Glicerol é um álcool gerado na produção de biodiesel, que corresponde 10% em relação ao biocombustível. Devido à crescente produção de biodiesel, pode ser utilizado como substrato para a obtenção de outros compostos, como o 2,3-butanodiol, através de vias fermentativas. Esta substância, que tem potencial de aplicação industrial e como combustível, pode ser obtida pela fermentação de glicerol pela bactéria anaeróbia facultativa Klebsiella oxytoca. Neste trabalho foram avaliados parâmetros e condições operacionais para o cultivo de K. oxytoca ATCC 8724, visando à obtenção de 2,3- butanodiol a partir de glicerol. Em razão do equilíbrio observado entre 2,3-butanodiol e acetoína, em proporção significativamente maior para o primeiro, no metabolismo fermentativo de K. oxytoca, a discussão dos resultados deste trabalho levam em conta a soma das concentrações destes compostos. Os resultados indicaram que este microrganismo metaboliza eficientemente o glicerol, visto que a velocidade média de crescimento celular neste substrato, em 8 horas de cultivo em frascos sob agitação, foi de 0,44 g/L/h, superior à obtida com glicose (0,38 g/L/h) nas mesmas condições. Observou-se que para substratos sacaríneos, que o metabolismo microbiano pode ser dividido em duas fases: na primeira fase, sem limitação de oxigênio, ocorre acentuado crescimento celular, em razão da prevalência da respiração, que resulta em substancial ganho energético para o microrganismo, enquanto na segunda fase, com limitação de oxigênio dissolvido, o fluxo de carbono é cada vez mais dirigido à formação de produtos de fermentação. Assim, em ensaios em regime descontínuo conduzidos em biorreator de bancada, o uso de uma velocidade característica de transferência de oxigênio (OTR) intermediária, da ordem de 17 mmol/L/h, proporcionou resultados superiores em termos de produção de 2,3-butanodiol, com conversão de 60 g/L de glicerol em 17,3 g/L do produto. Em regime descontínuo, a mais alta conversão de glicerol em produto foi alcançada com concentração inicial de substrato de 129 g/L, sendo produzidos, em 48 horas, 53,6 g/L de 2,3-butanodiol, o que significa um rendimento superior a 83% em relação ao máximo teórico. Com concentrações iniciais de glicerol de até 60 g/L, não foi constatado efeito inibitório sobre o crescimento celular. Por outro lado, o uso de 160 g/L de glicerol inicial levou a uma drástica redução do rendimento do processo (apenas 56,3%) e a uma concentração residual de substrato de 98 g/L, após 72 de cultivo. Com a condução do processo em regime descontínuo alimentado, como alternativa para contornar os efeitos de inibição pelo substrato, resultados expressivos foram alcançados com a massa de glicerol equivalente à que seria necessária para ter-se 202 g/L em regime descontínuo. Nestas condições, 92,1 g/L de 2,3-butanodiol e rendimento de 92,6%, foram alcançados, em 84 horas de fermentação. Os resultados revelam, o grande potencial de uso de glicerol como substrato para a produção de 2,3-butanodiol em escala industrial. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-02-24T17:53:50Z No. of bitstreams: 1 Dissertacao Tiago Romio.pdf: 1717457 bytes, checksum: 861ff4780512e09b8f504992b102d1ec (MD5) / Made available in DSpace on 2015-02-24T17:53:50Z (GMT). No. of bitstreams: 1 Dissertacao Tiago Romio.pdf: 1717457 bytes, checksum: 861ff4780512e09b8f504992b102d1ec (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Glycerol is a by-product of biodiesel production, which accounts for approximately 10% of the biofuel. Since a large volume of it is formed in industry, glycerol could be used as a substrate to obtain other compounds, such as 2,3-butanediol, through fermentative routes. This substance, which has potential for application in industry and as fuel, can be obtained by glycerol fermentation with the facultative anaerobe bacterium Klebsiella oxytoca. In this work, parameters and operational conditions for the cultivation of K. oxytoca ATCC 8724, envisaging 2,3-butanediol production from glycerol, were assessed. Due to the equilibrium between 2,3-butanediol and acetoin, in a significantly higher proportion for the first product, in the fermentative metabolism of K. oxytoca, the discussion of this work takes in account the sum of concentrations of these compounds. The results have shown that the microorganism is able to efficiently metabolize glycerol once cell growth rate on this substrate, after 8 hours of cultivation in shake flasks, was 0.44 g/L/h, higher than that obtained with glucose (0.38 g/L/h) under the same conditions. As previously described for saccharides, it was observed that the microbial metabolism can be divided into two phases: in the first phase, without limitation of oxygen, an intense cell growth occurs due to the prevalence of respiration, that results in a substantial gain of energy for the microorganism, whereas in the second phase, under oxygen limitation, most of carbon flux is driven to the formation of fermentation products. Thus, in batch runs carried out in a bench bioreactor, the use of an intermediate characteristic oxygen transfer rate (OTR) of about 17 mmol/L/h, led to superior results in terms of 2,3-butanediol production, with conversion of 60 g/L of glycerol to 17.3 g/L of product. In batch mode, the highest conversion of glycerol to product was achieved with 129 g/L of initial substrate concentration, with the production of 53.6 g/L 2,3-butanediol, in 48 hours, which means a yield of 83% in relation to the theoretical maximum. With initial glycerol concentrations up to 60 g/L, no inhibitory effect on cell growth was observed. On the other hand, the use of 160 g/L of glycerol led to a drastic decrease in the process yield to 56.3% and to a residual concentration of substrate of 98 g/L after 72 h of cultivation. By carrying out the process in fed-batch mode, as an alternative to overcome the substrate inhibitory effects, remarkable results have been attained with the mass of glycerol that would be needed to have an initial concentration of 202 g/L in batch mode. Under these conditions, a final concentration of 92.1 g/L of 2,3-butanediol, corresponding to a yield of 92.6%, was achieved after 84 hours of fermentation. The results show clearly the high potential of the use of glycerol as a substrate for 2,3- butanediol production in industrial scale.

Glicerol é um álcool gerado na produção de biodiesel, que corresponde 10% em relação ao biocombustível. Devido à crescente produção de biodiesel, pode ser utilizado como substrato para a obtenção de outros compostos, como o 2,3-butanodiol, através de vias fermentativas. Esta substância, que tem potencial de aplicação industrial e como combustível, pode ser obtida pela fermentação de glicerol pela bactéria anaeróbia facultativa Klebsiella oxytoca. Neste trabalho foram avaliados parâmetros e condições operacionais para o cultivo de K. oxytoca ATCC 8724, visando à obtenção de 2,3- butanodiol a partir de glicerol. Em razão do equilíbrio observado entre 2,3-butanodiol e acetoína, em proporção significativamente maior para o primeiro, no metabolismo fermentativo de K. oxytoca, a discussão dos resultados deste trabalho levam em conta a soma das concentrações destes compostos. Os resultados indicaram que este microrganismo metaboliza eficientemente o glicerol, visto que a velocidade média de crescimento celular neste substrato, em 8 horas de cultivo em frascos sob agitação, foi de 0,44 g/L/h, superior à obtida com glicose (0,38 g/L/h) nas mesmas condições. Observou-se que para substratos sacaríneos, que o metabolismo microbiano pode ser dividido em duas fases: na primeira fase, sem limitação de oxigênio, ocorre acentuado crescimento celular, em razão da prevalência da respiração, que resulta em substancial ganho energético para o microrganismo, enquanto na segunda fase, com limitação de oxigênio dissolvido, o fluxo de carbono é cada vez mais dirigido à formação de produtos de fermentação. Assim, em ensaios em regime descontínuo conduzidos em biorreator de bancada, o uso de uma velocidade característica de transferência de oxigênio (OTR) intermediária, da ordem de 17 mmol/L/h, proporcionou resultados superiores em termos de produção de 2,3-butanodiol, com conversão de 60 g/L de glicerol em 17,3 g/L do produto. Em regime descontínuo, a mais alta conversão de glicerol em produto foi alcançada com concentração inicial de substrato de 129 g/L, sendo produzidos, em 48 horas, 53,6 g/L de 2,3-butanodiol, o que significa um rendimento superior a 83% em relação ao máximo teórico. Com concentrações iniciais de glicerol de até 60 g/L, não foi constatado efeito inibitório sobre o crescimento celular. Por outro lado, o uso de 160 g/L de glicerol inicial levou a uma drástica redução do rendimento do processo (apenas 56,3%) e a uma concentração residual de substrato de 98 g/L, após 72 de cultivo. Com a condução do processo em regime descontínuo alimentado, como alternativa para contornar os efeitos de inibição pelo substrato, resultados expressivos foram alcançados com a massa de glicerol equivalente à que seria necessária para ter-se 202 g/L em regime descontínuo. Nestas condições, 92,1 g/L de 2,3-butanodiol e rendimento de 92,6%, foram alcançados, em 84 horas de fermentação. Os resultados revelam, o grande potencial de uso de glicerol como substrato para a produção de 2,3-butanodiol em escala industrial. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Glycerol is a by-product of biodiesel production, which accounts for approximately 10% of the biofuel. Since a large volume of it is formed in industry, glycerol could be used as a substrate to obtain other compounds, such as 2,3-butanediol, through fermentative routes. This substance, which has potential for application in industry and as fuel, can be obtained by glycerol fermentation with the facultative anaerobe bacterium Klebsiella oxytoca. In this work, parameters and operational conditions for the cultivation of K. oxytoca ATCC 8724, envisaging 2,3-butanediol production from glycerol, were assessed. Due to the equilibrium between 2,3-butanediol and acetoin, in a significantly higher proportion for the first product, in the fermentative metabolism of K. oxytoca, the discussion of this work takes in account the sum of concentrations of these compounds. The results have shown that the microorganism is able to efficiently metabolize glycerol once cell growth rate on this substrate, after 8 hours of cultivation in shake flasks, was 0.44 g/L/h, higher than that obtained with glucose (0.38 g/L/h) under the same conditions. As previously described for saccharides, it was observed that the microbial metabolism can be divided into two phases: in the first phase, without limitation of oxygen, an intense cell growth occurs due to the prevalence of respiration, that results in a substantial gain of energy for the microorganism, whereas in the second phase, under oxygen limitation, most of carbon flux is driven to the formation of fermentation products. Thus, in batch runs carried out in a bench bioreactor, the use of an intermediate characteristic oxygen transfer rate (OTR) of about 17 mmol/L/h, led to superior results in terms of 2,3-butanediol production, with conversion of 60 g/L of glycerol to 17.3 g/L of product. In batch mode, the highest conversion of glycerol to product was achieved with 129 g/L of initial substrate concentration, with the production of 53.6 g/L 2,3-butanediol, in 48 hours, which means a yield of 83% in relation to the theoretical maximum. With initial glycerol concentrations up to 60 g/L, no inhibitory effect on cell growth was observed. On the other hand, the use of 160 g/L of glycerol led to a drastic decrease in the process yield to 56.3% and to a residual concentration of substrate of 98 g/L after 72 h of cultivation. By carrying out the process in fed-batch mode, as an alternative to overcome the substrate inhibitory effects, remarkable results have been attained with the mass of glycerol that would be needed to have an initial concentration of 202 g/L in batch mode. Under these conditions, a final concentration of 92.1 g/L of 2,3-butanediol, corresponding to a yield of 92.6%, was achieved after 84 hours of fermentation. The results show clearly the high potential of the use of glycerol as a substrate for 2,3- butanediol production in industrial scale.

Various methods for the production of bioethanol using different feedstocks have been researched on. In most work on bioethanol synthesis from sugar cane, tops and leaves have been regarded as waste and generally removed and thrown away. In this work, lignocellulosic sugarcane leaves and tops were not discarded but instead used as biomass to evaluate their hydrolyzate content. The leaves and tops were hydrolysed using different methods, namely concentrated acid, dilute acid pre-treatment with subsequent enzyme hydrolysis and compared with a combination of oxidative alkali pretreatment and enzyme hydrolysis. Subsequent fermentation of the hydrolyzates into bioethanol was done using the yeast saccharomyces cerevisae. Acid hydrolysis has the problem of producing inhibitors, which have to be removed and this was done using overliming with calcium hydroxide and compared to sodium hydroxide neutralization. Oxidative alkali pre-treatment with enzyme hydrolysis gave the highest yields of fermentable sugars of 38% (g/g) using 7% (v/v) peroxide pre-treated biomass than 36% (g/g) for 5% (v/v) with the least inhibitors. Concentrated and dilute acid hydrolysis each gave yields of25% (g/g) and 22% (g/g) yields respectively although for acid a neutralization step was necessary and resulted in dilution. Alkaline neutralization of acid hydrolyzates using sodium hydroxide resulted in less dilution and loss of fermentable sugars as compared to overliming. Higher yields of bioethanol, 13.7 (g/l) were obtained from enzyme hydrolyzates than 6.9 (g/l) bioethanol from dilute acid hydrolyzates. There was more bioethanol yield 13.7 (g/l) after 72h of fermentation with the yeast than 7.0 (g/l) bioethanol after 24h. However, the longer fermentation period diminishes the value of the increase in yield by lowering the efficiency of the process.

Nitrogen fertilizers are extensively used to enhance the growth of biomass crops. This study was conducted to determine the effect of N rates on the biomass yield and quality, and N uptake of several crops. The experiment was conducted at Fargo and Prosper, ND, in 2010 and 2011. The crops studied were forage sweet sorghum [Sorghum bicolor L. Moench], sorghum x sudangrass [Sorghum bicolor var. sudanense (Piper) Stapf.], kenaf [Hibiscus cannabinus L.], and reed canarygrass [Phalaris arundinacea L.]. The different crops constituted the main plots and the nitrogen rates were regarded as subplots. The five N rates were 0, 75, 100, 150, and 200 kg N ha-1. Forage sweet sorghum and sorghum x sudangrass had the greatest dry matter biomass yield. Nitrogen fertilization increased biomass yield for each of the crops. The results indicate that forage sorghum and sorghum x sudangrass have the greatest potential as a feedstock.

Orientador: Mauricio Boscolo / Banca: Devaney Ribeiro do Carmo / Banca: João Cláudio Thoméo / Resumo: Este estudo teve como foco a otimização do processo de produção de biodiesel etílico por transesterificação entre etanol e óleo de soja e catalisado por óxidos mistos derivados de materiais tipo hidrotalcita (Ox-MgAl, Ox-Lu1%, Ox-Yb1%, Ox-Zn10%Fe10% e OxW2,5%). As condições reacionais que afetam o rendimento desta reação foram investigadas. A metodologia de superfície de resposta (MSR) baseada no Planejamento Composto Central de quatro fatores em cinco níveis foi empregada em duas etapas. No primeiro planejamento experimental as variáveis do processo foram temperatura de reação, tempo de reação, razão molar etanol/óleo e massa de catalisador, enquanto que o rendimento do biodiesel foi a variável resposta principal. No segundo planejamento experimental, as variáveis do processo foram o tempo de reação e razão molar etanol/óleo, sendo a massa de catalisador e a temperatura mantidas constantes. Foram obtidos cinco modelos codificados de segunda ordem que descrevem o rendimento do biodiesel em função do tempo e da razão molar etanol/óleo de soja e as condições ótimas de cada catalisador foram encontradas. Os experimentos foram realizados sob estas condições para confirmar a validade do modelo e o maior rendimento de biodiesel etílico obtido utilizando as variáveis otimizadas. O catalisador Ox-Yb1% proporcionou o maior rendimento (83,8%) depois de 15,5 horas com razão molar etanol/óleo de soja igual a 37/1. Os valores experimentais concordaram com os resultados previstos pela MSR... / Abstract: This study focused on the optimization of the biodiesel production process by transesterification between ethanol and soybean oil and catalyzed by mixed oxides derived from hydrotalcite type materials (MgAl, MgAlLu, MgAlYb, MgAlZnFe and MgAlW). The reaction conditions that affect the yield of this reaction were investigated. The response surface methodology (MSR) based on the Central Composite Planning of four factors at five levels was employed in two steps. In the first experimental design the process variables were reaction temperature, reaction time, ethanol / oil molar ratio and catalyst mass, while the biodiesel yield was the main response variable. In the second experimental design, the process variables were the reaction time and the ethanol / oil molar ratio, the catalyst mass and the temperature kept constant. Five second order coded models were obtained that describe the biodiesel yield as a function of time and the ethanol / soybean oil molar ratio and the optimum conditions of each catalyst were found. The experiments were carried out under these conditions to confirm the validity of the model and the highest yield of ethylic biodiesel obtained using the optimized variables. The MgAlYb catalyst gave the highest yield (83.8%) after 15.5 hours with molar ratio ethanol / soybean oil equal to 37/1. The experimental values agreed with the results predicted by the MSR and the optimization models were validated / Mestre

Recent years have seen a dramatic increase in first generation bio-fuel production, mainly driven by concerns of climate change and rising prices of transportation fossil fuels. Due to significant pressure on the few available food sources, second generation bio-fuels have entered the fray, as a sustainable alternative. This research‟s aim was to search for cellulolytic micro-organisms and enzymes from the gut of the dung beetle, Euoniticellus intermedius, (Coleoptera: Scarabaeida) that can be used in the production of second generation bio-fuels. Dung beetle larvae were dissected and the gut micro-flora cultured in cellulose medium. Bacterial growth and cellulase activity was monitored on a daily basis. DNA isolation was then done on the cellulose medium-cultured microbes and the isolated DNA cloned in E. coli. The clones were screened for cellulase activity using plate assays. A total of 7 colonies out of 160 screened colonies showed positive CMC (endo-β-1,4-glucanase) and MUC (cellobiohydrolase) activities. Sequencing of these positive colonies yielded mostly bacteria belonging to the Enterobacteriaceae family, most of which have not been previously reported to have cellulase activity. This study‟s findings prove that in addition to this dung beetle‟s gut being a fruitful source of microbial biodiversity, it is also a potential source of cellulolytic micro-organisms and enzyme activities that will aid the function and design of future bioreactors for the bio-fuel industry.

No description available.

Algae are primary producers in aquatic ecosystems and are thus the most important organisms in maintaining ecosystem functioning and stability. The usage of algae by humans is quite extensive; they act as an ingredient in aquaculture feed, a potential biomedical resource, as a fertiliser and as a nutritional source. Recently, algae have been identified as a third generation biofuel feedstock for fuel generation which essentially means that algae are more efficient, net carbon neutral and have less impacts on the environment. Algae as organisms are extremely sensitive to changes in the immediate environment. The interaction of parameters with each other causes minute changes in the environment which may alter the algae biomass present and the lipids that can be extracted from the biomass. The focus of this study is to model and determine which conditions maximise algal biomass and the subsequent lipids that can be extracted from the biomass. This will allow biofuel producers to understand which conditions are the best for harvesting algae in artificial conditions or harvesting algae from the wild. Furthermore, the model developed has broad application for biofuel specialists, pollution remediation specialists and biologists. This model developed is able to determine the present state of the algal bloom and uses the present state to predict the future state of bloom hence determining the optimal conditions to harvest. The model was developed under optimal ranges described by the Food and Agriculture Organisation (FAO) and designed to replicate the most common combinations of parameters present in the wild. For the purposes of this study, various combinations of parameters within their optimal ranges that is temperature (18 – 24°C), salinity (20 – 24 p.p.t.) and photoperiod (25 – 75% light exposure) were assessed. The model was run for 72 hours with sampling every 6 hours. Every six hours, algal growth was measured by the biomass present (chloro-pigments used as estimators); this was done by fluorescence. Lipids were then extracted from algal biomass using the Bligh and Dyer method (1959). Spline curves were fitted to the data and analysis performed using Mathematica 8.0. It was found that photoperiod was the most important variable in controlling algal growth. Furthermore, lipids extracted from biomass were at their highest when algae were exposed to the conditions 75% light exposure, 21°C and 22 p.p.t. These conditions would allow for the highest amount of biofuel to be produced. Generally, algae biomass trend graphs mimic lipid trend graphs over the 72 hour period that is when lipids are at their maximum, biomass concentrations are at their maximum. It can be concluded from time model that the best time to harvest biomass is 48 hours from the initial start time of algal growth to gain the highest amount of lipids for biofuel production. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 103-106). Also available on the World Wide Web.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 65).