Lignocellulosic bioethanol is currently being explored as a substitution to fossil fuels. Many lignocellulosic materials are being examined but the importance is to find those with attractive agro-energy features. Producing lignocellulosic ethanol is challenging because lignocellulosic biomass is resistant to chemical and biological degradation. To reduce biomass recalcitrance, a pretreatment stage is required. Pretreatment is considered to be the most intensive operating/operating cost component of cellulosic ethanol production. Therefore, research is heavily focused on understanding the effect of pretreatment technologies on the fundamental characteristics of lignocellulosic biomass. The first study in the thesis investigates Buddleja davidii as a potential biomass source for bioethanol production. The work focuses on the determination of ash, extractives, lignin, hemicellulose, and cellulose content in this plant, as well as detailed elucidation of the chemical structures of both lignin and cellulose by NMR spectroscopy. The study showed that B. davidii has several unique agro-energy features as well as some undesired characteristics. The second study presents research on the ethanol organosolv pretreatment (EOP) of B. davidii and its ability to produce enzymatically hydrolysable substrates. It was concluded that the removal of hemicellulose, delignification, reduction in the degree of polymerization (DP) of cellulose, and the conversion of crystalline cellulose dimorphs (Iα/Iβ) to the easily degradable para-crystalline and amorphous celluloses were the characteristics accounted for efficient enzymatic deconstruction of B. davidii after EOP. The third study provides a detailed elucidation of the chemical structure of ethanol organosolv lignin (EOL) of B. davidii by NMR spectroscopy. Such research was needed to understand the pretreatment mechanism in the context of delignification and alteration of the lignin structure. Future applications of the resulted EOL will be valuable for industrially viable bioethanol production process. EOP mainly cleaved β-O-4' interlinkages via homolysis, decreased the DP of lignin, and increased the degree of condensation of lignin. EOL had low oxygen content, molecular weight, and aliphatic OH as well as high phenolic OH, which are qualities that make it suitable for different co-product applications. The last study provides information on the anatomical characteristics of pretreated B. davidii biomass after EOP. The importance of this research was to further understand the alterations that occur to the cellular structure of the biomass which can then be correlated with its enzymatic digestibility. The results concluded that the physical distribution of lignin within the biomass matrix and the partial removal of middle lamella lignin were key factors influencing enzymatic hydrolysis.

Sorghum is the fifth most important cereal crop in the world and ranks third in Africa, and it is potentially the number one cereal for the semi-arid environments in sub-Saharan Africa. Sorghum varieties have been developed specifically for grain, fodder or stem sugar but not for dual-purpose combining grain and stem sugar. Such varieties could be beneficial to the resource-poor farmers by providing grain for food and sugar rich stalks that can be sold for bioethanol production. However, there are no suitable dual-purpose cultivars on the market. There is also limited information about the combining ability, gene action and genetic effects and relationships between stem sugar and grain yield which is required in devising appropriate strategies for developing dual-purpose sorghum varieties. Furthermore, there is also lack of information about the perceptions of resource-poor, small-scale farmers and other important stakeholders on the potential of dual-purpose sorghum production and the value chain. Therefore, the objectives of this study were to: (i) investigate the awareness of the farmers, industry and other stakeholders on the dual-purpose sorghum varietal development and its feasibility, (ii) screen germplasm for use as source materials useful for grain yield and stem sugar traits, (iii) investigate the inheritance and heterosis levels attainable in grain yield components and stem sugar traits in dual-purpose sorghums, (iv) determine the relationships between stem sugar traits and grain yield components in dual-purpose sorghums, and (v) investigate the fertility restoration capacities of selected male-fertile lines used as male parents through the evaluating seed set in experimental dual-purpose hybrids. Two surveys were conducted to establish stakeholders’ level of awareness and perceptions on the potential and feasibility of developing and utilising dual-purpose sorghums in Southern Africa. One survey was carried out in the semi-arid tropical lowlands in Zimbabwe under the conditions of small-scale and resource-poor farmers while the other, which targeted sugar industries, plant breeders, engineers, political leaders, economists and extension workers, was conducted in South Africa and Zimbabwe. Data were analysed using SPSS computer package. Results showed that both farmers and the non-farmer stakeholders were in agreement on the view that dual-purpose sorghum would be a viable enterprise that could alleviate poverty, enhance food security, create rural employment and boost rural development in southern African countries. Farmers were willing to adopt the cultivars if they were made available. The stakeholders also suggested mechanisms to overcome the infrastructural, economic and technical challenges associated with the technology. Screening of regional and international germplasm collection held at the University of KwaZulu- Natal in South Africa revealed high genetic variability for grain yield, stem brix and stem biomass yield that can be exploited in dual-purpose sorghum cultivar development. Ten lines were selected for inclusion as parents in the dual-purpose sorghum breeding programme. The selections were crossed to eight cytoplasmic male-sterile lines originating from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in accordance with a North Carolina Design II mating scheme. The 18 parents, together with the 80 experimental hybrids generated and two check varieties were evaluated for grain yield and stem sugar traits in six tropical low- and mid-altitude environments in Mozambique, South Africa and Zimbabwe. Stem sugar concentration and stem biomass were measured at the hard dough stage of each entry due to maturity differences between the genotypes. Grain yield was measured and adjusted to 12.5% moisture content. Data were analysed in GenStat computer package following a fixed effects model. Both additive and non-additive gene effects were important in controlling stem brix, stem biomass, grain yield and the associated traits in dual-purpose sorghum. This showed that breeding progress can be achieved through hybridisation and selection. Cultivars showing high stability, and high standard and better-parent heterosis for the three traits were identified implying that breeding for general adaptation was an option and that productivity could be enhanced by breeding hybrid cultivars. The relationships between traits were estimated using correlation and path-coefficients analysis. Grain yield was found to be negatively and significantly associated with stem brix but was positively and significantly associated with stem biomass. This implied that breeding for high stem brix might compromise grain yield but selection for high stem biomass improved grain yield. Stem biomass and stem brix were not significantly correlated. The general negative relationship between grain and stem brix was attributed to the predominance of entries with contrasting performances for the two traits. However, the relationship between grain yield and stem brix of the top 20 performing entries showed a non-significant relationship between stem brix and grain yield suggesting that the traits were independent of each other. This finding was confirmed by the presence of crosses that combined high performance for both stem brix and grain yield as well as stem biomass among the hybrids. The relationships between stem brix and stem biomass for the top 20 performers remained non-significant while that between stem biomass and grain yield became stronger, positive and significant. Direct selection for stem brix and grain yield was shown to be more important than indirect selection, while selection for stem biomass improves grain yield but had no effect on stem brix. Therefore, it is possible to breed dualpurpose sorghum cultivars and the identification of genotypes combining the desirable traits is prudent in addition to general relationships information. The study on fertility restoration capacities as evaluated through hybrid seed set showed that fertility restoration was under the control of genes with both additive and non-additive action. Since restoration is conferred by a single dominant gene (Rf1), this could have arisen from the action of the modifier genes that have been previously reported to influence it. This showed that fertility restoration can be improved through breeding. Hybrid combinations showing complete seed set and high performance for grain, stem brix and stem biomass were identified and are potential dual-purpose sorghum cultivars. Overall, the study showed that development of dualpurpose sorghum cultivars would be feasible and genotypes identified as potential cultivars in this study will be forwarded for further testing across many sites and seasons in the target environments. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The purpose of the study was to investigate the potential tree taxa that could be grown as a source of biomass in the Cape Winelands region. The trials comprises of two different aspects. The first being the estimation of potential volume, density and biomass of a pair of six year-old stands of E. gomphocephala and E. cladocalyx families at two climatically different sites within the study region. The second part of the study was the early growth assessment of alternative taxa that could be planted in the region compared to the regional mainstay E. cladocalyx. The volume of families was estimated using appropriate volume equations and using the form height were none were available. The best volume yield varied from 4.6 to 11.2 m3 ha-1a-1, at the dry and sub-humid sites, respectively. Wood density, estimated from non-destructive samples at both sites, varied from 620 (sub-humid) to 588 kg m-3 (dry site). The estimated biomass production rate of the top producing families yielded 2.7 and 6.9 t ha -1a -1 at the dry and sub-humid sites, respectively. In terms of estimated biomass and survival, E. gomphocephala was more suited to the dry site, while E. cladocalyx displayed superior yield than E. gomphocephala on the sub-humid site, but not significantly so. Early growth assessment of the trial of alternative taxa found that the hybrid E. grandis × camldulensis and E. grandis × urophylla had superior biomass indices, but were more susceptible to infestation by Thaumastocoris peregrinus and Gonipterus scuttelatus. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om potensiële boom taksa vir gebruik as ’n bron van biomassa in die Kaapse Wynlandstreek te ondersoek. Die proewe behels twee aspekte: eerstens die beraming van die potensiële volume, digtheid en biomassa van sesjaaroue opstande met families van E. gomphocephala en E. cladocalyx by twee klimatologies verskillende groeiplekke in die studiegebied; tweedens die beoordeling van die vroeë groei van alternatiewe taksa wat in die streek geplant kan word in vergelyking met die streek se historiese staatmaker-spesie E. cladocalyx. Die volume van die families is beraam deur gebruik te maak van toepaslike volumevergelykings, en met behulp van ’n vormfaktor waar vergelykings nie beskikbaar was nie. Die volume aanwas by die droë en sub-humiede groeiplekke was onderskeidelik 4.6 en 11.2 m3 ha-1j-1. Houtdigtheid is beraam deur nie-destruktiewe monsters uit die opstand te neem. Gemiddelde digthede het variëer van 588 (sub-humied) tot 620 kg m-3 (droë groeiplek). Die beraamde biomassaproduksie van die top-families beloop onderskeidelik 2.7 en 6.9 t ha -1j -1 vir die droë en sub-humiede groeiplekke. In terme van beraamde biomassa en oorlewing, is E. gomphocephala meer geskik vir droër groeiplekke , terwyl E. cladocalyx by die sub-humiede groeiplek ’n hoër opbrengs as E. gomphocephala getoon het, hoewel nie betekenisvol nie. Beramings van die vroeë groei by die proef met alternatiewe taksa het getoon dat die basters E. grandis × camldulensis en E. grandis × urophylla hoër biomassa-indekse het, maar meer vatbaar is vir besmetting deur Thaumastocoris peregrinus en Gonipterus scuttelatus. / Centre for Renewable and Sustainable Energy Studies

Les travaux de cette thèse concernent la modélisation et l'optimisation de chaînes d’approvisionnement en biomasses pour de futures bio-raffineries. En effet, des chaînes d'approvisionnement efficaces sont essentielles pour fournir aux installations de conversion, de façon régulière, des quantités suffisantes de biomasse de qualité à des prix raisonnables. Le problème est tout d'abord décrit puis modélisé.Un modèle de réseau et un modèle de données sont ensuite développés pour permettre de décrire la structure de la chaîne d'approvisionnement et ses données, sans affecter le modèle mathématique sous-jacent. Ce dernier (MILP) combine pour la première fois divers aspects, soit originaux, soit gérés séparément dans la littérature. A partir des demandes de la raffinerie, une résolution exacte précise les activités logistiques dans le réseau et les équipements nécessaires, afin de minimiser le coût total composé des coûts de récoltes, de transport et de stockage. Des études de cas sont décrites pour illustrer ce modèle de planification tactique multi-biomasse et multi-période. Un modèle plus compact est aussi élaboré pour traiter des instances de très grandes tailles. Il est illustré par une étude de cas réelle pour une bio-raffinerie prévue près de Compiègne. Pour finir, les développements effectués pour la mise en place d’un prototype logiciel d’aide à la décision sont présentés et des recommandations d’un futur logiciel commercial sont proposées / The research works of this thesis address the problem of modeling and optimizing biomass supply chains for biorefineries. Indeed, efficient supply chains are essential to provide conversion facilities with sufficient quantities of quality biomass at reasonable prices. The problem is described and modeled.A network model and a data model are developed to allow to describe the structure of the supply chain and its data, without affecting the underlying mathematical model. The latter is a mixed-integer linear programming that combines for the first time various aspects, either original or tackled separately in the literature. For given refinery needs, its exact resolution by CPLEX specifies the logistic activities in the network (amounts harvested, baled, transported, stored etc.) and the necessary equipment, in order to minimize a total cost including harvesting costs, transport costs and storage costs. Case studies are described to illustrate this multi-biomass and multi-period tactical planning model.A more compact model is also elaborated to cope with large-scale instances. It is illustrated using a real case study for a bio-refinery planned near Compiègne, France.Finally, the developments conducted for the implementation of a prototype of decision-support application are presented and recommendations for coming to a commercial software are proposed

CAPES; CNPq; Fundação Araucária / No presente trabalho foram estudadas as respostas de sensores óticos baseados em rede de período longo em cascata (CLPG) na avaliação de biocombustíveis (biodiesel de soja e etanol) em diferentes situações de não conformidade, simulando casos de possíveis adulterações ou ainda falhas no processo de fabricação. Para tanto, os dispositivos serviram como transdutores de índice de refração das substâncias analisadas. Em uma das aplicações dos sensores foram avaliadas misturas entre biodiesel de soja e óleo de soja comercial, sendo observado o desempenho do sensor ótico ao longo de toda a faixa de concentração de óleo em biodiesel (0 – 100%) e, as características metrológicas foram calculadas para três faixas de operação do sistema, abrangendo diferentes faixas de concentrações. Para as faixas 1 a 3, a sensibilidade variou de 0,06 – 0,30 nm / % v/v e a resolução de 0,17 a 0,03 % / v/v. Com o intuito de comparar resultados, as mesmas amostras de biodiesel-óleo foram avaliadas com técnicas de ultrassom, obtendo para esse, sensibilidade de 0,70 m/s / % v/v e resolução de 0,4 %. Outra situação estudada foi com relação às misturas entre biodiesel de soja e metanol e a resposta do sensor ótico apresentou resolução de 0,007 – 0,001 % / v/v. Por meio dessas respostas pôde-se desenvolver um método analítico no qual se utiliza o sensor ótico para a determinação de constituintes em misturas ternárias (biodiesel-óleo-metanol), desde que associando à operação do sensor a variação de temperatura das amostras. Em outra parte do trabalho, o sensor ótico também foi empregado na avaliação de etanol. A resposta do sensor para misturas etanol-metanol apresentou resolução de 0,19 % / v/v, enquanto que, a avaliação dessas mesmas substâncias utilizando o ultrassom, apresentou resolução de 0,26 % / v/v. Outra situação analisada com o sensor ótico, para a análise da conformidade do etanol combustível, foram amostras apresentando misturas ternárias (etanol-metanol-água) em que se fez necessária a avaliação dessas misturas por meio de um refratômetro de Abbe e medidas de densidade. Os resultados encontrados apresentaram-se promissores ao relacionar os dados refratométricos em relação às densidades obtidas para cada amostra, uma vez que, apenas um desses parâmetros não seria capaz de identificar a conformidade do produto. Foi possível então determinar, dentre todos os resultados, uma região de conformidade para o etanol combustível. / In the present work were studied the responses of the optical sensors based on cascaded long period gratings (CLPG) to evaluate biofuels (soy biodiesel and ethanol) in different situations of non-compliance, simulating cases of possible tampering or failures in the process of manufacturing. To this end, the devices served as refractive index transducers of the analyzed substances. One of the applications of the sensors were evaluate mixtures of soybean biodiesel and commercial soybean oil, observing the performance of the optical sensor over the whole range of biodiesel oil concentration (0 - 100%) and the metrological characteristics were calculated for three system operating ranges covering different concentration ranges. In lanes 1 through 3, the sensitivity ranged from 0.06 to 0.30 nm /% v / v and the resolution from 0.17 to 0.03% / v / v. In order to compare the results, the same samples of biodiesel oil, were assessed by ultrasound techniques for obtaining this, a sensitivity of 0.70 m / sec / v / v% and resolution of 0.4%. Another situation studied envolved mixtures of soybean biodiesel and methanol and the response of the optical sensor showed resolution from 0.007 to 0.001% / v / v. Through these responses could be developed an analytical method which uses the optical sensor for the determination of constituents of ternary mixtures (biodiesel - soybean oil - methanol) associating to the sensor the right temperature of the samples. Another part of the work, the optical sensor was used in the evaluation of ethanol. The sensor response for ethanol-methanol mixtures showed resolution of 0.19% / v / v, while the evaluation of those substances using ultrasound, showed resolution of 0.26% / v / v. Another situation observed using the optical sensor was the analysis of ethanol fuel with samples having ternary mixtures (ethanol-methanol-water) in which the evaluation of these mixtures by means of a refractometer Abbe and density measurements made necessary. The results presented in these analyses are promising when related the refractometric to densities datas obtained for each sample, since only one of these parameters would not be able to identify the product conformity. It was then possible to determine, among all results, a compliance region for ethanol fuel.

CAPES; CNPq; Fundação Araucária / No presente trabalho foram estudadas as respostas de sensores óticos baseados em rede de período longo em cascata (CLPG) na avaliação de biocombustíveis (biodiesel de soja e etanol) em diferentes situações de não conformidade, simulando casos de possíveis adulterações ou ainda falhas no processo de fabricação. Para tanto, os dispositivos serviram como transdutores de índice de refração das substâncias analisadas. Em uma das aplicações dos sensores foram avaliadas misturas entre biodiesel de soja e óleo de soja comercial, sendo observado o desempenho do sensor ótico ao longo de toda a faixa de concentração de óleo em biodiesel (0 – 100%) e, as características metrológicas foram calculadas para três faixas de operação do sistema, abrangendo diferentes faixas de concentrações. Para as faixas 1 a 3, a sensibilidade variou de 0,06 – 0,30 nm / % v/v e a resolução de 0,17 a 0,03 % / v/v. Com o intuito de comparar resultados, as mesmas amostras de biodiesel-óleo foram avaliadas com técnicas de ultrassom, obtendo para esse, sensibilidade de 0,70 m/s / % v/v e resolução de 0,4 %. Outra situação estudada foi com relação às misturas entre biodiesel de soja e metanol e a resposta do sensor ótico apresentou resolução de 0,007 – 0,001 % / v/v. Por meio dessas respostas pôde-se desenvolver um método analítico no qual se utiliza o sensor ótico para a determinação de constituintes em misturas ternárias (biodiesel-óleo-metanol), desde que associando à operação do sensor a variação de temperatura das amostras. Em outra parte do trabalho, o sensor ótico também foi empregado na avaliação de etanol. A resposta do sensor para misturas etanol-metanol apresentou resolução de 0,19 % / v/v, enquanto que, a avaliação dessas mesmas substâncias utilizando o ultrassom, apresentou resolução de 0,26 % / v/v. Outra situação analisada com o sensor ótico, para a análise da conformidade do etanol combustível, foram amostras apresentando misturas ternárias (etanol-metanol-água) em que se fez necessária a avaliação dessas misturas por meio de um refratômetro de Abbe e medidas de densidade. Os resultados encontrados apresentaram-se promissores ao relacionar os dados refratométricos em relação às densidades obtidas para cada amostra, uma vez que, apenas um desses parâmetros não seria capaz de identificar a conformidade do produto. Foi possível então determinar, dentre todos os resultados, uma região de conformidade para o etanol combustível. / In the present work were studied the responses of the optical sensors based on cascaded long period gratings (CLPG) to evaluate biofuels (soy biodiesel and ethanol) in different situations of non-compliance, simulating cases of possible tampering or failures in the process of manufacturing. To this end, the devices served as refractive index transducers of the analyzed substances. One of the applications of the sensors were evaluate mixtures of soybean biodiesel and commercial soybean oil, observing the performance of the optical sensor over the whole range of biodiesel oil concentration (0 - 100%) and the metrological characteristics were calculated for three system operating ranges covering different concentration ranges. In lanes 1 through 3, the sensitivity ranged from 0.06 to 0.30 nm /% v / v and the resolution from 0.17 to 0.03% / v / v. In order to compare the results, the same samples of biodiesel oil, were assessed by ultrasound techniques for obtaining this, a sensitivity of 0.70 m / sec / v / v% and resolution of 0.4%. Another situation studied envolved mixtures of soybean biodiesel and methanol and the response of the optical sensor showed resolution from 0.007 to 0.001% / v / v. Through these responses could be developed an analytical method which uses the optical sensor for the determination of constituents of ternary mixtures (biodiesel - soybean oil - methanol) associating to the sensor the right temperature of the samples. Another part of the work, the optical sensor was used in the evaluation of ethanol. The sensor response for ethanol-methanol mixtures showed resolution of 0.19% / v / v, while the evaluation of those substances using ultrasound, showed resolution of 0.26% / v / v. Another situation observed using the optical sensor was the analysis of ethanol fuel with samples having ternary mixtures (ethanol-methanol-water) in which the evaluation of these mixtures by means of a refractometer Abbe and density measurements made necessary. The results presented in these analyses are promising when related the refractometric to densities datas obtained for each sample, since only one of these parameters would not be able to identify the product conformity. It was then possible to determine, among all results, a compliance region for ethanol fuel.

The search for alternatives to the fossil oil and concern about environmental pollution has increasingly supported the importance of biofuels. The production of bio-oil from aquatic plants (water hyacinth) has become as interesting alternative due to its rapid growth rate, robust nature and unrelated to the food chain. The present work aimed to study the application of conventional and catalytic pyrolysis to convert aquatic plants like Eichhornia crassipes (EC) and Eichhornia azurea (EA) in bio-oil, employing Ferrierite and Y zeolite as catalysts. These plants were obtained in Aracaju-SE and Itabaiana-SE, respectively. The micropyrolys is were performed at three temperatures (400, 500 and 600 °C). The catalytic micropyrolysis using Ferrierite and Y zeolite was performed in the same condition applying 1 and 5% of catalysts w/w. The bio-oils solutions obtained were characterized by GC/MS and GC-FID. The micropyrolysis performed in the absence of catalyst showed similar chromatographic profiles to the biomasses tested, with the composition of bio-oils showing phenolic compounds, acids and alcohols. With Ferrierite as catalyst at 5% in the micropyrolysis and performing a study from the total area of the obtained chromatograms was observed the higher yield by GC-FID caused by the increased formation of small molecular mass compounds from biomasses. However, when used 1% of the same catalyst to EC was not observed a very significant difference in relation with no catalyst pyrolysis. To the EA in this condition was observed a significant yield reduction when performed at 500 °C. When used Y catalyst for EA pyrolysis a smaller yield was observed at all studied temperatures that shows a significantly inhibited formation of compounds derived from these lignocelullosic biomasses. However for the EC catalytic pyrolysis with 5% of Y catalyst at 500 °C we observed the largest decrease in the yield from the chromatograms area. The bio-oils characterization gave compounds identified belong to the following classes: alcohol, phenol, and sugar acids. The bio-oils from catalytic pyrolysis of EC and EA biomass showed a high content of phenolic compounds and acidic compounds. / A procura por soluções alternativas para a substituição total ou parcial do petróleo e a preocupação com a poluição ambiental tem reforçado cada vez mais a importância da produção de biocombustíveis. Neste sentido a produção de bio-óleo a partir de plantas aquáticas tornou-se uma alternativa interessante. Estas plantas são invasoras e possuem alta taxa de crescimento, natureza robusta e não tem relação com a cadeia alimentar. Neste trabalho, biomassas provenientes de plantas aquáticas, obtidas em Itabaiana-SE e Aracaju-SE, das espécies crassipes (EC) e azurea (EA), ambas do gênero Eichhornia, foram submetidas a micropirólise convencional a três temperaturas, 400, 500 e 600 ºC, e catalítica empregando catalisadores do tipo zeólita Ferrierita e Y nas proporções de 1 e 5%. As soluções de bio-óleos produzidas foram caracterizadas por CG/EM e CG-FID. Na micropirólise realizada na ausência de catalisador foi observado semelhança na composição química do bio-óleo para todas as condições testadas. Empregando 5% de catalisador Ferrierita na micropirólise, e realizando um estudo da área total dos cromatogramas obtidos foram observados aumentos significativos a 400 ºC para EC (+53,74%) e para a EA (+43,67%). A 1% deste mesmo catalisador para a EC houve diminuição da área total nas três temperaturas, enquanto que para EA houve diminuição na área total a 500 ºC (-48,09%). Quando empregado a zeólita Y nas duas proporções foi observado menor capacidade de produção de bio-óleo para EA em todas as temperaturas estudadas. A maior diminuição de área foi a 600 ºC (-25,70%) a 1% de catalisador e quando utilizado 5% foi a 500 ºC (-84,34%), ou seja, houve a inibição significativa na formação de bio-óleo. Para a EC foi observado a maior diminuição da capacidade de conversão térmica catalítica desta biomassa em bio-óleo na condição de 5% de zeólita Y, a 500 ºC (-33,23%) e na condição de 1% de zeólita Y, a 600 ºC (-46,77%). Os principais compostos identificados nos bio-óleos obtidos foram das classes do álcoois, fenóis, ácidos e açúcares. O bio-óleo obtido por pirólise catalítica das biomassas EC e EA apresentou um alto teor de compostos fenólicos e ácidos.

Biomass gasification has attracted the interest of researchers because it produces zero carbon to the atmosphere. This technology does not only produce syngas but also the byproducts which can be used for various application depending on quality.The study conducted at Melani village in Alice in the Eastern Cape of South Africa was aimed at investigating the possible applications of the gasification byproducts instead of being thrown away. Pine wood was employed as the parent feedstock material for the gasifier. Biomass gasification by-products were then collected for further analysis. The studied by-products included tar(condensate), char, soot and resin. These materials were also blended to produce strong materials.The essence of the blending was to generate ideal material that is strong but light at the same time.The elemental analysis of the samples performed by CHNS analyser revealed that carbon element is in large quantities in all samples. The FTIR spectra showed almost similar results for all the studied samples, since the samples are end products of lignocellulosegasification. SEM gave the sticky images of resin as well as porous char structures. Char showed a higher heating value of 35.37MJ/Kg when compared to other by-products samples.

Low cover crop biomass production is a major obstacle to the success of conservation agriculture currently promoted as panacea to the inherent problem of soil erosion and loss of soil productivity in the Eastern Cape (EC). Therefore, this study evaluated cover crop management strategies for optimizing biomass production for better soil cover, soil nitrogen (N) and phosphorus (P) fertility, weed control and maize yields. The strategies tested are cover crop bicultures, selection of an adapted lupin cultivar and seeding rate, and the feasibility of rain fed winter cover cropping. The cover crop experiments were carried in rotation with summer maize between the winter of 2009 and summer of 2010/2011. Biculture trial was carried out by seeding oat (Avena sativa) and vetch (Vicia dasycarpa) at three mixture ratios and as sole crops under irrigation. On a separate irrigated trial, two lupin cultivars (Lupinus angustifolius var Mandelup & Qualinock) were seeded to a range of seeding rate, 40 to 220 kg ha-1. To study the feasibility of rain fed winter cover cropping, oat, vetch, rye (Lolium multiflorum), barley (Hordeum vulgare), radish (Raphanus sativa) and triticale (Triticale secale) were relayed into a maize crop in February, March and April of 2010. The irrigated trials were followed with SC701 maize cultivar, whilst the rain fed trial was followed with DKC61-25 maize cultivar. Bicultures gave higher cover crop biomass than sole vetch, increasing with an increase in the oat component of the mixture. Increased N and P uptake was observed with bicultures compared to sole oat, however, the levels were comparable to sole vetch. Sole vetch increased soil inorganic N and P at maize planting, whilst the slow decomposition by sole oat residue resulted in mineral lock up. Bicultured cover crop residues had intermediate decomposition rates and resulted in optimum levels of inorganic N and P for prolonged periods compared to sole crops. Weed suppression by the bicultures was comparable to sole cover crops. Biculturing technology significantly (P<0.05) increased maize grain yield compared to sole oat and the yields were comparable to those from sole vetch. For lupins, 206 kg ha-1 seeding rate gave the optimum biomass yield. Weed dry weights in both cover crop and maize crop decreased with an increase in lupin biomass. Comparable soil total N and inorganic P values at maize planting, were observed from plots planted to 120, 180 and 220 kg ha-1. Maize grain yield increased with an increase in lupin seeding rate. The study on rain fed winter cover cropping had most cover crop species’ biomass decreasing with each delay in planting except for radish, which increased. Vetch produced the highest amounts of biomass from February and March planting whilst radish had the highest biomass in April planting. The two species resulted in the greatest N improvement compared to the other species. Regardless of the grazing, the grass specie residues managed to persist to the next cropping season and the residue remaining were comparable to that of radish and vetch. Late-planted cover crops had the greatest residue remaining than early-planted, as a result, April planted cover crops provided better weed suppression than March and April planted. Vetch provided the highest maize grain yield (4005 kg ha-1) whilst all other species tested had comparable grain yields. The results suggested that bicultures could be grown to give sufficient biomass for both weed suppression and soil fertility improvement. Furthermore, increasing lupin plant densities improve its function as a cover crop with respect to weed suppression, soil fertility improvement and maize yields. The study also showed that for dry land systems, February and March planted vetch and April planted radish can provide the greatest biomass and maize yield improvement.

The overall objective of the whole study was to assess whether conservation agriculture (CA) systems can work in the Eastern Cape Province (EC). The CA systems were engaged through cover cropping to address land degradation problems by emphasizing high biomass production in order to realize short term benefits such as moisture conservation, weed suppression and soil fertility benefits under rainfed conditions in the central region of the Eastern Cape province. Since rainfall is the most limiting factor to crop production in the EC, a within season rainfall distribution analysis was conducted to expose the quality of the season (onset, end and duration) and hence the feasibility of CA systems to guide agronomic decisions by farmers in EC. To assess season parameters, thirty four years of daily rainfall was collected from the University of Fort Hare Research station and used to conduct the rainy pentad (5 day rainfall totals) analysis and the daily rainfall analysis using INSTAT software programme. Based on the pentad analysis, results showed that Alice does not have a rainy season in 1 out of 2 years (50% probability) but has one in 1 out of 4 years (25% probability level). This criterion proved to be harsher and conservative when compared to the daily rainfall approach which is more precise in measuring trends on season parameters. The daily rainfall analysis indicated a 65% feasibility for the dry land cropping systems in the EC. The pentad analysis however was effective in illustrating seasonality and it showed that the wet season begins on the 1st of November, ending on the 22nd of March lasting for 140 days. Though the season duration appeared too long, the existence of dry spells during critical growth stages adversely affects the quality of the season. The daily rainfall analysis also managed to derive a signal which can guide planting decisions. For planting to be successful, this analysis determined that 20 mm of rain should be received in two consecutive days after the 1st of November. A screening trial for cover crop biomass production and weed suppression was conducted on-station Fort Hare Research Farm (32°46' S and 26° 50' E), and Msobombvu village (MSBV) (32°44' S, and 26° 55' E) over two seasons (2007/08 and 2008/09). Six summer cover crops i.e. cowpea (Vigna unguiculata), dolichos lablab (Dolichos argenteus), sunnhemp (Crotalaria juncea), buckwheat (Fagopyrum sagittatum), forage sorghum (Sorghum bicolor) and sunflower (Helianthus annus) were evaluated for biomass yield, and weed suppression. Decomposition rates, moisture conservation and residual effects of these cover crops on the succeeding main crop were also evaluated under dryland conditions. The screening trial was laid in randomized complete block design replicated three times. Forage sorghum (Sorghum bicolor) and sunflower (Helianthus annus) were identified as high biomass producers and their dry matter yields ranged from 8 -12 t ha-1. These cover crops can be useful in generating high biomass in rainfed cropping systems in the EC. Other cover crops produced 3 - 4 t ha-1 of biomass which fell short of the 6 t ha-1 expected benchmark. However, these biomass yields were important in weed management since all cover crop species showed a similar degree of weed suppression which surpassed the weed fallow treatment. As dead mulches, the cover crops failed to show residual moisture conservation and weed control benefits for the succeeding maize crop mainly because of poor residue persistence, and low harvestable fallow rainfall. Buckwheat (Fagopyrum esculentum), was selected for further investigations in a follow up trial on station in 2008/09 season because of its weed smothering qualities, suitability to short cycle rotations, and possible allelopathic properties. The trial aimed at finding weed and cost effective management options of buckwheat that are none detrimental to the succeeding maize crop. Results showed that cropping systems where buckwheat is followed by a main crop may not work as they are unprofitable with respect to R100 rand invested. Though perceived to have allelopathic properties, buckwheat failed to demonstrate the possibilities of allelopathic action against weeds. Intercropping trial was conducted on-station in 2007/8-2008/09 seasons to try and find better ways of fitting legume cover crops into maize based cropping systems without compromising production of staple cereals on limited landholdings. The trials evaluated three factors in factorial combination, cover crop planting date, intercropping strategy, and cover crop species. The trial was laid as 2 x 2 x 3 factorial arranged in a split-split plot design. The main plot factor was cover crop planting date, cover crops simultaneously planted with maize and cover crop planted two weeks after planting maize (DKC 61-25). The sub-plot factor was intercropping strategy, strip intercropping and betweenrow intercropping. The sub-sub-plot factor was cover crop species, Dolichos lablab (Dolichos argenteus (Highworth), and Cowpea Vigna ungiculata (Agrinawa) plus control plots of sole maize. Results showed that same time planting of leguminous cover crops with maize using the in-between row intercropping patterns can derive appreciable system biomass (maize/cover crop) yields, utilize land efficiently whilst getting favourable maize grain yield. Based on the rainfall analysis, results showed that the probability of success when relay seeding cover crops after two weeks into standing maize is low (15% chances of success). This suggests that relay intercropping strategies would not work due to the unavailability of a good quality season.