<p> Using soluble organic carbon in the form of glucose as a growth limiting nutrient, the kinetics of mixed microbial populations (mainly bacterial in content) were studied using completely mixed batch and continuous biochemical reactors, in order to determine if kinetic data obtained from these two processes is identical and reproducible. </p> <p> Significant differences were found in the metabolic activity of of bacteria growing in batch and continuous culture; also periods of continuous culture were found to alter the kinetics of subsequent batch cultures. Simultaneous batch experiments and consecutive batch experiments were found to be substantially reproducible with respect to kinetic data, but inconsistency was obtained in continuous culture kinetic data. The degree of dispersion of the bacteria was also found to be different in batch and continuous culture; continuous operation gave rise to dispersed growth of bacteria, whereas batch operation gave rise to flocculent bacterial growth. </p> / Thesis / Master of Engineering (MEngr)

<p> Biodegradation of benzene, a common groundwater contaminant, occurs readily in the presence of oxygen; however, at contaminated sites, aerobic bacteria often deplete the available oxygen, resulting in anaerobic conditions. Field and laboratory studies have shown that the anaerobic biodegradation of other aromatic hydrocarbons such as toluene occurs readily, while anaerobic benzene biodegradation has only been documented in a handful of studies. Despite these difficulties, benzene biodegradation has been shown to occur under iron-reducing, sulphate-reducing and methanogenic conditions, but not under nitrate-reducing conditions.</p> <p> The goal of this thesis research was to enrich and characterize the benzene-degrading microbial populations in microcosms and transfer cultures derived from soil from four different sites. Cultures were amended with potential exogenous electron acceptors (nitrate, sulphate, ferric iron) and the rates of biodegradation under different terminal electron accepting processes were determined. Sustained, anaerobic benzene biodegradation was obtained in transfer cultures containing less than 1% of the original soil inoculum. The rate of benzene degradation was variable, ranging from 1 μM/d to more than 75 μM/d. Growth of bacteria was linked to benzene degradation under sulphate-reducing and nitrate-reducing conditions. Growth was very slow, with doubling times of 9-30 days estimated by modelling benzene depletion curves to the Monod kinetic equation. The rate of benzene degradation was influenced most by biomass concentration and much less by the terminal electron accepting process.</p> <p> The ratio of moles of electron acceptor depleted to moles of benzene degraded was calculated and compared to the theoretically predicted ratios to confirm putative terminal electron acceptors. Anaerobic benzene degradation linked to iron reduction, sulphate reduction and methanogenesis was observed in enrichment cultures, corroborating results from previous studies. In addition, in some enrichment cultures, benzene degradation was linked to nitrate reduction. This is the first report demonstrating benzene degradation linked to nitrate reduction.</p> / Thesis / Master of Engineering (MEngr)

Microbial structures are present in every living organism, so it is important to classify them for subsequent research of their origin and function. Bruker, s.r.o is developing the MBT Pathfinder for this purpose, which automates the transfer of colonies to MALDI plates, where the subsequent analysis of the sample takes place. Transferred colonies can be selected manually or using an algorithm that ensures automatic colony segmentation. This algorithm must be learned on a training set, which has huge influence on its accuracy. This work deals with measuring the influence of a dataset on the accuracy of this learning algorithm.

A análise da qualidade microbiana de matérias-primas e de produtos por meio da técnica convencional de contagem de microrganismos exige demanda elevada de trabalho e fornece resultados em período de tempo não compatível com o desenvolvimento da tecnologia. A indústria farmacêutica e cosmética necessita de liberação rápida de seus produtos, assim métodos alternativos podem reduzir o tempo de trabalho e custo. O método de ATP bioluminescência detecta a presença ou ausência de microrganismos em até 24 horas. O método baseia-se na reação do ATP (adenosina trifosfato) provenientes do microrganismo com o complexo luciferina - luciferase, produzindo luz. Os componentes da formulação de produtos cosméticos, como os corantes e os pigmentos podem interferir na reação e influenciar na leitura da Unidade Relativa de Luz (URL). O objetivo do experimento foi validar método de ATP bioluminescência para avaliação da qualidade microbiana do pigmento Green Nº 7 e dos corantes FD&C Blue Covanor e o FD&C Red Nº 5, usados em produtos cosméticos, verificando se esses podem interferir na reação de ATP-bioluminescência , utilizando os meios de cultura TAT(Tryptone-Azolectin-Tween) , DE ( Dey Engly Neutralization Broth) e LB (Letheen Broth) . A primeira etapa da validação do sistema ATP bioluminescência foi determinar o Efeito da Amostra nas suspensões o qual verifica a presença de ATP não microbiano. A sensibilidade do ensaio foi analisada por meio do teste de limite de detecção inoculando-se os microorganismos Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 na suspensão das amostras. Para C. albicans não foi possível a detecção pois houve a necessidade de tempo maior de incubação. O meio de cultura TAT sem acréscimo de polissorbato 80 apresentou as melhores condições para a validação do pigmento Green Nº 7. Para corantes há necessidade ainda de uma investigação mais criteriosa, estudando outros meios de cultura, reagentes e condições que propiciem resultados adequados em conformidade com as especificações para a validação. / The analysis of the microbiology quality of raw materiais and finished products by means of the conventional technique of counting of microorganism demands high time of work and supplies resulted in period of not compatible time with the development of the technology. The rapid methods provide reliable and cost effective analysis for the microbiological evaluation the pharmaceutical and cosmetic industry. The ATP Bioluminescence detect the presence or absence of microorganisms the reduction in detection times and analysis from 72 hours to 24 hours. The bioluminescence assay is based upon the light-producing enzyme luciferase that will hydrolyze ATP to produce light. Light production is detected by a luminometer and recorded as relative light units (RLU). The purpose of this investigation was to develop and validate the use an ATP bioluminescence assay for detection microbial contamination in artificially contaminated commercial Green Nº 7 pigment and FD&C Blue Covanor e o FD&C Red Nº 5 dyes with some microbial cultures, TAT (Tryptone-Azolectin-Tween) , DE (Dey Engly Neutralization Broth) e LB (Letheen Broth), and to compare the results against standard microbiological analysis. The first step in validation of the ATP bioluminescence system was to determine the sample effect of the sample suspensions on the bioluminescence reaction where analyzed to determine whether the sample contained nonmicrobial ATP. The sensitivity of the assay to detect different levels of Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 was analyzed by spiking into the samples suspensions. For C. albicans contamination detection has not been possible because it has required more time than bacteria. The microbial culture TAT without addition of polissorbato 80 has presented the best conditions for the validation of the Green pigment n° 7. For dyes has still been necessity of studying other microbial culture, reagents and conditions that they propitiate resulted adequate in compliance with the specifications for the validation.

A análise da qualidade microbiana de matérias-primas e de produtos por meio da técnica convencional de contagem de microrganismos exige demanda elevada de trabalho e fornece resultados em período de tempo não compatível com o desenvolvimento da tecnologia. A indústria farmacêutica e cosmética necessita de liberação rápida de seus produtos, assim métodos alternativos podem reduzir o tempo de trabalho e custo. O método de ATP bioluminescência detecta a presença ou ausência de microrganismos em até 24 horas. O método baseia-se na reação do ATP (adenosina trifosfato) provenientes do microrganismo com o complexo luciferina - luciferase, produzindo luz. Os componentes da formulação de produtos cosméticos, como os corantes e os pigmentos podem interferir na reação e influenciar na leitura da Unidade Relativa de Luz (URL). O objetivo do experimento foi validar método de ATP bioluminescência para avaliação da qualidade microbiana do pigmento Green Nº 7 e dos corantes FD&C Blue Covanor e o FD&C Red Nº 5, usados em produtos cosméticos, verificando se esses podem interferir na reação de ATP-bioluminescência , utilizando os meios de cultura TAT(Tryptone-Azolectin-Tween) , DE ( Dey Engly Neutralization Broth) e LB (Letheen Broth) . A primeira etapa da validação do sistema ATP bioluminescência foi determinar o Efeito da Amostra nas suspensões o qual verifica a presença de ATP não microbiano. A sensibilidade do ensaio foi analisada por meio do teste de limite de detecção inoculando-se os microorganismos Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 na suspensão das amostras. Para C. albicans não foi possível a detecção pois houve a necessidade de tempo maior de incubação. O meio de cultura TAT sem acréscimo de polissorbato 80 apresentou as melhores condições para a validação do pigmento Green Nº 7. Para corantes há necessidade ainda de uma investigação mais criteriosa, estudando outros meios de cultura, reagentes e condições que propiciem resultados adequados em conformidade com as especificações para a validação. / The analysis of the microbiology quality of raw materiais and finished products by means of the conventional technique of counting of microorganism demands high time of work and supplies resulted in period of not compatible time with the development of the technology. The rapid methods provide reliable and cost effective analysis for the microbiological evaluation the pharmaceutical and cosmetic industry. The ATP Bioluminescence detect the presence or absence of microorganisms the reduction in detection times and analysis from 72 hours to 24 hours. The bioluminescence assay is based upon the light-producing enzyme luciferase that will hydrolyze ATP to produce light. Light production is detected by a luminometer and recorded as relative light units (RLU). The purpose of this investigation was to develop and validate the use an ATP bioluminescence assay for detection microbial contamination in artificially contaminated commercial Green Nº 7 pigment and FD&C Blue Covanor e o FD&C Red Nº 5 dyes with some microbial cultures, TAT (Tryptone-Azolectin-Tween) , DE (Dey Engly Neutralization Broth) e LB (Letheen Broth), and to compare the results against standard microbiological analysis. The first step in validation of the ATP bioluminescence system was to determine the sample effect of the sample suspensions on the bioluminescence reaction where analyzed to determine whether the sample contained nonmicrobial ATP. The sensitivity of the assay to detect different levels of Escherichia coli ATCC 8739, Burkholderia cepacea ATCC 25416, Staphylococcus aureus ATCC 6538, Candida albicans ATCC 10231 was analyzed by spiking into the samples suspensions. For C. albicans contamination detection has not been possible because it has required more time than bacteria. The microbial culture TAT without addition of polissorbato 80 has presented the best conditions for the validation of the Green pigment n° 7. For dyes has still been necessity of studying other microbial culture, reagents and conditions that they propitiate resulted adequate in compliance with the specifications for the validation.