sugarcane fibre.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
A biomassa lignocelulósica contém quantidades significativas de fontes de carbono, sendo assim uma fonte de energia renovável. O presente trabalho teve como objetivo estabelecer meios líquidos e sólidos para o estudo dos efeitos dos inibidores presentes nos hidrolisados do bagaço de cana-de-açúcar e, por fim, estabelecer um coquetel de inibidores que permitisse o crescimento e a fermentação da levedura Saccharomyces cerevisiae no meio líquido estabelecido. Por esta razão, o conjunto de resultados deste trabalho compreende três partes. A primeira parte foi dedicada ao estabelecimento de meios sólidos e líquidos para comparação de leveduras na presença do inibidor mais abundante do hidrolisado do bagaço de cana, o ácido acético. No meio sólido YPD, as diferentes linhagens de leveduras ensaiadas sofreram menos os efeitos inibitórios deste ácido do que o meio sintético solidificado. Em meio líquido, foi necessário adicionar 2% de extrato de levedura para ativar o crescimento da levedura 63M, mas este efeito foi suprimido em presença de ácido acético. As variações em pH inicial (3,5 – 5,5) afetaram mais a produção de etanol do que a biomassa, ao passo que a viabilidade não variou. A segunda parte deste trabalho foi dedicada ao estabelecimento de um meio sintético que permitisse o crescimento e fermentação da linhagem 63M em presença de ácido acético. O aumento de 33% em biomassa na presença de 83 mmol/L de ácido acético foi devido à elevação da glicose (10-18%) e do inóculo (5-10 mg/mL). As concentrações crescentes e variadas de ácido acético em meio sintético foi utilizado para estudar seus efeitos sobre o crescimento (inibição acima de 50 mmol/L), a viabilidade (acima de 250 mmol/L) e a produção de etanol (acima de 83 mmol/L). As concentrações de outros inibidores...
Lignocellulosic biomass contains significant quantities of carbon sources, being a renewable energy source. The aim of the present work was to determine liquid and solid media for the study of the effects of inhibitors present in hydrolysates of sugarcane bagasse, and to establish a cocktail of inhibitors that allow the growth and the fermentation of the yeast Saccharomyces cerevisiae in the liquid medium established. Thus, the results of this work consist of three parts. The first part was dedicated to establishing solid and liquid media in order to compare different yeast strains in the presence of the most abundant inhibitor found in hydrolysates of sugarcane bagasse, the acetic acid. On YPD solid medium, this acid had less inhibitory effect on the different yeast strains tested than on the synthetic solid medium. In liquid medium, it was necessary to add 2% yeast extract to activate the growth of the strain 63M, but this effect was abolished in the presence of acetic acid. Variations in the initial pH (3.5 - 5.5) affected more the ethanol production than the biomass, while the viability was not influenced. The second part of this work was dedicated to establishing a synthetic medium that allows the growth and fermentation of the strain 63M in the presence of acetic acid. The 33% increase in biomass in the presence of 83 mmol/L acetic acid was due to the high glucose concentration (10-18%) and inoculum (5-10 mg/mL) used. The increasing concentrations of acetic acid in the synthetic medium were used to study its effects on growth (inhibition above 50 mmol/L), viability (over 250 mmol/L) and ethanol production (above 83 mmol/L). The concentrations of the other inhibitors had different limits of tolerance by the yeast... (Complete abstract click electronic access below)

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTITUIÇÕES COMUNITÁRIAS DE ENSINO PARTICULARES
O Brasil é o maior produtor de cana-de-açúcar do mundo, produzindo a maior quantidade de resíduo em forma de bagaço, que atualmente é queimado na indústria para geração de energia elétrica, apesar de ainda possuir potencial para produzir outros compostos de maior valor agregado, como etanol de segunda geração, ácido lático, butanodiol e etc. Neste trabalho, foi avaliado o desempenho do pré-tratamento do bagaço de cana-de-açúcar utilizando peróxido de hidrogênio em meio alcalino. Com o intuito de retirar a lignina para liberar os carboidratos no meio, foram realizados experimentos variando a temperatura (25 graus Celsius – 45 graus Celsius) e concentração de peróxido de hidrogênio (1,5 por cento - 7,5 por cento) a pH 11,5 por 1 h em um shaker orbital a 100 rpm. O desempenho do pré-tratamento foi medido utilizando o método gravimétrico de Klason para quantificar a lignina, o HPLC para determinar as concentrações de xilose e glicose e o infravermelho para determinar mudanças na estrutura da biomassa. A análise de Klason indicou 45 graus Celsius /7,5 por cento como melhor condição de solubilização, com 75,4 por cento de solubilização, as análises de HPLC indicaram 45 graus Celsius/7,5 por cento como melhor condição para a obtenção de glicose com concentração de 1,66 g/L e 25 graus Celsius/7,5 por cento para obtenção de xilose com concentração de 0,82 g/L e as análises de FT-IR indicaram 25 graus Celsius /1,5 por cento como melhor condição de oxidação, com 66,9 por cento de oxidação de lignina. Para cada análise, foi proposto um modelo de rede neural artificial. A rede das análises de Klason teve a topologia trainlm/logsig/4 com SSE 0,00723 e R2 0,995, a rede das análises de glicose teve topologia trainlm/logsig/4 com SSE 0,0328 e R2 0,97384, a rede das análises de xilose teve topologia trainlm/logsig/5 com SSE 0,289 e R2 0,87441 e a rede das análises de FT-IR teve topologia trainlm/logsig/5 com SSE 0,0316 e R2 0,98414.
Brazil leads the world in sugarcane production, consequently produces also the greatest amount of sugarcane bagasse. Currently, this sugarcane bagasse is leveraged for power generation in the mills, but this biomass still has a potential for production of others value-added compounds such as the second-generation ethanol, lactic acid, butanediol and etc. The present work was carried out in order to study the efficiency of the delignification process of sugarcane bagasse with alkaline hydrogen peroxide. Two variable were assessed experimentally: temperature (25 Celsius degrees - 45 Celsius degrees) and H2O2 concentration (1.5 percent -7.5 percent) at pH 11.5 for 1 h in an orbital shaker at 100 rpm. The Klason Method was used to measure concentration of extracted lignin, HPLC was used to measure the concentration of glucose and xylose and FT-IR analysis was applied to identify lignin structure in the samples. The Klason analysis indicated the 45 Celsius degrees/7,5 percent as the optimum condition with 75,4 percent of the lignin solubilidized, the glucose analysis indicated 45 Celsius degrees/7,5 percent as the optimum condition with a concentration of 1,66 g/L, the xylose analysis indicated 25 Celsius degrees/7,5 percent as the optimum condition with a concentration of 0,82 g/L, and the FT-IR analysis indicated 25 Celsius degrees/1,5 percent as the optimum condition with 66,9 percent of the lignin oxidized. For each analysis, an ANN model was proposed. The network of the Klason analysis had a trainlm/logsig/4 topology with SSE 0,00723 and R2 0,995, the network of the glucose analysis had a trainlm/logsig/4 topology with SSE 0,0328 and R2 0,97384, the network of the xylose analysis had a trainlm/logsig/5 topology with SSE 0,289 and R2 0,87441, the network of the FT-IR analysis had a trainlm/logsig/5 topology with SSE 0,0316 and R2 0,98414.

Renewable energy sources have been proposed as a viable option to mitigate the consumption and the dependence of fossil fuels. Among the available alternatives, lignocellulosic biomass has shown great potential for bioenergy generation, and biofuels as ethanol can be obtained by fermentation from sugars present in cellulosic and hemicellulosic fractions of biomass. However, for the efficient release of fermentable sugars during the enzymatic hydrolysis step, a pretreatment process is required to modify the material in its structure and composition. In this context, hydrodynamic cavitation (HC) was proposed in this work as a new and promising alternative for pretreatment of sugarcane bagasse. Firstly, the variables NaOH concentration, solid/liquid (S/L) ratio and HC process time were optimized in HC assisted pretreatment. In optimized conditions (0.48 mol/L of NaOH, 4.27% of S/L ratio and 44.48 min), high lignin removal (60.4%) and enzymatic digestibility of cellulose fraction (97.2%) were obtained. Based in those results, new variables (inlet pressure, temperature, alkali concentration) were included for evaluation in a second stage of the study aiming to reduce the HC pretreatment time. In this case, temperature and álcali concentration showed more significance on lignin removal and hydrolysis yield of carbohydrate fraction in pretreated biomass. No significant difference in pretreatment efficiency was observed in 20 and 30 min of process time in the best conditions (70 °C, 3 bar of inlet pressure and 0.3 mol/L of NaOH). The dimensionless cavitation number influence also was evaluated in two levels (0.017 and 0.048), resulting higher efficiency using low cavitation number which was obtained using orifice plate with 16 holes (1 mm of diameter). Using the last optimized conditions and lower temperature (60 °C instead 70 °C) in order to avoid the foam formation when black liquor is reused, other alkalis (Ca(OH)2, Na2CO3, KOH) were evaluated in combination with HC and compared to the use of NaOH. High enzymatic conversions of carbohydrate fraction were observed in biomass pretreated using KOH-HC and NaOH-HC; additionally, NaOH black liquor was reused in 10 sequential batches. The pretreated biomass using fresh and reused black liquor were mixed and used for simultaneous saccharification and fermentation process (SSF) in interconnected column reactors, resulting in 62.33% of hydrolysis of total carbohydrate fractions and 17.26 g/L of ethanol production (0.48 g of ethanol/g of glucose and xylose consumed). Finally, the addition of oxidant agent (H2O2) in the alkali HC-process was optimized. In selected conditions (0.29 mol/L of NaOH, 0.78 % v/v of H2O2 and 9.8 min), 95,43% and 81.34% of enzymatic hydrolysis yield of cellulose and hemicellulose fraction were achieved respectively, using 5% of solid loading (S/L) in the hydrolysis process. When packed bed flow-through column reactor using 20% of S/L was used, 74.7% cellulose hydrolysis yield was reached. Sugars present in hydrolysate were also fermented into ethanol in bubble column reactor resulting in a yield value of 0.49 g/g and 0.68 g/L.h of productivity. By analyzing the results as a whole, HC was shown as a promising technology to accelerate the pretreatment time under mild conditions, showing advantages as simplicity of system and possibility to application in industrial scale.
O uso de fontes de energia renováveis tem sido proposto como uma alternativa viável para reduzir o consumo e a dependência de combustíveis fósseis. Entre as alternativas disponíveis, a biomassa lignocelulósica apresenta grande potencial para geração de bioenergia, sendo que biocombustíveis como o etanol podem ser obtidos por fermentação a partir de açúcares presentes em suas frações celulósicas e hemicelulósicas. No entanto, para a liberação eficiente de açúcares fermentáveis na etapa de hidrólise enzimática, é necessário um processo prévio de pré-tratamento para modificar a estrutura e composição do material. Neste contexto, no presente trabalho a cavitação hidrodinâmica (CH) foi proposta como uma nova e promissora alternativa para o pré-tratamento do bagaço de cana-de-açúcar. Em uma primeira etapa, as variáveis concentração de NaOH, relação sólido/líquido (S/L) e tempo de processo foram otimizadas no pré-tratamento assistido por CH. Em condições otimizadas (0,48 mol/L de NaOH, 4,27% de relação S/L e 44,48 min), elevados valores de remoção de lignina (60,4%) e digestibilidade enzimática da fração de celulose (97,2%) foram obtidos. Com base nesses resultados, novas variáveis (pressão à montante, temperatura e concentração de álcali) foram incluídas para avaliação em uma segunda etapa do estudo com o objetivo de reduzir o tempo de pré-tratamento com CH. Neste caso, a temperatura e a concentração de álcalis foram as mais importantes na remoção de lignina e influenciaram na hidrólise das frações carboidrato da biomassa pré-tratada. Não houve diferença significativa na eficiência do pré-tratamento em 20 e 30 minutos de tempo de processo nas melhores condições (70 ° C, 3 bar de pressão a montante e 0,3 mol/L de NaOH). A influência do adimensional -número de cavitação? também foi avaliada em dois níveis (0,017 e 0,048), resultando em maior eficiência usando o número de cavitação mais baixo, que foi obtido usando placa de orifício com 16 furos (1 mm de diâmetro). Usando estas condições otimizadas e menor temperatura (60 ° C ao invés de 70 ° C) para evitar a formação de espuma quando o licor negro é reutilizado, outros álcalis (Ca (OH)2, Na2CO3, KOH) foram avaliados em combinação com CH e comparados com o uso de NaOH. Conversões enzimáticas elevadas das frações carboidrato foram observadas em material pré-tratado utilizando KOH-CH e NaOH-CH; além disso, o licor negro de NaOH foi reutilizado em 10 bateladas sequenciais. As biomassas pré-tratadas com licor negro reutilizado e fresco foram misturadas e utilizadas em processo de sacarificação e fermentação simultâneas (SSF) em reatores de coluna interligados, resultando em 62,33% de hidrólise das frações carboidrato e 17,26 g/L de produção de etanol (0,48 g de etanol/g de glicose e xilose consumidos). Finalmente, a adição de agente oxidante (H2O2) no processo alcalino-CH foi otimizado. Nas condições selecionadas (0,29 mol/L de NaOH, 0,78% v/v de H2O2 e 9,8 min), 95,43% e 81,34% de rendimento de hidrólise enzimática das frações de celulose e hemicelulose, respectivamente, foram obtidos utilizando 5% de carregamento de sólidos (S/L) no processo de hidrólise. Quando foi utilizado reator de coluna de leito fixo com 20% de S/L, atingiu-se 74,7% de rendimento de hidrólise de celulose. Os açúcares presentes no hidrolisado também foram fermentados em etanol em um reator de coluna de bolhas, resultando em um valor de rendimento de 0,49 g/g e 0,68 g/L.h de produtividade. Analisando-se os resultados de uma forma global, demonstrou-se que a CH é uma tecnologia promissora para acelerar o tempo de pré-tratamento em condições amenas, mostrando vantagens como simplicidade do sistema e possibilidade de aplicação em escala industrial.

The aim of this study was to optimize methane production by investigating hydrothermal pretreatment of sugarcane bagasse impregnated with acid (H2SO4) and alkaline H2O2 using substrate (g kg-1) -inoculum (g kg-1) ratio of 1:2. Batch reactors were realized under mesophilic conditions (37 °C). A central composite design (CCD) involving three factors; temperature (°C), time (min), and chemical compound concentration (H2O2 (%v/v) and H2SO4 (%w/v)) was utilized to optimize hydrothermal pretreatment. Thirty-two hydrothermal pretreatments were conducted according to CCD. H2O2 assisted hydrothermal pretreatment resulted in higher solid recovery (93.13%), higher percent glucan increase (139.52%), and lower lignin recovery (76.48%) in pretreated solid fraction in comparison to H2SO4 impregnated hydrothermal pretreatment. In the latter case, lower solid yield (12.27%), glucan recovery (187.01%) and higher lignin recovery (358.85%) was recorded. Higher COD solubilization (25.20 g L-1), lower total phenolic (content 658.13 ppm), higher sulfate (7240 mg L-1), furfural (925.77-2216.47 mg L-1) and 5-hydroxymehtylfurfural (70.95-970.08 mg L-1) were observed in liquid hydrolysate of H2SO4 assisted hydrothermal pretreatment. While lower COD solubilization (17.75 mg L-1), higher total phenolic content (3005.63 ppm), lower concentration of furfural (0-56.91 mg L-1) and 5-hydroxymethylfurfural (2.56-56.60 mg L-1) was recorded with H2O2 assisted hydrothermal pretreatment. Concerning methane production for H2O2 assisted conditions, 5.59 Nmmol g-1 TVS (2% H2O2) to 13.49 Nmmol g-1 TVS (6% H2O2) was recorded. However, pretreatment with 7.36% H2O2 resulted in 14.43 Nmmol g-1 TVS, which was 118.16% higher comparing to untreated sugarcane bagasse (6.60 Nmmol g-1 TVS). Methanogenic inhibition was recorded for most of the H2SO4.pretreated reactor (1 – 3 %w/v H2SO4). Minimum CH4 production observed was 0.58 Nmmol g-1 TVS in pretreatment O-HSO (2% w/v H2SO4). Acetic acid was the predominant volatile fatty acid observed in digestion process of H2O2 treated batch reactor however was not recorded in H2SO4 treated batch reactors. Microbial community analysis indicated the prevalence of unclassified AUTHM297, Clostridium, and Treponema related genera in H2O2 treated reactors. Genera related aromatic compound degradation were identified and abundant in H2SO4 treated reactors. Methanolinea, Methanobacterium, and Methanosaeta were abundant methanogens in both pretreatments. Hydrogen peroxide assisted hydrothermal pretreatment was verified as a better choice for methane production comparing to sulfuric acid assisted hydrothermal pretreatment primarily on account of higher lignin solubilization, higher glucan recovery, and lower furanic compounds production.
O objetivo deste estudo foi otimizar a produção de metano investigando as condições do pré-tratamento hidrotérmico assistido do bagaço da cana de açúcar sob impregnação de ácido (H2SO4) e álcali (H2O2) utilizando-se a razão substrato (g kg-1) inóculo (g kg-1) de 1:2. Os reatores em batelada foram mantidos em condições mesofílicas (37 ºC). Para otimizar as condições de pré-tratamento hidrotérmico, o design de composto central rotacional (DCCR) foi realizado utilizando três fatores: temperatura (ºC), tempo (min) e concentração do composto químico (H2O2 (%v/v) e H2SO4 (% p/v)). Trinta e dois pré-tratamentos hidrotérmicos foram realizados de acordo com a concepção do DCCR. O pré-tratamento hidrotérmico assistido do bagaço, com H2O2 resultou em maior recuperação de sólidos (93,13%), elevado percentual de glicana (139,52%) e menor recuperação de lignina (76,48%) da fração sólida pré-tratada, se comparada aquele com H2SO4. Nesse último caso, observou-se menor rendimento de sólidos (12,27%) e glucanas (187,01%) e maior recuperação de lignina (358,85%). No líquido hidrolisado do pré-tratamento hidrotérmico assistido do bagaço com H2SO4 foi observada elevada solubilização de DQO (25,20 g L-1), menor teor de fenóis totais (658,13 mg L-1), elevado sulfato (7240 mg L-1), furfural (925,77 - 2216,47 mg L-1 e 5-hidroximetilfurfural (70,95 - 970,08 mg L-1). Enquanto, foi registrado menor solubilização de DQO (17,27 g L-1), maior teor de fenóis totais (3005,63 ppm), e menor concentração de furfural (0 - 56.91 mg L-1), 5-hidroximetilfurfural (2,56 - 50,60 mg L--1 com H2O2. Em relação ao a produção de metano nas condições com H2O2, observou-se 5.59 Nmmol g-1 STV (2%v/v H2O2) a 13.49 Nmmol g-1 STV (6%v/v H2O2). No tratamento com 7.36% de H2O2 observou-se 14,43 Nmmol g-1 STV que foi 118.16% maior se comparado com o bagaço não-tratado (6,60 Nmmol g-1 STV). Inibição metanogênica foi observada na maioria dos reatores pré-tratados com H2SO4 (1 – 3% p/v), e a produção mínima observada foi de 0.58 Nmmol g-1 TVS no pré-tratamento com 2% p/v de H2SO4. Ácido acético foi o principal ácido orgânico volátil observado somente no reatores por tratamento de H2O2. Por meio da A análise da comunidade microbiana, para o domínio Bacteria, foi observado prevalência dos gêneros AUTHM297, Clostridium e Treponema nos reatores cujo substrato foi pré-tratado com H2O2. Gêneros relacionados à degradação de compostos aromáticos foram identificados e estiveram em maior abundância nos reatores cujo substrato foi pré-tratado com H2SO4. Methanolinea, Methanobacterium, e Methanosaeta foram os microrganismos do domínio Archaea mais abundantes e identificados em ambos os pré-tratamentos. O pré-tratamento hidrotérmico assistido com H2O2 foi a melhor opção em relação ao H2SO4, devido a maior solubilização de lignina, maior recuperação de glucano e baixa produção de compostos furânicos.

This document studies the stabilization of the soil used as a subgrade, by adding locally available materials such as rice husk ash (RHA) and sugarcane bagasse ash (SCBA). These aggregates were added to the soil in substitution by weight between 5%, 7.5% and 10%. By adding these, the expansiveness is reduced while the maximum dry density increases, in addition the tendency of CBR is increasing and then tends to decrease proportionally to the addition of the aforementioned aggregates. This indicates a peak in CBR and expandability. The best result obtained from CBR was 33.75% with the 5% replacement mixtures.

Les résidus de biomasse, comme la bagasse de canne à sucre, ont un grand potentiel pour fournir des sources d’énergie renouvelables. Cependant, ses propriétés naturelles telles que sa faible densité, son faible pouvoir calorifique et sa sensibilité à la biodégradation peuvent limiter son utilisation. Pour améliorer son efficacité énergétique, la pyrolyse lente–processus de décomposition thermique dans un environnement pauvre en oxygène–peut être appliquée en transformant la biomasse en un charbon riche en carbone. Dans un scénario typique de pyrolyse lente, la biomasse est lentement chauffée pour produire principalement du charbon, dont les vapeurs organiques sont souvent considérées comme des produits secondaires. Cependant, il y a un intérêt à récupérer ce sous-produit en condensant la vapeur organique générée pendant la pyrolyse à des fins diverses. De plus, ce produit a une longue histoire en raison de ses avantages en tant que bio-pesticide utilisé par les agriculteurs traditionnels, notamment dans les pays asiatiques. Dans cette étude, la bagasse a été pyrolysée pour co-produire du charbon et du liquide de pyrolyse (huile de pyrolyse) en utilisant un réacteur de laboratoire à lit fixe. Différents paramètres ont été testés, tels que les températures (400 °C et 500 °C), la vitesse de chauffe (1 °C/min et 10 °C/min) et le temps de séjour (30 min et 60 min). Cette étude vise à évaluer le potentiel de valorisation de la bagasse dans le but de densifier l’énergie (conversion de la biomasse en charbon) et de valoriser l’utilisation de son sous-produit (liquide de pyrolyse) pour la protection du bois. Les résultats ont montré que le rendement en charbon diminue avec l’augmentation de la température de pyrolyse mais entraîne une amélioration favorable du pouvoir calorifique; tout en générant une masse élevée de rendement liquide. Les conditions de pyrolyse optimales pour co-produire le charbon et le liquide de pyrolyse étaient la température de 500 °C et la vitesse de chauffe de 10 °C/min, donnant 28,97% de charbon et 55,46% de liquide. Les principaux composés du liquid de pyrolyse étaient l’eau, l’acide acétique, le glycolaldéhyde, la 1-hydroxy-2-propanone, le méthanol, l’acide formique, le lévoglucosane, le furfural, suivis de quelques composés phéno- liques et de dérivés du guaiacol. Le liquid de pyrolyse présente également une activité anti-fongique et anti-termite à des concentrations relativement faibles dans les essais biologiques sur boîtes de Pétri. Lorsqu’il est traité au bois de hêtre et de pin, le liquid de pyrolyse indique une bonne protection contre les termites (Reticulitermes flavipes) et les champignons Basidiomycete (Coniophora puteana et Rhodonia placenta, une pourriture cubique et Trametes versicolor, une pourriture fibreuse) à une concentration de 50% et 100%. Cependant, il reste lessivée lorsqu’il est exposé à l’eau ou à une forte humidité, ce qui indique que des études futures devraient être menées pour trouver comment diminuer sa lessivabilité.Mots clés: biomasse, charbon, pyrolyse lente, bagasse de canne à sucre, liquide de pyrolyse, protection du bois
Biomass residue—such as sugarcane bagasse—has great potential in providing renewable energy sources. However, its natural properties such as low density, low calorific value, and biodegradation susceptibility can limit its utilization. To improve its energy efficiency, slow pyrolysis—the process of thermal decomposition in an oxygen-deficient environment—can be applied by transforming the biomass into carbon-rich char. In a typical slow pyrolysis scenario, biomass is slowly heated to produce mainly char, where the organic vapors are often considered secondary products. However, there is an interest to recover this by-product by condensing the organic vapor generated during pyrolysis for various purposes. Moreover, this product has a long history due to its benefits as a bio-pesticide used by traditional farmers, notably in Asian countries. In this study, bagasse was slow-pyrolyzed to co-produce char and pyrolysis liquid using a laboratory fixed bed reactor. Different parameters were tested, such as temperatures (400 °C and 500 °C), heating rate (1 °C/min and 10 °C/min), and holding time (30 min and 60 min). This study aims to evaluate the valorization potential of bagasse with the purpose of energy densification (conversion of biomass into char) and valorizing the utilization of its by-product (pyrolysis liquid) for wood protection.Results showed that the yield of char decrease with the increase of pyrolysis temperature but results in the favorable calorific value improvement; while at the same time generating a high mass of liquid yield. The optimum pyrolysis condition to co-produce char and pyrolysis liquid was at 500 °C temperature and 10 °C/min of heating rate, yielding 28.97% char and 55.46% liquid. The principal compounds of pyrolysis liquid were water, acetic acid, glycolaldehyde, 1-hydroxy-2-propanone, methanol, formic acid, levoglucosan, furfural, followed by some phenol compounds and guaiacol derivatives. Pyrolysis liquid also exhibits anti-fungal and anti-termite activity at relatively low concentrations in the Petri-dishes bioassays. When treated to beech and pine wood, pyrolysis liquid indicates good protection towards termites (Reticulitermes flavipes) and Basidiomycete fungi (Coniophora puteana and Rhodonia placenta, cubic rot and Trametes versicolor, a fibrous rot) at concentration 50% and 100%. However, it remains leachable when exposed to water or high humidity, which indicates that future studies should be conducted to find out how to decrease its leachability.Keywords: biomass, char, slow pyrolysis, sugarcane bagasse, pyrolysis liquid, wood protection

As oil use increases at a rate unsustainable for the environment and unmatchable by current levels of oil production, a major shift towards renewable energy is necessary. By expanding the current knowledge of lignin biosynthesis and its manipulation in sugarcane, this PhD contributes to the production of economically viable second generation bioethanol, a fuel produced from plant biomass. The findings of this thesis contribute to the limited knowledge of lignin biosynthesis and deposition in sugarcane, and the application of biotechnology to produce sugarcane, and the resulting bagasse, with a modified cell wall. Reducing or modifying the lignin content in the cell wall of bagasse can reduce production costs and increase yields of bioethanol. This makes bioethanol more economically competitive with oil as an alternative energy source. A move to using bioethanol over fossil based transport fuels will have global economic and environmental benefits.

This project modelled a thermal liquefaction industrial facility for biofuel production from sugarcane bagasse using the process modelling software ASPEN Plus. Techno-economic models of liquefaction, pyrolysis and gasification processes were completed to assess the comparative feasibility of these thermochemical biofuel production processes. Model liquefaction biocrudes, were developed in ASPEN Plus using simulated distillation data and this method's utility in modelling biocrudes was validated.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O bioetanol é um combustível produzido por meio da fermentação do açúcar do caldo da cana, que representa apenas um terço do carbono (energia), presente na planta. Atualmente, estão sendo feitos esforços para o aproveitamento do restante da biomassa, divididos entre as folhas e bagaço do colmo. Esta biomassa lignocelulósica poderia ser aproveitada para produção de etanol, desde que submetida a processos hidrolíticos químicos (ácidos e bases) e enzimáticos gerando açúcares fermentescíveis. Pela fermentação alcoólica é possível a produção de etanol a partir da mistura de açúcares liberados. Neste trabalho procurou-se a padronização de procedimentos para avaliar o pré-tratamento físico e químico do bagaço da cana-de-açúcar, aliado a diferentes tratamentos térmicos a partir de duas granulometrias de bagaço (1,1 e 2,5 mm). Para o delineamento experimental, utilizou-se tratamentos ajustados em fatorial 4 X 5, sendo que as variáveis foram a influência do tempo de pré-tratamento (0, 15, 30, 45 e 60 minutos) e concentração de ácido sulfúrico (H2SO4) a 7 e 9%. Estes fatores exerceram influência sobre o desempenho da pré-hidrólise, medido pela liberação açúcares redutores (AR) na solução e a % de espécies químicas no bagaço prétratado
Bioethanol fuel is produced through the fermentation of sugar cane juice, which representes only a third of the carbon (energy) present in the plant. Currently, efforts are being made to the use of the remaining biomass, divided among the leaves and seed stalk. This lignocellulosic biomass could be used for ethanol production, provided that undergo hydrolytic process chemicals (acids and bases) and enzymatic generating fermentable sugars. For fermentation is possible to produce ethanol from mixed sugars released. This research is the standardization of procedures to assess the pre-treatment physical and chemical properties of bagasse from sugar cane, coupled with different thermal treatments from two particle sizes of mulch (1,1 and 2,5 mm). For this experiment, we used adjusted treatments in a factorial 4 x 5, and the variables were the influence of time of pretreatment (0, 15, 30, 45 and 60 minutes) And concentration of sulfuric acid (H2SO4) 7 and 9%. These factors have exerted influence on the performance of pre-hydrolysis, measured by the release sugars (RS) in the solution, and% of chemical species in the pretreated bagasse

Orientador : Yong Kun Park
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola
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Resumo: A informação apresentada neste trabalho mostra os resultados da pesquisa na produção de glicose e xilose do bagaço de cana de açúcar e sua subsequente fermentação a -etanol peIa levedura PaehysoZen tannophiZus NRRL y-2460. O bagaço de cana de açúcar foi submetido a processos de pré-tratamentos com alcali e de explosão -autohidrólise antes da sua sacarificação enzimática e ácida com celulases do Triehoderma reesei QM 94Z4 e com solução 5% de H2S04, respectivamente. Quando o bagaço de cana de açúcar foi tratada a 2000C durante 4,0 minutos com uma relação água: bagaço de 8:1, o rendimento de extração da hemicelulose pelo pré-tratamento, com alcali, forneceu uma fração fermentecível a etanol. Após a neutralização da solução até pH 5,0, a hemicelulose foi recuperada do filtrado obtido no pré-tratamento com alcali por uma precipitação com álcool etilico (95%), seguido de um processo de deslignificação com etanol à 700C por 4 horas. Ambas frações de hemicelulose, do processo de explosão - autohidrólise (fração IV) e do pré-tratamento com alcali (fração 11) foram submetidos a uma hidrólise ácida e enzimática. A sacarificação foi inibida por substâncias de baixo peso molecular não voláteis, introduzidas pelo processo de explosão-autohidrólise do bagaço de cana de açúcar. Estas substâncias inibidoras foram eliminadas por um processo de diálise. A eficiência da sacarificação foi de 36-94%, depedendo da concentração de sólidos presentes no líquido de autohidrólise. O maior grau de sacarificação correspondeu a fração de hemicelulose obtida pelo pré-tratamento alcalino (fração II) seguida da fração de hemicelulose dialisada, obtida pelo processo de explosão-autohidrólise (fração IV). A levedura pachysoLen tannophiLus NRRL y-2460 foi capaz de transformar a D-xilose, D-glicose e ambos hidrolisados do bagaço de cana de açúcar obtidos de acordo ao indicado acima, a etanol, sob as condições de fermentação de 32oC, 200 rpm., e pH 2,5-3,0. Meios de cultura contendo urna concentração inicial de 24,5 9 de D-xilose/L, rendeu 0,158 9 de etanol/g de D-xilose consumida. Durante a fermentação alcoólica da D-glicose à concentração inicial de 21,5 9 de D-glicose/L, a produção de etanol foi 0,384 g/g de D-glicose consurnida. A fermentação aIcoólica dos hidrolisados enzirnáticosdas frações IV e II do bagaço de cana de açúcar, produziram 0,098 e 0,10 9 de etanol/ 9 de açúcar redutor consumidos resp~ctivamente. Os hidrolisados ácidos destas frações produziram muito pouco ou nada de etanol. Os baixos rendimentosde etanol foram o resultado das condições sub-ótimas de fermentação, principalmente à condição de aeração que favoreceu a formação de biomassa
Abstract: The information presented in this work covers research findings on the pJ:ioduétii'on 'of glucose an xylose from sugar cane bagasse and the subsequentdirect fermentation of those sugars to obtain ethanol by the yeast PaahysoZentannophiZus NRRL y-2460. Sugar cane bagasse was subjected to heat explosion and alkali pre-treatments prior to enzymatic and acid saccharification with T~iahode~ma ~ee8ei QM 94Z4 cellulases and 5% H2S04 solution, respectively. When the sugar cane bagasse was. treated at 2009C for 4 minutes at a water-to-solids ratio of 8:1, the yield of hemicellulose extration was maximum. A sodium hydroxide extration yielded a hemicellulose fraction available for fermentation to ethanol. After the neutralization of the solution to pH 5.0, the hemicelulose was recovered from the liquid filtrates of the alkali pre-treatment, by ethylalcohol (95%) precipitation followed by deslignification with ethanol at 709C for 4 hours. Both hemicellulose fractions from the heat explosion (fraction IV) and alkali pre-treatments (fraction 11), were subjected to enzymatic and acid hydrolyses. The saccharification was inhibited by low molecular weight-non volatile substances, introduced by the heat explosion process of the sugar cane bagasse. Those inhibitory substances were eliminated by a dialyzed processo The saccharification efficie~cy was between 36 and 94%, depending of the solids concentration presen't in the auto-hydrolyzed liquido The highest degree of saccharification corresponded to the hemicellulose fraction obtained by the alkali pre-treatment (fraction lI), fo11owed by the dia1yzed hemice11u1ose rãction obtained from the heat exp1osion process (fraction IV) . The yeast PaahysoZen tannophiZus NRRL y-2460 was found to be capab1e of converting D-xilose, D-g1ucose and both enzymatic hydro1ysates from sugar cane bagasse, obtained by theOabove mentioned pre-treatments, to ethanol under the fermentation conditions of 32QC, 200 rpm and pH 2.5-3.0 Batch cu1ture initia11y containing 24.5 go of D-xylose/t, yie1ded 0.158 9 of ethanol/g of D-xylose consumed. During D-glucose fermentation at an initia1 concentration of. 21.5 9 of D-glucose/L the productti.on of ethanol of the enzymatic hydrolysates of the hemicel1ulose fraction of the sugar cane bagasse, gave 0.098 and 0.10 9 ethanol/g of reducing . sugars consumed for fractions IV and 11, respectively. Both acid hydrolysates of these fractions gave negligible quantities of ethanol. The low yield of ethanol obtained were the.result of the sub-optimal fermentation conditions, particularly the aeration condition through out the process which promote mainly biomass production
Doutorado
Doutor em Ciência de Alimentos

Orientador: Cecília Laluce
Coorientador: Karen F. de Oliveira.
Banca: Sandra Regina Pombeiro Sponchiado
Banca: Nilce maria Martinez Rossi
Resumo: A biomassa lignocelulósica contém quantidades significativas de fontes de carbono, sendo assim uma fonte de energia renovável. O presente trabalho teve como objetivo estabelecer meios líquidos e sólidos para o estudo dos efeitos dos inibidores presentes nos hidrolisados do bagaço de cana-de-açúcar e, por fim, estabelecer um coquetel de inibidores que permitisse o crescimento e a fermentação da levedura Saccharomyces cerevisiae no meio líquido estabelecido. Por esta razão, o conjunto de resultados deste trabalho compreende três partes. A primeira parte foi dedicada ao estabelecimento de meios sólidos e líquidos para comparação de leveduras na presença do inibidor mais abundante do hidrolisado do bagaço de cana, o ácido acético. No meio sólido YPD, as diferentes linhagens de leveduras ensaiadas sofreram menos os efeitos inibitórios deste ácido do que o meio sintético solidificado. Em meio líquido, foi necessário adicionar 2% de extrato de levedura para ativar o crescimento da levedura 63M, mas este efeito foi suprimido em presença de ácido acético. As variações em pH inicial (3,5 - 5,5) afetaram mais a produção de etanol do que a biomassa, ao passo que a viabilidade não variou. A segunda parte deste trabalho foi dedicada ao estabelecimento de um meio sintético que permitisse o crescimento e fermentação da linhagem 63M em presença de ácido acético. O aumento de 33% em biomassa na presença de 83 mmol/L de ácido acético foi devido à elevação da glicose (10-18%) e do inóculo (5-10 mg/mL). As concentrações crescentes e variadas de ácido acético em meio sintético foi utilizado para estudar seus efeitos sobre o crescimento (inibição acima de 50 mmol/L), a viabilidade (acima de 250 mmol/L) e a produção de etanol (acima de 83 mmol/L). As concentrações de outros inibidores... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Lignocellulosic biomass contains significant quantities of carbon sources, being a renewable energy source. The aim of the present work was to determine liquid and solid media for the study of the effects of inhibitors present in hydrolysates of sugarcane bagasse, and to establish a cocktail of inhibitors that allow the growth and the fermentation of the yeast Saccharomyces cerevisiae in the liquid medium established. Thus, the results of this work consist of three parts. The first part was dedicated to establishing solid and liquid media in order to compare different yeast strains in the presence of the most abundant inhibitor found in hydrolysates of sugarcane bagasse, the acetic acid. On YPD solid medium, this acid had less inhibitory effect on the different yeast strains tested than on the synthetic solid medium. In liquid medium, it was necessary to add 2% yeast extract to activate the growth of the strain 63M, but this effect was abolished in the presence of acetic acid. Variations in the initial pH (3.5 - 5.5) affected more the ethanol production than the biomass, while the viability was not influenced. The second part of this work was dedicated to establishing a synthetic medium that allows the growth and fermentation of the strain 63M in the presence of acetic acid. The 33% increase in biomass in the presence of 83 mmol/L acetic acid was due to the high glucose concentration (10-18%) and inoculum (5-10 mg/mL) used. The increasing concentrations of acetic acid in the synthetic medium were used to study its effects on growth (inhibition above 50 mmol/L), viability (over 250 mmol/L) and ethanol production (above 83 mmol/L). The concentrations of the other inhibitors had different limits of tolerance by the yeast... (Complete abstract click electronic access below)
Mestre

This is an experimental study into the permeability and compressibility properties of bagasse pulp pads. Three experimental rigs were custom-built for this project. The experimental work is complemented by modelling work. Both the steady-state and dynamic behaviour of pulp pads are evaluated in the experimental and modelling components of this project. Bagasse, the fibrous residue that remains after sugar is extracted from sugarcane, is normally burnt in Australia to generate steam and electricity for the sugar factory. A study into bagasse pulp was motivated by the possibility of making highly value-added pulp products from bagasse for the financial benefit of sugarcane millers and growers. The bagasse pulp and paper industry is a multibillion dollar industry (1). Bagasse pulp could replace eucalypt pulp which is more widely used in the local production of paper products. An opportunity exists for replacing the large quantity of mainly generic paper products imported to Australia. This includes 949,000 tonnes of generic photocopier papers (2). The use of bagasse pulp for paper manufacture is the main application area of interest for this study. Bagasse contains a large quantity of short parenchyma cells called ‘pith’. Around 30% of the shortest fibres are removed from bagasse prior to pulping. Despite the ‘depithing’ operations in conventional bagasse pulp mills, a large amount of pith remains in the pulp. Amongst Australian paper producers there is a perception that the high quantity of short fibres in bagasse pulp leads to poor filtration behaviour at the wet-end of a paper machine. Bagasse pulp’s poor filtration behaviour reduces paper production rates and consequently revenue when compared to paper production using locally made eucalypt pulp. Pulp filtration can be characterised by two interacting factors; permeability and compressibility. Surprisingly, there has previously been very little rigorous investigation into neither bagasse pulp permeability nor compressibility. Only freeness testing of bagasse pulp has been published in the open literature. As a result, this study has focussed on a detailed investigation of the filtration properties of bagasse pulp pads. As part of this investigation, this study investigated three options for improving the permeability and compressibility properties of Australian bagasse pulp pads. Two options for further pre-treating depithed bagasse prior to pulping were considered. Firstly, bagasse was fractionated based on size. Two bagasse fractions were produced, ‘coarse’ and ‘medium’ bagasse fractions. Secondly, bagasse was collected after being processed on two types of juice extraction technology, i.e. from a sugar mill and from a sugar diffuser. Finally one method of post-treating the bagasse pulp was investigated. The effects of chemical additives, which are known to improve freeness, were also assessed for their effect on pulp pad permeability and compressibility. Pre-treated Australian bagasse pulp samples were compared with several benchmark pulp samples. A sample of commonly used kraft Eucalyptus globulus pulp was obtained. A sample of depithed Argentinean bagasse, which is used for commercial paper production, was also obtained. A sample of Australian bagasse which was depithed as per typical factory operations was also produced for benchmarking purposes. The steady-state pulp pad permeability and compressibility parameters were determined experimentally using two purpose-built experimental rigs. In reality, steady-state conditions do not exist on a paper machine. The permeability changes as the sheet compresses over time. Hence, a dynamic model was developed which uses the experimentally determined steady-state permeability and compressibility parameters as inputs. The filtration model was developed with a view to designing pulp processing equipment that is suitable specifically for bagasse pulp. The predicted results of the dynamic model were compared to experimental data. The effectiveness of a polymeric and microparticle chemical additives for improving the retention of short fibres and increasing the drainage rate of a bagasse pulp slurry was determined in a third purpose-built rig; a modified Dynamic Drainage Jar (DDJ). These chemical additives were then used in the making of a pulp pad, and their effect on the steady-state and dynamic permeability and compressibility of bagasse pulp pads was determined. The most important finding from this investigation was that Australian bagasse pulp was produced with higher permeability than eucalypt pulp, despite a higher overall content of short fibres. It is thought this research outcome could enable Australian paper producers to switch from eucalypt pulp to bagasse pulp without sacrificing paper machine productivity. It is thought that two factors contributed to the high permeability of the bagasse pulp pad. Firstly, thicker cell walls of the bagasse pulp fibres resulted in high fibre stiffness. Secondly, the bagasse pulp had a large proportion of fibres longer than 1.3 mm. These attributes helped to reinforce the pulp pad matrix. The steady-state permeability and compressibility parameters for the eucalypt pulp were consistent with those found by previous workers. It was also found that Australian pulp derived from the ‘coarse’ bagasse fraction had higher steady-state permeability than the ‘medium’ fraction. However, there was no difference between bagasse pulp originating from a diffuser or a mill. The bagasse pre-treatment options investigated in this study were not found to affect the steady-state compressibility parameters of a pulp pad. The dynamic filtration model was found to give predictions that were in good agreement with experimental data for pads made from samples of pretreated bagasse pulp, provided at least some pith was removed prior to pulping. Applying vacuum to a pulp slurry in the modified DDJ dramatically reduced the drainage time. At any level of vacuum, bagasse pulp benefitted from chemical additives as quantified by reduced drainage time and increased retention of short fibres. Using the modified DDJ, it was observed that under specific conditions, a benchmark depithed bagasse pulp drained more rapidly than the ‘coarse’ bagasse pulp. In steady-state permeability and compressibility experiments, the addition of chemical additives improved the pad permeability and compressibility of a benchmark bagasse pulp with a high quantity of short fibres. Importantly, this effect was not observed for the ‘coarse’ bagasse pulp. However, dynamic filtration experiments showed that there was also a small observable improvement in filtration for the ‘medium’ bagasse pulp. The mechanism of bagasse pulp pad consolidation appears to be by fibre realignment. Chemical additives assist to lubricate the consolidation process. This study was complemented by pulp physical and chemical property testing and a microscopy study. In addition to its high pulp pad permeability, ‘coarse’ bagasse pulp often (but not always) had superior physical properties than a benchmark depithed bagasse pulp.

This is an experimental study into the permeability and compressibility properties of bagasse pulp pads. Three experimental rigs were custom-built for this project. The experimental work is complemented by modelling work. Both the steady-state and dynamic behaviour of pulp pads are evaluated in the experimental and modelling components of this project. Bagasse, the fibrous residue that remains after sugar is extracted from sugarcane, is normally burnt in Australia to generate steam and electricity for the sugar factory. A study into bagasse pulp was motivated by the possibility of making highly value-added pulp products from bagasse for the financial benefit of sugarcane millers and growers. The bagasse pulp and paper industry is a multibillion dollar industry (1). Bagasse pulp could replace eucalypt pulp which is more widely used in the local production of paper products. An opportunity exists for replacing the large quantity of mainly generic paper products imported to Australia. This includes 949,000 tonnes of generic photocopier papers (2). The use of bagasse pulp for paper manufacture is the main application area of interest for this study. Bagasse contains a large quantity of short parenchyma cells called ‘pith’. Around 30% of the shortest fibres are removed from bagasse prior to pulping. Despite the ‘depithing’ operations in conventional bagasse pulp mills, a large amount of pith remains in the pulp. Amongst Australian paper producers there is a perception that the high quantity of short fibres in bagasse pulp leads to poor filtration behaviour at the wet-end of a paper machine. Bagasse pulp’s poor filtration behaviour reduces paper production rates and consequently revenue when compared to paper production using locally made eucalypt pulp. Pulp filtration can be characterised by two interacting factors; permeability and compressibility. Surprisingly, there has previously been very little rigorous investigation into neither bagasse pulp permeability nor compressibility. Only freeness testing of bagasse pulp has been published in the open literature. As a result, this study has focussed on a detailed investigation of the filtration properties of bagasse pulp pads. As part of this investigation, this study investigated three options for improving the permeability and compressibility properties of Australian bagasse pulp pads. Two options for further pre-treating depithed bagasse prior to pulping were considered. Firstly, bagasse was fractionated based on size. Two bagasse fractions were produced, ‘coarse’ and ‘medium’ bagasse fractions. Secondly, bagasse was collected after being processed on two types of juice extraction technology, i.e. from a sugar mill and from a sugar diffuser. Finally one method of post-treating the bagasse pulp was investigated. The effects of chemical additives, which are known to improve freeness, were also assessed for their effect on pulp pad permeability and compressibility. Pre-treated Australian bagasse pulp samples were compared with several benchmark pulp samples. A sample of commonly used kraft Eucalyptus globulus pulp was obtained. A sample of depithed Argentinean bagasse, which is used for commercial paper production, was also obtained. A sample of Australian bagasse which was depithed as per typical factory operations was also produced for benchmarking purposes. The steady-state pulp pad permeability and compressibility parameters were determined experimentally using two purpose-built experimental rigs. In reality, steady-state conditions do not exist on a paper machine. The permeability changes as the sheet compresses over time. Hence, a dynamic model was developed which uses the experimentally determined steady-state permeability and compressibility parameters as inputs. The filtration model was developed with a view to designing pulp processing equipment that is suitable specifically for bagasse pulp. The predicted results of the dynamic model were compared to experimental data. The effectiveness of a polymeric and microparticle chemical additives for improving the retention of short fibres and increasing the drainage rate of a bagasse pulp slurry was determined in a third purpose-built rig; a modified Dynamic Drainage Jar (DDJ). These chemical additives were then used in the making of a pulp pad, and their effect on the steady-state and dynamic permeability and compressibility of bagasse pulp pads was determined. The most important finding from this investigation was that Australian bagasse pulp was produced with higher permeability than eucalypt pulp, despite a higher overall content of short fibres. It is thought this research outcome could enable Australian paper producers to switch from eucalypt pulp to bagasse pulp without sacrificing paper machine productivity. It is thought that two factors contributed to the high permeability of the bagasse pulp pad. Firstly, thicker cell walls of the bagasse pulp fibres resulted in high fibre stiffness. Secondly, the bagasse pulp had a large proportion of fibres longer than 1.3 mm. These attributes helped to reinforce the pulp pad matrix. The steady-state permeability and compressibility parameters for the eucalypt pulp were consistent with those found by previous workers. It was also found that Australian pulp derived from the ‘coarse’ bagasse fraction had higher steady-state permeability than the ‘medium’ fraction. However, there was no difference between bagasse pulp originating from a diffuser or a mill. The bagasse pre-treatment options investigated in this study were not found to affect the steady-state compressibility parameters of a pulp pad. The dynamic filtration model was found to give predictions that were in good agreement with experimental data for pads made from samples of pretreated bagasse pulp, provided at least some pith was removed prior to pulping. Applying vacuum to a pulp slurry in the modified DDJ dramatically reduced the drainage time. At any level of vacuum, bagasse pulp benefitted from chemical additives as quantified by reduced drainage time and increased retention of short fibres. Using the modified DDJ, it was observed that under specific conditions, a benchmark depithed bagasse pulp drained more rapidly than the ‘coarse’ bagasse pulp. In steady-state permeability and compressibility experiments, the addition of chemical additives improved the pad permeability and compressibility of a benchmark bagasse pulp with a high quantity of short fibres. Importantly, this effect was not observed for the ‘coarse’ bagasse pulp. However, dynamic filtration experiments showed that there was also a small observable improvement in filtration for the ‘medium’ bagasse pulp. The mechanism of bagasse pulp pad consolidation appears to be by fibre realignment. Chemical additives assist to lubricate the consolidation process. This study was complemented by pulp physical and chemical property testing and a microscopy study. In addition to its high pulp pad permeability, ‘coarse’ bagasse pulp often (but not always) had superior physical properties than a benchmark depithed bagasse pulp.

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Orientador: Sandra Regina Pombeiro Sponchiado
Co-orientador: Rubens Monti
Banca: Heloiza Ferreira Alves do Prado
Banca: Luis Henrique Souza Guimarães
Banca: Sarita Candida Rabelo
Banca: Sandra Helena Cruz
Resumo: Não disponível.
Abstract: Not available.
Doutor

Orientador: Jorge Luís Akasaki
Banca: Haroldo de Mayo Bernardes
Banca: Malik Cheriaf
Resumo: O setor sucro-alcooleiro vem se expandindo nos últimos tempos, alavancado principalmente pelo advento da bioenergia. No Brasil, a produção de cana-de-açúcar vem avançando em áreas destinadas à pecuária extensiva e a outras culturas importantes como a soja, o milho e a laranja e concerne à geração de energia elétrica pela queima do bagaço (cogeração) e ao uso de etanol como combustível de veículos automotores. Contudo, a produção de açúcar, álcool e energia a partir da cana-de-açúcar pode causar problemas ambientais em decorrência da geração de resíduos como a cinza do bagaço de cana-de-açúcar. Diante do panorama mundial de crescimento do setor sucro-alcooleiro aliado ao desenvolvimento sustentável, é de grande importância a realização de estudos que visem o aproveitamento destes resíduos. Deste modo, este trabalho mostra a viabilidade técnica da utilização da cinza resultante do processo de queima do bagaço para a geração de energia como adição mineral, em argamassas. Foram realizados ensaios de caracterização química, difração de raios-X, microscopia eletrônica de varredura e atividade pozolânica da cinza do bagaço de cana-deaçúcar. Além disto, um estudo da moagem do material foi realizado, juntamente com a composição de argamassas contendo a cinza em diversos teores de substituição ao agregado miúdo. Através da resistência à compressão e à tração por compressão diametral e módulo de elasticidade, foram analisadas suas propriedades mecânicas. Também foram verificadas algumas propriedades relacionadas com a durabilidade do material, como a retração por secagem, absorção por capilaridade e reatividade acelerada pelo método acelerado de expansão em barras de argamassa
Abstract: The sugar-alcohol sector has expanding in the last years, mainly due to advent of the renewable energy sources and bioenergy. In Brazil, the sugarcane production has advancing towards areas of cattle creation and agriculture, such as soya bean, corn and orange and concerning to electrical energy production through the burning bagasse and alcohol used like vehicle fuel. However, sugar, alcohol and energy production from sugarcane could cause other environmental problems in result to the wastes production such as sugarcane bagasse ash. In the presence of worldwide growth of sugar and alcohol industry and the sustainable development, it is very important the achievement of studies that reuse these wastes. Thus, this work shows technical viability on using sugar-cane bagasse ash (SCBA) obtained from sugar-cane bagasse burnt, as mineral addition, in mortars. It was made some tests on the SCBA, such as the chemical characterization, X-ray diffraction, pozzolanic activity, and also, images obtained by scanning electron microscope. Moreover, grinding of SCBA was carried out, and mortars were prepared with some different amounts of SBCA as replacement of fine aggregate by mass. Through the compressive strength, splitting tensile strength and modulus of elasticity its mechanical properties were verified, and also some properties related to material durability as drying shrinkage, water absorption by capillarity, potential alkali reactivity of aggregates by mortar-bar method
Mestre

The microorganisms growing in sugarcane bagasse piles during storage can metabolise lignocellulose and survive in this relatively extreme environment. These microbes have potential fibre degradation applications, such as in livestock feed. This thesis isolated and characterised new microorganisms and enzymes with a focus on lignin degradation. A specific Thielavia terrestris fungal strain was identified as an efficient lignin degrader. The strain could use sugarcane bagasse as a low-cost carbon source to grow and produce thermostable ligninolytic enzymes. The strain and enzymes have a variety of industrial applications, including for the improvement of bagasse as a component of livestock feed.

Aquesta tesi es centra en l'avaluació de la fermentació en estat sòlid (FES) de residus agroindustrials, com alternatiu per a la producció d'aromes de valor afegit. Dos grups de compostos han estat considerats com a objectius. Les aromes de fruita, inclosos alguns compostos volàtils com aldehids, cetones, alcohols i èsters. D'aquests, els èsters alifàtics són aquells amb més valor afegit donat el seu particular olor a fruites. El segon grup són els aromes de roses, constituïts pel 2-feniletil alcohol (2-FA) i el 2-feniletil èster (2-FE); compostos utilitzats com a additius gràcies al seu olor a roses. En tots dos casos, l'objectiu ha estat el desenvolupament de bioprocessos basats en l'ús de residus, emprant com el bagàs de canya i les melasses de remolatxa. Amb aquest objectiu, s'ha utilitzat el llevat Generalment Reconeguda com Segur Kluyveromyces marxianus. La bioproducció de les aromes de fruita s'exposen a la primera secció. Aquesta inclou la selecció del substrat, així com l'avaluació preliminar d'algunes de les variables que afecten al procés. Un cop seleccionat el substrat, la producció d'aquests compostos ha estat avaluada a escala laboratori en bioreactors de 0.5L operats en discontinu. D'aquest apartat es pot indicar que el procés es veu significativament afectat per la temperatura i el cabal d'aire. Es va trobar que la màxima producció de volàtils (incloses totes les espècies quantificades) va ser de 161 mgVol per gram de substrat inicial en base seca (gST), a 40°C, 0.14 Lh-1g-1ST i addicionant un 35% de melasses. D'altra banda, la màxima producció d'èsters va ser obtinguda a 30°C, 0.11 Lh-1g-1ST i addicionant un 25% de melasses, aconseguint-se 47 mgEstg-1ST. Finalment, partint de l'optimització del procés a escala laboratori, el procés va ser avaluat a escales superiors (4.5 i 22L). En aquest cas, l’estudi s'ha enfocat en l'efecte que tenen les estratègies d'operació sobre l'acompliment global del procés. Així, la FES en discontinu s'ha comparat amb el procés emprant barrejat intermitent i operant en fed-batch. Aquesta última estratègia ha resultat ser una eina que afecta positivament la selectivitat cap als èsters, millorant al mateix temps alguns dels índexs de rendiment que descriuen el procés. La bioproducció d'aromes de rosa per FES és el objectiu de la segona secció. Inicialment s’ha fet l'avaluació de la FES en condicions estèrils en bioreactors de 0.5L. En aquest cas, es va desenvolupar un estudi inicial sobre les variables d'operació que afecten el procés, així com de diverses estratègies per millorar la producció. Es va trobar que la producció de 2-FA i 2-FE està associada amb l'activitat microbiològica del K. marxianus, i per tant, allargar aquesta activitat resulta en un factor decisiu per millorar la producció. En aquest sentit, l'addició de fonts addicionals de carboni, o l'ús de fed-batch han resultat ser alternatives eficients per millorar la producció de 2-FA i 2-FE. Partint dels resultats a escala laboratori, el procés va ser estudiat a escales més grans (1.6 i 22L) retirant algunes de les limitacions associades als processos a aquesta escala, com el control de temperatura i l'esterilització dels substrats. L'anàlisi d'aquesta part s’ha enfocat a l'ús d'estratègies d'operació com a eines per millorar l'acompliment global del procés. Així, la fermentació en discontinu ha estat contrastada amb la FES per fed-batch i la discontinua seqüencial. En aquest cas, la producció assolida en el procés en discontinu (17 mg2-FA+2-FE per gram de substrat inicial sec) va ser millorada a l'implementar les estratègies alternatives, aconseguint-se 19.2 mg2-FA+2-FEg-1ST al cas del fed-batch. De manera global, els resultats presentats constitueixen un pas endavant en el desenvolupament de la FES com a alternativa per produir aromes com a compostos de valor afegit a partir de residus agroindustrials.
Esta tesis se centra en la evaluación de la fermentación en estado sólido (FES) de residuos agroindustriales, como alternativa para la producción de aromas de valor añadido. Dos grupos de compuestos se consideraron como objetivos a estudiar. Los aromas frutales, que incluyen algunos compuestos volátiles como aldehídos, cetonas, alcoholes y ésteres. De estos, los ésteres alifáticos se consideran los de mayor valor añadido dado el olor a frutas que proveen. El segundo, los denominados aromas de rosas, conformados por el 2-feniletil alcohol (2-FA) y el 2-feniletil éster (2-FE); compuestos empleados como aditivos dado el olor a rosas que proveen. En ambos casos, el objetivo fue el desarrollo de bioprocesos basados en el uso de residuos, empleando como materias primas el bagazo de caña y las melazas de remolacha. Con este objetivo, se utilizó la levadura Generalmente Reconocida como Segura Kluyveromyces marxianus. La bioproducción de los aromas frutales se expone en la primera sección. Esta incluye la selección del sustrato, así como la evaluación preliminar de algunas de las variables que afectan al proceso. Una vez seleccionado el sustrato, la producción de estos compuestos ha sido evaluada a escala laboratorio en bioreactores de 0.5L operados por lotes. De allí se concluye que el proceso es significativamente afectado por la temperatura y el caudal de aire. Se encontró que la máxima producción de volátiles (incluidas todas las especies cuantificadas) fue de 161 mgVol por cada gramo de sustrato inicial en base seca (gST), a 40°C, 0.14 Lh-1g-1ST y adicionando un 35% de melazas. También, la máxima producción de ésteres fue alcanzada a 30°C, 0.11 Lh-1g-1ST y 25% de melazas, con 47 mgEstg-1ST. Finalmente, partiendo de la optimización del proceso por lotes, el proceso fue evaluado en escalas superiores (4.5 y 22L). Allí, la evaluación se enfocó en el efecto que tienen las estrategias de operación sobre el desempeño global del proceso. Así, la FES por lotes se comparó ante el proceso con mezclado intermitente y operando por lotes alimentados. Esta última estrategia resultó ser una herramienta que afecta positivamente la selectividad hacia los ésteres, mejorando además los índices de desempeño que describen el proceso. La bioproducción de aromas de rosa es el objetivo de la segunda sección. Inicialmente se aprecia la evaluación de la FES en bioreactores de 0.5L. Allí, se realizó un barrido inicial sobre las variables de operación que afectan el proceso, así como de algunas estrategias para mejorar la producción. Se encontró que la producción de 2-FA y 2-FE está asociada con la actividad microbiológica del K. marxianus, con lo cual extenderla es un factor que resulta decisivo para mejorar la producción. La adición de fuentes adicionales de carbono, o el uso de una alimentación fraccionada resultaron ser eficientes para mejorar la producción. Partiendo de los resultados a escala laboratorio, el proceso fue valorado a escalas mayores (1.6 y 22L) eliminando algunas de las limitaciones asociadas al trabajo a dicha escala como el control de temperatura y la esterilización de los sustratos. El análisis de esta parte se enfocó en el uso de estrategias de operación como herramientas para mejorar el desempeño global del proceso. Allí, la fermentación por lotes se contrastó ante la FES por lotes alimentados y empleando lotes secuenciales. Así, la producción alcanzada en el proceso por lotes de 17 mg2-FA+2-FE por gramo de sustrato inicial seco fue mejorada al implementar dichas estrategias, alcanzando 19.2 mg2-FA+2-FEg-1ST en el caso de lotes alimentados y 21 mg2-FA+2-FEg-1ST en los lotes secuenciales. De modo global, los resultados presentados constituyen un paso adelante en el desarrollo de la FES como alternativa para producir estos compuestos de valor añadido a partir de residuos agroindustriales.
This thesis focuses on the use of solid-state fermentation (SSF) as an alternative approach to the bioproduction of value-added aroma compounds through the valorization of selected agro-industrial residues. Specifically, two groups of objective aroma compounds have been studied. First, the fruit-like compounds, among which could be included a set of volatile scented species such as aldehydes, ketones, alcohols and esters. From these, the straight-chain esters could be catalogued as those more appreciated due to their high fruit-like aroma profile. The second group of species studied here are the semi-volatile compounds known as rose-like compounds, which are constituted by 2-phenethyl alcohol (2-PE) and 2-phenethyl acetate (2-PEA), two value-added species widely used as additives due to the rose-like odor they provide. In both cases, the aim was to develop residue-based bioprocesses using as raw materials the agro-industrial residue sugarcane bagasse (SCB) and the industry by-product sugar beet molasses (SBM). With this aim, the Generally Recognized As Safe (GRAS) yeast Kluyveromyces marxianus was used in the study. Developments related to the bioproduction of fruit-like compounds are exposed in the first section of the thesis. They include the initial substrate screening and an initial assessment of the operational variables affecting the process. Then, the optimization of the fruit-like compounds production in a batch SSF at 0.5 L system is developed. In that sense, it was found that the bioproduction is significantly affected by operational variables like the temperature and the air flow rate. While the maximum volatile production (including all the quantified species) was 161 mgVol per gram of dry substrate (g-1TS) at 40°C, 0.14 L h-1 g-1TS and 35% SBM, the ester species were maximized at 30°C, 0.11 L h-1 g-1TS and 25% SBM up to 47 mgEst g-1TS. Finally, based on the optimization of the batch SSF at lab scale, the evaluation of the process at bench-scale was performed (4.5 and 22 L scales). In this case, the analysis has been focused on the effects of some operational strategies named intermittent mixing and fed-batch SSF in the global performance of the bioprocess. Fed-batch has shown interesting characteristics affecting the selectivity of the ester species and also improving some of the evaluated performance indices. Bioproduction of the rose-like compounds via SSF is the core of the second section of this thesis. In this case, the first part is devoted to the evaluation of the feasibility of the process under sterile conditions in a batch SSF 0.5 L system. It was found that extending the K. marxianus activity is a key factor to increase the 2-PE and 2-PEA production. In this sense, by adding supplementary carbon sources to the media or splitting the substrate load (as a manner of a fed-batch mode) resulted in efficient and consistent ways to promote the biotransformation of these compounds. Based on the results at 0.5 L, the process was further evaluated at bench-scale (1.6 and 22 L scales) by releasing some of the constraints found at lab-scale such as the temperature control and the sterilization of the substrates. Again, the analysis was focused on the assessment of the operational strategies fed-batch and sequential-batch as alternative approaches to enhance the global behavior of the process. Here, strategies have succeeded increasing the 2-PE and 2-PEA production from 17 mg2-PE+2-PEA per gram of dry substrate (g-1TS) in a batch scenario, up to 19.2 mg2-PE+2-PEA g-1TS by using a fed-batch approach, and until 21 mg2-PE+2-PEA g-1TS through a sequential-batch. Overall, the results exposed in this thesis represent a step forward in the development of SSF as an alternative approach for producing valuable aroma compounds from agro-industrial wastes.

Orientador: Pedro de Oliva Neto
Banca: Dejanira de Franceschi de Angelis
Banca: Sandra Regina Ceccato-Antonini
Resumo: A utilização de solvente Organosolv em condições de acidez e temperaturas elevadas para a realização da deslignificação de bagaço de cana e hidrólise da fração de hemicelulose tem sido muito estudada e existem muitos parâmetros experimentais já descritos na literatura. Tem sido obtidos bons resultados de deslignificação e hidrólise parcial do bagaço a partir do prétratamento ácido com solvente Organosolv utilizando misturas de etanol e água, normalmente em proporções iguais de volume de cada. Este estudo descreve um método de deslignificação e hidrólise da hemicelulose do bagaço da cana combinando a utilização da mistura dos solventes orgânicos, acetona e álcool, com água e solução ácida diluída. A mistura do solvente organosolv (acetona+álcool/água - 1:1 v/v), concentração ácida de 0,5 - 2,0% de H2SO4, e tempo de reação de 30 a 120 minutos e 5,0% de bagaço (p/v) foi realizado para o pré-tratamento. O efeito do ácido, solvente e temperatura no rendimento e extensão da deslignificação e hidrólise da oram estudados. Os resultados obtidos indicam importantes diferenças no pré-tratamento ácido com solvente Organosolv, devido ao uso da acetona e concentração ácida empregados nos experimentos deste estudo. Os melhores resultados foram obtidos com 1,0% de H2SO4 e 120 °C. Sob estas condições o rendimento de açúcares obtidos da hidrólise ácida da porção de hemicelulose do bagaço de cana foi de 7.53%. Estes resultados demonstram um rendimento de açúcares fermentescíveis que podem ser utilizados como fonte de carbono para a fermentação alcoólica por Pachysolen tannophilus. A conversão de Xilose em etanol por Pachysolen tannophilus é relativamente ineficiente nas condições de fermentação estudada. Esta ineficiência é atribuída em partes, ao consumo de etanol pela levedura concorrente à sua produção, baixa eficiência... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The utilization of Organosolv solvents under acid and high temperature conditions in the delignification and hemicelulose and cellulose hydrolysis of wood and bagasse has already been reported in the literature for several experimental parameters. Organosolv treatment of sugarcane bagasse has also been reported and has shown good results with ethanol-water mixtures, normally at volume ratios close to unit. This study describes a method of the delignification hemicelulose hydrolysis of sugarcane bagasse combining the use of ethanol+acetone/water mixtures and diluted acid solutions. Ethanol+acetone/water mixture (1:1 v/v), acid concentration of 0,5 - 2,0% of H2SO4, reaction times from 30 to 120 min, and 5,0% of sugarcane bagasse (w/v) was carried out for bagasse pre-treatment. The effect of acid, solvent and temperature on the yield and extent of delignification and hemicelulose hydrolysis was studied. The obtained results indicate important differences from the Organosolv process, which may be due to the presence of acetone and acid concentration employed in this work. The best results were obtained at 1,0% of H2SO4 and 120 °C. Under these conditions the sugar yield obtained from hemicelulose hydrolysis from sugarcane bagasse 7.53%. These results shows that the sugar yield obtained can be used as carbon source for Pachysolen tannophilus fermentation to produce ethanol. The conversion of D-xylose to ethanol by the yeast Pachysolen tannophilus is relatively inefficient in batch culture. The inefficiency has been attributed in part to concurrent utilization of ethanol, slow fermentation metabolism of the yeast and to the formation of xylitol and other by-products. The xylose concentration in the must was 2,0% during 120 hours of fermentation. The best ethanol yield was obtained in the first 24 hours, as the ethanol began to be consumed and the sugar concentration became low... (Complete abstract click electronic access below)
Mestre

Orientador: Fernando Broetto
Banca: José Pedro Serra Valente
Banca: Luciana Francisco Fleuri
Resumo: O bioetanol é um combustível produzido por meio da fermentação do açúcar do caldo da cana, que representa apenas um terço do carbono (energia), presente na planta. Atualmente, estão sendo feitos esforços para o aproveitamento do restante da biomassa, divididos entre as folhas e bagaço do colmo. Esta biomassa lignocelulósica poderia ser aproveitada para produção de etanol, desde que submetida a processos hidrolíticos químicos (ácidos e bases) e enzimáticos gerando açúcares fermentescíveis. Pela fermentação alcoólica é possível a produção de etanol a partir da mistura de açúcares liberados. Neste trabalho procurou-se a padronização de procedimentos para avaliar o pré-tratamento físico e químico do bagaço da cana-de-açúcar, aliado a diferentes tratamentos térmicos a partir de duas granulometrias de bagaço (1,1 e 2,5 mm). Para o delineamento experimental, utilizou-se tratamentos ajustados em fatorial 4 X 5, sendo que as variáveis foram a influência do tempo de pré-tratamento (0, 15, 30, 45 e 60 minutos) e concentração de ácido sulfúrico (H2SO4) a 7 e 9%. Estes fatores exerceram influência sobre o desempenho da pré-hidrólise, medido pela liberação açúcares redutores (AR) na solução e a % de espécies químicas no bagaço prétratado
Abstract: Bioethanol fuel is produced through the fermentation of sugar cane juice, which representes only a third of the carbon (energy) present in the plant. Currently, efforts are being made to the use of the remaining biomass, divided among the leaves and seed stalk. This lignocellulosic biomass could be used for ethanol production, provided that undergo hydrolytic process chemicals (acids and bases) and enzymatic generating fermentable sugars. For fermentation is possible to produce ethanol from mixed sugars released. This research is the standardization of procedures to assess the pre-treatment physical and chemical properties of bagasse from sugar cane, coupled with different thermal treatments from two particle sizes of mulch (1,1 and 2,5 mm). For this experiment, we used adjusted treatments in a factorial 4 x 5, and the variables were the influence of time of pretreatment (0, 15, 30, 45 and 60 minutes) And concentration of sulfuric acid (H2SO4) 7 and 9%. These factors have exerted influence on the performance of pre-hydrolysis, measured by the release sugars (RS) in the solution, and% of chemical species in the pretreated bagasse
Mestre