Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O melÃo representa a maior parte das exportaÃÃes de frutas frescas produzidas no Brasil, sendo cultivado em larga escala nos estados do Rio Grande do Norte e CearÃ. Todo o cultivo comercial desta curcubitÃcea nestas duas regiÃes à realizado sob condiÃÃes de irrigaÃÃo. Assim, medidas de uso eficiente da Ãgua tornam-se essenciais para esta cultura. A melhoria na eficiÃncia do uso da Ãgua irà depender principalmente de um manejo que entregue à planta somente a quantidade de Ãgua necessÃria para o seu pleno desenvolvimento. Neste sentido, o presente trabalho teve por objetivo avaliar o crescimento das plantas, o estado hÃdrico, as trocas gasosas e a produÃÃo do meloeiro amarelo cultivado sob diferentes lÃminas de irrigaÃÃo. Para tanto, conduziram-se dois experimentos no Campo Experimental do Curu, no municÃpio de Paraipaba, CE, utilizando hÃbrido Gold Mine, com espaÃamento de 2,0 m x 0,4 m e irrigado por gotejamento. O primeiro experimento consistiu na avaliaÃÃo semanal do crescimento das plantas em resposta à aplicaÃÃo de trÃs diferentes lÃminas diÃrias de irrigaÃÃo: 100% 80% e 120% (T1, T2 e T3 respectivamente) da lÃmina calculada. No segundo experimento, alÃm dos tratamentos citados anteriormente, foi inserido outro fator: turno de rega de 24 e 48 horas, com quatro repetiÃÃes por tratamento. Neste, se avaliou as trocas gasosas, o potencial hÃdrico, os teores de carboidratos nas diversas partes das plantas e a produÃÃo e qualidade dos frutos. Em todos os tratamentos, as plantas apresentaram o menor potencial hÃdrico diÃrio no perÃodo de 12h00min Ãs 14h00min. Apesar de a condutÃncia estomÃtica decrescer ao longo do dia, a mesma se mantinha em valores suficientes para permitir uma taxa fotossintÃtica praticamente constante, com leve reduÃÃo apÃs o meio dia e decrÃscimo acentuado somente apÃs as 16h00min. Por sua vez, com exceÃÃo da transpiraÃÃo, que foi mais alta nas plantas irrigadas a cada 48 horas, o turno de rega e as lÃminas hÃdricas aplicadas nÃo influenciaram as trocas gasosas das plantas. Da mesma forma, a produÃÃo, o tamanho e a qualidade dos frutos de meloeiro praticamente nÃo foram influenciados pelos tratamentos aplicados. Assim, nas condiÃÃes experimentais utilizadas, o acrÃscimo ou diminuiÃÃo de 20% da lÃmina de Ãgua calculada recomendada para o melÃo na regiÃo, nÃo influenciou o desenvolvimento das plantas, nem tampouco a produÃÃo. Apenas a quantidade de sÃlidos solÃveis totais (ÂBrix) foi influenciada positivamente pelo o acrÃscimo de 20% da lÃmina calculada, quando aplicada diariamente. / The melon is the most exports of fresh fruit produced in Brazil, especially being produced in the states of Rio Grande do Norte and CearÃ. All this curcubitaceae commercial orchard in the two regions is performed under irrigated conditions. Thus, measures of efficient use of water become essential for this crop. The improvement in efficiency of water use will depend primarily on a management plan that deliver only the amount of water necessary for their full development. The study aimed to evaluate plant growth, water status, gas exchange and yield of yellow melon grown under different irrigation levels. Therefore, two experiments were conducted in the experimental field of Curu, Paraipaba, CE, using hybrid Gold Mine, with spacing of 2.0 m x 0.4 m, under drip irrigation. The first experiment consisted of weekly evaluation of plant growth in response to applying three different irrigation water levels: 100% 80% and 120% (T1, T2 and T3 respectively) of calculated levels. In the second experiment, in addition to the treatments mentioned above, was inserted another factor: the irrigation schedule of 24 to 48 hours, with four replicates. In this it, was evaluated gas exchange, water potential, the carbohydrate in different parts of the plant, yield and fruit quality. In all treatments the plants showed the lowest water potential daily between 12:00 to 2:00pm. Although stomatal conductance decreases during the day curse, it remained in amounts sufficient for photosynthetic rate nearly constant, with a slight reduction after noon and marked decrease only after 4:00pm. In turn, with the exception of transpiration, which was higher in plants irrigated every 48 hours, the irrigation water levels and the irrigation schedule did not affect gas exchange of plants. Likewise, the production, the size and quality of melon fruits were practically not influenced by treatments. Thus, under the experimental conditions used, the increase or decrease of 20% of irrigation water level calculated and recommended to the melon in the region, did not affect plant development, nor the production. Only the amount of total soluble solids was positively influenced by the addition of 20% of the water levels calculated, when applied daily

O crescimento da população mundial promove o aumento por consumo de alimentos e energia, além da necessidade de uso sustentável dos recursos naturais, a planta sorgo sacarino tem demonstrado eficiência na absorção e consumo de nutrientes fornecendo matérias-primas importantes como celulose, etanol, bioetanol e alimentos na forma de açúcares e farinhas. Porém, informações quanto à exigência nutricional e a adubação de sorgo sacarino são escassas. Sendo o N e o K os nutrientes mais exigidos por esta espécie, desenvolveu-se estudo aplicando combinações de doses de N e K na solução fornecida para o sorgo sacarino. Foi adotado o esquema fatorial 5² incompleto perfazendo treze combinações de N e K, das respectivas doses de N: 28, 112, 210, 336 e 462 mg.L-1 combinados com as doses de K: 19.5, 117, 234, 312 e 429 mg.L-1. O delineamento experimental foi de blocos casualizados e quatro repetições. Durante o experimento as variáveis avaliadas foram: determinação do índice SPAD, atividade da enzima redutase do nitrato (RNO3-), taxa de assimilação de CO2 ¬¬(A), carboxilação instantânea de CO2 (A/Ci) e os acúmulos de N e K nas sementes, folhas, caule e raiz das plantas, posteriormente calculou-se o desenvolvimento radicular e a produção de biomassa seca por planta. Os resultados demonstraram aumento no índice SPAD com o crescimento do sorgo sacarino em todos os tratamentos, porém as maiores atividades da redutase do nitrato foram verificadas nas plantas dos tratamentos 112N/117K e 112N/312K. A maior produção de biomassa, área foliar e acúmulo de N na parte aérea e raízes foram no tratamento 336N/117K. As maiores quantidades acumuladas de K nas plantas foram observadas no caule dos tratamentos 336N/117K, 336N/312K e 462N/429K. Quanto à taxa de assimilação de CO2 (A), verificou-se no sorgo sacarino maiores taxas fotossintéticas com as combinações 210N/429K. As combinações de doses de 28N/429K e 336N/117K apresentaram maior eficiência instantânea de carboxilação (A/Ci). A massa seca das folhas contabilizadas para a área foliar foi inferior àquela obtida no tratamento da combinação de dose de N e K de 210N/234K. Notou-se maior crescimento e desenvolvimento das plantas de sorgo sacarino com a combinação de doses de N e K de 336N/117K em termos de produção de biomassa / The world population growth promotes the increase in demand a consumption of foods, fibres and energy, besides the need to save the natural resources. Among the plants researched, sweet sorghum demonstrated efficiency when using for nutrients and water and providing important feedstocks such as cellulose, ethanol, bioethanol and food in the way of sugars and flours. However, information from sweet sorghum crop management practices is still scarce, mainly concerning the mineral nutrition and fertilization. As the nutrients nitrogen and potassium the most required up by the plant of nitrogen combinations were nitrogen rates and potassium in sweet sorghum, hybrid BRS 506. It was set up a factorial scheme 5² incomplete, accounting thirteen combinations of nitrogen (N) and potassium (K). The respective doses of N: 28, 112, 210, 336 and 462 mg L-1 combined with K rates: 19.5, 117, 234, 312 and 429 mg L-1. The experimental design was a randomized block with four replications. Throughout the experiment, major variables were: evaluated estimating chlorophyll content, the activity of nitrate reductase, leaf CO2 assimilation rate, instantaneous carboxylation efficiency, accumulation N and K, root development and dry mass production of the plant. The findings were analyzed statistically using the SAS statistical software and graphics by surface response design and mean comparison. The results demonstrated increased in the SPAD index with growth of sweet sorghum in all treatments, but the highest activities of nitrate reductase were found in plants of 112N / 112N and 117K / 312K treatments. The largest production of biomass, leaf area and Nitrogen accumulation of in the shoot and roots were found in the combination of doses 336N and 117K. For K the greatest quantities are accumulated on the stem, with the combinations of doses of 336N / 117K, 336N / 462N and 312K/429K. As to CO2 assimilation rate observed on the sweet sorghum higher photosynthetic rates with 210N / 429K combinations. The combinations of doses of 28 N / 429K and 336N / 117K had higher instantaneous carboxylation efficiency. The dry mass of the leaf area was less than 83% compared with that of control treatments. In growth and development of sweet sorghum plant to 336N and 117K combination provided better results in terms of the biomass productivity

A busca por fontes de energia renovável acontece em ritmo crescente em função do superaquecimento da Terra e mudanças climáticas causadas, especialmente, pela emissão de CO2. Entre as possibilidades de obter-se energia renovável, os biocombustíveis produzidos a partir do cultivo de microalgas apresentam-se como alternativa potencial. Microalgas podem alcançar altas taxas de produção a partir do consumo de energia luminosa, assimilação de nutrientes e biofixação de CO2 e sua biomassa pode dar origem a bioetanol, biogás, biodiesel e a outros bioprodutos de interesse biotecnológico. Visando avaliar a produção de biomassa e atividade metabólica, sob processo fotoautotrófico, 3 cepas de Chlorella sp. foram cultivadas em triplicata em fotobiorreatores bag (1ª ETAPA) e a cepa selecionada como mais produtiva foi cultivada em um fotobiorreator placa plana (2ª ETAPA) dimensionado para melhoramento de processos fotossintéticos. Para o cultivo, realizado em batelada, utilizou-se o meio M-8 com adição de 5% de CO2, radiação luminosa de 200 µmol.fótons.m-2.s-1 e fotoperíodo 12h claro/escuro. Foram monitoradas a assimilação de nutrientes, a taxa de CO2 biofixado, a produção de biomassa e determinado o perfil bioquímico. Na 1ª ETAPA, a cepa DAM04 apresentou o melhor desempenho com assimilação de 37,5% (157,61±17,39 de 420,00 mg.L-1) do nitrogênio e 16,1% (34,42±3,96 de 213,90 mg.L-1) do fósforo presente no meio de cultivo, taxa de CO2 biofixado de 0,193±0,019 g.L-1.d-1 e produção de biomassa de 2,22±0,21 g.L-1. A determinação do perfil bioquímico revelou acúmulo de lipídeos de 18,0±0,5%, constituídos por 50,0% de ácidos graxos saturados, 21,3% de monoinsaturados e 18,0% de polinsaturados e produtividade lipídica, proteica e de carboidratos de 25,20±1,80 mg.L-1.d-1, 62,02±4,43 mg.L-1.d-1 e 17,78±1,27 mg.L-1.d-1, respectivamente. Devido ao seu desempenho, a cepa DAM04 foi utilizada na 2ª ETAPA e o cultivo no fotobiorreator placa plana aumentou o desempenho da cepa em todos os parâmetros, implicando na assimilação de 89,1% (374,12±27,76 de 420,00 mg.L-1) do nitrogênio e 40,9% (87,37±10,12 de 213,90 mg.L-1) do fósforo, cerca de 3 vezes (de 0,193±0,019 para 0,593 g.L-1.d-1) da taxa de CO2 biofixado e da produção de biomassa (de 2,22±0,21 para 5,4 g.L-1) em relação ao fotobiorreator bag. O perfil bioquímico apresentou aumento na produtividade lipídica e proteica de, aproximadamente, 3 vezes (de 25,20±1,80 para 79,16±1,52 mg.L-1.d-1) e (de 62,02±4,43 para 168,44±1,25 mg.L-1.d-1), respectivamente, e 2 vezes na produtividade de carboidratos (de 17,78±1,27 para 40,46±0,33 mg.L-1.d-1) quando comparados ao fotobiorreator bag. A 2ª ETAPA reforçou o potencial da cepa DAM04 para aplicação na biossíntese de compostos bioenergéticos de aplicação na produção de biocombustíveis e coloca como desafio para futuros trabalhos a exploração do potencial das cepas para biofixação de maiores concentrações de CO2 e otimização da captação de radiação luminosa. / The search for renewable energy sources happens at an increasing rate due to the overheating of the earth and climate change caused especially by the emission of CO2. Some of the possibilities to obtain renewable energy, biofuels produced from microalgae cultivation are presented as potential alternative. Microalgae can achieve high production rates from light energy consumption, nutrient assimilation and CO2 biofixation and their biomass can give rise to bioethanol, biogas, biodiesel and other bio-products of biotechnological interest. Aiming to evaluate the production of biomass and metabolic activity under photoautotrophic process, 3 strains of Chlorella sp. was grown in triplicate in photobioreactor bag (1ª STAGE) and the most productive strain was seleted and grown in a photobioreactor flat plate (2ª STAGE) dimensioned for enhancing photosynthetic processes. For growing, performed, sequencing batch, we used the medium M-8 with addition of 5% CO2, light radiation 200 µmol.photons.m-2.s-1 and a photoperiod 12h light/dark. Were monitored assimilation of nutrients, CO2 biofixation rate, biomass production and determined the biochemical profile. In 1ªSTAGE, the DAM04 strain showed best performance with assimilation of 37,5% (157,61±17,39 of 420,00 mg.L-1) of nitrogen and 16,1% (34,42±3,96 of 213,90 mg.L-1) of phosphorus present in the medium, CO2 biofixation rate of 0,193±0,019 g.L-1.d-1 and biomass production 2,22±0,21 g.L-1. The determination of biochemical profile showed accumulation of lipids to 18,0± 0,5 %, consisting of 50,0 % of saturated fatty acids, 21,3 % of monounsaturated and 18,0 % polyunsaturated and lipid productivity, protein and carbohydrates of 25,2±1,80 mg. L-1.d-1, 62,02±4,43 mg. L-1.d-1 and 17,78±1,27 mg L-1.d-1, respectively. Due to its performance, DAM04 strain was used in STAGE 2 ª and cultivation in the photobioreactor flat plate increased strain performance in all parameters, resulting in the assimilation of 89,1 % (374,12±27,76 of 420,00 mg. L-1) of nitrogen and 40.9 % (87,37 of 213,90±10,12 mg. L-1) of phosphorus, about 3 times (of 0,193±0,019 to 0,593 g. L-1.d-1) of CO2 biofixation rate and biomass production (of 2,22±0,21 to 5,4 g. L-1) relative to the photobioreactor bag . The biochemical profile showed an increase in lipid and protein productivity of approximately 3 times (of 25,20±1,80 to 79,16±1,52 mg. L-1.d-1) and (of 62,02±4,43 to 168,44±1,25 mg. L-1.d-1), respectively, and 2 times in the productivity of carbohydrates (of 17,78±1,27 to 40,46±0,33 mg. L-1.d-1) compared to the photobioreactor bag. The 2 ª STAGE reinforced the potential of DAM04 strain for use in the biosynthesis of bioenergetic compounds application in the production of biofuels and puts as a challenge for future studies exploring the potential of strains to biofixation of higher CO2 concentrations and optimization capture light radiation.

A caracterização fisiológica da cultura de soja auxilia na compreensão do comportamento da planta em resposta ao ambiente, permitindo estabelecer estratégias de manejo mais eficientes. Sendo assim, o presente trabalho teve por objetivo: (i) analisar a taxa fotossintética e transpiratória por unidade foliar, caracterizando a participação de cada estrato foliar, (ii) avaliar a fotossíntese líquida e respiração em estratos foliares após a aplicação de fungicidas e (iii) verificar a influência da senescência foliar natural, induzida por doença e controlada pela aplicação de fungicidas em folhas do estrato inferior com diferentes níveis de desfolha. O experimento I foi conduzido em câmara de crescimento na área experimental do Campus da ESALQ/USP no Departamento de Ciências Biológicas, em Piracicaba-SP, em 2007, onde foram realizadas avaliações de trocas gasosas. O experimento II foi instalado na estação experimental da Basf em Santo Antônio da Posse-SP, em 2011, neste experimento foram realizadas avaliações de fotossíntese líquida e respiração no estrato superior e inferior de plantas com aplicação de estrobilurina e triazol. O experimento III foi conduzido no Campus II do UNIPAM em Patos de Minas-MG, em 2011, onde se avaliou a influência das folhas senescentes do estrato inferior ao nível de 0, 25, 50, 75 e 100% de desfolha e aplicação de fungicidas. De acordo com os resultados encontrados no experimento I é possível inferir que a participação de cada unidade foliar da planta de soja na fotossíntese líquida total e na transpiração total se dá em função do seu estádio de desenvolvimento. A aplicação de estrobilurina Piraclostrobina + Epoxiconazol direcionada em folha do estrato inferior apresentam incrementos na fotossíntese líquida e decréscimos na atividade respiratória. A retirada de folhas do estrato inferior de plantas de soja ocasiona decréscimos na formação e enchimento de vagens e consequentemente diminuição da produtividade que variam de 1140, 1740 e 1680 kg ha-1, em plantas com 100% de desfolha, para os tratamentos 1 (testemunha), 2 (Piraclostrobina + Epoxiconazol) e 3 (Epoxiconazol), respectivamente. / The physiological characterization of the soybean crop helps in understanding the behavior of the plant in response to the environment, allowing establishing more effective management strategies. Therefore, this study aimed to: (i) analyze the photosynthetic and transpiration rates per leaf area unit, featuring the participation of each stratum leaf, (ii) evaluate the net photosynthesis and respiration in lower layer leaves after application of foliar fungicides and (iii) verify the influence of natural leaf senescence induced by disease and controlled by applying fungicides on the lower layer leaves with different levels of defoliation. The experiment was carried out in growth chamber at the Biology Department in Piracicaba, São Paulo State, in 2007, where assessments of gas exchange were made. The experiment II was installed at the Basf experimental station in Santo Antonio da Posse, São Paulo State, in 2011, where net photosynthesis and respiration were evaluated in the upper and lower layer leaves of the plants with strobilurin and triazol application. The experiment III was carried out in the Campus II of UNIPAM, in Patos de Minas, Minas Gerais State, in 2011, where the influence of lower layer senescent leaves were evaluated at 0, 25, 50, 75 and 100% of defoliation and fungicides application. According to the results of experiment I, the participation of each foliar unit of soybean plant on the total net photosynthesis and transpiration was inferred as function of its phenological stage of development. The application of Pyraclostrobin (strobilurin) + Epoxiconazol in the lower layer leaves present increments on net photosynthesis and decreases the respiratory activity. The removal of the lower layer leaves of soybean plants caused a decreasing of pod formation and filling and, consequently, decreases productivity ranging from 1140, 1740 and 1680 kg ha-1 in plants with 100% defoliation, for the treatments 1 (untreated), 2 (Pyraclostrobin + Epoxiconazole) and 3 (Epoxiconazole), respectively.

Orientador: Telma Teixeira Franco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-23T04:10:59Z (GMT). No. of bitstreams: 1 Lacerda_LucyMaraCaciaFerreira_D.pdf: 5787877 bytes, checksum: 81afde238358667a3fdefa912b6c3725 (MD5) Previous issue date: 2013 / Resumo: O uso de microalgas em processos de mitigação ambiental e produção de energia renovável vêm ganhando destaque, mas a otimização das etapas de "upstream" e "downstream" são essenciais para que a viabilidade técnica e econômica seja alcançada e o processo implementado em escala industrial. As condições que maximizam o crescimento celular, a mitigação de CO2, o acúmulo de lipídios e proporcionam um perfil de ácidos graxos, compatível com a produção de biodiesel de elevada qualidade, foram avaliados em função de diferentes temperaturas (18-42 ºC), disponibilidade de carbono na forma de CO2 (ar-40%), disponibilidade de luz (4-192 ?mol.m-2.s-1) e disponibilidade de nitrogênio na forma de NaNO3 (0,25-1,00 g.L-1). A recuperação da biomassa a partir do processo de floculação foi avaliada em função do tipo de floculante (orgânico e inorgânico), dose do floculante (0,005-0,300 g.L-1), pH (4-11) e concentração celular (0,1-1,0 g.L-1). As condições de cultivo selecionadas foram: 108 ?mol.m-2.s-1, 26,5 ºC, 0,25 g.L-1 de NaNO3 e 8,05 % de CO2, sendo obtidos os seguintes resultados: Xmax/X0=14,78 (razão da concentração celular máxima pela concentração inicial); ?max=1,02 d-1 (máxima velocidade específica de crescimento); ?=0,50 d (duração da fase lag); Pmax=0,58 g.L-1.d-1 (produtividade máxima); Pmean=0,31 g.L-1.d-1 (produtividade média); CBmax=1,06 g.L-1.d-1 (Máxima taxa de incorporação de carbono); CBmean=0,55 g.L-1.d-1 (média da taxa de incorporação de carbono); 50% de lipídios e 90% dos FAMES (ésteres metílicos de ácidos graxos) correspondendo aos principais FAMES do biodiesel (C16:0, C18:0, C18:1, C18:2 e C18:3). A predição da qualidade do biodiesel produzido a partir do óleo de microalga forneceu os seguintes resultados: CN=56 (número de cetano), CFPP = 0,8 °C (ponto de entupimento de filtro a frio), ? = 863 kg/m³ (densidade), II = 97 gI2/100g (índice de iodo), ?HC = 39,2 kJ/g (calor de combustão), OSI = 13,8 h (índice de estabilidade oxidativa), e ? = 3,93 mm².s (viscosidade) estando dentro dos valores especificados pelas normas ANP255/2003, EN14213-14214 e ASTM6751. As condições para eficiências de recuperação (RE) da biomassa superiores a 95% foram: intervalos de pH 4,0 a 11,0 (floculante orgânico); 5,0 a 7,0 (FeCl3) e de 7,0 a 8,0 (Al2(SO4)3; razão de gfloculante/gbiomassa de: 0,08 gorgânico/gbiomassa, 0,40gAl2(SO4)3/gbiomassa. O impacto da disponibilidade de luz no interior de fotobiorreatores foi estimada para diferentes disponibilidades de luz (108-700 ?mol.m-2.s-1) e a partir de dados de concentração celular, concentração de pigmentos e geometria do reator, sendo verificada a perda de aproximadamente 85% da luz disponível na superfície para cultivos com concentração celular de até 2 g.L-1 em fotobiorreatores de 8 cm de diâmetro. A produção de biomassa e bicombustíveis em software comercial SuperPro designer v8.5 fomos simuladas e associadas à análise econômica / Abstract: The use of microalgae in environmental carbon dioxide mitigation processes and renewable energy production are gaining attention, but the optimization of "upstream" and "downstream" process is essential to promote technical and economic feasibility and make with the industrial scale became true. The conditions that maximize biomass growth, carbon dioxide mitigation, lipid content, and produce a fatty acid profile suitable for a high quality biodiesel was evaluated as function of different temperatures (18-42 ºC), carbon availability as CO2 (air-40%), light intensity (4-192 ?mol.m-2.s-1), and nitrogen availability as NaNO3 (0.25-1.00 g.L-1). Biomass harvesting using flocculation process was evaluated as function of flocculant type (organic and inorganic), flocculant dosage (0.005-0.3 g.L-1), pH (4-11), and biomass concentration (0.1-1.0 g.L-1). The selected conditions were: 108 ?mol.m-2.s-1, 26.5 ºC and 8.05% de CO2, with the following results: Xmax/X0=14.78 (maximum and initial cell concentration ratio); ?max=1.02 d-1 (maximum specific growth rate), ?=0.50 d (lag phase duration); Pmax=0.58 g.L-1.d-1 (maximum productivity); Pmean=0.31 g.L-1.d-1 (mean productivity); CBmax=1.06 g.L-1.d-1 (maximum carbon incorporation rate); CBmean=0.55 g.L-1.d-1 (mean carbon incorporation rate); 50% of lipid content, and 90% of samples FAMES (fatty acid methyl ester) corresponding to the mainly biodiesel FAMES (C16:0, C18:0, C18:1, C18:2 e C18:3). Biodiesel quality prediction using samples of microalgae oil show the following results: CN=56 (cetane number), CFPP = 0.8 °C (could filter plugging point), ? = 863 kg/m³ (density), II = 97 gI2/100g (iodine index), ?HC = 39.2 kJ/g (heat of combustion), OSI = 13.8 h (oil stability index), and ? = 3.93 mm².s (viscosity), and the values were compatible with different quality standards ASTM-D6751, EN14214/14213, and ANP 255/2003. Recovery efficiency (RE) of 95% or more can be obtained with pH 4,0 to 11,0 (organic flocculant); 5,0 to 7,0 (FeCl3), and 7,0 to 8,0 (Al2(SO4)3; gflocculant/gbiomass of: 0,08gorganic/gbiomass, 0,40gAl2(SO4)3/gbiomass). The impact of light availability in the center of photobioreactor was predicted as function of cell concentration, pigments concentration and photobioreactor design, being observed approximately 85% of loss in the incident light availability in cultures is less than 2 g.L-1. Biomass production process and biofuels production process were simulated using a commercial software SuperPro Designer v8.5 followed by economic analysis / Doutorado / Processos em Tecnologia Química / Doutora em Engenharia Quimica

Ce travail a pour objectif la mise en place d'un procédé de phytostabilisation sur un ancien site industriel, la Vieille Usine d'Auzon (43, France). La caractérisation pédochimique du site atelier a révélé une pollution polymétallique par l'As, Pb, Sb, Cd et Cu. L'As, de par sa concentration totale et sa biodisponibilité dans le sol, est considéré comme le polluant le plus présent et le plus toxique. L'étude floristique réalisée sur le site a relevé une flore métallicole dominée par des pseudométallophytes électives telles que Agrostis capillaris, Equisetum arvense, ou les Euphorbiacées. De manière générale, la majorité des espèces présentes sur la friche industrielle a accumulé de très faibles quantités de polluants (As, Pb) dans ces parties aériennes. Dans un deuxième temps, les travaux ont porté sur les effets induits par les ETM au niveau physiologique et biochimique chez des modèles végétaux, Agrostis capillaris, Solanum nigrum, Vicia faba et Cannabis sativa. Ces données ont mis en évidence la sensibilité de V. faba et la tolérance de S. nigrum à la pollution aux ETM, un maintien de l'activité physiologique mais un ralentissement de la croissance de C. sativa sur sol pollué et une tolérance adaptative d'A. capillaris à la pollution du sol. Par ailleurs, une culture en hydroponie de S. nigrum et V. faba en présence d'As inorganique, arsénite et arséniate, à différentes concentrations a permis de mettre en évidence deux effets de l'As. Celui-ci a provoqué une altération de la structure et du fonctionnement des PSII, plus sensibles à l'As(III), et, une inhibition de l'activité oxygénase et carboxylase de la Rubisco, cible privilégiée de l'As(V). Enfin, ces résultats ont été utilisés dans le cadre de l'expérimentation in situ pour la validation d'un procédé de phytostabilisation sur la friche industrielle d'Auzon. Les effets de la combinaison d'une association d'espèces prairiales et d'un amendement de grenaille de fer zérovalent ou/et de compost ont pu être caractérisés. L'ajout de grenaille de fer au sol complété par un apport de compost a accentué la réduction de la disponibilité de l'As et dans une moindre mesure de Sb. De plus, il a permis d'enrichir le sol en élément minéraux et organiques et a ainsi facilité l'implantation d'un couvert végétal constitué d'espèces végétales à phénotype d'exclusion. Cette expérience in-situ a donc permis de mettre en avant la faisabilité d'un procédé de phytostabilisation dans la dépollution et la revalorisation de sites industriels. / This work aims to the establishment of a phytostabilization process on an old industrial site, "La Vieille Usine" in Auzon (43, France). The pedochemical characterization revealed a polymetallic pollution by As, Pb, Sb, Cd, Cu. The As, by its total content and its bioavailability, is considered as the most concentrated and toxic. A floristic study noted a metallicolous flora dominated by elective pseudometallophyte species such as Agrostis capillaris, the dominant specie, Equisetum arvense, or Euphorbiaceae. Broadly speaking, the majority of species on the industrial site has accumulated very low amounts of pollutants (As, Pb) in these shoots. To better understand the trace element effects on different plants, Agrostis capillaris, Solanum nigrum, Cannabis sativa and Vicia faba were grown on the Auzon’s soil under controlled conditions. These data highlighted (i) the sensitivity of V. faba and the tolerance of S. nigrum to trace element pollution; (ii) for C. sativa, the maintenance of its physiological activity but a slowdown of its growth; (iii) the adaptative tolerance of A. capillaris to soil pollution. In addition, a hydroponics culture of S. nigrum and V. faba in the presence of different concentrations and different oxidation degrees (arsenite and arsenate) of inorganic As allowed to identify two main effects of As at physiological and biochemical level. First, it alters the structure and function of PSII, which seems more sensitive to As(III), and, secondly, it inhibits the carboxylase and oxygenase activities of Rubisco, the main target of As(V). These data were then used to conduct an in-situ experiment based on a phytostabilization process on the industrial wasteland of Auzon. The effects of the combination of an grassland species association with a zerovalent iron shot and/or compost amendment were characterized. The addition of iron shot on the soil completed with compost decreased the available fraction of As and to a lesser extent Sb. Moreover, the amendments allowed to enrich the soil with mineral and organic elements and to facilitate the establishment of vegetal cover composed by tolerant plants with an exclusion phenotype. This in-situ experience enabled to highlight the feasibility of a phytostabilization method in the depollution of industrial sites as in their enhancement.

La photosynthèse consiste en la conversion photo-induite du dioxyde de carbone et de l'eau en matière organique et en dioxygène. Utilisée par les algues, les plantes ou certaines bactéries, la photosynthèse est pourtant intrinsèquement bridée puisque seulement 4 % de l'énergie lumineuse sont convertis en énergie chimique. Sous forte irradiation, ceci peut engendrer une dénaturation de l'appareil photosynthétique. Par ailleurs, dans le contexte environnemental actuel, cette limitation représente également une opportunité d'utiliser l'énergie non convertie sous forme d'énergie électrique. Le travail présenté dans ce manuscrit a donc pour but de créer une voie secondaire d'écoulement des électrons photosynthétiques excédentaires afin de réduire l'endommagement du système sous forte irradiation et de les transcrire sous la forme d'un photo-courant. C'est pourquoi un système impliquant une électrode collectrice de carbone et des médiateurs redox de type quinone a été envisagé. La capacité acceptrice de certaines quinones, connues pour être de bons accepteurs du Photosystème II, a été évaluée au moyen d'études de fluorescence. La facilité de restitution des électrons dérivés par les quinones réduites a été quant à elle étudiée par électrochimie. Au bilan, les meilleures quinones (DCBQ, PPBQ) permettent d'obtenir des photo-courants de l'ordre de quelques µA.cm-2. La corrélation entre données expérimentales et théorie a également permis de mieux cerner le mécanisme de dérivation des électrons photosynthétiques par les quinones exogènes mais aussi de mettre en évidence des effets d'empoisonnement et/ou de perte d'accepteur dans les membranes. / Photosynthesis can be views as the conversion of carbon dioxide and water into organic matter and dioxygen. Used by algae, plants or some bacteria, photosynthesis efficiency is limited because only 4% of light energy is converted into chemical energy. Under high light conditions, this can induce serious damages of the photosynthetic machinery. Besides, if considering the current environmental context, this limitation is an opportunity to use the part of not converted energy to generate some useable electricity. The aim of the work developed in this manuscript is thus to create an additional pathway for derivating the photosynthetic electrons flow. In this way, the system damages are expected to be reduced under hight light conditions as well as some photocurrent to be generated. This is why an experimental set-up involving carbon working electrode and some quinone type redox mediators has been developed. The quinone ability to accept some electrons from Photosystem II has been studied by the mean of fluorescence techniques. Their ability to be re-oxidised at the carbon electrode surface has been investigated by cyclic voltametry. As a conclusion, the best quinones (selected after the fluorescence investigations) are DCBQ and PPBQ and correspond to photocurrent values about several µA.cm-2. A correlation between experimental data and theoretical predictions helped us to best understand the photosynthetic electrons derivation pathway and to evidence concomitant phenomenon like poisoning and quinone partition effects.

Acid rmne drainage (AMD) is a major pollution problem througbout the world, adversely affecting both surface and groundwaters. AMD is principally associated with the mining of sulphide ores. The most commonly associated minerals being sulphur, copper, zinc, silver, gold, lead and uranium. As conventional methods for removing heavy metals from wastewater are often prohibitively expensive, the implementation of biological processes for the removal of heavy metals has become a realistic practice. The objectives of this project was firstly to establish the effect of copper, lead and nickel, heavy metals commonly found in AMD waters, on the enzyme carbonic anhydrase, which is an integral part of the carbon concentrating mechanism (CCM) and secondly, to determine the feasibility of using the alkalinity generated by Spindina for the precipitation of heavy metals from solution. Initially, batch flask experiments were performed and it was found that the algae were able to utilise the bicarbonate supplied in the medium, under CO, limiting conditions, through the induction of their CCM, resulting in the generation of carbonate. The effect of the inhibitors, acetazolamide (AZ) and ethoxyzolamide (EZ), were also investigated in order to determine the importance of carbonic anhydrase (CA) in inorganic carbon accumulation and photosynthesis. Results obtained were consistent with those observed in literature and it was found that at IOOf.LM AZ and EZ, complete inhibition of photosynthesis and carbonic anhydrase occurred, with no oxygen being evolved. The results obtained from the inhibitor experiments substantiate the findings that carbonic anhydrase is an important part of the CCM, and that the dehydration of bicarbonate to carbon dioxide and hydroxide ions, is in fact an enzymatic process regulated by the enzyme carbonic anhydrase and is essential for efficient photosynthesis. The effect of heavy metals on Spirulina was also investigated. Lead, copper and nickel were all found to cause a reduction in the synthesis of chlorophyll a, which resulted in a decrease in photosynthetic efficiency and eventually death of the culture. The morphology of the algae was also severely affected by heavy metals, with degradation and aJmost complete disintegration of the algal filaments occurring. Using the Wilbur-Anderson assay method, carbonic anhydrase activity was found to be lower in the experimental flasks containing heavy metals, than the control flasks, reducing the algae's ability to utilise the bicarbonate in solution for effective photosynthesis. The Wilbur-Anderson assay method did not prove to be a reliable method for measuring changes in enzyme activity as results were found to be erratic. Therefore attempts were made to use an oxygen electrode as an alternative method for determining the effects of various parameters on enzyme activity and photosynthesis, this proved to be more successful. Because of the toxic effects of heavy metals on Spirulina it was decided that the use of the biogenic alkalinity generated by the algae for the precipitation of heavy metals may be successfully employed as an alternative method for bioremediation and metal recovery. Carbonate reacts readily with metals, therefore the carbonate produced by this algal system was used for the precipitation of metals. It was possible to categorise the precipitation reactions observed into three groups, namely those metals which, a) precipitate as hydroxides, b) precipitate as carbonates generated from the dissociation of bicarbonate and c) metals which can only precipitate if there is free carbonate present in solution.

Grass species within South Africa show a photosynthetic subtype and phylogenetic response to rainfall gradients, with Panicoideae species (NADP-Me and NAD-Me) inhabiting mesic environments, while Aristidoideae species (NADP-Me) inhabit more arid environments. It is predicted that climate change will alter rainfall patterns within southern Africa, which could have implications for grassland distributions and functional composition. Globally, and in South Africa, species distributions indicates that NAD-Me species have a preference for more arid environments, but this may be complicated by phylogeny as most NAD-Me species belong to the Chloridoideae subfamily. Additionally, differences in the metabolism and energetic requirements of different carboxylation types are expected to confer different ecological advantages, such as drought tolerance, but the role of these different pathways is not well understood. Based on natural distribution and photosynthetic subtype differences, it was hypothesised that Panicoideae NADP-Me species would be less drought tolerant than Panicoideae NAD-Me and Aristidoideae NADP-Me species and that subtypes and lineages would show different drought recovery rates. Furthermore, drought sensitivity would be of a metabolic and not a stomatal origin and plants that maintained favourable leaf water status would be more drought tolerant and recover faster. This was tested experimentally by comparing Panicoideae species (NADP-Me and NAD-Me) and NADP-Me species (Panicoideae and Aristidoideae). Plants were subjected to a progressive 58 day drought period and a recovery phase where gas exchange, chlorophyll fluorescence and leaf water relations were measured at select intervals. In conjunction with this, a rapid drought experiment was performed on Zea mays (NADP-Me: Panicoideae) plants where similar parameters were measured. Photosynthetic drought and recovery responses showed both a subtype and phylogenetic response. Panicoideae species were less drought tolerant than Aristidoideae species, although Panicoideae NAD-Me showed better recovery rates than Panicoideae NADP-Me species, while Aristidoideae species recovered the quickest. Panicoideae NAD-Me and Aristidoideae species maintained higher leaf water status during drought which contributed to the maintenance of PSII integrity and thus facilitated rapid photosynthetic recovery. During drought Panicoideae species showed greater metabolic limitations over Aristidoideae species and for the first time, lower metabolic limitations were associated with osmotic adjustment. This is a novel finding whereby osmotic adjustment and the subsequent maintenance of leaf water are key to preventing metabolic limitations of photosynthesis in C₄ grasses. Results from the Z. mays rapid drought study showed the limitations to photosynthesis were exclusively metabolic and unlikely to be a direct consequence of turgor loss. It was apparent that the response to drought was stronger amongst lineages, as NADP-Me species from different subfamilies showed a significant difference in drought tolerances. Aristidoideae species’ exceptional drought tolerance and predicted increased aridification could favour these species over Panicoideae species under future climates.

The greater photosynthetic nitrogen use efficiency (PNUE) of C4 compared with C3 plants may explain the relative success of C4 grasses in nutrient poor environments. This study compared the responses in photosynthetic parameters, leaf nitrogen and biomass allocation between the C3 and C4 subspecies of Alloteropsis semialata supplied soil nitrogen at three levels. Photosynthesis was assessed by means of CO2 response curves and the leaf nitrogen content assayed. Plants were destructively harvested, leaf areas determined and the dry biomass of functional plant components was measured. Results confirmed that the higher PNUE of C4 plants allowed them to accumulate more biomass than C3 plants at the high nitrogen level, despite smaller leaf areas. The greater productivity of C4 plants enabled them to invest more in storage and sexual reproduction than in leaves when compared to the C3 plants. In contrast the C3 plants invested biomass in less efficient and more nitrogen demanding leaves and bigger root systems. PNUE and photosynthetic rates were not significantly affected by nitrogen-limitation in either subspecies and the major response was a decrease in biomass accumulation and an increase in biomass allocation to roots. This altered root to shoot ratio was accompanied by a lowered allocation to sexual reproduction in the C4 subspecies, but an unaltered allocation to leaves, while in the C3 subspecies there was a decrease in leaf allocation. In a further experiment, the C4 subspecies was supplied three levels of nitrogen provided as nitrate, or alternatively as ammonium plus nitrate, and leaves were excised to within 5 cm of the ground at the start of treatment. Prior to flowering, photosynthesis was assessed by means of CO2 response curves and the plants were destructively harvested. Leaf areas and the dry biomass of functional plant components were determined, and at levels of nitrogen supply higher than those found in savanna soils the rate of photosynthesis was increased. Leaf re-growth was reduced by severe nitrogen limitation and co-provision of nitrate and ammonium had no significant effect other than increased tillering. Both subspecies of Alloteropsis semialata are adapted to nutrient poor environments and maintain photosynthetic rates by reducing leaf area. The C4 subspecies is likely to show greater resilience in disturbance-prone environments by exploiting its higher PNUE to allocate greater resources to storage and sexual reproduction, while the C3 subspecies is usually found in environments with closed canopies which favour vegetative growth, and allocate greater resources to leaves and roots.