Thesis (Ph.D.)--University of Wisconsin--Madison, 2007. / Includes bibliographical references (p. 143-152). Also available on the Internet.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Feb. 17, 2009). PDF text: 196 p. : ill. (some col.) ; 2 Mb. UMI publication number: AAT 3324854. Includes bibliographical references. Also available in microfilm and microfiche formats.

Seaweed biomass has been identified as a potential fermentation substrate for third generation biofuel processes due to its high carbohydrate content and its potential for mass cultivation without competing for agricultural land, fresh water and fertilisers. This thesis aimed to develop and advance existing processes to convert brown seaweeds into bioethanol. The main kelp species chosen as biomass candidates were Laminaria digitata, Laminaria hyperborea, Saccharina latissima and Alaria esculenta due to their abundance in Scottish waters and their identified potential for mariculturing. These kelp species were chemically characterised to identify seasonal variations, to recommend suitable seaweed candidates for bioethanol production and predict best harvest times. This has only been demonstrated before on one species - L. digitata. The chemical composition analyses were carried out over a 14 months sampling period, which focused on the storage carbohydrates laminarin and mannitol and the structural carbohydrates alginate, cellulose, fucoidan and xylose. In addition to carbohydrates the protein, nitrogen, carbon, polyphenol, ash and metal content was also profiled. Chemical profiling identified all four kelps as potential fermentation candidates, where maximum carbohydrate contents coincided with lowest ash and polyphenol content, usually seen in autumn. Biomass pre-treatment and saccharification are up-stream processes aimed at enhancing extraction of carbohydrates and converting those into fermentable substrates. Conversion of seaweed biomass into fermentation substrate evaluated acids and enzymes for seaweed pre-treatment and saccharification. Methodologies focused on optimising saccharification yields were developed to identify process critical parameters and develop methods for routine analysis of seaweed biomass. Results demonstrated that dilute acid hydrolysis was were less effective in releasing fermentable sugars, and also resulted in higher salinities compared to enzymatic hydrolysis using hemicellulosic and cellulosic enzymes, which were the preferred method of saccharification. All seaweeds in this thesis were assessed as fermentation substrates using the yeasts S. cerevisiae and P. angophorae, that principally ferment glucose or mannitol, respectively. Small-scale fermentation assays were developed for both yeasts to maximise ethanol yields and achieve process robustness. Both yeasts achieved a maximum ethanol yield of 0.17 g g-1 using Laminaria spp. On the basis of results, S. cerevisiae is recommended as the most useful yeast at this present point for ethanol fermentation from seaweed hydrolysates because of its tolerance to high salinity and ethanol concentrations. As salinity can negatively affect non-halotolerant enzymes, isolation of marine microorganisms was therefore carried out with the aim to highlight their enzymatic potential in seaweed saccharification. This was achieved through the isolation of two members of the genus Pseudoalteromonas, where saccharification yields using crude intracellular enzyme preparations exceeded those of dilute acids. In addition, the fermentative potential of microbial isolates as future ethanologenic strains was also evaluated. Understanding of the metabolic pathways is needed to fully assess the potential of those strains for genetic alteration. In conclusion, this thesis has demonstrated that up to ca. 20 g l-1 of ethanol can be produced from kelp species that grow on the west coast of Scotland. The procedure developed and used to produce ethanol requires further development, specifically the need for ethanol-fermenting microorganisms that can utilize mannitol and alginate; use of marine-adapted enzymes for saccharifiction; and the development of processes to achieve substrate concentration with reduced salinities. Comparison of theoretical ethanol yields from seaweed biomass with ethanol yields from terrestrial crops showed that the complete utilisation of all three major seaweed carbohydrates (laminarin, mannitol and alginate) from kelp species is needed for the process to be able to compete with 1st generation biofuel processes.

With the gradual depletion of the non-renewable fossil fuel resources and the emerging environmental concerns, the need of exploring renewable synthesis routes of our daily basic stocks is rising. Due to the large contribution to the global primary energy (up to 40% in some countries), biomass has recently been advocated to be one of the most promising alternatives for fossil fuel. This thesis focuses on the catalytic transformations of biomass or biomass derived molecules into valuable small alcohols such as methanol, ethanol, and propanol, which can be used as both fuel and chemical synthesis intermediates. Novel catalysts with high activity and selectivity toward target products are desperately required in the development of renewable chemical synthesis routes. In the past 200 years, platinum metal catalysts have been widely used in the industry. But nowadays, Pd is attracting increasing attentions due to (i) its similar physicochemical properties to those of Pt, (ii) its higher natural abundance than Pt. Alloying has been demonstrated as an effective method in enhancing the catalytic properties of noble metals. In this thesis, a new and facile method for the preparation of supported bimetallic NPs with tunable compositions is developed. Through the establishment of a type II hetero-junction in support, controllable amounts of metallic atoms can be derived from the reduction of the metal oxide support, with the assistance of a supported noble metal. A series of extremely small Pd-based bimetallic NPs with a variety of modifier atoms at tunable compositions, namely PdFe, PdCo, PdNi and PdZn, have been synthesized by this method. These novel bimetallic NPs are applied to the catalytic conversion of biomass or biomass derived molecules containing repeating vicinal diol units. It is demonstrated that the catalytic performance of Pd in bimetallic phase is governed by the d-band structure. The high degree of d-band filling and high d-band center position favour the selective C-O cleavage in hydrogenolysis of vicinal diol units. On the other hand, the selective C-C cleavage can be achieved by lowering the d-band filling of the Pd-based bimetallic NPs. The specificity of C-C bond rupture over that of C-O increases in order of PdZn < PdNi < PdCo < PdFe, with progressive d-band filling reduction, eventually reaches 95% in a series of vicinal diols hydrogenolysis. As a result, small alcohols are produced with high selectivity as the degradation products of biomass molecules when PdFe bimetallic NPs are employed as catalyst. Conversely, by incorporating Co atoms at high concentration, PdCo exhibits a high selectivity in breaking C-O bond of ethylene glycol due to the raised d-band center position and gives ethanol as the main product. Pd@Zn bimetallic NPs with an imperfect core(Pd)-shell(Zn) structure were used in a methanol synthesis route from biomass transformation via CO₂ hydrogenation (CO₂/H₂ is produced from low temperature reforming of biomass resource). The Zn shell not only enhances the catalytic activity of Pd metal towards methanol synthesis, but also suppresses the reverse water gas shift (RWGS) reaction in which CO is produced as a by-product. Methanol can be produced as the main product over CO on the Zn rich Pd@Zn surface, even at low pressure. The methanol turnover frequency (TOF) on the exposed Pd site reaches 1.9 ×10^-1 s^-1 with a selectivity of 70% at 2 MPa. The enhancement is attributed to the increasing d-band filling of Pd@Zn bimetallic NPs by the progressive decoration of Zn on Pd surface, which selectively stabilizes the precursor of methanol (HCOO) over that of CO (COOH). Also, the PdZn catalyst with high ability in dissociating H2 reduces the activation barrier for methanol synthesis. The results presented in this thesis, for the first time, signify the possibility of fine-tuning of product specificity of biomass conversion simply by rationally modifying the electronic properties of the Pd-based catalysts. More importantly, these catalysts will help to diversify the energy generation and relieve our dependence on fossil fuels.

Orientador: Julio Santana Antunes / Co orientador: José Luz Silveira / Banca: Celso Eduardo Tuna / Banca: José Rui Camargo / Resumo: Na atualidade, estão sendo desenvolvidas diversas tecnologia que aproveitam os recursos renováveis com a finalidade de gerar energia e diminuir emissão de poluentes ao meio ambiente. Entre essas tecnologia podemos citar a gaseificação, composta de métodos de conversão da biomassa em um gás combustível pobre. Nese caso, a biomassa deve ser gaseificada e condicionada para produzir gás de síntese que pode acionar um motor de combustão interna (MCI). A utilização do processo de gaseificação integrado a um MCI é uma opção atraente para emprego em comunidades isoladas, visto que oferece a possibilidade de obter calor por recuperação (água quente) e energia elétrica no conjunto motor/gerador de forma independente. Este trabalho tem como objetivo avaliar tecnicamente, economicamente e ecologicamente um gaseificador de biomassa tipo downdraft, integrado a um sistema de geração de energia em pequeno porte, através do desenvolvimento de um software na plataforma Delphi. O estudo permite conhecer através do balanço de energia, os parâmetros energéticos envolvidos em cada volume de controle considerado no estudo (Gaseificador, Trocador de Calor, Motor de Combustão Interna). A análise econômica considera todos os custos fixos e variáveis envolvidos para a geração de eletricidade no conjunto motor/gerador de 5 kWe acionado por gás de síntese e os investimentos capitais em cada equipamento do sistema (gaseificador, conjunto motor/gerador e trocador de calor). Os cálculos permitem determinar os custos de geração de gás de síntese, água quente e eletricidade, e também a receita anual esperada. A análise ecológica consideraos fatores de emissões obtidos pela combustão do gás de síntese no MCI. Estes fatores foram comparados considerando a combustão da gasolina, do diesel e do biodiesel, permitindo analisar se o sistema de gaseificação de biomassa integrado a um MCI é ecologicamente viável. / Abstract: Nowadays, as result new systems in more efficient technological versions have beem developed for minimize pollutant emissions as wood gasification. Biomass gasification consisting of conversion methods of the biomass into poor fuel gas (syngas), in this case a syngas is used in internal combustion engine (ICE) for electrical produce. The use of biomass gasification associated into ICE makes the systems attractive for used in isolated communities because allows to independently. The aim of this work is made software to allow technical, economical and ecological studies of a owndraft gasifier integratedinto ICE. The technical study allows know alls parameters involve in which considered volume control (Gasifier, Heat Exchager, ICE). The economical study allows know eletricity cost production, syngas cost production, hot water cost production and expected annual saving considering alls fix cost involve to electrical generation in ICE. The ecological study depends on the environmental impact caused by CO2 SO2 NOx and particulate material (PM) emissions. The emissions factors obtained from syngas burn in internal combustion engines is compare to emissions factors obtained from gasoline burn, biodiesel, natural gas burn and diesel burn, allowing analyze ecological feasibility of gasifier/ice system. / Mestre

Orientador: Leandro Cardoso de Morais / Banca: Clovis Augusto Ribeiro / Banca: Renata Fracacio Francisco / Banca: Fabio Minoru Yamaji / Banca: Manuel Enrique G Guandique / Resumo: O Brasil se encontra entre os países de maior produção agrícola do mundo. Diante desse fato, o país tem se tornado alvo de pesquisadores no que diz respeito à reutilização de resíduos provenientes de atividades agroindustriais. Esses resíduos são considerados biomassas com grande potencial para a produção de uma energia limpa, bem como, biocombustíveis que podem ser utilizados sem agredir o meio ambiente. Além disso, essas biomassas também podem ser utilizadas em tratamento de águas e efluentes, agindo como adsorvedores de poluentes que não são, necessariamente, removidos por meio do tratamento convencional. Diante disso, o estudo dessas biomassas tem sido de extrema importância para o país, visando descobrir o potencial de biomassas alternativas que são capazes de promover o desenvolvimento de novas tecnologias. O trabalho objetivou o estudo da biomassa Capsicum spp., visando a obtenção de um produto rentável e ambientalmente favorável. A biomassa e o resíduo sólido da pirólise foram submetidos a diversos testes de caracterização e identificação analítica, como análise elementar, análise imediata, rendimento gravimétrico (RG), análise térmica (AT), microscopia eletrônica de varredura (MEV), espectroscopia de infravermelho com transformada de Fourier (FTIR), difração de Raios-X (DRX), poder calorífico superior (PCS) e inferior (PCI) e testes de adsorção. As análises térmicas mostraram que a decomposição da biomassa e seus biocarvões variaram entre 150°C e 500°C, as etapas de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil is among the countries with the highest agricultural production in the world and the country has become the target of researchers with regard to the reuse of waste from agroindustrial activities. These wastes are also called biomass with great potential for bioenergy production, as well as biofuels that can be used without harming the environment. In addition, such biomass can also be used in water and effluent treatment, acting as adsorbents for pollutants which are not necessarily removed by conventional treatment. Therefore, the study of these biomass has been extremely important for the country, aiming to discover the potential of alternative biomass that are capable of promoting the development of new technologies. The study aimed to study the biomass Capsicum spp., in order to obtain a profitable and environmentally favorable product. The biomass and the solid residue of the pyrolysis were subjected to several tests of characterization and analytical identification, such as ultimate analysis, proximate analysis, gravimetric yield and gravimetric yield factor, thermal analysis, scanning electron microscopy (SEM), infrared spectroscopy with Fourier transform (FTIR), X-ray diffraction (XRD), Higher Heating Values (HHV), Lower Heating Values (LHV) and adsorption tests. Thermal analyzes showed that biomass and biochar decomposition varied between 150 ° C and 500 ° C, the dehydration stages reached a maximum of 150 ° C. At about 600 ° C there was the formation of carbo... (Complete abstract click electronic access below) / Doutor

Orientador: Edwil Aparecida de Lucca Gattás / Banca: Rosemeire Cristina Linhari Rodrigues Pietro / Banca: Maristela de Freitas Sanches Peres / Banca: Rubens Monti / Banca: Eleonora Cano Carmona / Resumo: No presente trabalho, inicialmente foi feito um estudo da Metodologia de Superfície de Resposta (RSM) que tem sido adotada com muita freqüência na otimização com várias aplicações na biotecnologia. Foi feita uma revisão na literatura científica dos conhecimentos existente, onde se priorizou as bases teóricas da RSM que consiste em: trabalho preliminar, onde são determinados as variáveis independentes e seus níveis; seleção do projeto experimental com a previsão e verificação da validade da equação do modelo e, representação gráfica da equação do modelo e determinação das condições ótimas de operação. Em seguida a RSM foi aplicada na otimização de biomassa pela levedura recombinante Pichia pastoris. Pichia pastoris que é uma levedura metilotrófica, geneticamente manipulada para expressar proteínas heterólogas que são de grande valor biotecnologico na pesquisa básica e em usos industriais na produção de grande variedade de proteínas heterólogas. Glicerol quinase (GK; EC 2.7.1.30) é uma enzima chave no metabolismo do glicerol e catalisa glicerol para glicerol-3- fosfato na biossíntese de fosfolípidos. Nessa etapa foi conduzido um estudo para determinar um meio otimizado para a produção de biomassa máxima pela recombinante Pichia pastoris com cultivo em frascos agitados usando 2,31% (p/v) de glicerol como fonte de carbono. A otimização foi realizada por metodologia de superfície de resposta (RSM). Em experimentos preliminares, realizados seguindo um planejamento Plackett-Burman, o conteúdo de glicerol (Gli) e tempo de crescimento (t) foram selecionados como os fatores mais importantes na produção de biomassa. Assim, os ensaios subsequentes foram realizados para a otimização da produção de biomassa, seguindo um delineamento composto central rotacionado... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this study, was initially used to study the response surface methodology (RSM) has been adopted frequently in optimization with many applications in biotechnology. A review of scientific literature on existing knowledge, which prioritized the theoretical foundations of RSM consisting of: preliminary work, where they are certain independent variables and their levels; project selection with the prediction and experimental verification of the validity of equation model and graphical representation of the model equation and determination of optimal operating conditions. RSM was then applied to the optimization of biomass by recombinant yeast Pichia pastoris in GK4 clone obtained from a previous selection of four clones from a cloning process of genetically modified yeast. Pichia pastoris is a methylotrophic yeast that has been genetically engineered to express heterologous proteins that are prized for basic research and industrial biotechnology purposes in the production of wide variety of heterologous proteins. Glycerol kinase (GK; EC 2.7.1.30) is a key enzyme in glycerol metabolism and catalyzes glycerol to glycerol-3-phosphate in the biosynthesis of phospholipids. The present study was undertaken to determine an optimized medium for the maximal biomass production of recombinant Pichia pastoris in shaker cultures using 2.31% (w/v) glycerol as the carbon source. Optimization was carried out by response surface methodology (RSM). In preliminary experiments, performed following a Plackett-Burman design, glycerol content (Gly) and growth time (t) were selected as the most important factors on biomass production. Therefore, subsequent experiments were carried out for optimization biomass production, following a central composite rotatable design as a function of Gly and time. Gly showed to have a significant... (Complete abstract click electronic access below) / Doutor

Doctor of Philosophy / Department of Biological & Agricultural Engineering / Donghai Wang / Among potential alternative liquid fuels, bioethanol is the widest utilized transportation fuels and mainly made from grains. Cellulosic biofuels provide environmental benefits not available from grain or sugar-based biofuels and are considered as a solid foundation to meet transportation fuels needs in a low-carbon economy, albeit with electrified vehicles and other technical advances. The objective of this research was to develop and optimize various bioprocessing units to boost cellulosic bioethanol titers and yields in order to accelerate the commercialization of cellulosic bioethanol production. The results showed high-solids biomass bioconversion (12%, w/v) was inefficient in the laboratory rotary shaker. However, a horizontal reactor with good mixing was effective for high solids loading (20%, w/v), yielding 75 g/L of glucose. To achieve the minimal economical ethanol distillation requirement of 40 g/L, integrated bioprocesses were conducted to boost ethanol titers and yields through co-fermentation of starchy grain and cellulosic biomass. The maximum ethanol concentration (68.7 g/L) was achieved at the corn flour and hydrothermal-treated corn stover ratio of 12:12 using raw starch granular enzyme with the ethanol yield of 86.0%. Co-fermentation of starchy substrate with hydrolysate liquor from saccharified biomass was able to significantly enhance ethanol concentration and reduce energy cost for distillation without sacrificing ethanol yields. These results indicated integration of first and second generation ethanol production could significantly accelerate the commercialization of cellulosic biofuel production. Novel technology, modified simultaneous saccharification and fermentation, was firstly established to enhance ethanol titers and yields, which achieved high ethanol titers of 72.3 g/L at high biomass loadings of 30% (w/v) with 70.0% ethanol yield.

The factors controlling primary production in the Southern Ocean were investigated over two years during two cruises of the South African National Antarctic Program (SANAP). The first cruise was conducted to the region of the eastern Atlantic sector of the Southern Ocean during the collaborative Scandinavian/South African Antarctic expedition conducted in austral summer (DecemberIFebruary) 1997-1998. Production studies were conducted in the vicinity of the Marginal Ice Zone (MIZ), Interfrontal Zone (IFZ) and Antarctic Polar Front(APF). The second cruise was conducted during the Third Marion Island Oceanographic Survey (MIOS III) to the region of the Sub-Antarctic Prince Edward Islands in austral autumn (April/May) 1998. Size-fractionated production rates were estimated by 14C incorporation using standard JGOFS protocols. Oceanographic data from the first cruise suggest that the three regions can be divided into two distinct regimes. Stations occupied in the vicinity of the MIZ and the APF were characterised by a shallow mixed layer depth « 40m) while at the IFZ-stations, the mixed layer depth exceeded the 1% light depth. Microphytoplankton dominated integrated chlorophyll-a biomass in the MIZ (total chlorophyll a ranged between 15.4 and 41.3 mg Chi-a. m-2) and at the APF (range between 10.7 and 31.4 mg Chi-a. m-2) , comprising > 50% of total chlorophyll-a at all these stations. Xl Within the IFZ (2 stations), nanophytoplankton dominated total integrated Chl-a biomass (range between 5.6 and 8.8 mg Chi-a. m-2) comprising, on average, 36% of the total. Picophytoplankton comprised an average of 12% of the total Chl-a biomass (range between 3.1 and 5.9 mg Chi-a. m-2) in the MIZ, 36% in the IFZ (range between 6.4 and 7.8 mg Chl-a . m-2) and 20% in the vicinity of the APF (range between 6.8 and 10.6 mg Chi-a. m-2). Total integrated primary production ranged between 316 and 729 mg C . m-2. d-1 at stations occupied in the vicinity of the MIZ, and between 292 and 317 mg C . m·2• d-l within the IFZ. At stations occupied in the region of the APF, total integrated production ranged between 708 and 926 mg C . m-2• dol. The contribution of various size fractions to total productivity generally displayed the same pattern as integrated Chl-a biomass. Microphytoplankton formed the most important contributor to total production at stations occupied in the MIZ and at the APF. Within the IFZ, nanophytoplankton dominated total daily production. Nutrient data suggest that concentrations of macro nutrients within the upper water column were above the threshold where growth would be limited. Preliminary results showed that concentrations of iron (Fe) were highest in the southern region of the MIZ and in the vicinity of the APF. During the second cruise, conducted in the vicinity of the Sub-Antarctic Front (SAF) and in the upstream, inter-island and downstream regions of the Prince Edward Islands, there was evidence of fresh water run-off from the islands, (i.e. decreased salinities and increased concentrations of ammonia and nitrate). Oceanographic data collected at the various production stations indicated that the upper water column was well mixed throughout the survey. Total integrated biomass during the study ranged between 8.5 and 20.1 mg Chi-a. m-2• No distinct patterns in total Chl-a biomass were evident. Picophytoplankton dominated total biomass comprising> 45 % of total pigment at all stations. Nanophytoplankton were the second most important contributor to total integrated biomass. Generally xu microphytoplankton contributed < 10 % of total ChI-a. Total daily integrated production was highest (442.6 mg Chi-a. m-2) at the single station occupied in the vicinity of the SAF. Outside this region, total areal production was lower, ranging from 94.5 to 353.0 mg C . m-2. d-1. With the exception of the station occupied in the vicinity of the SAF, total productivity was dominated by nanophytoplankton, which comprised between 48 and 66% of the total. Concentrations of macronutrients did not appear to be limiting to phytoplankton growth. The absence of a phytoplankton bloom in the vicinity of the islands appears to have been related to water column stability, which was influenced by the prevailing oceanographic regime during the survey. Previous studies have shown that when the SAF lies in close proximity to the islands, advecting forces prevail, resulting in the islands functioning as a flow-through system. During this study, the SAF lay immediately north of the islands. As a consequence no water was trapped in the leeward side of the islands. The results of the two cruises suggest that phytoplankton production in the four systems investigated: the Marginal Ice Zone (MIZ), Antarctic Polar Front (APF), Inter Frontal Zone (IFZ) and Prince Edward Islands (PEl), was largely controlled by water column stability. It is probable that the availability of iron, particularly in the region of the MIZ and APF, may have further contributed to the elevated production recorded in these two regions.

>Magister Scientiae - MSc / Lignocellulosic biomass, a waste component of the agricultural industry, is a promising source for use in bioethanol production. Due to a complex structure, the synergistic action of lignocellulosic enzymes is required to achieve complete digestion to fermentable sugars. This study aimed to isolate, identify and characterise novel lignocellulase producing bacteria from thermophilic straw-based compost (71°C). Colonies with different morphological characteristics were isolated and screened for lignocellulosic activity. A facultative aerobic isolate RZ1 showed xylanase, cellulase and lipase/esterase activity. In addition to these activities, it was also able to produce proteases, catalases, amylases and gelatinases. RZ1 cells were motile, rod-shaped, Gram positive and endospore forming. The growth temperature of isolate RZ1 ranged from 25-55°C with optimal growth at 37°C. The 16S rRNA gene sequence was 99% identical to that of Bacillus subtilis strain MSB10. Based on the biochemical and physiological characteristics and 16S rRNA gene sequence, isolate RZ1 is considered a member of the species B. subtilis. A small insert genomic library with an average insert size of 5 kb was constructed and screened for lignocellulosic activity. An E.coli plasmid clone harbouring a 4.9 kb gDNA fragment tested positive for xylanase activity. The xyl R gene was identified with the aid of transposon mutagenesis and the deduced amino acid sequence showed 99% similarity to an endo-1-4-β-xylanase from B. pumilus. High levels of xylanases were produced when isolate RZ1 was cultured (37°C) with beechwood xylan as a carbon source. On the other hand, the production of xylanases was inhibited in the presence of xylose. Marked xylanase activity was measured in the presence of sugarcane bagasse, a natural lignocellulosic substrate. While active at 50°C, higher xylanase activity was detected at 37°C. Isolate RZ1 also produced accessory enzymes such as β-xylosidases and α-L-arabinofuranosidases, able to hydrolyse hemicellulose.