This thesis examines the role of dissolved inorganic nutrients in generating changes in phytoplankton community and pigment composition and if such changes can affect the production of the antioxidant astaxanthin in the ecosystem via pelagic copepods. The background of my studies is the possible relationship between eutrophication and a reproductive disturbance in Baltic populations of Atlantic salmon (M74), which is associated with astaxanthin and thiamine deficiencies and oxidative stress. In the southern Baltic Sea, changes in nutrient loads correlate with observed trends of flagellates replacing diatoms in the phytoplankton. Copepods are the main producers of astaxanthin and a major link between phytoplankton and higher trophic levels. In laboratory and field experiments in the Baltic Sea proper and the Norwegian Sea, I show that astaxanthin synthesis in copepods is fast and depends on pigment composition of the phytoplankton diet. Among single-species diets, a diatom and a green algal cyst yielded the highest astaxanthin levels in copepods, and another diatom species, a green alga and a cyanobacterium the lowest. In nutrient-generated phytoplankton blooms in mesocosms, copepods grazing on diverse communities dominated by weakly silicified diatoms produced more astaxanthin compared with copepods grazing on communities dominated by strongly silicified diatoms. This suggests that diatoms invested in defence mechanisms and escaped grazing at surplus Si. A nutrient-starved diatom culture subjected to intraspecific competition exhibited decreased pigment levels, increased thiamine levels and increased oxidative stress. My results suggest that diatoms are beneficial for astaxanthin and thiamine production compared to other phytoplankton groups, but not under all circumstances. Copepod growth and development also responded to inorganic nutrient availability and affected total astaxanthin production per volume seawater, with highest production when the copepods grazed on diatoms. From an ecosystem perspective, increased N and P loads seem to promote high astaxanthin production, but not when diatoms disappear completely.

La digestion anaérobie est un processus biologique dans lequel un consortium microbien complexe fonctionnant en absence d’oxygène transforme la matière organique en biogaz, principalement en méthane et en dioxyde de carbone. Parmi les substrats organiques, les lipides sont les plus productifs de méthane par rapport aux glucides et aux protéines; mais leur dégradation est très difficile, en raison de leur hydrolyse qui peut être l’étape limitante. Les algues peuvent être une source importante pour la production de méthane à cause de leur contenu en lipides potentiellement élevé. L’objectif de cette étude était, par conséquent, d’évaluer la production en méthane des microalgues en utilisant la technique du BMP (Biochemical méthane Potential) et d’identifier les limites de biodégradion des lipides dans la digestion anaérobie. Le plan expérimental a été divisé en plusieurs étapes: 1) Comparer le potentiel énergétique en méthane des macroalgues par rapport aux microalgues. 2) Faire le criblage de différentes espèces de microalgues d’eau douce et marines afin de comparer leur potentiel en méthane. 3) Déterminer l'impact des prétraitements sur la production de méthane de quelques microalgues ciblées. 4) Identifier les limites de biodégradation des lipides algaux dans la digestion anaérobie, en étudiant les étapes limitantes de la cinétique des lipides et de chacun des acides gras à longues chaines. Les résultats ont montré que les microalgues produisent plus de méthane que les macroalgues. Les BMP des microalgues d'eau douce et marines n'ont montré aucune différence en termes de rendement en méthane. Les résultats des prétraitements ont montré que le prétraitement thermique (microonde) semblait être plus efficace que le prétraitement chimique (alcalin). Les tests de contrôle du BMP faits sur l'huile de palme, l’huile de macadamia et l'huile de poisson ont montré que l'hydrolyse des huiles en glycérol et en acides gras à longues chaines n'était pas l'étape limitante dans la production de méthane. L'ajout de gras dans les échantillons de Phaeodactylum dégraissée a augmenté le rendement de méthane et cette augmentation a été corrélée à la quantité de matières grasses ajoutées. / Anaerobic digestion is a biological process in which an anaerobic microbial consortium converts organic matter into biogas, primarily methane and carbon dioxide. Among the organic substrates, lipids are the most productive of methane in comparison to carbohydrates and proteins; but their degradation is very difficult, due to their hydrolysis which can be the limiting step. Algae can be an important source for methane production because of their potentially high content of lipids. The objective of this study was, therefore, to evaluate the methane production of microalgae using the Biochemical methane Potential (BMP) technique and to identify the limit of biodegradation of lipids in the anaerobic digestion. The experimentation plan was divided into the following stages: 1) Compare the energy potential in methane of macroalgae versus microalgae. 2) Screen different species of freshwater and marine microalgae to compare their methane potential. 3) Determine the impact of mild pretreatment of targeted microalgae on the methane production. 4) Identify the limits of biodegradation of algal lipids in the anaerobic digestion by studying kinetics limiting steps of lipids and individual LCFA (Long Chain Fatty Acids). The results showed that microalgae produce more methane than macroalgae. The BMP of freshwater and marine microalgae showed no difference in terms of methane yield. The results of pretreatment showed that the thermal (microwave) pretreatment seemed to be more effective than the chemical (alkaline) pretreatment. A BMP control test done on palm oil, macadamia oil and fish oil showed that the hydrolysis of oils in glycerol and LCFA was not the limiting step in the production of methane. The addition of fat in the samples of defatted Phaeodactylum increased the methane yield and this augmentation was correlated to the quantity of fat added.

Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry, Durban University of Technology, Durban, South Africa, 2015. / Fossil fuel reserves have been diminishing worldwide thus making them very scarce in the long term. These fuel sources and their by-products which are used commercially tend to produce large quantities of emissions. Some of them are believed to be toxic to flora and fauna. It is primarily for this reason that researchers worldwide have begun to seek out alternative sources of environmentally safe fuel. Biodiesel from algae is one of these sources that have been examined over the last few decades. Biodiesel has been produced from other plant-based material and waste oils in countries like America and Japan. However, the use of food based crops for biodiesel production has been challenged as it has an impact on food production on an international scale. Algae have only recently been investigated for their feasibility for biodiesel production on a large scale. The aim of this study was to investigate and develop technologies for biodiesel production from algae. The species of algae chosen were chlorella sp and scenedesmus sp., since they are indigeneous to Kwazulu Natal in South Africa. Samples were obtained from a local raceway pond and prepared for analysis. Drying protocols used freeze, oven and sun drying for initial preparation of the samples for analysis. Sun drying was the least energy intensive but most time consuming. At laboratory scale, oven drying was chosen as the best alternative. Lipid extraction methods investigated were the separating funnel method, the soxhlet method, microwave assisted extraction (MAE) and the expeller press. Thirteen solvents covering a range of polarities were used with the extraction methods to determine the efficiency of the solvent with these methods. Optimization of the MAE method was conducted using both the one factor at a time (OFAT) method and a design of experiment (DOE) statistical method. The shelf life of algal biomass was determined by ageing the samples for approximately three months. Direct and in-situ transesterification of lipid extracts to produce biodiesel was investigated using both acid and base catalysis. Qualitative and quantitative analyses were conducted using Fourier transform infra-red (FTIR) and gas chromatography (GC). Chemical and physical characterization of the biodiesel produced from the algal lipid extracts were compared to both local and international standard specifications for biodiesel. In terms of extraction efficiency, it was found that soxhlet and microwave assisted extraction methods were almost equally good. This was proved by the MAE method yielding an average of 10.0% lipids for chloroform, ethanol and hexane after 30 mL of solvent was used in an extraction time of 10 minutes, while the soxhlet method yielded 10.36% lipids using an extraction volume of 100 mL of solvent with an extraction time of 3 hours. Chloroform, ethanol and hexane were more efficient than the other ten solvents used. This was shown by these three solvents producing lipid quantities between 10% to 11% while all the other solvents produced lipid quantities between 2 and 10 %. The best extraction efficiency was achieved by the binary solvent mixture made up of chloroform and ethanol in a 1:1 ratio. Under the conditions optimized, this solvent ratio yielded a lipid content of 11.76%. The methods chosen and optimized for extraction are very efficient, but the actual cost of production of biodiesel need to be determined. Physical methods like the expeller press are not feasible for extraction of the type of biomass produced unless algae are pelletized to improve extraction. This will impact on the cost of producing biodiesel. The transesterification protocols investigated show that the base catalysis produced biodiesel with a ratio of saturates to unsaturates conducive to a good fuel product. The direct esterification method in this study proved to be better than the in-situ method for biodiesel production. The in-situ method was also more labour intensive. Chromatography was found to be a fast and efficient method for qualitative and quantitative determination of biodiesel. Characterization tests showed that the quality of biodiesel produced was satisfactory. It also showed that the methods used in this study were feasible for the satisfactory production of biodiesel which meets local and international specifications.

Made available in DSpace on 2016-06-02T19:32:06Z (GMT). No. of bitstreams: 1 4940.pdf: 1724181 bytes, checksum: edce5d0a5db2ddb6103377e2a01b20fd (MD5) Previous issue date: 2011-08-26 / Universidade Federal de Sao Carlos / The chemical compounds called triacylglycerides (TAGs) have been the main source for biodiesel. The isolation of high lipid yield microalgae is important for the success of algae biomass production for biodiesel and, therefore, a search not only for organisms that fulfill such profile, but also for techniques effective in rapid lipid detection is fundamental. A number of methodologies on the characterization of microalgae lipid production, such as FTIR and RMN spectroscopy and spectrofluorimetry using the Nile Red dye are presented in this study. The Fourier Transform Infrared Spectroscopy (FTIR) technique have been largely used in biological system studies due to its rapid analysis, no pretreatment data gathering and easy biochemical characterization of intact cells. This study proposes a technical optimization of the FTIR technique for microalgae usage purposes as a practical approach for concomitantly prospecting large amounts of microalgae species with focus on biodiesel production. The Red Nile fluorescence has been successfully applied in microalgae lipid determination. In this research, the lipid (neutral) amount was determined by fluorescence in 430-570nm and a linear correlation established with the data gathered through gravimetry. After prospecting a number of species from the laboratory s stock cultures, the freshwater microalgae Scenedesmus sp (Clone MJ13) has been selected for study under traditional growth practices and under conditions of different nitrogen and phosphorus concentrations. The results showed a fast metabolic answer of Scenedesmus sp to the nutritional availability and the efficiency of the FTIR spectroscopy as a fast and reliable method for the determination of lipid production in a prospecting process. / A principal fonte para o biodiesel tem sido os compostos químicos denominados triacilglicerídeos (TAGs). O Isolamento de microalgas com alto rendimento lipídico é a chave para o sucesso da produção de biodiesel a partir de biomassa algal. Desta forma fazse necessário uma busca não somente por organismos que atendam tal exigência, mas também por técnicas eficazes que nos auxiliem na investigação destes. No presente estudo foram apresentadas algumas metodologias úteis na caracterização da produção de lipídeos por microalgas, tais como as espectroscopias de FTIR e RMN e a espectrofluorimetria com o corante Vermelho do Nilo. A técnica de espectroscopia de Infravermelho com Transformada de Fourier (FTIR) vem sendo muito utilizada nos estudos de sistemas biológicos, devido a sua rapidez de análise, obtenção de dados sem tratamento prévio e facilidade na caracterização bioquímica de células intactas. Foi proposto neste trabalho, uma otimização da técnica de FTIR para utilização em microalgas, como um método prático de prospectar concomitantemente uma grande quantidade de espécies de microalgas com finalidade de produção de biodiesel. A fluorescência por vermelho do Nilo tem sido aplicada com sucesso na determinação de lipídeos em microalgas. Desta forma a quantidade de lipídeos (neutros) foi determinada pela fluorescência em 430-570nm, e feita uma correlação linear com os dados obtidos por gravimetria. Após prospecção de várias espécies do banco de culturas do laboratório, foi selecionada a microalga de água doce Scenedesmus sp (Clone MJ13) para um estudo de caso em condições normais de cultivo e sob condições de diferentes concentrações de nitrogênio e fósforo. Os resultados demonstraram uma rápida resposta metabólica da Scenedesmus sp às mudanças na disponibilidade de nutrientes e indicam a eficiência da espectroscopia de FTIR como um método confiável e rápido para a determinação de produção lipídica em um processo de prospecção.

Made available in DSpace on 2016-06-02T19:32:07Z (GMT). No. of bitstreams: 1 5046.pdf: 1658349 bytes, checksum: a29e678386c15bfb307df8abcd53cc26 (MD5) Previous issue date: 2013-02-23 / Universidade Federal de Minas Gerais / Effluents from sewage treatment plants usually have high concentration of inorganic nutrients such as nitrogen (N) and phosphorus (P), which can be used for algal growth. Due to this possibility, the use of such wastewater can become a strategy for reducing the cost of microalgae production and/or reduction of costs in sewage treatment plants. This would result in the reduction of coliform bacteria and nutrients thereby improving the quality of effluent to be discharged. This research aimed to monitor the native community of microalgae and coliform bacteria from wastewater produced from anaerobic treatment of municipal sewage. Two bioassays were performed, an aerated and a non-aerated. Five liters samples of the wastewater were incubated in a greenhouse with semi-controlled environment using batch mode. The results showed no significant variation in pH for any of the bioassays. A reduction of 99.9% of colony forming units (CFU/mL) of both total coliforms and Escherichia coli was obtained after short period incubation. The concentrations of nutrients (N and P) decreased in the aerated bioassay, but not in the non aerated one. The growth curve of microalgae community presented an initial adjustment/adaptation phase only in the aerated bioassay, whereas in the nonaerated, microalgae growth was exponential since the beginning of incubation. The microalgae Chlorophyceae Chlorella vulgaris was dominant in the phytoplankton community in both bioassays coming to 99% of the total biomass. In the aerated bioassay, 12 taxa distributed into five classes were present (Chlorophyceae, Cyanophyceae, Chrysophyceae, Bacillariophyceae and Euglenophyceae), whereas in the non-aerated, only three classes were identified (Chlorophyceae, Cyanophyceae and Euglenophyceae), with 6 taxa. We conclude that the anaerobic sewage effluent supported algal growth, mainly the Chlorophyceae Chlorella vulgaris and improved the anaerobic sewage treatment wastewater quality, reducing their potential for eutrophication. We also conclude that effluent aeration is most useful when the objective is the production of microalgae and nutrients reduction. / Os efluentes de estações de tratamento de esgoto apresentam elevada concentração de nutrientes inorgânicos, como nitrogênio (N) e fósforo (P), que podem ser usados para o crescimento algal. Dada à essa possibilidade, o uso desse resíduo pode tornar-se uma estratégia para a redução dos custos de produção de microalgas e/ou abatimento de gastos em estações de tratamento de esgoto. Isso teria como consequência a redução dos nutrientes e de bactérias coliformes no efluente, melhorando assim sua qualidade antes do descarte final. Esta pesquisa teve como objetivo principal monitorar a comunidade de microalgas nativas e bactérias coliformes em efluente resultante de tratamento anaeróbio de esgoto municipal. Foram realizados 2 bioensaios, um aerado e outro não aerado em amostras de 5 L incubadas em casa de vegetação com ambiente semicontrolado. Os resultados mostraram que não houve variação significativa do pH para qualquer um dos bioensaios. Detectou-se redução de 99,9% de unidades formadoras de colônias (UFC/mL) tanto de coliformes totais, quanto Escherichia coli. O bioensaio aerado apresentou redução nas concentrações de nutrientes (N e P). A curva de crescimento da comunidade de microalgas apresentou uma fase de adaptação inicial apenas no bioensaio aerado, enquanto que no não aerado, o crescimento foi exponencial desde o início da incubação. Chlorella vulgaris foi a microalga dominante na comunidade fitoplanctônica em qualquer um dos bioensaios (99% do total). No bioensaio aerado, 12 táxons distribuídos em 5 classes algais estiveram presentes (Chlorophyceae, Cyanophyceae, Chrysophyceae, Euglenophyceae e Bacillariophyceae), enquanto que no não aerado, apenas 3 classes foram identificadas (Chlorophyceae, Cyanophyceae e Euglenophyceae), com 6 táxons. Dos resultados obtidos, conclui-se que o efluente de esgoto anaeróbio suportou o crescimento algal, principalmente da Chlorophyceae Chlorella vulgaris, que melhorou a qualidade do efluente, reduzindo seu potencial de eutrofização. Conclui-se ainda que a aeração do efluente é indicada quando se objetiva, além da produção de microalgas, a redução de nutrientes.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-11T23:43:24Z No. of bitstreams: 1 JOSÉ FRANCIRALDO DE LIMA – TESE (PPGEP) 2016.pdf: 11638647 bytes, checksum: edab69542eea5017c7786eea5cef2ded (MD5) / Made available in DSpace on 2018-06-11T23:43:24Z (GMT). No. of bitstreams: 1 JOSÉ FRANCIRALDO DE LIMA – TESE (PPGEP) 2016.pdf: 11638647 bytes, checksum: edab69542eea5017c7786eea5cef2ded (MD5) Previous issue date: 2016-08 / As microalgas produzem quantidades elevadas de compostos, principalmente lipídeos e açúcares. Quando essas são submetidas a variações de nutrientes podem elevar consideravelmente a concentração desses compostos, os quais são empregados para a produção de alimentos, biocombustíveis, cosméticos e componentes farmacêuticos. Esta pesquisa objetivou realizar o cultivo da microalga Chlorella sp., em fotobiorreator aberto de campo com diferentes concentrações de nutrientes, em seis tratamentos distintos (TC, T1, T2, T3, T4 e T5), secar as biomassas dos diferentes tratamentos e caracterizá-las quanto aos parâmetros físicos, químicos e físicos-químicos, como também construir suas isotermas de adsorção de umidade a 25ºC. A estirpe utilizada neste trabalho foi isolada da barragem da Conceição, localizada na Fazenda Tamanduá, Santa Teresinha, PB, e o meio utilizado foi meio MC. (Medium Chlorella ellipsodea). As características da microalga durante 16 dias de cultivo foram avaliadas com relação ao crescimento celular (peso úmido e peso seco), teor de lipídeos e açúcares totais. De acordo com os resultados verificou-se que a maior produção de biomassa daChlorella sp. em termos de peso seco, foi alcançada nos tratamentos TC, T1, T2 e T5 no 10º dia de cultivo e que com a redução nos tratamentos das concentrações de nitrogênio, fósforo, potássio e ferro houve aumento da síntese de lipídeos; para os tratamentos T3 e T4 o maior peso seco foi atingido no 12º e 16º dias de cultivo, respectivamente. A redução nas concentrações dos elementos nitrogênio, fósforo, potássio e ferro não favoreceru o aumento da produção dos minerais, proteínas, clorofila e feofitina. Os modelos de GAB, Peleg e Oswin podem ser usados para estimar as isotermas de adsorção de umidade, a 25ºC, da Chlorella sp. secas de todos os tratamentos,e foram classificadas como tipo II (TC, T1 e T5) e tipo III (T2, T3 e T4). Diante dos resultados constatou-se que a produção da biomassa da Chlorella sp. apresenta grande potencial de aplicação industrial para a produção de lipídeos e carboidratos com menores concentrações de NPK e ferro, que são os elementos de maior custo na produção de biomassa para aplicações nas áreas de alimentos e energia. / Microalgae produce high amounts of the compounds, mainly lipids and sugars. When these are subjected to nutrient variations can greatly increase the concentration of these compounds, which are used for food production, biofuel, cosmetic and pharmaceutical components. This research aimed to carry out the cultivation of icroalgae Chlorella sp.,Open photobioreactor field with different concentrations of nutrients in six different treatments (TC, T1, T2, T3, T4 and T5), dry biomasses of different treatments and character- them as to the physical, chemical and physical-chemical parameters, but also build their moisture adsorption isotherms at 25 ° C. The strain used in this study was isolated from the Conception dam, located in Tamanduá Farm, Santa Teresinha, PB, and the medium was medium MC. (Medium Chlorella ellipsodea). The microalgae features for 16 days of culture were evaluated with respect to cell growth (wet weight, dry weight), lipid content and total sugars. According to the results it was found that the higher biomass Chlorella sp. in terms of dry weight was achieved in the TC treatment, T1, T2 and T5 on the 10th day of culture and treatments with the reduction in the concentrations of nitrogen, phosphorus, potassium and iron was increased lipid synthesis; for treatments T3 and T4 the highest dry weight was achieved in the 12th and 16th day of cultivation, respectively. The reduction in the concentrations of the elements nitrogen, phosphorus, potassium and iron did not favor increased production of minerals, proteins, chlorophyll and pheophytin. The models of GAB, Oswin Peleg and can be used to estimate the moisture adsorption isotherms at 25 ° C, the Chlorella sp. dry all treatments and were classified as Type II(CT, T1 and T5) and type III (T2, T3 and T4). From the results it was found that the production of biomass Chlorella sp. It has great potential forindustrial application for the production of lipids and carbohydrates with lower NPK and ironconcentrations, which are the largest cost component in the production of biomass for applications in the areas of food and energy.

L’équilibre de l’écosystème microbien du caecum (Ca) et du colon ventral droit (Cn) équin peut être rompu par un changement brusque d’aliments et par une ration riche en amidon, et conduire à l’apparition de coliques. Chez des chevaux soumis à ces deux pratiques alimentaires, nous avons étudié les modifications de ces écosystèmes, de l’écosystème microbien fécal et de paramètres sanguins. Nous avons également testé la supplémentation composée de Saccharomyces cerevisiae et de microalgues Schizochytrium limacinum dans le cadre d’une collaboration avec Alltech. Nous avons montré que les écosystèmes microbiens du Ca et du Cn, stables lors d’un régime foin, pouvaient être rapidement modifiés par le stress provoqué par les deux pratiques alimentaires. Chez les chevaux supplémentés certains taxons bactériens potentiellement fibrolytiques ont augmenté dans le Ca et le Cn, et les dysbioses résultant d’un régime riche en amidon ont été limitées. Nous avons identifié plusieurs paramètres fécaux et sanguins reflétant les variations de l’écosystème microbien du Ca et Cn lors d’un changement de régime: les groupes bactériens fonctionnels, les abondances relatives de taxons bactériens (la famille XIII de Clostridiales, Succinivibrionaceae et des genres appartenant à Ruminococcaceae, Lachnospiraceae ou Prevotellaceae), les proportions et le ratio d’AGV, la concentration de valerate, les lipopolysaccharides fécaux ainsi que le beta-hydroxybutyrate sanguin. Ces paramètres semblent prometteurs pour diagnostiquer les dysbioses du gros intestin équin et prévenir l’apparition des coliques chez le cheval. / The balance of the microbial ecosystem of the caecum (Ca) and the right ventral colon (Cn) of the horse can be disturbed by an abrupt change of feed and by a high-starch diet, and lead to appearance of colic. We investigated the alterations of these ecosystems, of the faecal microbial ecosystem and of blood parameters in horses subjected to these two dietary practices. In addition, we tested a supplementation combining the yeast Saccharomyces cerevisiae and the microalgae Schizochytrium limacinum, in a context of partnership with Alltech. We showed that the Ca and Cn microbial ecosystems were stable under a hay diet, and can rapidly be modified under a stress caused by the two dietary practices. In supplemented horses, some potential fibrolytic bacterial taxa increased in the Ca and Cn, and the dysbiosis resulting from a high-starch diet were limited. We identified several faecal and blood parameters reflecting the variations of the Ca and Cn microbial ecosystem under a change of diet: the bacterial functional groups, the relative abundances of bacterial taxa (family XIII of Clostridiales, Succinivibrionaceae and genera belonging to Ruminococcaceae, Lachnospiraceae or Prevotellaceae), the proportion of acetate and propionate, the VFA ratio, the valerate concentration, the faecal lipopolysaccharides and the blood beta-hydroxybutyrate. These parameters appeared promising to diagnose dysbiosis in the proximal hindgut and thus prevent colic appearance in horses.

A energia é algo essencial para a vida, auxiliando no desenvolvimento e conforto da humanidade, porém são necessários constantes avanços para produção de energias mais limpas e utilização com maior eficiência. Dentro deste enfoque destacam-se as fontes renováveis de energia, as quais atendem requisitos básicos de sustentabilidade e reduzida agressão ao ambiente. Nesta pesquisa o objetivo principal consistiu na avaliação da produtividade de microalgas em Lagoas de Alta Taxa (LAT) alimentadas com esgoto sanitário (bruto e pré-tratado em reator UASB) e operadas em condições de clima subtropical. A separação da biomassa algal foi realizada pelo processo de Flotação por Ar Dissolvido (FAD), utilizando dois coagulantes inorgânicos (cloreto férrico e sulfato de alumínio) e dois floculantes orgânicos (Sulfloc 5000 e Tanac sg). Foi também avaliada a remoção de matéria orgânica e nutrientes pelas lagoas e processo de flotação. A atividade experimental compreendeu duas Etapas, em função do TDH das lagoas, sendo que na Etapa I (TDH= 3 dias) a LAT-A foi alimentada por esgoto bruto e a LAT-B com efluente de reator UASB. Nesta Etapa foi empregado sistema de coagulação/floculação helicoidal para formação dos flocos de biomassa a serem separados na unidade de flotação. Na Etapa II as duas lagoas foram operadas com TDH= 6,1 dias e alimentadas com efluente do reator UASB. Nesta Etapa foi empregado sistema de coagulação/floculação mecanizado, devido à baixa eficiência obtida pelo floculador helicoidal. Durante a Etapa I, o emprego do coagulante cloreto férrico com dosagens de 20 mg/L resultou em maior eficiência de remoção de matéria orgânica (DQO5, DBO), sólidos e nutrientes (Pt, NTK), seguido pelo floculante orgânico sulfloc 5000 com dosagem de 50 mg/L. Na Etapa II o floculante orgânico Tanac sg resultou em maior eficiência, exceto na remoção de Pt, onde cloreto férrico com dosagem de 40 mg/L apresentou melhor resultado. A presença de microalgas na LAT- B, estimada pelo parâmetro Sólidos Suspensos Voláteis (SSV) durante a Etapa I e Etapa II foi de 90,7 ± 44,1 mg/L e 125,6 ± 68,3 mg/L respectivamente, obtendo produtividade de algas de 9,1 ± 4,4 g/(m²∙d) e 6,2± 3,4g/(m²∙d). Cabe também destacar que na primavera (setembro - dezembro) foram verificados os valores médios mais elevados de SSV, de 112,1 ± 55,1 mg/L para Etapa I e 159,8 ± 71,0 para Etapa II. Nesta pesquisa, a produtividade de algas na Etapa I, expressa em g/(m²∙d), atingiu valores 38 % mais elevados que na Etapa II devido a maior vazão aplicada. Porém na Etapa II foi obtido efluente final com melhor qualidade, o qual é um aspecto de importância para definição dos parâmetros recomendados para projeto de lagoas de alta taxa de produção de algas. / Energy is something essential for life, assisting in the development and comfort of humanity, however constant advances for the production of cleaner energy and more efficiently use is necessary. Within this approach the renewable source of the energy deserve attention, which meet basic requirements of sustainability and reduced environmental nuisance. In this research the main objective consisted of evaluating the productivity of microalgae cultivate on High Rate Ponds (HRP) fed with domestic wastewater (raw and pretreated in UASB) and operated in subtropical conditions. The biomass separation was performed by Dissolved Air Flotation (DAF), testing two inorganic coagulants (ferric chloride and aluminum sulfate) and two organics flocculants (Sulfloc 5000 and Tanac sg). It was also evaluated the removal of organic matter and nutrients obtained by the flotation process and raceways. The experiment involved two stages, according to the hydraulic retention time (HRT) of the pounds, where in Stage I (HRT = 3 days) the LAT- A was feed by raw wastewater and the LAT- B with UASB reactor effluent. In this Stage a coagulation/flocculation helical system was used to form flocs of biomass to be separated in the flotation unit. During Stage II the ponds were operated with a HRT= 6.1 days and fed with effluent from UASB. In this Stage was used a mechanical coagulation/flocculation system, owing to the low efficiency obtained by helical flocculator. During Stage I, the use of ferric chloride coagulant with dosages of 20 mg/L resulted in higher removal efficiency of organic matter (COD, BOD5), solids and nutrient (Pt, TKN), followed by the organic flocculant sulfloc 5000 with dosing 50 mg/L. In Stage II the organic flocculant Tanac sg resulted in greater efficiency, except for Pt removal, where ferric chloride at dosage of 40 mg/L showed better results. The amount of algae biomass in LAT- B, estimated by the parameter Volatile Suspended Solids (VSS) was 90.7 ± 44.1 mg/L and 125.6 ± 68.3 mg/L, during Stage I and II respectively, providing productivity of algae at 9.1 ± 4.4 g / (m²∙d)at Stage I and 6.2 ± 3.4 g / (m²∙d) ate Stage II. It is also worth noting that in the spring (September to December) were recorded the highest average values of VSS, namely 112.1 ± 55.1 mg/L for Stage I and 159.8 ± 71.0 for Stage II. In this research, algal productivity in Stage I in g / (m² ∙ d), reached values 38% higher than in Stage II due to increased flow applied. But in Stage II it was obtained better quality effluent, which is an aspect of importance for defining the recommended parameters for design and operation of high rate of algae production in raceways.

A separação de microrganismos fotossintetizantes no tratamento de efluentes possui dois aspectos fundamentais. O primeiro refere-se à qualidade do efluente tratado e seu impacto sobre os recursos hídricos e, o segundo, refere-se ao potencial deste material como fonte de energia renovável. Diversos trabalhos tem demostrado elevada eficiência na separação de algas no tratamento de efluentes. Entretanto, quando considerado o cultivo de microalgas para utilização da biomassa como matéria prima, para produção de biocombustível por exemplo, mais estudos científicos são necessários. Entre as operações de separação sólido-líquido, normalmente empregadas no tratamento de efluentes, a flotação por ar dissolvido tem se mostrado uma tecnologia vantajosa, pois, além de ser capaz de separar partículas com diâmetro reduzido e baixa velocidade de sedimentação, também permite a obtenção de um material flotado com maior percentual de sólidos, desejável para redução dos custos de processamento da biomassa algal. O objetivo deste trabalho foi avaliar a separação de microalgas cultivadas em uma lagoa de tratamento de esgoto de alta taxa através do processo de coagulação-floculação e flotação por ar dissolvido. Como contribuição aos estudos de separação por FAD, foi avaliado a estabilidade do material flotado submetido a uma agitação mecânica, utilizando a técnica de captura e análise de imagens digitais, segundo um parâmetro chamado porcentagem de área (αa) Este parâmetro é definido como o percentual de pixels pretos em relação ao total de pixels da imagem, e demonstra a instabilidade do material flotado. Os coagulantes cloreto férrico e Tanfloc SG (Tanac®) e os floculantes sintéticos do tipo poliacrilamidas (SNF Floerger®) catiônico (FO4550SH), aniônico (FA920SH) e não iônico (FA920SH) foram investigados em diferentes dosagens e combinações. O presente estudo mostrou que a separação de algas através deste sistema é viável tecnicamente, sendo que os melhores resultados apresentaram uma remoção de turbidez de 92% para a combinação de cloreto férrico (20mg/L) + FO4550SH (2mg/L) e 97% para Tanfloc SG (20mg/L) + AN956SH (1mg/L). Em relação à estabilidade do material flotado, as amostras que continham apenas coagulantes apresentaram valores de αa entre 4,26 e 5,49, indicando uma baixa estabilidade do material flotado. Enquanto as combinações de cloreto férrico (20mg/L) + FO4550SH(0.5mg/L) e Tanfloc SG (20mg/L) +FO4550SH (1 e 2mg/L) foram as que produziram um material flotado com maior estabilidade, apresentando αa=0,35 e αa=0,40, respectivamente, demonstrando que o uso dos polímeros proporciona uma maior estabilidade do material flotado, quando este está sujeito a turbulências. / Separation of photosynthetic microorganisms in the effluent treatment has two fundamental aspects. The first refers to the quality of the treated effluent and its impact on water resources, and the second refers to the potential of this material as a source of renewable energy. Several studies show high efficiency in the separation of algae in effluent treatment. However, more scientific studies are required considering the cultivation of microalgae for the use of them as a raw material for biomass, like biofuel for instance. Among solid-liquid separation operations normally employed in effluents treatment, dissolved air flotation has been shown to be an advantageous technology in order to separate algae, because allows not only the separation of particles with reduced diameter and low sedimentation velocity, but also produces a floating material with higher percentage of solids, which is desirable for reducing the processing costs of the algal biomass. The aim of this work was to evaluate the separation of microalgae originated on a high rate pond through the coagulation, flocculation and dissolved air flotation (DAF) processes. As a contribution to the DAF separation studies, the stability of the floating material was evaluated against mechanical agitation, using the technique of digital image analysis, according to a parameter called area percentage (αa) This parameter is defined as the percentage of pixels in relation to the total pixels of the image, and demonstrates the instability of the floating material. The ferric chloride and Tanfloc SG (Tanac®) coagulants and the synthetic flocculants polyacrylamide types (SNF Floerger®) cationic (FO4550SH), anionic (FA920SH) and nonionic (FA920SH) were investigated in different concentrations and combinations. The present study showed that algae separation through this system is technically feasible. The best results showed a turbidity removal of 92% for the combination of ferric chloride (20mg/L) + FO4550SH (2mg/L) and 97% for Tanfloc SG (20mg/ L) + AN956SH (1mg/L). In relation to the stability of the floated material, the samples containing only coagulants presented values of αa between 4.26 and 5.49, indicating a low stability of the floated material. While the ferric chloride (20mg / L) + FO4550SH (0.5mg / L) and Tanfloc SG (20mg / L) + FO4550SH (1 and 2mg / L) combinations were the ones that produced a floated material with greater stability, 0.35 and α = 0.40, respectively, demonstrating that the use of the polymers provides greater stability of the floated material when it is subjected to turbulence.

O presente trabalho avaliou o crescimento da microalga Dunaliella tertiolecta pela biofixação do CO2 liberado pela produção de cerveja, reciclando um dos gases responsáveis pelo efeito estufa, reduzindo custo da matéria-prima CO2 e agregando valor ao produzir lipídeos e carotenoides naturais. Para isso a microalga foi cultivada em sistemas integrados entre fotobiorreatores e fermentadores. A diferença nos cultivos foi o tipo e a quantidade de CO2 produzida pelas fermentações. Inicialmente se fez fermentações com meio YPD (Yeast Peptone Dextrose) em fermentadores de 2 L acoplados a cada 24 h aos fotobiorreatores em 4 condições distintas, sendo o último fermentador colocado sempre em 144 h de cultivo de microalgas: 30 g L-1 de dextrose a partir de 72 h de cultivo de microalgas, 60 g L-1 de dextrose a partir de 72 h de cultivo de microalgas, 30 g L-1 de dextrose a partir de 24 h de cultivo de microalgas e variando a concentração de (10 à 60) g L-1 de dextrose a partir de 24 h de cultivo de microalgas (YPD (10-60)/24). Os maiores valores para biomassa, carotenoides, produtividades e lipídeos foram obtidos na condição YPD (10-60)/24. Para reproduzir a essa condição utilizando mosto de cerveja, foi calculada a conversão de substrato em produto para, então, acoplar diariamente volumes diferentes de mosto de cerveja em cultivos de microalgas. Os valores obtidos para os cultivos com CO2 desprendidos por estas fermentações foram 1,10 ± 0,05 g L-1 de biomassa, 0,18 ± 0,01 g L-1 d-1 de produtividade de biomassa, 0,58 ± 0,06 d-1 foi a velocidade específica de crescimento, 4,74 ± 0,59 mg g-1 de carotenoides por biomassa, 0,86 ± 0,06 mg L-1 d-1 de produtividade de carotenoides e 13,5 ± 0,4 % (em massa) de lipídeos. Estes valores foram praticamente o dobro dos valores obtidos para o cultivo com CO2 do ar atmosférico, demonstrando que a integração entre fermentadores e fotobiorreatores é uma boa alternativa para indústria alimentícia. Todos cultivos com D. tertiolecta apresentaram o mesmo perfil de carotenoides representado por 46,7 ± 2,0 % de luteína, 22,5 ± 1,6 % de β-caroteno, 9,50 ± 0,66 % de zeaxantina, 1,10 ± 0,16 % de α-caroteno e 20,2 ± 3,0 % para outros. / This study evaluated the growth of microalgae Dunaliella tertiolecta for CO2 biofixation released by brewing, recycling one of the greenhouse gases, reducing cost of raw material CO2 and adding value to produce lipids and natural carotenoids. For this, microalgae were cultivated in integrated systems between photobioreactors and fermenters. The difference in the cultures was the culture medium and the amount of CO2 produced. Initially, fermentation with medium YPD (Yeast Peptone Dextrose) in 2 L fermenters were coupled every 24 h to photobioreactors in 4 different conditions: 30 g L-1 of dextrose from 72 h culture of microalgae; 60 g L-1 of dextrose from 72 h culture of microalgae; 30 g L-1 of dextrose from 24 h culture of microalgae; and ranging dextrose concentration of (10 to 60) g L-1 from 24 h culture of microalgae (YPD (10-60)/24). The highest values for biomass, carotenoids, productivities and lipids were obtained in the condition YPD (10-60)/24. To reproduce this condition using beer wort, the substrate to product yield was determined and different volumes of beer wort where daily coupled to microalgae cultivations. The values obtained for cultures with CO2 released from these fermentations were 1.10 ± 0.05 g L-1 of biomass, 0.18 ± 0.01 g L-1 d-1 of biomass productivity, 0.58 ± 0.06 d-1 for the specific growth rate, 4.74 ± 0,59 mg g-1 of carotenoids per biomass, 0.86 ± 0.06 mg L-1 d-1 of carotenoids productivity and 13.5 ± 0.4 % (mass fraction) of lipids. These values were almost twice the values observed in the cultivation with CO2 of atmospheric air, showing that the integration between fermenters and photobioreactors is a good alternative to increase microalgae growth. All cultures with D. tertiolecta showed the same profile of carotenoids represented by 46.7 ± 2.0 % of lutein, 22.5 ± 1.6 % of β-carotene, 9.50 ± 0.66 % of zeaxanthin, 1.10 ± 0.16 % of α-carotene and 20.2 ± 3.0 % for others.