Intoxicações alimentares são uma das causas mais significativas de mortalidade em países desenvolvidos e em desenvolvimento, sendo as contaminações bacterianas as responsáveis pela maioria dos casos. Dentre elas destacam-se as causadas por espécies de Staphylococcus, que são nocivas tanto pela infecção do organismo hospedeiro, quanto pela intoxicação por enterotoxinas termoestáveis presentes em alimentos contaminados e mal acondicionados. Além disso, a capacidade de S. aureus formarem biofilmes confere maior proteção contra agentes de controle. Neste contexto, torna-se importante desenvolver novos métodos visando inibir estes agentes patogênicos. Uma alternativa ao emprego de conservantes sintéticos é a utilização de biossurfatantes, como os ramnolipídeos (RL) que, além de apresentarem alta estabilidade a temperatura, pH e concentração salina, apresentam baixa toxicidade e são biodegradáveis. O objetivo deste trabalho foi avaliar o efeito do pH na atividade antimicrobiana dos RL sobre células planctônicas e sésseis de Staphylococcus aureus (ATCC 8095) e comparar seu efeito ao do dodecil sulfato de sódio (SDS). Os resultados mostraram que o pH exerce grande influência na ação dos surfatantes, sendo mais efetiva em valores de pH menores. Em pH 5, os RL apresentaram ação bactericida (CBM=19,5 mg L-1) superior ao SDS (CBM=39,1 mg L-1), sendo capazes de inibir e remover 80% dos biofilmes em concentrações de 156,2 mg L-1 e reduzir em cerca de 40 % a hidrofobicidade da superfície celular de S. aureus. Em valores de pH maiores a ação dos RL não superou a do SDS, porém estes ainda mostraram resultados promissores, principalmente na remoção de biofilmes evidenciado pela microscopia confocal. A espectroscopia FTIR revelou que quando em pH 6, 7 e 8 S. aureus, possivelmente, induz alterações em sua membrana celular a fim de diminuir a sensibilidade aos surfatantes. As imagens de MEV mostraram que os RL promovem deformações nas células, podendo levá-las a ruptura. O aumento da força iônica, promovido pela adição de NaCl no meio, favoreceu a ação antimicrobiana dos RL, o que torna a aplicação dos RL em alimentos bastante promissora. / Food poisoning can be considered one of the most significant causes of mortality in developed and developing countries with bacterial contamination being responsible for the majority of cases. Among them are those caused by Staphylococcus species that can beharmful, both from the infection of the host organism as the intoxication by thermostable enterotoxins present in contaminated and poorly conditioned food. In addition, the ability to form biofilms gives S. aureus greater protection against control agents. Under this context, it becomes important to develop new methods to inhibit those pathogens. An alternative to the use of synthetic preservatives are biosurfactants such as rhamnolipids (RL), which shows high stability to temperature, pH and salt concentration along with the fact that they have low toxicity and are biodegradable. The aim of this study was to evaluate the effect of pH on the antimicrobial activity of RL on planktonic and sessile Staphylococcus aureus cells (ATCC 8095) and compare its effect to that of the sodium dodecyl sulfate (SDS). The results showed that pH exerts a great influence on the action of surfactants, with greater effectiveness at lower pH. At pH 5, RL presented higher bactericidal action (CBM = 19.5 mg L-1) than SDS (CBM = 39.1 mg L-1), also being able to inhibit and remove 80% of biofilms at concentrations of 156. 2 mg L- 1 and reduce the hydrophobicity of S. aureus cell surface by about 40%. At higher pH values, the action of RL did not exceed that of SDS, neverthelessthey showed promising results, mainly on the removal of biofilms evidenced by confocal microscopy. FTIR spectroscopy revealed that at pH 6, 7 and 8,S. aureus possibly induces changes in its cell membrane in order to decrease the sensitivity to surfactants. The MEV images showed that the RL cause deformations in the cells, which can lead to rupture. The increase in ionic strength, promoted by the addition of NaCl in the medium, favored the antimicrobial action of RL, which makes the application of RL in foods very promising.

Mangroves are tropical and subtropical coastal ecosystems located in estuarine zones, important for the maintenance of biogeochemical cicles, marine fauna reproduction and the economy. However, these environments are under constant pressure, including contamination by oil and its derivatives threatens these environments. The use of microbial biosurfactants for environmental decontamination has been considered an eco-friendly alternative. The aim of this research was to collect and characterize biosurfactant-producing bacterial strains that emulsify oil products in Rio Cocà Mangrove, Fortaleza, CearÃ. One collection in rainy season and other one in dry season were made in two points, one of them in Cocà Ecological Park and another one in the river mouth. A total, 4 soil samples, 4 water samples and 4 Laguncularia racemosa seedlings were collected. The samples were homogenized and a fraction was added in Erlemeyers containing Bushnell-Haas broth added with kerosene and gasoline and incubated at 30 C for periods of 48 and 72 h. Inocula were made on the surface of TSA agar medium, incubated at 35ÂC for 48 h and then colonies were selected and isolated. The strains were characterized and verified the purity of cultures by Gram staining technique. Biosurfactant production capacity was assessed by drop collapse test and the detected emulsion was after assessed by volume and stability emulsification tests and emulsifier activity test. A total, 58 strains were isolated, 50 are Gram-negative and 8 are Gram-positive, separated according the source: 21 from water, 21 from sediment and 16 from the rhizosphere of seedlings. A total of 55 strains (95%) had positive results in the drop collapse test. All 10 strains with emulsification volume above 50% in 24 hours also exhibited stability above 50% up to 168 hours. Five strains showed emulsifying activity above 2,00 UAE, while 29 strains showed activity between 1,00 and 2,00 UAE. We concluded that it is possible to isolate biosurfactant-producing bacteria from Rio Cocà mangrove and that the most efficient strains in the tests were isolated from the point located in the Cocà Ecological Park. / Manguezais sÃo ecossistemas costeiros tropicais e subtropicais, localizados em zonas estuarinas, importantes para a manutenÃÃo dos ciclos biogeoquÃmicos, reproduÃÃo de espÃcies marinhas e para a economia. Apesar disso, sofrem constantemente pressÃo ambiental, incluindo a contaminaÃÃo por petrÃleo e derivados. O uso de biossurfactantes microbianos para descontaminaÃÃo ambiental tem sido considerado uma alternativa mais sustentÃvel. O objetivo da presente pesquisa foi coletar e caracterizar cepas bacterianas produtoras de biossurfactantes que emulsifiquem derivados de petrÃleo no Mangue do Rio CocÃ, Fortaleza, CearÃ. Foi realizada uma coleta no perÃodo chuvoso e outra no perÃodo seco em dois pontos no Rio CocÃ, sendo um deles no Parque EcolÃgico do Cocà e outro na foz do rio. No total, foram coletadas 4 amostras de solo, 4 de Ãgua e 4 de plÃntulas de Laguncularia racemosa. As amostras coletadas foram homogeneizadas e uma fraÃÃo foi acrescentada em Erlenmeyers contendo caldo Bushnell-Haas adicionado de querosene e gasolina e incubados em estufa a 30ÂC por perÃodos de 48 e 72 h. A partir do crescimento, visualizado pela turvaÃÃo do meio, foram feitos inÃculos sobre a superfÃcie do meio Ãgar TSA, que foram incubadas em estufa a 35ÂC por 48 h e posteriormente as colÃnias crescidas foram selecionadas e isoladas. As cepas foram caracterizadas e a pureza das culturas foi verificada pela tÃcnica de coloraÃÃo de Gram. A capacidade de produÃÃo dos biossurfactantes foi detectada pelo teste do colapso da gota e o emulsificante detectado foi posteriormente avaliado pelos testes de volume e estabilidade de emulsificaÃÃo e atividade emulsificante. Foram isoladas 58 cepas, sendo 50 delas Gram-negativas e 8 Gram-positivas, assim separadas de acordo com a origem: 21 de Ãgua, 21 de sedimento e 16 da rizosfera das plÃntulas. No total, 55 cepas (95%) tiveram resultados positivos no teste do colapso da gota. Todas as 10 cepas que apresentaram volume de emulsificaÃÃo acima de 50% em 24 horas tambÃm apresentaram estabilidade acima de 50% atà 168 horas. Cinco cepas apresentaram atividade emulsificante acima de 2,00 UAE, enquanto 29 cepas mostraram atividade entre 1,00 e 2,00 UAE. Conclui-se que à possÃvel isolar bactÃrias produtoras de biossurfactantes do Mangue do Rio Cocà e que as cepas mais eficientes nos testes realizados foram isoladas do ponto localizado no Parque EcolÃgico do CocÃ.

Made available in DSpace on 2017-07-10T19:24:02Z (GMT). No. of bitstreams: 1 NatassiaJersakCosmann.pdf: 3297912 bytes, checksum: 048acfc2831615070bd43aebbc58396b (MD5) Previous issue date: 2015-02-19 / The effluent from poultry slaughterhouse has high concentration of organic matter, thus, it is essential to carry out a treatment before being disposed in the environment. A physico-chemical pretreatment is usually put forward mostly in order to remove fat. Recently, the addition of microbial metabolites, which act out to emulsify or break down fats, is studied as an alternative pre-treatment. The biosurfactants are metabolic products from several microorganisms and can solubilize and emulsify a solution composed of two immiscible liquids; thereby it promotes greater availability of components responsible for biodegradation. In this regard, this study aimed at evaluating the anaerobic treatment of effluent from poultry slaughterhouse when using surfactin produced in cassava. The obtained biosurfactant was characterized by High Performance Liquid Chromatography (HPLC) as surfactin in 30% crude extract concentration, with excellent emulsifying properties, emulsion stability of hydrocarbons and green oils, so that Critical Micelle Concentration (CMC) was 28 mg. L-1. It was also observed, according to the methodology of specific methanogenic activity (SMA), that surfactin did not inhibit microbial community present in sludge to be used as inoculum during the anaerobic biodigestion. It was also registered that methane production and reduction of Soluble Chemical Oxygen Demand (SCOD) was very similar among the applied treatments. Pretreatment of effluent from poultry slaughterhouse with the produced surfactin was carried out under the following conditions: 150 mL working volume, 150 rpm stirring and the incubation time of six hours. The effects of temperature variables (25, 30, 42.5, 55 and 60 ° C) and surfactin concentration (6, 13.27, 31, 48.73 and 56 mg.L-1) on SCOD increase were evaluated by the method of delineation Central Composite Rotational (DCCR). It was observed that the 4.5-hour time was enough to solubilize COD at its maximum concentration and at higher temperatures and concentrations of surfactin (above CMC), the greatest values of increase were reached in COD solubility. The anaerobic treatment of pretreated effluents under the aforementioned conditions was developed based on the following conditions: 34 °C without stirring, with eudiometers to check methane production and with destructive samples for temporal analysis of physico-chemical parameters. Microbiological analysis of anaerobic sludge was carried out for initial and final inoculum characterization among treatments according to the methodologies of Fluorescent In Situ Hybridization (FISH) and Gram stain. It was observed that effluent from poultry slaughterhouse can be submitted to anaerobic digestion, methane production in biogas. The cumulative volume of methane at the end of the trial for the control treatment, in which there was no surfactin addition in the pretreatment, was the lowest observed among the treatments. SCOD removal was the same among the studied treatments as well as the removal of oils and greases (GL), which may have been provided with the temperature effect on the effluent constituents rather than a direct action in phase of biosurfactant pretreatment. The assays monitoring through destructive samples allowed observing a temporal behavior of the control parameters directly involved in anaerobic digestion and note that the process developed properly. From the microbiological analyses, it was observed that the biosurfactant surfactin did not inhibit the emergence of bacterial genera commonly present in anaerobic wastewater treatment and presented in all treatments a great number of microbial species. In general, it can be inferred that the biosurfactant surfactin did not significantly change any of the poultry slaughterhouse effluent properties, which allow improvements in anaerobic biodegradation and consequent increased production of methane. / O efluente de agroindústrias abatedoras de aves apresenta elevada concentração de matéria orgânica, e, em razão disso, há a necessidade de realização de um tratamento antes de ser descartado no ambiente. Comumente promove-se um pré-tratamento físico-químico a fim de remover, principalmente, a gordura. Mais recentemente, a adição de metabólitos microbianos, que agem a fim de emulsionar ou quebrar as gorduras, é estudada como pré-tratamento alternativo. Os biossurfactantes são produtos do metabolismo de diversos microrganismos e possuem a capacidade de emulsionar e solubilizar uma solução composta por dois líquidos imiscíveis, e assim promover maior disponibilidade dos componentes presentes para a biodegradação. Neste sentido, o presente trabalho teve como objetivo geral avaliar o tratamento anaeróbio de efluente de abatedouro de aves ao utilizar surfactina produzida em manipueira. O biossurfactante obtido foi caracterizado por Cromatografia Líquida de Alta Eficiência (CLAE) como a surfactina em concentração de 30% no extrato bruto, com excelentes propriedades emulsificantes, estabilidade de emulsões de hidrocarbonetos e óleos vegetais e Concentração Micelar Crítica (CMC) de 28 mg.L-1. Verificou-se também, de acordo com a metodologia de Atividade Metanogênica Específica (AME), que a surfactina não inibiu a comunidade microbiana presente no lodo a ser utilizado como inóculo na biodigestão anaeróbia, ao verificar que a produção de metano e redução da Demanda Química de Oxigênio Solúvel (DQOs) foi muito semelhante entre os tratamentos aplicados. O pré-tratamento do efluente de abatedouro de aves com a surfactina produzida foi realizado nas seguintes condições: 150 mL de volume útil, agitação de 150 rpm e tempo de incubação de até seis horas. Os efeitos das variáveis temperatura (25, 30, 42,5, 55 e 60ºC), e da concentração de surfactina (6, 13,27, 31, 48,73 e 56 mg.L-1) sobre o aumento da DQOs foram avaliadas pela metodologia de Delineamento Composto Central Rotacional (DCCR). Observou-se que o tempo de 4,5 horas foi suficiente para solubilizar a DQO em sua máxima concentração, e que nas maiores temperaturas e concentrações de surfactina (acima da CMC) encontraram-se os maiores valores de aumento da solubilização da DQO. O tratamento anaeróbio dos efluentes pré-tratados nas condições já mencionadas foi desenvolvido com as seguintes condições: 34ºC, sem agitação, com eudiômetros para verificar a produção de metano e com amostras destrutivas para análise temporal dos parâmetros físico-químicos. A análise microbiológica do lodo anaeróbio foi realizada para caracterização inicial e final do inóculo entre os tratamentos a partir das metodologias de Fluorescent In Situ Hybridization (FISH) e coloração de Gram. Foi possível observar que o efluente de abatedouro de aves é passível de biodigestão anaeróbia, com produção de metano no biogás. O volume acumulado de metano ao final do experimento para o tratamento controle, em que não houve a adição de surfactina no pré-tratamento, foi o menor observado entre os tratamentos. A remoção da DQOs apresentou-se igual entre os tratamentos aplicados assim como a remoção de Óleos e Graxas (OG), os quais podem ter sido disponibilizados com o efeito da temperatura sobre os constituintes do efluente ao invés de uma ação direta do biossurfactante na etapa de pré-tratamento. O acompanhamento dos ensaios, por meio das amostras destrutivas, permitiu observar o comportamento temporal dos parâmetros de controle diretamente envolvidos na biodigestão anaeróbia e constatar que o processo se desenvolveu adequadamente. A partir das análises microbiológicas foi possível observar que o biossurfactante surfactina não inibiu o aparecimento dos gêneros bacterianos comumente presentes em tratamentos anaeróbios de efluentes e apresentou, em todos os tratamentos, grande riqueza de espécies microbianas. De maneira geral, pode-se inferir que o biossurfactante surfactina não alterou significativamente quaisquer das propriedades do efluente de abatedouro de aves que permitissem melhorias na biodegradação anaeróbia e consequente maior produção de metano.

Made available in DSpace on 2017-05-12T14:47:17Z (GMT). No. of bitstreams: 1 NatassiaJersakCosmann.pdf: 3297912 bytes, checksum: 048acfc2831615070bd43aebbc58396b (MD5) Previous issue date: 2015-02-19 / The effluent from poultry slaughterhouse has high concentration of organic matter, thus, it is essential to carry out a treatment before being disposed in the environment. A physico-chemical pretreatment is usually put forward mostly in order to remove fat. Recently, the addition of microbial metabolites, which act out to emulsify or break down fats, is studied as an alternative pre-treatment. The biosurfactants are metabolic products from several microorganisms and can solubilize and emulsify a solution composed of two immiscible liquids; thereby it promotes greater availability of components responsible for biodegradation. In this regard, this study aimed at evaluating the anaerobic treatment of effluent from poultry slaughterhouse when using surfactin produced in cassava. The obtained biosurfactant was characterized by High Performance Liquid Chromatography (HPLC) as surfactin in 30% crude extract concentration, with excellent emulsifying properties, emulsion stability of hydrocarbons and green oils, so that Critical Micelle Concentration (CMC) was 28 mg. L-1. It was also observed, according to the methodology of specific methanogenic activity (SMA), that surfactin did not inhibit microbial community present in sludge to be used as inoculum during the anaerobic biodigestion. It was also registered that methane production and reduction of Soluble Chemical Oxygen Demand (SCOD) was very similar among the applied treatments. Pretreatment of effluent from poultry slaughterhouse with the produced surfactin was carried out under the following conditions: 150 mL working volume, 150 rpm stirring and the incubation time of six hours. The effects of temperature variables (25, 30, 42.5, 55 and 60 ° C) and surfactin concentration (6, 13.27, 31, 48.73 and 56 mg.L-1) on SCOD increase were evaluated by the method of delineation Central Composite Rotational (DCCR). It was observed that the 4.5-hour time was enough to solubilize COD at its maximum concentration and at higher temperatures and concentrations of surfactin (above CMC), the greatest values of increase were reached in COD solubility. The anaerobic treatment of pretreated effluents under the aforementioned conditions was developed based on the following conditions: 34 °C without stirring, with eudiometers to check methane production and with destructive samples for temporal analysis of physico-chemical parameters. Microbiological analysis of anaerobic sludge was carried out for initial and final inoculum characterization among treatments according to the methodologies of Fluorescent In Situ Hybridization (FISH) and Gram stain. It was observed that effluent from poultry slaughterhouse can be submitted to anaerobic digestion, methane production in biogas. The cumulative volume of methane at the end of the trial for the control treatment, in which there was no surfactin addition in the pretreatment, was the lowest observed among the treatments. SCOD removal was the same among the studied treatments as well as the removal of oils and greases (GL), which may have been provided with the temperature effect on the effluent constituents rather than a direct action in phase of biosurfactant pretreatment. The assays monitoring through destructive samples allowed observing a temporal behavior of the control parameters directly involved in anaerobic digestion and note that the process developed properly. From the microbiological analyses, it was observed that the biosurfactant surfactin did not inhibit the emergence of bacterial genera commonly present in anaerobic wastewater treatment and presented in all treatments a great number of microbial species. In general, it can be inferred that the biosurfactant surfactin did not significantly change any of the poultry slaughterhouse effluent properties, which allow improvements in anaerobic biodegradation and consequent increased production of methane. / O efluente de agroindústrias abatedoras de aves apresenta elevada concentração de matéria orgânica, e, em razão disso, há a necessidade de realização de um tratamento antes de ser descartado no ambiente. Comumente promove-se um pré-tratamento físico-químico a fim de remover, principalmente, a gordura. Mais recentemente, a adição de metabólitos microbianos, que agem a fim de emulsionar ou quebrar as gorduras, é estudada como pré-tratamento alternativo. Os biossurfactantes são produtos do metabolismo de diversos microrganismos e possuem a capacidade de emulsionar e solubilizar uma solução composta por dois líquidos imiscíveis, e assim promover maior disponibilidade dos componentes presentes para a biodegradação. Neste sentido, o presente trabalho teve como objetivo geral avaliar o tratamento anaeróbio de efluente de abatedouro de aves ao utilizar surfactina produzida em manipueira. O biossurfactante obtido foi caracterizado por Cromatografia Líquida de Alta Eficiência (CLAE) como a surfactina em concentração de 30% no extrato bruto, com excelentes propriedades emulsificantes, estabilidade de emulsões de hidrocarbonetos e óleos vegetais e Concentração Micelar Crítica (CMC) de 28 mg.L-1. Verificou-se também, de acordo com a metodologia de Atividade Metanogênica Específica (AME), que a surfactina não inibiu a comunidade microbiana presente no lodo a ser utilizado como inóculo na biodigestão anaeróbia, ao verificar que a produção de metano e redução da Demanda Química de Oxigênio Solúvel (DQOs) foi muito semelhante entre os tratamentos aplicados. O pré-tratamento do efluente de abatedouro de aves com a surfactina produzida foi realizado nas seguintes condições: 150 mL de volume útil, agitação de 150 rpm e tempo de incubação de até seis horas. Os efeitos das variáveis temperatura (25, 30, 42,5, 55 e 60ºC), e da concentração de surfactina (6, 13,27, 31, 48,73 e 56 mg.L-1) sobre o aumento da DQOs foram avaliadas pela metodologia de Delineamento Composto Central Rotacional (DCCR). Observou-se que o tempo de 4,5 horas foi suficiente para solubilizar a DQO em sua máxima concentração, e que nas maiores temperaturas e concentrações de surfactina (acima da CMC) encontraram-se os maiores valores de aumento da solubilização da DQO. O tratamento anaeróbio dos efluentes pré-tratados nas condições já mencionadas foi desenvolvido com as seguintes condições: 34ºC, sem agitação, com eudiômetros para verificar a produção de metano e com amostras destrutivas para análise temporal dos parâmetros físico-químicos. A análise microbiológica do lodo anaeróbio foi realizada para caracterização inicial e final do inóculo entre os tratamentos a partir das metodologias de Fluorescent In Situ Hybridization (FISH) e coloração de Gram. Foi possível observar que o efluente de abatedouro de aves é passível de biodigestão anaeróbia, com produção de metano no biogás. O volume acumulado de metano ao final do experimento para o tratamento controle, em que não houve a adição de surfactina no pré-tratamento, foi o menor observado entre os tratamentos. A remoção da DQOs apresentou-se igual entre os tratamentos aplicados assim como a remoção de Óleos e Graxas (OG), os quais podem ter sido disponibilizados com o efeito da temperatura sobre os constituintes do efluente ao invés de uma ação direta do biossurfactante na etapa de pré-tratamento. O acompanhamento dos ensaios, por meio das amostras destrutivas, permitiu observar o comportamento temporal dos parâmetros de controle diretamente envolvidos na biodigestão anaeróbia e constatar que o processo se desenvolveu adequadamente. A partir das análises microbiológicas foi possível observar que o biossurfactante surfactina não inibiu o aparecimento dos gêneros bacterianos comumente presentes em tratamentos anaeróbios de efluentes e apresentou, em todos os tratamentos, grande riqueza de espécies microbianas. De maneira geral, pode-se inferir que o biossurfactante surfactina não alterou significativamente quaisquer das propriedades do efluente de abatedouro de aves que permitissem melhorias na biodegradação anaeróbia e consequente maior produção de metano.

Thesis (M.S.) -- Mississippi State University. Department of Chemical Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.S.) -- Mississippi State University. Dave C. Swalm School of Chemical Engineering. / Title from title screen. Includes bibliographical references.

Thesis (M.S.) -- Mississippi State University. Dave C. Swalm School of Chemical Engineering. / Title from title screen. Includes bibliographical references.

Οι επιφανειοδραστικοί παράγοντες είναι αμφίφιλα μόρια, αποτελούμενα από μια υδρόφιλη κεφαλή και μια υδρόφοβη ουρά. Η ιδιαίτερη δομή τους τα καθιστά ικανά να μειώνουν τις επιφανειακές και διεπιφανειακές τάσεις, μεταξύ διαφορετικών υγρών φάσεων, αλλά και μεταξύ αέριων-υγρών φάσεων. Η ιδιότητα τους αυτή, σε συνδυασμό με την ικανότητά τους να δομούν γαλακτώματα ελαίων σε νερό (oil in water) ή νερού εντός ελαίων (water in oil), αποδεικνύεται ιδιαίτερα χρήσιμη και εν δυνάμει εφαρμόσιμη, σε πολλούς τομείς της σύγχρονης βιομηχανίας. Από την σύνθεση απορρυπαντικών ουσιών και προϊόντων προσωπικής υγιεινής, την παραγωγή φυτοφαρμάκων, παρασιτοκτόνων, ζιζανιοκτόνων και μυκητοκτόνων, έως τη σύνθεση φαρμακευτικών σκευασμάτων, αλλά και τη χρήση τους για την ανάκτηση ελαίων και τη βιοεξυγίανση χερσαίων και υδρόβιων συστημάτων, φαίνεται η υψηλή σημασία των ουσιών αυτών. Σήμερα, οι χημικοί επιφανειοδραστικοί παράγοντες χρησιμοποιούνται ευρέως στο εμπόριο, τόσο λόγω του χαμηλού κόστους παραγωγής τους, όσο και της αποδοτικότητάς τους. Ωστόσο, οι βιολογικά συντιθέμενοι επιφανειοδραστικοί παράγοντες, προσφέρουν μια πληθώρα πλεονεκτημάτων έναντι των αντίστοιχων χημικών. Είναι πιο συμβατοί με το περιβάλλον, λιγότερο τοξικοί, συντίθενται από μια πληθώρα μικροοργανισμών και διαρκώς ανακαλύπτονται νέοι βιοεπιφανειοδραστικοί παράγοντες με διαφορετικές ιδιότητες. Εάν η σύνθεσή τους συνδυαστεί με την παραγωγή κέρδους, τότε θα έχουν όλα τα φόντα να παραγκωνίσουν τους χημικά συντιθέμενους ανταγωνιστές τους. Ιδιαίτερα σημαντική είναι η σύνθεση βιοεπιφανειοδραστικών παραγόντων από ζύμες, καθώς οι μικροοργανισμοί αυτοί, στην πλειοψηφία τους, είναι ασφαλέστεροι από τα βακτήρια. Επιπλέον, η χρήση γλυκερόλης, που αποτελεί υδατοδιαλυτό υπόστρωμα, ως μοναδική πηγή άνθρακα και ενέργειας, οδηγεί σε πλήρη απελευθέρωση των ουσιών αυτών στο μέσο καλλιέργειας, στις περιπτώσεις που αυτές παράγονται. Στην παρούσα εργασία διερευνήθηκε η ικανότητα έξι στελεχών ζυμών να αυξάνονται, να συσσωρεύουν ενδοκυτταρικά λιπίδια και να συνθέτουν βιοεπιφανειοδραστικούς παράγοντες παρουσία υποστρώματος γλυκερόλης. Η ανάπτυξη όλων των ζυμών ήταν ικανοποιητική, εκτός από την περίπτωση της C. tropicalis, η οποία δεν αναπτύχθηκε, στο παρόν υπόστρωμα. Επιπλέον συσσώρευσαν ενδοκυτταρικά λιπίδια σε διαφορετικά ποσοστά, η σύσταση των οποίων σε λιπαρά οξέα ήταν τυπική για αυτούς τους μικροοργανισμούς. Δύο εκ των στελεχών που μελετήθηκαν, τα C. curvatus και P. ciferrii, βρέθηκε να συνθέτουν βιοεπιφανειοδραστικούς παράγοντες με γαλακτωματοποιητική ικανότητα. Για την πρώτη δεν έχει αναφερθεί στο παρελθόν η ικανότητα σύνθεσης τέτοιων ουσιών, ωστόσο για τη δεύτερη, είναι γνωστό ότι συνθέτει πλήρως ακετυλιωμένες τετραακέτυλ-φυτοσφιγγοσίνες, που αποτελούν πρόδρομα μόρια των σφιγγολιπιδίων, σημαντικό κλάσμα λιπιδίων των κυτταρικών μεμβρανών στα θηλαστικά. / Surfactants are amphiphilic molecules, comprising of a hydrophilic head group and a hydrophobic tail group. Their unusual structure makes them capable of reducing surface tension at the air/water interfaces and the interfacial tension at oil/water interfaces. This ability, which is sometimes associated, in the case of emulsifiers, with the formation of oil-in-water or water-in-oil emulsions, is very useful in many areas of industry. Many detergents and personal care products, as well as, many herbicides, pesticides and fungicides utilize surfactants as main ingredients. Their antimicrobial and anti-adhesive properties, makes them possible pharmaceutical agents. They can be also used in oil recovery and bioremediation processes. All these usages prove the great importance of surfactant agents. Today most of the commercially used surfactants are chemically synthesized, due to their low cost and high yield. However, biosurfactants present many advantages over the chemical ones. The first are more compatible with the environment, they present lower toxicity, they can be synthesized by many different microorganisms and newly synthesized biosurfactants, with various abilities, are being discovered all time. As soon as their production gets accompanied with profit, they will become extremely competitive over the chemically synthesized surfactants. The synthesis of biosurfactants from yeasts is quite important. These microorganisms, in their majority, are safer than bacteria. In addition, using glycerol, which is a water soluble substrate, as the only carbon and energy source, leads biosurfactants to be fully secreted in the culture medium. In the present study, the ability of six yeast strains to grow, accumulate intracellular lipids and produce biosurfactants on the presence of glycerol, was investigated. Growth of all microorganisms studied was satisfying, except for C. tropicalis, which showed no significant growth, on the current medium. They also accumulated intracellular lipids in various amounts. The fatty acid composition of these lipids was typical of these microorganisms. Two of the yeast strains studied, namely C. curvatus και P. ciferrii, was found to produce biosurfactants with emulsifying ability. No previous literature exists about the first one, producing such kind of agents. However, P. ciferrii is known to produce fully acetylated tetraacetyl-phytosphingosines, which constitute precursors of sphingolipids, an important fraction of lipids of mammalian cell membranes.

Made available in DSpace on 2014-06-11T19:32:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-20Bitstream added on 2014-06-13T21:05:14Z : No. of bitstreams: 1 costa_sgvao_dr_rcla.pdf: 982367 bytes, checksum: 52f037ca5cb5fbb958ef2b1a4f53f13c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho visou estudar a produção de biossurfactante e PHAs de Pseudomonas sp. em substratos alternativos oriundos do processamento de alimentos bem como determinar as propriedades, composição química e aplicações dos compostos obtidos. Foram isoladas 21 cepas bacterianas, sendo que duas cepas demonstraram capacidade de crescer no meio de cultivo proposto e produzir ramnolipídios e PHAs. Estas cepas foram identificadas como Pseudomonas aeruginosa e receberam as seguintes terminações: P. aeruginosa L2-1 e P. aeruginosa B1-3. Com relação a caracterização de ramnolipídios e PHAs, suas composições variaram de acordo com a fonte de carbono e a linhagem utilizada na fermentação. O meio manipueira adicionado com óleo de fritura (MOF) apresentou os melhores resultados, alcançando uma produção de PHA de 39% do peso seco de células e uma produção de ramnolipídios de 660 mg/L. A manipueira se mostrou um substrato alternativo com potencial para a produção de ramnolipídios e PHAs, principalmente quando adicionada com óleo de fritura, além de ser uma solução do ponto de vista ambiental e também agregar valor a estes resíduos. A manipueira adicionada de óleo de fritura pode reduzir os custos de produção permitindo a obtenção concomitante de ramnolipídios e PHAs. O ramnolipídio produzido pela linhagem P. aeruginosa L2-1 no substrato manipueira adicionado de óleo de fritura foi recuperado e apresentou excelentes propriedades tenso-ativas, (baixos valores de concentração micelar crítica e de tensão superficial e interfacial, excelente atividade emulficante e estabilidade da emulsão), além de potencial para uso na remediação de ambientes contaminados, removendo até 89% de petróleo na areia após processo de lavagem, conferindo características semelhantes e algumas vezes melhores que o ramnolipídio comercial JBR599 (Jeneil Biosurfactant Co.) / This work evaluated the rhamnolipid and PHAs production by Pseudomonas sp. in alternative low-cost substrates from food processing, determining the properties, applications and chemistry composition of compounds obtained. Were isolated 21 strains, being that 2 isolates were able to growth and produce rhamnolipids and PHAs in the substrates. These bacteria were identified as Pseudomonas aeruginosa. The polymers and surfactants produced were characterized by gas-chromatography mass spectrophotometry (GC-MS) and by high performance liquid chromatography-MS (HPLC-MS), and their composition was found to vary with the carbon source and the strain used in the fermentation. The best overall production of rhamnolipids and PHAs was obtained with cassava wastewater added with waste cooking oil (CWO) as the carbon source, with PHA production corresponding to 39% of the cell dry weight and rhamnolipids production being 660 mg/L. It would appear that CWO has the highest potential as alternative substrate, and its use may contribute to a reduction in the overall environmental impact generated by discarding such residues. The rhamnolipid produced by P. aeruginosa L2-1 in CWO showed excellent tension-active properties (low values of critic micellar concentration and superficial and interfacial tensions) and potential to use in remediation of contaminated environmental, removing 89% of petroleum after washing process in sand, with characteristics similar or better than commercial rhamnolipid JBR599 (Jeneil Biosurfactant Co.)

La récupération assistée des hydrocarbures par des microorganismes (MEOR) est une technologie potentiellement utilisable pour améliorer l’efficacité de l’extraction pétrolière. Cette technique utilise les capacités métaboliques de certaines souches bactériennes pour récupérer les huiles des réservoirs. Cependant, le manque de connaissances sur la physiologie et les activités métaboliques des microorganismes des réservoirs est un obstacle majeur pour le développement de cette approche. L’objectif de ce travail était d’étudier la physiologie des microorganismes indigènes de réservoirs pétroliers, en déterminant leurs capacités métaboliques, leurs conditions de croissances et leur positionnement taxonomique. Pour cela, trois activités physiologiques d’intérêt pour la MEOR : (1) la dégradation de l’hexadécane ;(2) la production de biosurfactant et (3) la formation de biofilm ont été évaluées sur 84 souches bactériens anaérobies isolées exclusivement de plusieurs réservoirs pétroliers. Ces isolats appartiennent à deux groupes métaboliques : les bactéries sulfato-réductrices (BSR) et les anaérobies fermentaires. Ainsi, cette prospection à donner une image de la diversité des souches de réservoirs possédant des activités appropriées pour la MEOR. Le séquençage et l’analyse phylogénétique du gène codant pour L’ARNr 16S a permet d’identifier deux nouvelles espèces bactériennes d’anaérobies fermentaires, SRL 4223 et SRL 4209 capables de produire des biosurfactants. Ainsi la caractérisation de ces deux isolats a révélé que la souche SRL 4223 présentait toutes les caractéristiques phénotypiques et génétiques autorisant sa classification un nouveau genre nommé Pleomorphochaeta caudata et que la souche SRL 4209 peut être affilié comme une nouvelle espèce de ce nouveau genre. / The Microbial enhanced oil recovery (MEOR) is a potentially useful technology to improve the efficiency of oil extraction. This technique utilizes microorganisms and/or their metabolites (biosurfactants, polymers, biomass…etc.) to recover oil from reservoirs. However, the lack of basic knowledge about physiology and metabolic capacities of reservoir microorganisms is a major obstacle for the development of this approach. The objective of this work was to study the physiology of indigenous reservoir microorganisms by determining their metabolic capacities, their growth conditions and their taxonomic position. For this, three activities related to MEOR: (1) hexadecane degradation; (2) biofilm formation and (3) biosurfactant production were evaluated on 84 anaerobic bacterial strains isolated exclusively from several petroleum reservoirs. These isolates belong to two metabolic groups: sulfate-reducing bacteria (SRB) and anaerobic fermentative bacteria. This study gives a picture of the diversity of indigenous strains possessing proper activities for MEOR. Sequencing and phylogenetic analysis of 16S rRNA gene identified two new species of fermentative bacteria: SRL 4223 and SRL 4209, capable of producing biosurfactants. Characterization of these isolates revealed that the strain SRL 4223 had all the phenotypic and genetic characteristics allowing its classification as a new genus named Pleomorphochaeta caudata and the strain SRL 4209 was affiliated as a new species of this genus.