Hannover, Universiẗat, Diss., 2003.

Consolidated bioprocessing is a one-step process that allows the direct microbial conversion of cellulosic substrates to ethanol and hydrogen. The fermentation was initially performed in batch cultures, in a pH and temperature controlled reactor using Clostridium thermocellum ATCC 27405. With an objective of increasing the production of ethanol and hydrogen, various types of fed-batch fermentations were investigated: variable volume (VV) fed-batch, fixed volume (FV) fed-batch, and semi-continuous fermentation. Semi-continuous processes were carried out at low (10-15 g/L) and high (20-25 g/L) cellulose concentrations. The maximum ethanol production obtained in batch, VV, FV, semi-continuous with low concentrations and high concentrations were 554 mmol, 336 mmol, 477 mmol, 695 mmol and 741 mmol respectively. In the same order, the total hydrogen production was 288 mmol, 364 mmol, 231 mmol, 434 mmol, and 387 mmol. Overall, the semi-continuous fermentation showed more promise in terms of large-scale deployment compared to batch, VV, and FV fed-batch. / October 2015

Monitoring the limiting reactant concentration is a key question to maximize the productivity and to guarantee the safety of exothermic fed-batch processes. However in most applications, the concentration cannot be measured in real-time since suitable devices do not exist or are too expensive; the concentrations are then measured by off-line analyses. In this context monitoring the concentrations via software sensors, or state observer based estimators, is an attractive option. The presence of model uncertainties is a major limitation when applying state observers to real processes. More precisely, in fed-batch exothermic reactors the bad knowledge of both the reaction kinetics and the heat transfer may prevent the use of classical observers. In this study, we propose two different approaches to estimate the concentration of the limiting reactant in a class of single phase exothermic fed-batch reactors with uncertain kinetics and heat transfer. The first approach is based on a finite time converging observer that provides an estimate for the reaction rate via the reactor energy balance equation. The concentration is then computed from the reaction rate estimate via a material balance equation. The main contribution of this approach is the use of a finite time observer to limit the reconstruction error by guaranteeing a small convergence time interval for the reaction rate estimate. The second approach is based on an interval observer that provides two bounds for the concentration by considering uncertainties related to both the heat transfer and the reaction kinetics. The final estimate is then computed as the mean of the bounds. A systematic tuning procedure has been developed for each of both estimation techniques. Both estimators have then been tested and validated with real data coming from the production of different kinds of resins carried out in 10 tons reactors.

Animal cell culture is widely used as a platform for the production of a variety of biopharmaceuticals. The development of an efficient and productive cell culture requires a deep understanding of intra-cellular mechanisms as well as extra-cellular conditions for optimal synthesis. Mathematical modeling can be an effective strategy to predict, control, and optimize cell performance under different culture conditions. This research presents the evaluation of Chinese hamster ovary (CHO) cell culture secreting recombinant anti-RhD monoclonal antibody (MAb) through different processing modes, namely batch, fed-batch and perfusion operations. The ultimate objective of this study was to establish a comprehensive dynamic model which may be used for model-based optimization of the cell culture for MAb production in both batch, fed-batch or perfusion systems. In analyzing process performance, the key potential cause of cell growth inhibition was attributed to lowering of pH in the culture possibly due to the accumulation of dissolved carbon dioxide. The most important finding in this regard was the significantly different observed maximum total viable cell density in two identical cultures differing in culture volume only (250mL and 500mL). However, the other byproduct metabolites such as lactate and ammonia and glucose depletion were also capable affecting growth adversely causing growth arrest, viability reduction, apoptosis initiation and progress. Employing the experimental results of nutrient consumption, metabolite and biomass production, a metabolic flux based methodology was developed for modeling the metabolism of a CHO cell line. The elimination of insignificant fluxes resulted in a simplified metabolic network which was the basis for modeling the significant extracellular metabolites. Using kinetic rate expressions for growing and non-growing subpopulations, a logistic model was first developed for cell growth and dynamic models were formulated to describe culture composition and monoclonal antibody (MAb) secretion. The viable cell population was assumed to consist of normal growing, normal non-growing and apoptotic cell subpopulations. The rate of apoptotic cell formation was assumed to have a second order dependence on the normal cell concentration. The proposed mathematical model for metabolites included distinct terms that reflected the metabolic rates of growing and non-growing cell populations. The model was validated for a range of glutamine and glucose concentrations. Good agreement was obtained between model predictions and experimental data. In subsequent steps the attempt was to correlate the growth kinetics to significant variables of the culture. The regulatory effects identified through each culture condition were combined for a rational design of a dynamic model constructed for the viable cell subpopulation. A Tessier-based model was applied for defining the fraction of growing cells as a function of a growth inhibitor, presumably dissolved carbon dioxide. Although only few variables appeared in the biomass model, all equations were solved simultaneously. The parameters were estimated using the Metropolis-Hastings algorithm and the fmincon function in MATLAB. The final model adequately predicted the effect of significant variables on the metabolic behavior of CHO cells in batch, fed-batch and perfusion systems.

Animal cell culture is widely used as a platform for the production of a variety of biopharmaceuticals. The development of an efficient and productive cell culture requires a deep understanding of intra-cellular mechanisms as well as extra-cellular conditions for optimal synthesis. Mathematical modeling can be an effective strategy to predict, control, and optimize cell performance under different culture conditions. This research presents the evaluation of Chinese hamster ovary (CHO) cell culture secreting recombinant anti-RhD monoclonal antibody (MAb) through different processing modes, namely batch, fed-batch and perfusion operations. The ultimate objective of this study was to establish a comprehensive dynamic model which may be used for model-based optimization of the cell culture for MAb production in both batch, fed-batch or perfusion systems. In analyzing process performance, the key potential cause of cell growth inhibition was attributed to lowering of pH in the culture possibly due to the accumulation of dissolved carbon dioxide. The most important finding in this regard was the significantly different observed maximum total viable cell density in two identical cultures differing in culture volume only (250mL and 500mL). However, the other byproduct metabolites such as lactate and ammonia and glucose depletion were also capable affecting growth adversely causing growth arrest, viability reduction, apoptosis initiation and progress. Employing the experimental results of nutrient consumption, metabolite and biomass production, a metabolic flux based methodology was developed for modeling the metabolism of a CHO cell line. The elimination of insignificant fluxes resulted in a simplified metabolic network which was the basis for modeling the significant extracellular metabolites. Using kinetic rate expressions for growing and non-growing subpopulations, a logistic model was first developed for cell growth and dynamic models were formulated to describe culture composition and monoclonal antibody (MAb) secretion. The viable cell population was assumed to consist of normal growing, normal non-growing and apoptotic cell subpopulations. The rate of apoptotic cell formation was assumed to have a second order dependence on the normal cell concentration. The proposed mathematical model for metabolites included distinct terms that reflected the metabolic rates of growing and non-growing cell populations. The model was validated for a range of glutamine and glucose concentrations. Good agreement was obtained between model predictions and experimental data. In subsequent steps the attempt was to correlate the growth kinetics to significant variables of the culture. The regulatory effects identified through each culture condition were combined for a rational design of a dynamic model constructed for the viable cell subpopulation. A Tessier-based model was applied for defining the fraction of growing cells as a function of a growth inhibitor, presumably dissolved carbon dioxide. Although only few variables appeared in the biomass model, all equations were solved simultaneously. The parameters were estimated using the Metropolis-Hastings algorithm and the fmincon function in MATLAB. The final model adequately predicted the effect of significant variables on the metabolic behavior of CHO cells in batch, fed-batch and perfusion systems.

Le vin est un milieu peu propice à la croissance de la levure mais il est néanmoins possible de la faire croître sur base de vin enrichit en nutriments et dilué pour diminuer la concentration en éthanol. En vue de l’élaboration des vins effervescents par une seconde fermentation, produire la levure Saccharomyces cerevisiae dans ces conditions est indispensable pour l’acclimater mais il s’agit d’un enjeu complexe qui doit prendre en compte de nombreux paramètres physico-chimiques mais aussi économiques. En effet, les paramètres opératoires peuvent induire des conditions de croissance pouvant affecter le développement de la levure. Seule la levure S. cerevisiae (Fizz+) a été utilisée car elle est spécialement sélectionnée pour cette seconde fermentation en vase clos. Le principal enjeu était donc d’obtenir une bonne adaptation de la levure à croître dans un milieu hydro-alcoolique, conditions contraignantes pour elle, mais aussi d’obtenir une production maximale.Nous avons tout d’abord étudié en fioles Erlenmeyer (250 mL) l’influence de divers paramètres : conditions physico-chimiques, concentrations en nutriments, concentration minimale en levure sèche active nécessaire à une bonne activité ainsi que son temps de réhydratation.Dans un deuxième temps, nous avons effectué des propagations en mode batch dans un bioréacteur (5 L) pour valider les conclusions réalisées à la suite de l’étude en Erlenmeyer et ainsi étudier l’influence de différentes aérations sur la production de S. cerevisiae. Les données obtenues ont servi de base pour comparer les améliorations apportées par le procédé développé en mode fed-batch. Les concentrations en levures obtenues suite à l’optimisation des conditions du milieu de culture en cinq litres sont supérieures d’un facteur cinq à celles obtenues dans la pratique en cave.Ensuite l’étude s’est concentrée sur le développement d’un nouveau procédé d’alimentation en nutriments pour cultiver S. cerevisiae en métabolisme respiratoire dans des cuves réalisées par la société partenaire du projet, OEno Concept. La nouveauté réside dans la façon de réguler la température de la culture qui se fait simultanément à l’apport des nutriments suite au dégagement de chaleur lors de la croissance de S. cerevisiae. Un brevet a été déposé sur cette technologie. Ce nouveau procédé a permis une augmentation de la productivité cellulaire, d’un facteur supérieur à quatre, car il a permis aux levures de s’adapter à cet environnement stressant et a favorisé l’oxydation du glucose au détriment de la fermentation. / Wine is an aggressive/stressful growth medium; it is depleted of micronutrients, rich in ethanol and very poor in assimilable nitrogen. Despite all these difficulties, it is possible to grow yeast in a medium largely based on wine by diluting the ethanol concentration and enriching the medium with micronutrients, a carbon source and assimilable nitrogen. It is, desirable to propagate Saccharomyces cerevisiae in such environment in order to produce a culture of yeast adapted to a second fermentation of alcoholic beverages. Production of microorganism in wine growing environment, is a complex issue that must take into account many, physicochemical and economic parameters. Indeed, the operating parameters can affect the development of yeast in a bioreactor. Therefore, it is important to know the most influential parameters on growth. The strain S. cerevisiae (Fizz+), a commercial strain that has been selected for the second fermentation in bottles, was used during this project. The propagation process served to increase the amount of yeast as well as to adapt the yeast to grow in an alcoholic environment. We first studied in shake-flasks cultures various physicochemical conditions such as nutrients concentration, the rehydration time and the minimum concentration of active dry yeast necessary for good yeast activity.In a second step, we performed batch fermentations in bioreactors (5 L) to confirm the conclusions from the shake-flask cultures and additionally to study the influence of aeration on S. cerevisiae production. The data obtained served as a basis for performing fed-batch cultures. The yeast concentrations obtained as a result of the optimization of the conditions of the culture medium in five liters were five times greater than those obtained in actual industrial production processes. The next step was to develop an automated fed-batch culture to grow S. cerevisiae respiratively in partnership with the industrial partner of the project, OEno Concept. The novelty of the process is the way in which the growth medium feed-rate is linked to the heat produced by the growing S. cerevisiae.This research has allowed an increase in cell productivity, by a factor greater than four, thanks to the novel process in stressful growth environment promoting respiration with regard to fermentation.

QC 20100618

As bactÃrias promotoras de crescimento em plantas (BPCP) representam uma parcela funcional ativa da biota do solo sÃo presentes na rizosfera no rizoplano e no interior de plantas hospedeiras O uso biotecnolÃgico dessas bactÃrias tem se intensificado nos Ãltimos anos O gÃnero Bacillus vem sendo continuamente citado em estudos relacionados a promoÃÃo de crescimento em espÃcies vegetais Algumas espÃcies podem ser aplicadas no tratamento de sementes, ÃrgÃos de propagaÃÃo vegetativa e mudas Diante disso o presente trabalho teve como objetivo avaliar a produÃÃo de biomassa de Bacillus sp (RAB9) com potencial uso na promoÃÃo de crescimento de mudas de bananeira A cepa Bacillus sp (RAB9) pertencente ao grupo das bactÃrias epifÃticas, foi isolada de rabanete proveniente da ColeÃÃo de Culturas do LaboratÃrio de Fitobacteriologia da Universidade Federal Rural de Pernambuco Os experimentos foram realizados em agitador orbital e em reator de bancada Em agitador orbital foi estudada a curva de crescimento da linhagem a 30ÂC para observar sua fase exponencial Para a produÃÃo de biomassa foram observados os efeitos da adiÃÃo do teor de peptona (5 a 50 g.L-1) no meio NYD (extrato de carne, extrato de levedura peptona de carne e dextrose) adiÃÃo de elementos secundÃrios (K2HPO4 e MgSO4) e fonte de nitrogÃnio inorgÃnico ((NH4)2SO4) Em reator de bancada foram realizados testes com diferentes vazÃes de ar em batelada simples bem como uma comparaÃÃo com batelada alimentada com o meio modificado As fermentaÃÃes nos reatores apresentaram formaÃÃo de espuma testes foram feitos com Ãleos vegetais (milho canola girassol soja) e mineral para verificaÃÃo do melhor antiespumante Posteriormente aos testes foram quantificadas a biomassa o aÃÃcar residual nitrogÃnio residual e nitrogÃnio amoniacal Com os resultados obtidos foi observado a importÃncia da adiÃÃo dos elementos (MgSO4 e (NH4)2SO4) ao meio NYD e da vazÃo de ar sobre o crescimento da cepa Com os parÃmetros estudados foram determinadas as melhores condiÃÃes para a produÃÃo de Bacillus sp RAB9 / The growth-promoting bacteria in plants (BPCP) represents a functional portion of the active biota soil rhizosphere are present in rhizoplane and within host plants The biotechnological use of these bacteria has intensified in recent years The genus Bacillus has been continually cited in studies related to growth promotion in plant species Some species can be applied as a seed treatment organs for the vegetative propagation and seedling Therefore this study aimed to assess the biomass of Bacillus sp (RAB9) with potential use in promoting growth of banana plantlets The strain Bacillus sp (RAB9) belonging to the group of epiphytic bacteria was isolated from radish from the Culture Collection of the Laboratory of Fitobacteriologia Federal Rural University of Pernambuco The experiments were performed on an orbital shaker and batch reactor In orbital shaker was studied growth curve of strain at 30ÂC to observe their exponential phase For the production of biomass were observed the effects of adding the content of peptone (5 to 50 g.L-1) in NYD medium (meat extract yeast extract meat peptone and dextrose) addition of secondary elements (K2HPO4 and MgSO4) and inorganic nitrogen source ((NH4)2SO4) In batch reactor tests were conducted with different air flows in simple batch and fed batch with a comparison with the modified medium The fermentations presented in the reactors foaming tests were made with vegetable oils (corn canola sunflower soybean) and to verify the best mineral defoamer Later tests were quantified biomass residual sugar residual nitrogen and ammonia nitrogen With the results noted the importance of the addition of elements (MgSO4 and (NH4)2SO4) in half NYD and air flow on the growth of strain With the studied parameters were determined the best conditions for the production of Bacillus sp RAB9

Orientador: Ranulfo Monte Alegre / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T21:39:56Z (GMT). No. of bitstreams: 1 Gonzales_TatianeAraujo_M.pdf: 808675 bytes, checksum: 754d8f090b92f6186edb2bc0bad0c5b2 (MD5) Previous issue date: 2004 / Resumo: O processo de batelada alimentada é útil para o estudo da cinética de processos fermentativos, pois permite a manutenção de baixos níveis de substrato por longo período de tempo, que é favorável à estimativa de parâmetros cinéticos; permite manter concentração celular constante e controlar a velocidade de crescimento em condições transientes. São as equações cinéticas que indicam como as variáveis de estado do processo em estudo interferem nas velocidades de crescimento e morte celular, de geração de produtos metabólicos e de consumo de substrato. Estudos de biorreatores de batelada alimentada têm sido freqüentemente relatados na literatura, entretanto para a modelagem destes processos necessita-se conhecer parâmetros cinéticos e informações sobre estes são escassas. A implantação do PROÁLCOOL no Brasil fez aumentar o número de destilarias. Atualmente, o processo de batelada alimentada responde por cerca de 60% do volume de etanol produzido. Outro processo fermentativo de alto valor comercial é a produção de ácido lático, uma vez que este tem grande aplicação no uso em alimentos, na área farmacêutica, de plásticos e indústria química. Desta forma, o objetivo deste trabalho foi estudar duas fermentações distintas com relação à cinética de produção e entender a fenomenologia do processo de batelada alimentada. Escolheram-se dois tipos de fermentações com cinética de produção diferentes, uma alcoólica e outra lática, o primeiro com produção associada ao crescimento e o outro de produção parcialmente associada ao crescimento. Realizaram-se ensaios de fermentações em batelada para obtenção dos parâmetros cinéticos e em batelada alimentada para aplicação dos parâmetros obtidos em modelos e estes em balanço de massa do processo batelada alimentada. Em seguida, foram conduzidas simulações do processo batelada alimentada com o auxílio do software AnaBio 1.0 e ajustados os parâmetros cinéticos através de análise visual, utilizando-se dois modelos encontrados na literatura: o modelo cinético de Monod e outro também baseado em Monod com inclusão de um termo de inibição pelo produto. Estes modelos representaram visualmente os dados experimentais de forma satisfatória para a fermentação alcoólica, no entanto, somente um ajuste regular dos dados experimentais em relação aos preditos foram obtidos para fermentação lática / Abstract: The fed-batch process is useful for studying of fermentation process kinetic, because it allows keeping low level of substrate for a long period, which is favorable to estimate kinetic parameters; it enables keeping a constant biomass concentration and controlling growing rate in transient conditions. The kinetic equations indicate how the process variables interfere in the cell growing rate and death, the metabolic product formation and substrate consumption. The bioreactors studies of fed-batch have been often found on specialized literature, however, its necessary to know the kinetic parameters that are not available. A very important program in Brazil, called PROALCOOL, leveraged a raise in the number of alcohol industries and 60% of ethanol assembled in this country, in the present time, use fed-batch process. Another interesting process is the production of lactic acid, which is important to food, pharmaceutical, plastic and chemical industry. Therefore the main objective of this project was to study two different fermentation processes to apply the material balance of the fed-batch reactor with determined parameters and known mathematical models. Two production kinetic fermentations were chosen, one alcoholic and another lactic. The first one is associated with the cell growth and the other is partially associated with cell growth. Some batch fermentations essays were carried out to obtain kinetics parameters and fed-batch processes were performed to study the kinetic process. Simulations of fed-batch process, running the software Anabio 1.0, were executed and the kinetic parameters fitted through visual analysis, using two known models, Monod kinetic model and Monod including inhibitory effect of product. Theses models were better visually represented by the alcoholic fermentation experimental data than lactic fermentation data. In the condition of the fed-batch assays the Monod or Monod with inhibitory effect of product inserted in the material balance do not describe these process / Mestrado / Mestre em Engenharia de Alimentos

No description available.