Orientador: Flávio Vasconcelos da Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-25T15:03:00Z (GMT). No. of bitstreams: 1 Ramos_VictorSantana_M.pdf: 2207177 bytes, checksum: 63cb53e77a107cef5979f71e6c8fb769 (MD5) Previous issue date: 2014 / Resumo: O desenvolvimento da biotecnologia tem proporcionado um crescimento em pesquisas acadêmicas, nas quais desenvolveram-se reatores conhecidos como airlifts, que são aplicados em bioprocessos diversos, tais como a fermentação alcóolica e o tratamento de efluentes. Assim, este trabalho possui como principais objetivos o projeto, a montagem e a instrumentação de um reator airlift de tubos concêntricos, de modo a obter em tempo real a fração de gás retido e a velocidade de circulação do líquido, e ainda estimar o coeficiente volumétrico de transferência de massa no sistema composto por solução aquosa de etanol e ar, aonde separa-se o etanol do meio através do arraste pelo gás carbônico presente no ar injetado (gas stripping). Os resultados obtidos no presente trabalho permitem concluir que o volume total do reator projetado e o design com as dimensões consideradas permitiram operar o airlift no regime hidrodinâmico de recirculação de gás, e capaz de promover a separação do etanol do meio através do arraste pelo ar comprimido alimentado. Os resultados mostraram que os parâmetros hidrodinâmicos, velocidade de circulação de líquido e fração de gás retido, são dependentes da velocidade superficial do gás alimentado e do volume de solução alcoólica presente na coluna (desnível), mostraram também que o coeficiente volumétrico de transferência de massa sofreu influências da concentração de etanol no meio, do desnível, da velocidade superficial de gás e da temperatura, sendo esta última a variável de maior influência entre as consideradas / Abstract: The development of biotechnology has provided an increase in academic research, which evolved reactors known as airlifts, which are applied in several bioprocesses, such as alcoholic fermentation and wastewater treatment. Thus, this work has as main objectives the design, assembly and automation of a concentric tube airlift reactor, in order to obtain in real time the gas hold-up and liquid circulation velocity, and still estimate the volumetric mass transfer coefficient in a system composed of air and aqueous ethanol, the latter was recovered from the carbon dioxide stripping gas in a refrigerated condenser. The results obtained in this study allow is possible to conclude that the airlift designed behaved satisfactorily and as expected, the total volume of the reactor and designed with the dimensions considered design allowed us to operate the reactor in the gas recirculation regime, and capable of promoting the separation of the ethanol by stripping. The results showed that the hydrodynamic parameters, liquid circulation velocity and gas hold-up, are dependent on the superficial gas velocity and the volume of alcohol solution on the column (dispersion height), also showed that the volumetric mass transfer coefficient was influenced by ethanol concentration, dispersion height, superficial gas velocity and temperature, the latter being the most influential among the considered variable / Mestrado / Sistemas de Processos Quimicos e Informatica / Mestre em Engenharia Química

A utilização de inóculos líquidos na produção de Shiitake (Lentinula edodes (Berk.) Pegler) é uma tecnologia promissora para a industrialização do cultivo em sistema axênico, uma vez que permite a inoculação do micélio de forma rápida e bem distribuída, reduzindo riscos de contaminação e o período de incubação dos substratos. Neste trabalho, o cultivo submerso para a produção de micélio de Shiitake foi avaliado em um biorreator airlift de circulação externa, idealizado e projetado no grupo, utilizando o meio de cultura Mushroom Complete Medium adicionado de micronutrientes, nas condições de operação: taxas de aeração: 0.16, 0.20, e 0.24 vvm e tamanhos de inóculo (i.s.): 1.0 g.L-1 e 2.0 g.L-1. Na melhor condição de operação (0.16 vvm e 1.0 g.L-1 i.s.), um modelo matemático foi desenvolvido usando o software EMSO para descrever a cinética da cultura em ajuste aos dados experimentais. Foram atingidos 15,47 g.L-1 de biomassa total, após 10 dias de cultivo, 0,516 d-1 de taxa máxima de crescimento específico, fatores de rendimento Yx/s 1,06 g.g-1, YP/X 0,485 (g.L-1).g-1, YP/S 0,140 (g.L-1).g-1 e produtividade PX 0,061 (g.L-1).h-1. A predição do modelo demonstrou ser um parâmetro confiável para estudos de aumento de escala já que descreveu bons resultados preditivos para biomassa em relação aos produtos do metabolismo (CO2 e síntese de H+ pela acidificação do meio) e ao consumo de nutrientes (O2 e glicose). A seleção e a avaliação de linhagens no cultivo também são fatores a serem considerados para obtenção de boas produtividades e, deste modo, o desempenho produtivo de cinco linhagens de Shiitake foi avaliado em cultivo axênico, utilizando um planejamento composto central (CCD) para avaliar as variáveis independentes: tempo de incubação I(t), e percentual de farelo de trigo em relação a serragem Eucalypitus saligna (representada pela relação carbono/nitrogênio (RC/N)), tendo a eficiência biológica (BE) e o peso unitário dos cogumelos como resultados de destino . Os substratos utilizados tiveram sua composição físico-química determinada e as taxas de suplementação do substrato foram otimizadas, não só para o rendimento em cultivo, mas também para o crescimento vegetativo do micélio. Os melhores resultados de BE em todas as linhagens foram obtidos em cultivos com RC/N 57,62/1, com indução dos primórdios em 130 dias de I(t). Os cogumelos colhidos nesta condição de produção tiveram sua composição centesimal determinada. Atividades enzimáticas amilolíticas e celulolíticas, β-glicosidase e proteases específicas foram realizadas em ensaios de colonização do substrato. Três linhagens foram selecionadas para o isolamento de esporos e hibridização intraespecífica. As linhagens híbridas foram comparadas com as parentais em termos de rendimento e síntese das enzimas extracelulares. Os resultados deste trabalho demonstraram que a linhagem cultivada tem um efeito considerável sobre o rendimento, sobre o peso unitário e sobre a síntese de enzimas extracelulares produzidas pelo fungo, tanto pelas linhagens híbridas, como pelas parentais. / The use of liquid inoculant production of Shiitake (Lentinula edodes (Berk.) Pegler) is a promising technology for the industrialization farming of this fungus in axenic system because it allows the mycelium inoculation in a quick and well distributed way, thus reducing the risks of contamination and the incubation time of cultures. In this work, the submerged cultivation for the production of Shiitake mycelium was evaluated in an airlift bioreactor of external circulation, conceived and designed in the group, using the culture medium Mushroom Complete Medium added of micronutrients, under the operating conditions: rates of aeration: 0.16, 0.20, and 0.24 vvm and inoculum sizes (i.s.): 1.0 g. L-1 and 2.0 g. L-1. Under the best operating condition (0.16 vvm and 1.0 g L-1 i.s.), a mathematical model was developed using the EMSO software to describe the kinetics of culture fittnes to experimental data. It was possible to obtain 15.47 g L-1 of total biomass, after 10 days of cultivation, a maximum specific growth rate of 0.516 d-1, yields of Yx/s 1,06 g.g-1, YP/X 0,485 (g.L-1).g-1, YP/S 0,140 (g.L-1).g-1 and PX (productivity) 0.061 (g.L-1).h-1. The prediction of the model has proven to be a reliable parameter for studies for scaling up because it was predictive for biomass considering the products of metabolism (CO2 and H+ synthesis by acidification of the medium) and nutrient consumption (O2 and glucose). The selection and evaluation of strains in cultivation are also factors to be considered to obtain good productivity and, therefore, the productive performance of five strains of Shiitake cultivated under axenic system, was carried out using a central composition design (CCD) to evaluate the independent variables: incubation time I(t), and percentage of wheat bran in relation to sawdust of Eucalypitus saligna (represented by the carbon/nitrogen ratio (RC/N)), and having the biological efficiency (BE) and the unit weight of the mushrooms as target results. The best results for BE for all the strains were obtained in cultures with RC/N 57.62/1, with primordia induced at 130 days of I(t). The substrates used had their physico-chemical composition determined and the rates of substrate supplementation have been optimized, not only for the cultivation yields, but also for vegetative growth of the mycelium. The mushrooms harvested in this condition of production had their centesimal composition determined. Amilolytic, cellulolytic, β-glucosidase and specific proteases activities were performed in tests of colonization of the substrate. Three strains were selected for the isolation of spores and intraspecific hybridization was carried out. Hybrid strains were compared with the parental strains in terms of yields and synthesis of extracellular enzymes. The results of this study showed that strain has a considerable effect on both the yield and the unit weight of mushrooms.

A utilização de inóculos líquidos na produção de Shiitake (Lentinula edodes (Berk.) Pegler) é uma tecnologia promissora para a industrialização do cultivo em sistema axênico, uma vez que permite a inoculação do micélio de forma rápida e bem distribuída, reduzindo riscos de contaminação e o período de incubação dos substratos. Neste trabalho, o cultivo submerso para a produção de micélio de Shiitake foi avaliado em um biorreator airlift de circulação externa, idealizado e projetado no grupo, utilizando o meio de cultura Mushroom Complete Medium adicionado de micronutrientes, nas condições de operação: taxas de aeração: 0.16, 0.20, e 0.24 vvm e tamanhos de inóculo (i.s.): 1.0 g.L-1 e 2.0 g.L-1. Na melhor condição de operação (0.16 vvm e 1.0 g.L-1 i.s.), um modelo matemático foi desenvolvido usando o software EMSO para descrever a cinética da cultura em ajuste aos dados experimentais. Foram atingidos 15,47 g.L-1 de biomassa total, após 10 dias de cultivo, 0,516 d-1 de taxa máxima de crescimento específico, fatores de rendimento Yx/s 1,06 g.g-1, YP/X 0,485 (g.L-1).g-1, YP/S 0,140 (g.L-1).g-1 e produtividade PX 0,061 (g.L-1).h-1. A predição do modelo demonstrou ser um parâmetro confiável para estudos de aumento de escala já que descreveu bons resultados preditivos para biomassa em relação aos produtos do metabolismo (CO2 e síntese de H+ pela acidificação do meio) e ao consumo de nutrientes (O2 e glicose). A seleção e a avaliação de linhagens no cultivo também são fatores a serem considerados para obtenção de boas produtividades e, deste modo, o desempenho produtivo de cinco linhagens de Shiitake foi avaliado em cultivo axênico, utilizando um planejamento composto central (CCD) para avaliar as variáveis independentes: tempo de incubação I(t), e percentual de farelo de trigo em relação a serragem Eucalypitus saligna (representada pela relação carbono/nitrogênio (RC/N)), tendo a eficiência biológica (BE) e o peso unitário dos cogumelos como resultados de destino . Os substratos utilizados tiveram sua composição físico-química determinada e as taxas de suplementação do substrato foram otimizadas, não só para o rendimento em cultivo, mas também para o crescimento vegetativo do micélio. Os melhores resultados de BE em todas as linhagens foram obtidos em cultivos com RC/N 57,62/1, com indução dos primórdios em 130 dias de I(t). Os cogumelos colhidos nesta condição de produção tiveram sua composição centesimal determinada. Atividades enzimáticas amilolíticas e celulolíticas, β-glicosidase e proteases específicas foram realizadas em ensaios de colonização do substrato. Três linhagens foram selecionadas para o isolamento de esporos e hibridização intraespecífica. As linhagens híbridas foram comparadas com as parentais em termos de rendimento e síntese das enzimas extracelulares. Os resultados deste trabalho demonstraram que a linhagem cultivada tem um efeito considerável sobre o rendimento, sobre o peso unitário e sobre a síntese de enzimas extracelulares produzidas pelo fungo, tanto pelas linhagens híbridas, como pelas parentais. / The use of liquid inoculant production of Shiitake (Lentinula edodes (Berk.) Pegler) is a promising technology for the industrialization farming of this fungus in axenic system because it allows the mycelium inoculation in a quick and well distributed way, thus reducing the risks of contamination and the incubation time of cultures. In this work, the submerged cultivation for the production of Shiitake mycelium was evaluated in an airlift bioreactor of external circulation, conceived and designed in the group, using the culture medium Mushroom Complete Medium added of micronutrients, under the operating conditions: rates of aeration: 0.16, 0.20, and 0.24 vvm and inoculum sizes (i.s.): 1.0 g. L-1 and 2.0 g. L-1. Under the best operating condition (0.16 vvm and 1.0 g L-1 i.s.), a mathematical model was developed using the EMSO software to describe the kinetics of culture fittnes to experimental data. It was possible to obtain 15.47 g L-1 of total biomass, after 10 days of cultivation, a maximum specific growth rate of 0.516 d-1, yields of Yx/s 1,06 g.g-1, YP/X 0,485 (g.L-1).g-1, YP/S 0,140 (g.L-1).g-1 and PX (productivity) 0.061 (g.L-1).h-1. The prediction of the model has proven to be a reliable parameter for studies for scaling up because it was predictive for biomass considering the products of metabolism (CO2 and H+ synthesis by acidification of the medium) and nutrient consumption (O2 and glucose). The selection and evaluation of strains in cultivation are also factors to be considered to obtain good productivity and, therefore, the productive performance of five strains of Shiitake cultivated under axenic system, was carried out using a central composition design (CCD) to evaluate the independent variables: incubation time I(t), and percentage of wheat bran in relation to sawdust of Eucalypitus saligna (represented by the carbon/nitrogen ratio (RC/N)), and having the biological efficiency (BE) and the unit weight of the mushrooms as target results. The best results for BE for all the strains were obtained in cultures with RC/N 57.62/1, with primordia induced at 130 days of I(t). The substrates used had their physico-chemical composition determined and the rates of substrate supplementation have been optimized, not only for the cultivation yields, but also for vegetative growth of the mycelium. The mushrooms harvested in this condition of production had their centesimal composition determined. Amilolytic, cellulolytic, β-glucosidase and specific proteases activities were performed in tests of colonization of the substrate. Three strains were selected for the isolation of spores and intraspecific hybridization was carried out. Hybrid strains were compared with the parental strains in terms of yields and synthesis of extracellular enzymes. The results of this study showed that strain has a considerable effect on both the yield and the unit weight of mushrooms.

A utilização de inóculos líquidos na produção de Shiitake (Lentinula edodes (Berk.) Pegler) é uma tecnologia promissora para a industrialização do cultivo em sistema axênico, uma vez que permite a inoculação do micélio de forma rápida e bem distribuída, reduzindo riscos de contaminação e o período de incubação dos substratos. Neste trabalho, o cultivo submerso para a produção de micélio de Shiitake foi avaliado em um biorreator airlift de circulação externa, idealizado e projetado no grupo, utilizando o meio de cultura Mushroom Complete Medium adicionado de micronutrientes, nas condições de operação: taxas de aeração: 0.16, 0.20, e 0.24 vvm e tamanhos de inóculo (i.s.): 1.0 g.L-1 e 2.0 g.L-1. Na melhor condição de operação (0.16 vvm e 1.0 g.L-1 i.s.), um modelo matemático foi desenvolvido usando o software EMSO para descrever a cinética da cultura em ajuste aos dados experimentais. Foram atingidos 15,47 g.L-1 de biomassa total, após 10 dias de cultivo, 0,516 d-1 de taxa máxima de crescimento específico, fatores de rendimento Yx/s 1,06 g.g-1, YP/X 0,485 (g.L-1).g-1, YP/S 0,140 (g.L-1).g-1 e produtividade PX 0,061 (g.L-1).h-1. A predição do modelo demonstrou ser um parâmetro confiável para estudos de aumento de escala já que descreveu bons resultados preditivos para biomassa em relação aos produtos do metabolismo (CO2 e síntese de H+ pela acidificação do meio) e ao consumo de nutrientes (O2 e glicose). A seleção e a avaliação de linhagens no cultivo também são fatores a serem considerados para obtenção de boas produtividades e, deste modo, o desempenho produtivo de cinco linhagens de Shiitake foi avaliado em cultivo axênico, utilizando um planejamento composto central (CCD) para avaliar as variáveis independentes: tempo de incubação I(t), e percentual de farelo de trigo em relação a serragem Eucalypitus saligna (representada pela relação carbono/nitrogênio (RC/N)), tendo a eficiência biológica (BE) e o peso unitário dos cogumelos como resultados de destino . Os substratos utilizados tiveram sua composição físico-química determinada e as taxas de suplementação do substrato foram otimizadas, não só para o rendimento em cultivo, mas também para o crescimento vegetativo do micélio. Os melhores resultados de BE em todas as linhagens foram obtidos em cultivos com RC/N 57,62/1, com indução dos primórdios em 130 dias de I(t). Os cogumelos colhidos nesta condição de produção tiveram sua composição centesimal determinada. Atividades enzimáticas amilolíticas e celulolíticas, β-glicosidase e proteases específicas foram realizadas em ensaios de colonização do substrato. Três linhagens foram selecionadas para o isolamento de esporos e hibridização intraespecífica. As linhagens híbridas foram comparadas com as parentais em termos de rendimento e síntese das enzimas extracelulares. Os resultados deste trabalho demonstraram que a linhagem cultivada tem um efeito considerável sobre o rendimento, sobre o peso unitário e sobre a síntese de enzimas extracelulares produzidas pelo fungo, tanto pelas linhagens híbridas, como pelas parentais. / The use of liquid inoculant production of Shiitake (Lentinula edodes (Berk.) Pegler) is a promising technology for the industrialization farming of this fungus in axenic system because it allows the mycelium inoculation in a quick and well distributed way, thus reducing the risks of contamination and the incubation time of cultures. In this work, the submerged cultivation for the production of Shiitake mycelium was evaluated in an airlift bioreactor of external circulation, conceived and designed in the group, using the culture medium Mushroom Complete Medium added of micronutrients, under the operating conditions: rates of aeration: 0.16, 0.20, and 0.24 vvm and inoculum sizes (i.s.): 1.0 g. L-1 and 2.0 g. L-1. Under the best operating condition (0.16 vvm and 1.0 g L-1 i.s.), a mathematical model was developed using the EMSO software to describe the kinetics of culture fittnes to experimental data. It was possible to obtain 15.47 g L-1 of total biomass, after 10 days of cultivation, a maximum specific growth rate of 0.516 d-1, yields of Yx/s 1,06 g.g-1, YP/X 0,485 (g.L-1).g-1, YP/S 0,140 (g.L-1).g-1 and PX (productivity) 0.061 (g.L-1).h-1. The prediction of the model has proven to be a reliable parameter for studies for scaling up because it was predictive for biomass considering the products of metabolism (CO2 and H+ synthesis by acidification of the medium) and nutrient consumption (O2 and glucose). The selection and evaluation of strains in cultivation are also factors to be considered to obtain good productivity and, therefore, the productive performance of five strains of Shiitake cultivated under axenic system, was carried out using a central composition design (CCD) to evaluate the independent variables: incubation time I(t), and percentage of wheat bran in relation to sawdust of Eucalypitus saligna (represented by the carbon/nitrogen ratio (RC/N)), and having the biological efficiency (BE) and the unit weight of the mushrooms as target results. The best results for BE for all the strains were obtained in cultures with RC/N 57.62/1, with primordia induced at 130 days of I(t). The substrates used had their physico-chemical composition determined and the rates of substrate supplementation have been optimized, not only for the cultivation yields, but also for vegetative growth of the mycelium. The mushrooms harvested in this condition of production had their centesimal composition determined. Amilolytic, cellulolytic, β-glucosidase and specific proteases activities were performed in tests of colonization of the substrate. Three strains were selected for the isolation of spores and intraspecific hybridization was carried out. Hybrid strains were compared with the parental strains in terms of yields and synthesis of extracellular enzymes. The results of this study showed that strain has a considerable effect on both the yield and the unit weight of mushrooms.

With greenhouse gas emissions (of which CO2 is the major component) being a major environmental concern, mitigation of those emissions is becoming increasingly imperative. The ability to use a fast growing, photosynthetic organism like microalgae that can survive primarily on nutrients such as sunlight and air (with increased CO2 levels) makes it a desirable agent for CO2 sequestration. The primary goal of this project is the engineering of the sequestration of CO2 using the cultivation of the microalgae species <i>Chlorella vulgaris</i>. Secondary goals of the project are the exploration and development of valuable by-products of the cultivation and the determination of whether utilizing microalgae to capture CO2 could be integrated economically into an industrial facility.<p> The batch growth kinetics of the photosynthetic algal species <i>C. vulgaris</i> were investigated using a well-mixed stirred bioreactor. The growth rate was found to increase as the dissolved CO2 increased to 150 mg/L (10% CO2 by volume in the gas), but fell dramatically at higher concentrations. Increasing the radiant flux also increased growth rate. With a radiant flux of 32.3 mW falling directly on the 500 mL culture media, the growth rate reached up to 3.6 mg of cells/L-h. Both pH variation (5.5 - 7.0) and mass transfer rate of CO2 (KLa between 6 h-1 and 17 h-1) had little effect on growth rate.<p> The operation of continuously stirred tank bioreactors (CSTBs) at minimum cost is a major concern for operators. In this work, a CSTB design strategy is presented where impeller stirring speed and aeration rate are optimized to meet the oxygen demand of growing cells, simultaneously minimizing the capital and operating cost. The effect of microbial species, ions in the culture medium, impeller style, as well as changing CSTB size and biomass input density on the optimum operating conditions, is examined. A study of the effects of various parameters on the CSTB design is shown.<p> Using the kinetic data collected in the batch growth study, a novel external loop airlift photobioreactor (ELAPB) was designed and tested. A model was developed for <i>C. vulgaris</i> growth in the ELAPB that incorporated growth behaviour, light attenuation, mass transfer, and fluid dynamics. The model predicts biomass accumulation, light penetration, and transient CO2 concentrations, and compares predictions to experimental data for radiant fluxes of 0.075 1.15 W/m2 and 0 20% CO2 enrichment of feed air, with a 10% average error. The effect of radiant flux and CO2 concentration is presented with discussion of radial and vertical profiles along the column. For a fed-batch culture at a biomass density of 170 mg/L, the penetration of the radiant flux was found to decrease by 50% within the first 1 cm, and 75% at 2 cm. Theoretical optimum growth conditions are determined to be 0.30 W/m2 and 6% CO2 enrichment of inlet feed air.<p> The algal culture was observed to be a workable electron acceptor in a cathodic half cell. A net potential difference of 70 mV was achieved between the growing <i>C. vulgaris</i> culture acting as a cathode and a 0.02 M potassium ferrocyanide anodic half cell. Surge current and power levels of 1.0 µA/mg of cell dry weight and 2.7 mW/m2 of cathode surface area were measured between these two half cells. The recently developed photosynthetic cathode was also coupled to a fermentative anode to produce a completely microbial fuel cell. Loading effects and the effect of changing culture conditions on fuel cell operation are reported. The maximum power output measured was 0.95 mW/ m2 at 90 V and 5000 ohms. A significant increase in this output is achieved with the addition of supplemental glucose to the anodic half cell and the enrichment of the feed air bubbled into the cathodic half cell with 10% CO2.<p> Two economic feasibility studies were performed on the integration of ELAPBs into an industrial facility. These integration studies operated the ELAPBs continuously as biocathodes in coupled microbial fuel cells (MFCs) that capture CO2 from an existing 130 million L/yr bioethanol plant, while generating electrical power and yielding oil for biodiesel to provide operational revenue to offset costs. The anodes for the coupled MFCs are the existing yeast batch fermentors, and the CO2 to be sequestered comes from the existing bioethanol production. Two different design schemes were evaluated, in both cases the maximum profit was achieved with the maximum number of tall columns operated in parallel. The first design evaluated a batch bioethanol facility with off-site oil processing, and the economic feasibility is demonstrated by the positive Net Present Worth achieved over the 20 year life of the plant, at a 10% rate of return on investment. The second design, for a continuous bioethanol operation, processes both oil and algae biomass on-site, but the economics of this second process are only positive (Internal Rate of Return 9.93%.) if the government provides financial assistance in the form of generous carbon credits (a speculative $100 per tonne of CO2 not yet attained) and a 25% capital equipment grant.

With greenhouse gas emissions (of which CO2 is the major component) being a major environmental concern, mitigation of those emissions is becoming increasingly imperative. The ability to use a fast growing, photosynthetic organism like microalgae that can survive primarily on nutrients such as sunlight and air (with increased CO2 levels) makes it a desirable agent for CO2 sequestration. The primary goal of this project is the engineering of the sequestration of CO2 using the cultivation of the microalgae species <i>Chlorella vulgaris</i>. Secondary goals of the project are the exploration and development of valuable by-products of the cultivation and the determination of whether utilizing microalgae to capture CO2 could be integrated economically into an industrial facility.<p> The batch growth kinetics of the photosynthetic algal species <i>C. vulgaris</i> were investigated using a well-mixed stirred bioreactor. The growth rate was found to increase as the dissolved CO2 increased to 150 mg/L (10% CO2 by volume in the gas), but fell dramatically at higher concentrations. Increasing the radiant flux also increased growth rate. With a radiant flux of 32.3 mW falling directly on the 500 mL culture media, the growth rate reached up to 3.6 mg of cells/L-h. Both pH variation (5.5 - 7.0) and mass transfer rate of CO2 (KLa between 6 h-1 and 17 h-1) had little effect on growth rate.<p> The operation of continuously stirred tank bioreactors (CSTBs) at minimum cost is a major concern for operators. In this work, a CSTB design strategy is presented where impeller stirring speed and aeration rate are optimized to meet the oxygen demand of growing cells, simultaneously minimizing the capital and operating cost. The effect of microbial species, ions in the culture medium, impeller style, as well as changing CSTB size and biomass input density on the optimum operating conditions, is examined. A study of the effects of various parameters on the CSTB design is shown.<p> Using the kinetic data collected in the batch growth study, a novel external loop airlift photobioreactor (ELAPB) was designed and tested. A model was developed for <i>C. vulgaris</i> growth in the ELAPB that incorporated growth behaviour, light attenuation, mass transfer, and fluid dynamics. The model predicts biomass accumulation, light penetration, and transient CO2 concentrations, and compares predictions to experimental data for radiant fluxes of 0.075 1.15 W/m2 and 0 20% CO2 enrichment of feed air, with a 10% average error. The effect of radiant flux and CO2 concentration is presented with discussion of radial and vertical profiles along the column. For a fed-batch culture at a biomass density of 170 mg/L, the penetration of the radiant flux was found to decrease by 50% within the first 1 cm, and 75% at 2 cm. Theoretical optimum growth conditions are determined to be 0.30 W/m2 and 6% CO2 enrichment of inlet feed air.<p> The algal culture was observed to be a workable electron acceptor in a cathodic half cell. A net potential difference of 70 mV was achieved between the growing <i>C. vulgaris</i> culture acting as a cathode and a 0.02 M potassium ferrocyanide anodic half cell. Surge current and power levels of 1.0 µA/mg of cell dry weight and 2.7 mW/m2 of cathode surface area were measured between these two half cells. The recently developed photosynthetic cathode was also coupled to a fermentative anode to produce a completely microbial fuel cell. Loading effects and the effect of changing culture conditions on fuel cell operation are reported. The maximum power output measured was 0.95 mW/ m2 at 90 V and 5000 ohms. A significant increase in this output is achieved with the addition of supplemental glucose to the anodic half cell and the enrichment of the feed air bubbled into the cathodic half cell with 10% CO2.<p> Two economic feasibility studies were performed on the integration of ELAPBs into an industrial facility. These integration studies operated the ELAPBs continuously as biocathodes in coupled microbial fuel cells (MFCs) that capture CO2 from an existing 130 million L/yr bioethanol plant, while generating electrical power and yielding oil for biodiesel to provide operational revenue to offset costs. The anodes for the coupled MFCs are the existing yeast batch fermentors, and the CO2 to be sequestered comes from the existing bioethanol production. Two different design schemes were evaluated, in both cases the maximum profit was achieved with the maximum number of tall columns operated in parallel. The first design evaluated a batch bioethanol facility with off-site oil processing, and the economic feasibility is demonstrated by the positive Net Present Worth achieved over the 20 year life of the plant, at a 10% rate of return on investment. The second design, for a continuous bioethanol operation, processes both oil and algae biomass on-site, but the economics of this second process are only positive (Internal Rate of Return 9.93%.) if the government provides financial assistance in the form of generous carbon credits (a speculative $100 per tonne of CO2 not yet attained) and a 25% capital equipment grant.

This thesis examined the biological treatment of gas streams containing benzene, toluene, ethylbenzene and o-xylene (BTEX) using solid-liquid two-phase partitioning bioscrubbers (SL-TPPBs). SL-TPPBs consist of a cell containing aqueous phase and a polymeric solid phase that sequesters poorly water soluble and/or toxic substrates, mitigating substrate toxicity in the aqueous phase and improving the gas mass transfer during treatment of VOC contaminated gases. An initial investigation of oxygen transport determined that the polymers in a stirred-tank SL-TPPB enhance gas-liquid mass transfer. In addition, a study on biodegradation kinetics of BTEX by a bacterial consortium identified and quantified substrate interactions such as inhibition, enhancement and cometabolism. The stirred-tank SL-TPPB was then experimentally investigated for treatment of BTEX gas streams during steady-state and dynamic step-change operation to determine performance of the system relative to other biotreatment methods. A mathematical model was developed to predict system performance, which included the microbial kinetic model structure and parameters estimated during kinetic and oxygen mass transfer studies. As a less energy intensive alternative, an airlift SL-TPPB was operated and characterized. The airlift SL-TPPB was compared to an airlift liquid-liquid TPPB (silicone oil as sequestering phase) and a single phase airlift over dynamic step-change loadings, which showed that the airlift SL-TPPB outperformed the single phase airlift by >30% and had similar performance to the liquid-liquid airlift. However, the airlift SL-TPPB performance was lower relative to the stirred-tank SL-TPPB by >15%. Steady-state operation of the airlift SL-TPPB identified a range of operating conditions that provided maximum performance and conditions that were not oxygen limited. This prompted a study of oxygen mass transfer and hydrodynamics in the airlift system, which identified that the addition of polymers to an airlift does not cause physical enhancement of the gas-liquid mass transfer coefficient, but improves aqueous phase mixing and enhances overall oxygen transfer rate. A tanks-in-series mathematical model was formulated to predict performance of the airlift SL-TPPB, wherein the number of tanks-in-series to describe mixing in the airlift was obtained from a residence time distribution analysis of the airlift system completed during the hydrodynamic investigation. This thesis contributes a low-energy solution for the effective treatment of gases contaminated with BTEX. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2009-08-18 16:16:22.598

Des travaux préliminaires réalisés en fiole d'Erlenmeyer ont montré que l'environnement hydrodynamique, caractérisé par la puissance dissipée volumique (P/V) et le coefficient de transfert en oxygène (kLa), jouait un rôle important lors du procédé de production de pristinamycines par Streptomyces pristinaespiralis (Mehmood, 2011). L'objectif de ce travail est donc d'étudier l'influence de ces deux phénomènes dans des bioréacteurs mécaniquement agités (STR), largement utilisés à l'échelle industrielle, et de type gazosiphon. Dans un premier temps, une description de l'environnement hydrodynamique global a été réalisée en STR. En ce qui concerne le bioréacteur gazosiphon, celui-ci a été conçu et dimensionné spécifiquement pour ce travail. Une caractérisation des écoulements dans ce bioréacteur a ensuite été réalisée par simulation numérique des écoulements. En appliquant les mêmes conditions hydrodynamiques que celles étudiées lors de culture en fioles d'Erlenmeyer, les performances en terme de croissance et de production de pristinamycines ont toujours été moindres en STR et en gazosiphon qu'en fiole. Ceci démontre que P / V, kLa mais également la dissipation maximum, ne constituent pas les bons paramètres d'extrapolation. Par contre, les performances mesurées semblent être reliée aux variations de formes morphologiques observées (présence et taille des pelotes) et à la physiologie des cellules au sein de ces structures. De façon surprenante, au cours de ce travail, le déclenchement de la production de pristinamycines a quasiment toujours été obtenu lors de la phase de croissance de S. pristinaespiralis. Nos travaux n'ont pas permis de mettre en évidence la raison de ce phénomène. Celui-ci est certainement la conséquence de plusieurs paramètres qui restent encore à préciser / Previous results performed in Erlenmeyer flasks have shown that the hydrodynamics, characterized by power dissipation per unit of volume (P/V) and volumetric oxygen mass transfer coefficient (kLa), impacted the production of pristinamycins by Streptomyces pristinaespiralis (Mehmood, 2011). The aim of this work is then to study the influence of these two parameters in a stirred tank bioreactor (STR), widely used in industry, and in an airlift bioreactor. This last bioreactor has been designed specifically for this work. In a first part, the hydrodynamic environment was described in STR and the fluid flows were simulated by computational fluid dynamics (CFD). Using the same hydrodynamic conditions in STR and in airlift bioreactor than in flasks, the process performance (bacterial growth and pristinamycin production) were always lower in STR and airlift bioreactor. This demonstrates that P / V, kLa and also maximum dissipation were not pertinent scale-up criteria for the pristinamycin production from flask to STR or airlift bioreactor. On the contrary, the determined performances seemed to be related to the changes in bacterial morphology (presence and size of pellets) and to the physiology of the cells inside these structures. Surprisingly, during this work, the initiation of the pristinamycin production occurred almost always during the growth phase of S. pristinaespiralis. This phenomenon was probably due to the conjunction of several parameters which remain to identify

Made available in DSpace on 2016-06-02T19:56:54Z (GMT). No. of bitstreams: 1 5928.pdf: 1538103 bytes, checksum: aa35e421fd67417964fb69c2b0a31753 (MD5) Previous issue date: 2014-02-28 / Agência Nacional de Petróleo / The performance of pneumatic bioreactors is highly related to their geometric characteristics, such as the bottom clearance, riser to downcomer cross sectional area ratio, liquid height and the gas-liquid separator design. Although new geometries have been proposed, it is still necessary deeper studies to obtain more adequate reactor projects for bioprocess applications. This study evaluated the influence of the gas-liquid separator design on the hydrodynamics and oxygen transfer of 10-L concentric-tube airlift bioreactors, using Newtonian and non- Newtonian fluids and in order to define the better set of geometric characteristics. To reach this aim, the gas-liquid separator openness angle (&#945;) varied from 30° to 90° and the volume fraction of fluid present on the gas-liquid separator section (FVL,GLS) varied from 0.10 to 0.30. The results indicated that for both fluids (Newtonian and non-Newtonian), the overall volumetric oxygen transfer coefficient (kLa) increased with the increase in &#945; and a decrease in FVL,GS. Meanwhile, this gas-liquid separator geometry caused low global gas hold-up (&#949;G), suggesting the reduction of mean bubble diameter (dB) for this condition. Operating with the non-Newtonian fluid at 5.0 vvm, the best gas-liquid separator geometry (&#945;=90°; FV L,GLS=0,10) exhibited kLa and &#949;G of 0,017 s-1 and 0,11, respectively. Moreover, this set of geometric characteristics lead to a gas-liquid flow with intermediate values for the drag coefficient (CD), suggesting moderate shear conditions. For the best geometry, the average shear rate varied from 1500 to 2400 s-1, in a similar range when compared to other airlift bioreactors. These results indicate the feasibility to use this bioreactor geometry in applications with shear-sensitive microorganisms. / O desempenho de biorreatores pneumáticos depende fortemente das suas características geométricas, como o vão livre na base, a razão entre as áreas de escoamento, a altura de líquido e o design da região de mistura. Embora diferentes geometrias tenham sido propostas na literatura, ainda há necessidade de estudos mais aprofundados, com o intuito de se obter projetos de biorreatores mais adequados aos bioprocessos. O presente estudo avaliou a influência da geometria da região de mistura na hidrodinâmica e transferência de oxigênio em biorreatores airlift de cilindros concêntricos de 10 L, empregando-se fluidos Newtonianos e não- Newtonianos, a fim de se definir o melhor conjunto de características geométricas. Para isso, variou-se o ângulo da região de mistura (&#945;) (ângulo entre a lateral da região de mistura e o eixo horizontal) de 30° a 90° e a fração volumétrica de líquido na região de mistura (FVL,RM) (razão entre o volume de líquido contido apenas na região de mistura e o volume de líquido total do biorreator) de 0,10 a 0,30. Os resultados mostraram que para ambos fluidos (Newtoniano e não-Newtoniano), o coeficiente volumétrico de transferência de oxigênio (kLa) aumentou com o incremento em &#945; e a diminuição de FVL,RM. Entretanto, esta configuração de geometria da região de mistura proporcionou baixa retenção gasosa (&#949;G), indicando baixos valores de diâmetro das bolhas (dB) nesta condição. Empregando-se a melhor geometria da região de mistura (&#945;=90°; FV L,RM=0,10), para o fluido não- Newtoniano, na condição de 5,0 vvm, obteve-se valores de kLa e &#949;G de 0,017 s-1 e 0,11, respectivamente. Além disso, verificou-se que esta combinação de parâmetros geométricos conduziu a um escoamento gás-líquido com valores intermediários de coeficiente de arrasto (CD), sugerindo condições amenas de cisalhamento. Através da estimativa da velocidade de cisalhamento média ( m &#61543;& ) para a melhor geometria em termos de transferência de oxigênio, observou-se uma variação entre 1500 e 2400 s-1, sendo estes valores da mesma ordem de grandeza quando comparados a outros biorreatores airlift. Esses resultados reforçam a viabilidade de utilização desta geometria em aplicações com microrganismos sensíveis ao cisalhamento.