Biobutanol represents a second generation biofuel, which can be producedfrom renewable resources by microorganisms. A Saccharomyces cerevisiae strainbearing the five butanol synthetic genes (hbd, adhe2, crt, ccr and ERG10) wasconstructed, where the hbd, adhe2, crt and ccr genes are derived from Clostridiumbeijerinckii, while ERG10 is a yeast gene. The genes were transformed individually onsingle cassettes, which integrated into specific chromosomal sites. The single integrantstrains were back‐crossed to create a strain bearing all five butanol synthetic genes. The butanol synthetic enzymes appeared to be highly expressed in the cytosol,however, very little butanol was obtained (< 10 ppm). Therefore, additional geneticmanipulations were made with a view to restoring any redox imbalance channellingthe carbon flux toward the butanol pathway. Deletion of the ADH1 gene in strains withthe butanol pathway improved production to ~250 ppm (203 mg/L) butanol. Furtherimprovement to 360 ppm (292 mg/L) was gained by overexpressing the ALD6 and ACS2genes, that are involved in synthesis of acetyl‐CoA; the precursor for butanolbiosynthesis. However, the replacement of ALD6 with ALD2, which produces NADHinstead of NADPH, didn’t improve butanol yields. In addition, no significantimprovement of butanol yield was obtained when dehydrogenase enzymes from theglycerol biosynthetic pathway were deleted. An initial assessment of the bestconditions for butanol production were semi‐anaerobic growth at 30°C in 2% glucosewith a starting OD600 of 0.1.In this project, another key question was addressed: does the sensitivity of cellsto short chain alcohols like butanol affect butanol production? Previous work in theAshe lab has identified specific point mutations in the translation initiation factor,eIF2B, which generate resistance or sensitive phenotypes to exogenously addedbutanol. Here a comparison of butanol production in sensitive and resistantbackgrounds showed that the butanol yield was 1.5‐2 fold higher in a butanol resistantstrain compared to the sensitive mutant. Generating a ‘super’ butanol resistant strainbearing a GCD2‐S131A mutation in eIF2B promoted a higher butanol yield per cell. However, another consequence of this mutation was reduced growth. So thecombination of these effects meant that the overall butanol concentration in mediawas similar to the control. Overall this work highlights that S. cerevisiae can producebutanol but that further optimisation both at the level of the strain and processengineering would be necessary before this would be of interest to the commercialsector.

No description available.

De nos jours, de nouvelles technologies sont développées pour produire efficacement des produits dérivés de matières premières autresque le pétrole, comme par exemple la biomasse. En effet, la biomasse et plus spécifiquement la biomasse non alimentaire possède un fort potentielcomme substitut aux ressources fossiles pour des raisons environnementales, économiques et politiques. Dans ce contexte, l’étude des bioraffineries offre de nouvelles opportunités pour le Process System Engineering et plus particulièrement pour des activités de recherche quivisent la conception de systèmes constitués d’entités interconnectés. En effet, le verrou principal se concentre sur la modélisation et l’optimisation multi-échelle de la bioraffinerie qui permet l’intégration de plusieurs échelles spatiales allant de l’échelle moléculaire à celle de l’unité de production. Ces différentes échelles sont essentielles pour décrire correctement le système puisqu’elles interagissent en permanence. La forte dilution des courants est le meilleur exemple pour illustrer ces interactions. En effet, la présence d’eau induit de nombreux problèmes thermodynamiques (azéotropes, etc.) à l’échelle moléculaire, ce qui impacte fortement la topologie du procédé notamment sur les étapes de séparation, de purification et detraitement des purges (pour limiter les pertes en produits). Ainsi, la performance de la séquence d’opérations unitaires de l’étape de purification dépend entièrement de la concentration en eau. De plus dans la conception de bioraffinerie, il est fréquent de coupler fermentation et séparation afin d’améliorer les performances de la fermentation et de limiter la présence d’eau dans l’étapede purification. Par ailleurs, la grande quantité d’eau à chauffer ou refroidir entraine la nécessité de réaliser l’intégration énergétique du réseaud’échangeurs du procédé afin de minimiser le coût les dépenses énergétiques. L’objectif de ce travail est alors de proposer une méthodologie générique et les outils associés afin de lever certains verrous de la modélisation et l’optimisation multi-échelle de la bioraffinerie. Basée sur une approche par superstructure, la finalité de la méthodologie est d’évaluer les performances des alternatives étudiées en termes technico-économiques, environnementaux et d’efficacité énergétique en vue de son optimisation multi-objectifs pour trouver la voie de traitement optimale pour le(s) bioproduit(s) d’intérêt. Le cas d’application retenu se focalise sur la production de biobutanol à partir du système Acétone-Butanol-Ethanolet d’une biomasse d’origine forestière. La première étape de la méthodologie proposée concerne la création de la superstructure de la bioraffineriebasée sur une décomposition de cette dernière en 5 étapes principales : le prétraitement, la fermentation, la séparation, la purification et letraitement des purges. Ensuite, la seconde étape consiste à modéliser chaque alternative de procédé. Cette modélisation utilise un modèlethermodynamique à coefficients d’activité afin de décrire le comportement fortement non-idéal des molécules du milieu. De plus, l’intégration du traitement des purges et de l’intégration énergétique durant cette étape permet d’améliorer le procédé. Enfin, la dernière étape s’intéresse à l’optimisation multiobjectif qui se focalise sur différents aspects : maximisation de la production, minimisation des coûts, du prix minimal de vente des bioproduits, des pertes en produits et de l’impact environnemental. Cette dernière étape inclut également des études de sensibilité sur les différents paramètres de la méthodologie : opératoires, économiques, environnementaux... A l’issu de l’optimisation, un compromis seratrouvé afin d’obtenir une bioraffinerie durable. / Nowadays, to replace chemical products derived from petrol, new technologies are developed to produce products derived from others feedstock than crude oil like biomass. Indeed, biomass and especially nonfood biomass has a high potential as substitute due to its environmental, economic and political interests. Inthis context, the study of biorefineries offers new opportunities in the Process System Engineering and especially in research activities which aim to design systems with interlinked compounds. Indeed, the main hurdle focuses on the modeling and the multiscale optimization of thebiorefinery that allows integratingseveral spatial scales from the molecular scale to the plant scale. These scales are essential to describe accurately the system because they interact. The large dilution of flows is the best example to show these interactions. Indeed, water induces many thermodynamic problems (azeotropes, etc.) at the moleculescale, that impact on the process design and mainly on the separation, the purification and the treatment of purges (to limit losses of products). In consequence, the sequence of unit operations of the purification step depends of the water concentration. Furthermore, in the design of the biorefinery, the fermentation and theseparation are usually combined in order to improve performances of the fermentation and limit the water concentration in the purification step. Moreover, the large amount of water that needs to be heated or cooled induces the need of the energy integration of the heat exchangers network to minimize energy consumption. The aim of this work is to propose a generic methodology with connected tools in order to overcome some hurdles caused by the modeling and the multiscaleoptimization of the biorefinery. Based on the superstructure approach, the purpose of the methodology is to estimate performances of considered alternatives in the technical, economic, environmental and energy efficient aspects in preparation for the multiobjective optimization which finds the optimal process for the productionof the interesting bioproduct. This work focuses especially on the production of biobutanol through the Acetone-Butanol-Ethanol system from forest biomass. The methodology begins with the creation of the superstructure of the biorefinery composed by 5 major steps: the pretreatment, the fermentation, the separation, the purification and the treatment of purges. Next, the methodology consists in modeling each alternative of process. It integrates a thermodynamic model with activity coefficients in order to describe accurately the greatly nonideal behavior of molecules. Moreover, the treatment of purges and the energy integration are integratedat this step in order to improve the process. Finally, the last step interests to the multiobjective optimization which focuses on different aspects: the maximization of production and the minimization of the costs, the minimal selling price of bioproducts, the losses of bioproducts and the environmental impact. This step includes also sensitivity analysis on different parameters of the methodology: operating, economic, environmental… After the optimization, a compromise is made in order to obtain sustainable biorefinery.

De nos jours, de nouvelles technologies sont développées pour produire efficacement des produits dérivés de matières premières autresque le pétrole, comme par exemple la biomasse. En effet, la biomasse et plus spécifiquement la biomasse non alimentaire possède un fort potentielcomme substitut aux ressources fossiles pour des raisons environnementales, économiques et politiques. Dans ce contexte, l’étude des bioraffineries offre de nouvelles opportunités pour le Process System Engineering et plus particulièrement pour des activités de recherche quivisent la conception de systèmes constitués d’entités interconnectés. En effet, le verrou principal se concentre sur la modélisation et l’optimisation multi-échelle de la bioraffinerie qui permet l’intégration de plusieurs échelles spatiales allant de l’échelle moléculaire à celle de l’unité de production. Ces différentes échelles sont essentielles pour décrire correctement le système puisqu’elles interagissent en permanence. La forte dilution des courants est le meilleur exemple pour illustrer ces interactions. En effet, la présence d’eau induit de nombreux problèmes thermodynamiques (azéotropes, etc.) à l’échelle moléculaire, ce qui impacte fortement la topologie du procédé notamment sur les étapes de séparation, de purification et detraitement des purges (pour limiter les pertes en produits). Ainsi, la performance de la séquence d’opérations unitaires de l’étape de purification dépend entièrement de la concentration en eau. De plus dans la conception de bioraffinerie, il est fréquent de coupler fermentation et séparation afin d’améliorer les performances de la fermentation et de limiter la présence d’eau dans l’étapede purification. Par ailleurs, la grande quantité d’eau à chauffer ou refroidir entraine la nécessité de réaliser l’intégration énergétique du réseaud’échangeurs du procédé afin de minimiser le coût les dépenses énergétiques. L’objectif de ce travail est alors de proposer une méthodologie générique et les outils associés afin de lever certains verrous de la modélisation et l’optimisation multi-échelle de la bioraffinerie. Basée sur une approche par superstructure, la finalité de la méthodologie est d’évaluer les performances des alternatives étudiées en termes technico-économiques, environnementaux et d’efficacité énergétique en vue de son optimisation multi-objectifs pour trouver la voie de traitement optimale pour le(s) bioproduit(s) d’intérêt. Le cas d’application retenu se focalise sur la production de biobutanol à partir du système Acétone-Butanol-Ethanolet d’une biomasse d’origine forestière. La première étape de la méthodologie proposée concerne la création de la superstructure de la bioraffineriebasée sur une décomposition de cette dernière en 5 étapes principales : le prétraitement, la fermentation, la séparation, la purification et letraitement des purges. Ensuite, la seconde étape consiste à modéliser chaque alternative de procédé. Cette modélisation utilise un modèlethermodynamique à coefficients d’activité afin de décrire le comportement fortement non-idéal des molécules du milieu. De plus, l’intégration du traitement des purges et de l’intégration énergétique durant cette étape permet d’améliorer le procédé. Enfin, la dernière étape s’intéresse à l’optimisation multiobjectif qui se focalise sur différents aspects : maximisation de la production, minimisation des coûts, du prix minimal de vente des bioproduits, des pertes en produits et de l’impact environnemental. Cette dernière étape inclut également des études de sensibilité sur les différents paramètres de la méthodologie : opératoires, économiques, environnementaux... A l’issu de l’optimisation, un compromis seratrouvé afin d’obtenir une bioraffinerie durable.

No description available.

Submitted by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T18:17:41Z No. of bitstreams: 1 CHOGI_Marianne_2016.pdf: 34489841 bytes, checksum: 761e8dfc342c5d6b967c9d2597dd8ae1 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T18:20:02Z (GMT) No. of bitstreams: 1 CHOGI_Marianne_2016.pdf: 34489841 bytes, checksum: 761e8dfc342c5d6b967c9d2597dd8ae1 (MD5) / Approved for entry into archive by Milena Rubi (milenarubi@ufscar.br) on 2017-08-08T18:20:08Z (GMT) No. of bitstreams: 1 CHOGI_Marianne_2016.pdf: 34489841 bytes, checksum: 761e8dfc342c5d6b967c9d2597dd8ae1 (MD5) / Made available in DSpace on 2017-08-08T18:20:15Z (GMT). No. of bitstreams: 1 CHOGI_Marianne_2016.pdf: 34489841 bytes, checksum: 761e8dfc342c5d6b967c9d2597dd8ae1 (MD5) Previous issue date: 2016-07-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Biofuels are produced from clean alternative energy sources and one example is biobutanol, a fuel that can be produced by fermentation of different raw materials. The production of butanol is carried out by fermentative metabolism of solvent-producing microorganisms, with acetone and ethanol as major byproducts (ABE fermentation). This work aims to produce biobutanol using strains Clostridium beijerinckii (ATCC 10132) and Clostridium acetobulylicum (ATCC 824) and four different inoculum: ES - swine effluent digester located in the Água Branca Farm in the municipality of Itu; LR - UASB sludge of sewage treatment plant from the city of Porto Feliz; ES - cattle manure; SL - Soil from sugarcane cultivation in Sorocaba region. Glucose and cassava wastewater were used as substrate. The biobutanol production efficiency was evaluated for each strain and inoculum in fermentation batch reactors in which the sole substrate was glucose or cassava wastewater. Both strains produced biofuel, and C. beijerinckii (ATCC 10132) was more efficient yielding 0.33±0.08 g L -1 butanol and 1.65±0.23 g L -1 of ethanol from 30 g L -1 of glucose. When cassava wastewater was used as substrate (10 g L -1 of reducing sugar), the production of butanol was 0.64±0.1 g L -1 and ethanol was 2.47±0.07 g L-1 in comparison to 0.27±0.13 g L -1 butanol and 1.72±0.18 g L -1 of ethanol produced when C. beijerinckii were fed with glucose 10 g L -1 as control. Fermentation inocula produced only butyric acid with concentrations of 0.31±0.04 g L -1 for cattle manure and 0.12±0.013 g L -1 for swine effluent. As the cattle manure showed higher production of butyric acid, this culture was chosen for fermentation with cassava wastewater at COD 5 g L-1 . First of all the inoculum´s DNA was amplified with the pair of primers Sj-F and Sj-R specific for the genus Clostridium. With the confirmation of the clostridia presence, the fermentation with cassava wastewater at 5 g L -1 of COD was performed. This fermentation was compared with the strain C.beijerinckii growing in medium without enrichment and cattle manure with and without medium enrichment. C. beijerinckii biofuel production was 0.02 g L -1 of butanol and 0.69 g L-1 of ethanol after 12 h of fermentation, while cattle manure fermentation yielded 0.168 g L -1 of ethanol after 106 h in enriched medium and 0.026 g L-1 of ethanol in medium without enrichment after 12 h. These results demonstrate the feasibility of using cassava as a substrate for the production of biobutanol, ethanol and the possibility of producing biobutanol by cattle manure and swine effluent since butyric acid is an intermediary product of the pathway leading to butanol synthesis. / O presente trabalho teve por objetivo a produção de biocombustíveis a partir de manipueira (efluente oriundo do processamento da mandioca) na presença de duas cepas Clostridium beijerinckii (ATCC 10132) e Clostridium acetobulylicum (ATCC 824), e quatro diferentes inóculos pré-tratados termicamente, sendo estes: ES - efluente de biodigestor de suinocultura situado na Granja Água Branca no município de Itu; LR – lodo anaeróbio de estação de tratamento de esgoto sanitário do município de Porto Feliz; EB - esterco bovino; SL - solo de cultivo de cana-de-açúcar da região de Sorocaba. Foram utilizados como substratos a manipueira e glicose separadamente. Ambas as cepas produziram biocombustíveis, no entanto a mais eficiente foi Clostridium beijerinckii (ATCC 10132) que produziu 0,33±0,08 g L -1 de butanol e 1,65±0,23 g L -1 de etanol a partir de 30 g L -1 de glicose. A partir desses resultados a produção de biocombustíveis foi avaliada nos dois diferentes substratos: manipueira e glicose, com a manipueira (10 g L -1 de açúcar redutor) obteve-se produção de butanol de 0,64±0,1 g L -1 e etanol de 2,47±0,070 g L -1 , enquanto nos ensaios com glicose a 10 g L -1 a produção de butanol foi de 0,27±0,13 g L-1 e etanol foi de 1,72±0,18 g L-1 . Os inóculos pré-tratados não produziram biocombustíveis com ambos os substratos, porém observou-se produção de ácido butírico de 0,31±0,04 g L -1 para o EB (esterco bovino) e 0,12±0,013 g L -1 para o ES (efluente de suinocultura). Como o inóculo EB apresentou uma maior produção de ácido butírico essa cultura foi escolhida para a fermentação com manipueira com demanda química de oxigênio (DQO) de 5 g L -1 (correspondendo a 2 g L -1 de açúcar redutor). Análises de biologia molecular foram realizadas para confirmar a presença do gênero Clostridium no inóculo EB, utilizando os primers Sj-F e Sj-R específico para o gênero Clostridium. Com a confirmação da presença desse, um novo ensaio com manipueira com DQO de 5 g L -1 foi realizado com a C. beijerinckii e com o inóculo EB visando definir a necessidade de adição de nutrientes à manipueira para obtenção de biocombustíveis. A fermentação da manipueira foi realizada com a cepa C. beijerinckii (CB) sem enriquecimento do meio e com inóculo esterco bovino com enriquecimento (EBE) e sem enriquecimento (EBS). Com a cepa padrão a produção de bicombustíveis foi de 0,02 g L-1 de butanol e 0,69 g L-1 de etanol em 12 h de fermentação. Para o EBE após 106 h de fermentação ocorreu a produção de etanol igual a 0,168 g L-1 e para o EBS após 12 h a produção para o mesmo álcool foi de 0,026 g L-1 . Esses resultados demonstraram a viabilidade da utilização da manipueira como substrato para a produção de butanol e etanol com cepas de Clostridium e a possibilidade de produção de butanol pelos inóculos, pois o ácido butírico é um produto intermediário da via que leva à síntese de butanol.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The biobutanol production by fermentative process has a great importance to increase the global supply of biofuel and becomes these able to replace the use of fossil fuel. The main difficulty associated to this production occurs due the not economic viability of applied production process. The aspects that have more contribution to this are the product inhibition at low concentration, low titer and the use of expensive substrates. This work is divided in four scientific articles which are focused in question involved to this solvent production. The first two are review papers about the topic, whereas the last two are research papers related to development of analytical methods and production process. The first paper reports to the main process development since 1980 year, by analyses of registered patents in relation to butanol production worldwide. The second paper presents a review from scientific articles about butyric fermentation published in recent years. The central characteristic of it is show the main troubles related to production, exhibiting the importance of the used substrate, as well as the choice of microorganism and separation process. Third paper presents a methodology to solvents determination from fermentation medium. This technique proposes a linear relationship between the density variation, sugar and solvents concentrations. The method proposed showed good results being promising to predict the ABE concentration in an easy and fast procedure. Fourth paper reports the development of the process to production of biobutanol by clostridial fermentation from sweet sorghum juice. Butanol is produced from substrate and small addition of yeast extract and tryptone, using 12.5% of initial inoculums size, at initial pH pH value equal to 5.5. In this work was demonstrated the possibility to produce biobutanol from sweet sorghum. / A produção de butanol a partir de processos fermentativos é de fundamental importância para aumentar a oferta mundial de biocombustíveis e permitir que estes substituam o uso de combustíveis fósseis. A principal dificuldade em relação a esta produção ocorre devido a não viabilidade econômica dos processos de produção aplicados. Os aspectos que mais contribuem para isto são a inibição pelo produto a baixas concentrações, baixa produtividade e uso de substratos caros. Este trabalho está dividido em quatro artigos científicos que estão voltados a questões envolvidas com a produção deste biocombustível. Os dois primeiros fazem uma revisão da literatura científica sobre o tópico, já os últimos são trabalhos científicos de desenvolvimento de metodologias e processos. O artigo 1 traz um ponto de vista em relação ao desenvolvimento do processo, desde o ano de 1980, através da análise das patentes registradas sobre produção de butanol no mundo. Além disso, a partir dos resultados é possível prever, parcialmente, como a tecnologia deverá avançar nos próximos anos. O artigo 2 faz uma revisão dos artigos científicos publicados sobre o fermentação butílica nos últimos tempos. A principal característica do mesmo é apontar os principais problemas relacionados à produção, mostrando a importância dada ao substrato utilizado, o microorganismo e os processos de separação. No artigo 3 uma metodologia para determinação de solventes no meio de fermentação é desenvolvida. Esta técnica propõe uma relação linear entre a variação da densidade, a concentração de açúcar e a concentração de solventes. Com sua aplicação o cromatógrafo pode ser dispensado e há somente a necessidade de um densímetro. O ajuste se mostrou bastante promissor e aparentemente capaz de predizer os resultados. Por fim, no artigo 4 é desenvolvido um processo para a produção de biobutanol via fermentação por clostridium a partir de sorgo sacaríneo. Butanol é produzido a partir do substrato sendo necessário um acréscimo pequeno de extrato de levedura e triptona com apenas 12,5% de volume de inóculo, com pH inicial ajustado em 5,5. Para a execução dos experimentos em meio anaeróbio foram elaborados aparatos alternativos e de baixo custo, que demonstraram ser eficientes na sua função. O principal ponto observado durante o trabalho é que é possível produzir biobutanol a partir de sorgo sacaríneo utilizando artefatos fabricados no laboratório para manutenção do meio anaeróbio.

Thesis (MScEng (Process Engineering))--Stellenbosch University, 2010. / ENGLISH ABSTRACT: Recently, improved technologies have been developed for the biobutanol fermentation process: higher butanol concentrations and productivities are achieved during fermentation, and separation and purification techniques are less energy intensive. This may result in an economically viable process when compared to the petrochemical pathway for butanol production. The objective of this study is to develop process models to compare different possible process designs for biobutanol production from sugarcane molasses. Some of the best improved strains, which include Clostridium acetobutylicum PCSIR-10 and Clostridium beijerinckii BA101, produce total solvent concentrations of up to 24 g/L. Among the novel technologies for fermentation and downstream processing, fedbatch fermentation with in situ product recovery by gas-stripping, followed by either liquid-liquid extraction or adsorption, appears to be the most promising techniques for current industrial application. Incorporating these technologies into a biorefinery concept will contribute toward the development of an economically viable process. In this study three process routes are developed. The first two process routes incorporate well established industrial technologies: Process Route 1 consist of batch fermentation and steam stripping distillation, while in Process Route 2, some of the distillation columns is replaced with a liquid-liquid extraction column. The third process route incorporates fed-batch fermentation and gas-stripping, an unproven technology on industrial scale. Process modelling in ASPEN PLUS® and economic analyses in ASPEN Icarus® are performed to determine the economic feasibility of these biobutanol production process designs. Process Route 3 proved to be the only profitable design in current economic conditions. For the latter process, the first order estimate of the total project capital cost is $187 345 000.00 (IRR: 35.96%). Improved fermentation strains currently available are not sufficient to attain a profitable process design without implementation of advanced processing techniques. Gas stripping is shown to be the single most effective process step (of those evaluated in this study) which can be employed on an industrial scale to improve process economics of biobutanol production. / AFRIKAANSE OPSOMMING: Onlangse verbeteringe in die tegnologie vir die vervaardiging van butanol via die fermentasie roete het tot gevolg dat: hoër butanol konsentrasies en produktiwiteit verkry kan word tydens die fermentasie proses, en energie verbruik tydens skeiding-en suiweringsprosesse laer is. Hierdie verbeteringe kan daartoe lei dat biobutanol op ʼn ekonomiese vlak kan kompeteer met die petrochemiese vervaardigings proses vir butanol. Die doelwit van die studie is om proses modelle te ontwikkel waarmee verskillende proses ontwerpe vir die vervaardiging van biobutanol vanaf suikerriet melasse vergelyk kan word. Verbeterde fermentasie organismes, wat insluit Clostridium acetobutylicum PCSIR-10 en Clostridium beijerinckii BA101, het die vermoë om ABE konsentrasies so hoog as 24 g/L te produseer. Wat nuwe tegnologie vir fermentasie en skeidingprosesse behels, wil dit voorkom of wisselvoer fermentasie met gelyktydige verwydering van produkte deur gasstroping, gevolg deur of vloeistof-vloeistof ekstraksie of adsorpsie, van die mees belowende tegnieke is om tans in die nywerheid te implementeer. Deur hierdie tegnologie in ʼn bioraffinadery konsep te inkorporeer sal bydra tot die ontwikkeling van ʼn ekonomies lewensvatbare proses. Drie prosesserings roetes word in die studie ontwikkel. Die eerste twee maak gebruik van goed gevestigde industriële tegnologie: Proses Roete 1 implementeer enkellading fermentasie en stoom stroping distillasie, terwyl in Proses Roete 2 van die distilasiekolomme vervang word met ʼn vloeistof-vloeistof ekstraksiekolom. Die derde proses roete maak gebruik van wisselvoer fermentasie met gelyktydige verwydering van produkte deur gas stroping. Die tegnologie is nog nie in die nywerheid bewys of gevestig nie. Om die ekonomiese uitvoerbaarheid van die proses ontwerpe te bepaal word proses modellering uitgevoer in ASPEN PLUS® en ekonomiese analises in ASPEN Icarus® gedoen. Proses Roete 3 is die enigste ontwerp wat winsgewend is in huidige ekonomiese toestande. Die eerste orde koste beraming van die laasgenoemde projek se totale kapitale koste is $187 345 000.00 (opbrengskoers: 35.96%). Die verbeterde fermentasie organismes wat tans beskikbaar is, is nie voldoende om ʼn proses winsgewend te maak nie; gevorderde proses tegnologie moet geïmplementeer word. Gasstroping is bewys as die mees effektiewe proses stap (getoets in die studie) wat op industriële skaal geïmplementeer kan word om die winsgewendheid van die biobutanol proses te verbeter. / Centre for Renewable and Sustainable Energy Studies

The global warming on earth has been obvious since the 1950’s. Fossil fuels have a big impact on the observed warming and it is time to replace them with more environmentally friendly fuels. Biobutanol has been proven to be a preferred substitute to fossil fuels. The yeast Saccharomyces cerevisiae is a potential butanol producer. A problem in the biobutanol production is that the product, butanol, is toxic to the producer. In this study four S. cerevisiae strains were investigated for 1- and 2-butanol tolerance with spot tests and growth measurements with different concentrations of 1- and 2-butanol.  One of the four strains, an ale yeast, showed a higher tolerance for 1- and 2-butanol. 2-butanol was overall more tolerated by the yeast. The gene expression for the genes TMC1, LPL1, FLR1 and RPN4 was also investigated at exposure of 3 % 2-butanol. RPN4 is important in the proteasome protein degradation, which is associated with butanol tolerance. TMC1, LPL1 and FLR1 are associated to RPN4, which make them potential genes coupled to butanol tolerance. The genes TMC1 and RPN4 showed an up-regulation when exposed to 3 % 2-butanol. In conclusion, 2-butanol is preferred as a biofuel produced by ale yeast and the ideal genes to use in genetic engineering to achieve a higher butanol tolerance is TMC1 and RPN4. These results contribute to the development of an effective production of biobutanol by S. cerevisiae.

Darbo tikslas – ištirti rapsų aliejaus peresterinimo procesą naudojant biobutanolį, įvertinti gauto biodyzelino savybes ir poveikį aplinkai. Darbo objektas – rapsų aliejaus riebalų rūgščių butilesteriai, gauti po rapsų aliejaus peresterinimo biobutanoliu. Darbo metodai – rapsų aliejaus peresterinimas butanoliu atliktas biotechnologiniu metodu, naudojant biokatalizatorių Lipozyme TL IM. Peresterinimo laipsnis, butilesterių ir parcialinių gliceridų kiekis nustatyti plonasluoksnės ir dujų chromatografijos metodais. Gauto biodyzelino savybės įvertintos pagal standarte LST EN 14214 pateiktas metodikas. Variklio eksploataciniai ir deginių emisijų tyrimai VGT universitete atlikti 1992 m. gamybos ,,Audi-80‘‘ automobilio dyzeliniu varikliu. Variklio išmetamųjų dujų analizei naudotas išmetamųjų dujų analizatorius AVL DiCom 4000. Biologinis degalų suirimas atliktas taikant OECD 301 F ,,Manometrinės respirometrijos‘‘ metodą AL 606 prietaisu. Darbo rezultatai. Nustatytos optimalios 2 stadijų rapsų aliejaus peresterinimo butanoliu proceso sąlygos. Pagaminti rapsų aliejaus riebalų rūgščių butilesteriai (RBE) atitinka standarto LST EN 14214 reikalavimus. Grynų butilesterių atsparumą oksidacijai daugiau kaip 6 val. padidina antioksidantas – IONOL BF 200 (2000 ppm). Vasaros ir pereinamuoju laikotarpiu gryni butilesteriai ir jų mišiniai su žieminiu dyzelinu ir butanoliu tinkami naudoti be specialių priedų. Maišant rapsų aliejaus riebalų rūgščių butilesterius su žieminiu dyzelinu ir butanoliu... [toliau žr. visą tekstą] / Aim of the work – to analyze the process of rapeseed oil transesterification by using biobutanol, to evaluate the characteristics of the derived biodiesel and its impact on the environment. Object of research – butyl esters of rapeseed oil received after the transesterification of rapeseed oil using biobutanol. Research methods – transesterification of rapeseed oil using biobutanol has been performed by applying biotechnological method, using biocatalyst Lipozyme TL IM. The level of transesterification and quantity of butyl esters and partial glycerides has been determined by methods of thin-layer and gas chromatography. The characteristics of the derived biodiesel have been evaluated according to the methodology provided by standard LST EN 14214. The analysis of engine exploitation and environmental characteristics have been performed at VGT university on the diesel engine of 1992 “Audi-80”. For the analysis of exhaust gases of engine the gas analyzer AVL DiCom 4000 has been used. Degradation of biological fuel has been performed according to OECD 301 F “Manometric respirometry” using AL 606 device. Results of research. Optimal conditions of 2-stage rapeseed oil transesterification process using butanol. Were determined the produced butyl esters of rapeseed oil meet the requirements of LST EN 14214 standards. Antioxidant JONOL BF 200 increases the oxidative stability of pure butyl esters. In summer or during transition period pure butyl esters and their mixtures with... [to full text]