A bactéria Zymomonas mobilis atraiu considerável interesse nas últimas décadas devido ao seu metabolismo único e eficientes características fermentativas na produção de etanol a partir de açúcares simples. No entanto, apesar das aparentes vantagens na conversão e taxas específicas quando comparada com as leveduras, estas ainda dominam o mercado produtivo de etanol. Dentre os diversos modelos encontrados na literatura para representar o processo fermentativo de glicose através de Z. mobilis, o modelo proposto por Jöbses et al. (1986) aparenta ser bem estruturado e ideal para a criação de estratégias de controle e otimização de processos fermentativos com este microrganismo, viabilizando sua utilização em escala industrial. Fermentações de Z. mobilis em regime contínuo apresentam comportamento oscilatório para baixas taxas de diluição, fenômeno este comprovado experimentalmente. Experimentos laboratoriais foram utilizados para a estimação de parâmetros do modelo de Jöbses, através da técnica de minimização da derivada do erro da função objetivo. O novo modelo ajustado apresenta dinâmica equivalente ao modelo original de Jöbses, fato este comprovado através da construção dos diagramas de bifurcação. Os diagramas de fase dos modelos apresentam algumas diferenças estruturais entre si, entretanto, a ocorrência de multiplicidade de estados estacionários em baixos valores de taxa de diluição está presente em todos. Em bioprocessos, a obtenção de informações sobre o sistema é um tanto complexa, devido a estes meios serem muito suscetíveis a distúrbios, contaminações, além de que medidas de concentrações são relativamente dispendiosas, associadas com um alto tempo morto, o que impossibilita, muitas vezes, a implementação de sistemas de controle eficientes. Para contribuir com a resolução deste problema foi desenvolvida uma nova inferência das variáveis de estado através da informação de consumo de hidróxido de sódio, utilizado no controle de pH do meio. Inferidores de variáveis de estado que utilizam a variação no consumo de hidróxido de sódio foram ajustados e apresentaram resultados promissores, mostrando a viabilidade do desenvolvimento de metodologias para este tipo de análise, tornando a caracterização de sistemas fermentativos mais rápida e acessível, não apenas em nível acadêmico, que a desenvolvida atualmente, principalmente devido ao baixo custo associado, e a dinâmica rápida deste tipo de sensor. / The bacterium Zymomonas mobilis has attracted considerable interest in recent decades due to their unique metabolism and efficient characteristics in the production of ethanol by simple sugars. However, despite the apparent advantages in the conversion and specific rates, when compared with yeast, there is no industrial-scale fermentations with these bacteria. Among the various models found in literature to represent glucose fermentation with Z. mobilis, the model proposed by Jöbses et al. (1986) appears to be well structured and ideal for the creation of control strategies and optimization methods for increase productions. Fermentation in continuous mode with this organism exhibit oscillatory behavior at low dilution rates, phenomenon showed or demonstrated by experiments performed on laboratory scale. A laboratorial experiment also was used for estimation of new parameters group of Jöbses models, using the technique of minimization of error derivative for objective function. The new adjusted model set presents dynamics similar to the original model, fact confirmed by bifurcation analyses of both models. The diagram for these models show structural differences, but both presents steady states multiplicity and Hopf bifurcations. The obtained of fermentation characteristics is very complex, due to these reactive means being very susceptible to disturbances, contamination, among others, and concentrations measures are relatively expensive and whit a high dead time associated, which often prevents the implementation of control tools. The proposed inference of state variables by consumption rate of hydroxide sodium, used for maintenance pH medium, was tested and confirmed. Virtual sensors using the information of consumption rate of hydroxide were adjusted and have shown promising results, demonstrating the feasibility of developing methods of analysis based on this methodology, making the characterization of fermentative systems faster and cheaper them currently developed, mainly due to low cost associated, and the dynamics of this fast type of sensor.

A bactéria Zymomonas mobilis atraiu considerável interesse nas últimas décadas devido ao seu metabolismo único e eficientes características fermentativas na produção de etanol a partir de açúcares simples. No entanto, apesar das aparentes vantagens na conversão e taxas específicas quando comparada com as leveduras, estas ainda dominam o mercado produtivo de etanol. Dentre os diversos modelos encontrados na literatura para representar o processo fermentativo de glicose através de Z. mobilis, o modelo proposto por Jöbses et al. (1986) aparenta ser bem estruturado e ideal para a criação de estratégias de controle e otimização de processos fermentativos com este microrganismo, viabilizando sua utilização em escala industrial. Fermentações de Z. mobilis em regime contínuo apresentam comportamento oscilatório para baixas taxas de diluição, fenômeno este comprovado experimentalmente. Experimentos laboratoriais foram utilizados para a estimação de parâmetros do modelo de Jöbses, através da técnica de minimização da derivada do erro da função objetivo. O novo modelo ajustado apresenta dinâmica equivalente ao modelo original de Jöbses, fato este comprovado através da construção dos diagramas de bifurcação. Os diagramas de fase dos modelos apresentam algumas diferenças estruturais entre si, entretanto, a ocorrência de multiplicidade de estados estacionários em baixos valores de taxa de diluição está presente em todos. Em bioprocessos, a obtenção de informações sobre o sistema é um tanto complexa, devido a estes meios serem muito suscetíveis a distúrbios, contaminações, além de que medidas de concentrações são relativamente dispendiosas, associadas com um alto tempo morto, o que impossibilita, muitas vezes, a implementação de sistemas de controle eficientes. Para contribuir com a resolução deste problema foi desenvolvida uma nova inferência das variáveis de estado através da informação de consumo de hidróxido de sódio, utilizado no controle de pH do meio. Inferidores de variáveis de estado que utilizam a variação no consumo de hidróxido de sódio foram ajustados e apresentaram resultados promissores, mostrando a viabilidade do desenvolvimento de metodologias para este tipo de análise, tornando a caracterização de sistemas fermentativos mais rápida e acessível, não apenas em nível acadêmico, que a desenvolvida atualmente, principalmente devido ao baixo custo associado, e a dinâmica rápida deste tipo de sensor. / The bacterium Zymomonas mobilis has attracted considerable interest in recent decades due to their unique metabolism and efficient characteristics in the production of ethanol by simple sugars. However, despite the apparent advantages in the conversion and specific rates, when compared with yeast, there is no industrial-scale fermentations with these bacteria. Among the various models found in literature to represent glucose fermentation with Z. mobilis, the model proposed by Jöbses et al. (1986) appears to be well structured and ideal for the creation of control strategies and optimization methods for increase productions. Fermentation in continuous mode with this organism exhibit oscillatory behavior at low dilution rates, phenomenon showed or demonstrated by experiments performed on laboratory scale. A laboratorial experiment also was used for estimation of new parameters group of Jöbses models, using the technique of minimization of error derivative for objective function. The new adjusted model set presents dynamics similar to the original model, fact confirmed by bifurcation analyses of both models. The diagram for these models show structural differences, but both presents steady states multiplicity and Hopf bifurcations. The obtained of fermentation characteristics is very complex, due to these reactive means being very susceptible to disturbances, contamination, among others, and concentrations measures are relatively expensive and whit a high dead time associated, which often prevents the implementation of control tools. The proposed inference of state variables by consumption rate of hydroxide sodium, used for maintenance pH medium, was tested and confirmed. Virtual sensors using the information of consumption rate of hydroxide were adjusted and have shown promising results, demonstrating the feasibility of developing methods of analysis based on this methodology, making the characterization of fermentative systems faster and cheaper them currently developed, mainly due to low cost associated, and the dynamics of this fast type of sensor.

In the diploma thesis are discussed the process of enzymatic hydrolysis of waste paper as a source for the production of bioethanol by bacteria Zymomonas mobilis. In the theoretical part summarize basic information about particular methods of hydrolysis, about paper used as a raw material for enzymatic hydrolysis, about possibilities of the fermentative production of bioethanol focusing on the method of simultaneous saccharification and fermentation comparison with enzymatic hydrolysis and fermentation. Suitable microorganisms for ethanolic fermentation and simultaneous saccharification and fermentation and their advantages and disadvantages, are further discussed in this part as well. The theoretical part ends with the suggestion of the technological process for production of bioetanol. It covers all necessary steps from the input of raw material to the separation of produced ethanol. In the experimental part various parameters of hydrolysis, fermentation and simultaneous saccharification and fermentation were optimized using enzymes from Novozymes® company and the Zymomonas mobilis CCM2770 and Zymomonas mobilis LMG457 bacterium. The conversion rate of paper cellulose to gluckose and production of ethanol were observed by HPLC/RI method. Type of buffer, quantity of cells, enzyme and substrate were optimized in order to maximize the efficiency of the process. All experiments were performed on paper containing high amount of cellulose and for comparison on standard medium which contains gluckose. The highest yields was achieved with the use of Novozymes® Cellulosic ethanol enzyme Kit. The strain Zymomonas mobilis LMG457 has demonstrated as a better producer.

Diploma thesis deals with use of Zymomonas mobilis for the production of bioethanol from waste paper. There were used three kinds of substrate (cardboard, drawing and office paper) to optimize of bioethanol production. Individual papers were subjected to the same pre treatment, namely a milling, a combination of microwave irradiation and NaOH, a combination of microwave irradiation and H2SO4 and combination microwave irradiation, H2SO4 and NaOH. The substrates were decomposed by enzymatic hydrolysis after pre treatment to evaluate the best pre-treatment. Simultaneous saccharification and fermentation was carried out for each substrate (with two of the best pre-treatment). The samples were taken during the hydrolysis and the simultaneous saccharification and fermentation, and were determined by HPLC. Growth curves of Zymomonas mobilis were constructed, as the most appropriate for SSF was chosen temperature of 40 ° C in which the exponential phase took place at the time of 6 15 hours. During hydrolysis was monitored glucose concentration in the solution. The maximum concentration of glucose was in the cardboard (microwaves + H2SO4 + NaOH) 16.46 gdm-3, a drawing (microwaves + H2SO4 + NaOH) 31.78 gdm-3, and office paper (microwaves + H2SO4) 25.04 gdm-3. The concentration of ethanol for SSF was highest in the same cases as in the hydrolysis. The cardboard was the maximum concentration of bio ethanol 9.5 gdm-3, for the drawing 16.1 gdm-3 and for the office paper 12.13 gdm-3.