The theoretical overview summarize the characteristics of algae and their primary and secondary metabolism. It also deals with inhibitors of ascorbic acid, glutathione and polyphenolic compounds synthesis. The practical part studies the influence of selected inhibitors (BSO, Lyc, AIP) and CdCl2 on the secondary metabolites production and biomass growth in freshwater microalgae Scenedesmus quadricauda. The content of secondary metabolites (eg. caffeic acid, chlorogenic acid, salicylic acid, cinnamic acid, p-coumaric acid) was detected by HPLC-MS. Furthermore, the total antioxidant capacity, the total polyphenol content and the total flavonoid content was determined spectrophotometrically. All the inhibitors used, reduced S. quadricauda growth in comparison with control samples. The most pronounced inhibitory effect was observed in the samples treated with Lyc + Cd after 7 days of experiment. All the treated samples responded to the stress factors by altering metabolic pathways and inhibiting growth. As a result, there were changes in the composition and the amount of selected secondary metabolites versus the control samples. At the same time, in most cases, the biosynthesis of polyphenolic and flavonoid substances has been stimulated. The oxidative reduction equilibrium and the induction of oxidative stress were probably impaired.

No description available.

Microalgae are one of the oldest types of lifeforms on this planet and dead algae are one source for the oil that we extract from the ground. This oil has a major part in the technology advances of humanity, to levels unimaginable not long ago. Unfortunately, this oil is one of the major reasons for the global warming and other environmental issues caused by humans. Therefore, much effort is made on new technologies to decrease the use of fossil oil and other fossil material in favor for so called renewable sources. In this work focus is on production of biomass that can be used for processing to other bulk materials, mainly chemicals. This is also a highly potential market, the amount of materials derived from fossil sources are at least 422 million metric tons per year. The issue though is that the production costs for algae are still fairly high and can’t compete with the market price of fossil raw materials. Two algae species, Scenedesmus obliquus and Coelastrella sp., were cultivated in 6 pilot size ponds (500 L) and the results were compared to a lab experiment (0.5 L). The lab experiment was earlier performed by the author’s supervisors with the same species. The algae in the ponds were cultivated outdoor with flue gas in semi-closed ponds and the resulting biomass was allowed to sediment spontaneously. Scenedesmus obliquus was successfully cultivated in the pilot, but the system was not suitable for cultivation of Coelastrella sp. The main aim of this work was to evaluate if it is possible to predict the amount of biomass produced in the pilot cultivation based on the results from the previously performed lab cultivation. The conclusion based on the results in this work is that it not possible to predict the biomass production in the pilot based on lab experiments. The properties and behavior of different algae species can be very different in different systems, and the setups in this study differed too much. However, the results indicate that the pilot system has a high efficiency and can maintain a monoculture outdoors for at least 18 days as well as that the supply of flue gas highly affects the growth of the algae Scenedesmus obliquus.

Made available in DSpace on 2016-06-02T19:32:06Z (GMT). No. of bitstreams: 1 4940.pdf: 1724181 bytes, checksum: edce5d0a5db2ddb6103377e2a01b20fd (MD5) Previous issue date: 2011-08-26 / Universidade Federal de Sao Carlos / The chemical compounds called triacylglycerides (TAGs) have been the main source for biodiesel. The isolation of high lipid yield microalgae is important for the success of algae biomass production for biodiesel and, therefore, a search not only for organisms that fulfill such profile, but also for techniques effective in rapid lipid detection is fundamental. A number of methodologies on the characterization of microalgae lipid production, such as FTIR and RMN spectroscopy and spectrofluorimetry using the Nile Red dye are presented in this study. The Fourier Transform Infrared Spectroscopy (FTIR) technique have been largely used in biological system studies due to its rapid analysis, no pretreatment data gathering and easy biochemical characterization of intact cells. This study proposes a technical optimization of the FTIR technique for microalgae usage purposes as a practical approach for concomitantly prospecting large amounts of microalgae species with focus on biodiesel production. The Red Nile fluorescence has been successfully applied in microalgae lipid determination. In this research, the lipid (neutral) amount was determined by fluorescence in 430-570nm and a linear correlation established with the data gathered through gravimetry. After prospecting a number of species from the laboratory s stock cultures, the freshwater microalgae Scenedesmus sp (Clone MJ13) has been selected for study under traditional growth practices and under conditions of different nitrogen and phosphorus concentrations. The results showed a fast metabolic answer of Scenedesmus sp to the nutritional availability and the efficiency of the FTIR spectroscopy as a fast and reliable method for the determination of lipid production in a prospecting process. / A principal fonte para o biodiesel tem sido os compostos químicos denominados triacilglicerídeos (TAGs). O Isolamento de microalgas com alto rendimento lipídico é a chave para o sucesso da produção de biodiesel a partir de biomassa algal. Desta forma fazse necessário uma busca não somente por organismos que atendam tal exigência, mas também por técnicas eficazes que nos auxiliem na investigação destes. No presente estudo foram apresentadas algumas metodologias úteis na caracterização da produção de lipídeos por microalgas, tais como as espectroscopias de FTIR e RMN e a espectrofluorimetria com o corante Vermelho do Nilo. A técnica de espectroscopia de Infravermelho com Transformada de Fourier (FTIR) vem sendo muito utilizada nos estudos de sistemas biológicos, devido a sua rapidez de análise, obtenção de dados sem tratamento prévio e facilidade na caracterização bioquímica de células intactas. Foi proposto neste trabalho, uma otimização da técnica de FTIR para utilização em microalgas, como um método prático de prospectar concomitantemente uma grande quantidade de espécies de microalgas com finalidade de produção de biodiesel. A fluorescência por vermelho do Nilo tem sido aplicada com sucesso na determinação de lipídeos em microalgas. Desta forma a quantidade de lipídeos (neutros) foi determinada pela fluorescência em 430-570nm, e feita uma correlação linear com os dados obtidos por gravimetria. Após prospecção de várias espécies do banco de culturas do laboratório, foi selecionada a microalga de água doce Scenedesmus sp (Clone MJ13) para um estudo de caso em condições normais de cultivo e sob condições de diferentes concentrações de nitrogênio e fósforo. Os resultados demonstraram uma rápida resposta metabólica da Scenedesmus sp às mudanças na disponibilidade de nutrientes e indicam a eficiência da espectroscopia de FTIR como um método confiável e rápido para a determinação de produção lipídica em um processo de prospecção.

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, Republic of South Africa, in fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering. Johannesburg, 2016 / The process of photosynthesis is of great importance as it is the reaction of carbon dioxide (CO2) and water with the help of light, ’free’ energy from the sun, to form useful carbohydrates and oxygen. Photosynthesis is therefore useful both in carbon dioxide mitigation and growing bio-feedstocks towards making biofuel. This thesis aims to address two areas for analysing the photosynthesis process: 1. Looking at the physical limits of the growth; and 2. Improving the production rate of some aquatic plants, such as duckweed and microalgae. To address the first aim, the fundamental concepts of thermodynamics were used to analyse the photosynthetic process. It was found that the theoretical minimum number of moles of photons (NP) required (9–17) is less than the values reported by other researchers, suggesting that the photosynthesis process is highly irreversible and inefficient (operating at 35% efficiency or less). This is because the number of moles of photons will increase with greater process irreversibility (when the entropy generated is greater than zero). If the photosynthesis process is indeed that irreversible then the removal of heat (the heat not used by other cellular processes) by the plant becomes a major problem. It is suggested that transpiration, and other cellular processes, are the processes by which that is done, and it is shown that the water needs of the plant for transpiration would dwarf those needed for photosynthesis. Knowing the fundamental limits to growth could also be of use because if an organism was growing at a rate close to this value there would be no advantage to try to do genetic modification to improve its rate. Following the ideas presented above a spectrophotometer was used not only to obtain the absorption spectrum of algae, but it was also used to grow small samples at specific light wavelengths. The algae species researched was Desmodesmus spp., which, for example, is used to remediate waste water or as a source of feedstock for biofuel production. It also tolerates high CO2 concentrations. This simple experimental method demonstrated that a specific light wavelength (in particular the Secomam Prim spectrophotometer) 440 nm was preferred for the algae growth. It was recommended that this specific light wavelength would be best for growth. It might also be useful to know this fact particularly when designing photobioreactors, as this could reduce the amount of heat released into the surroundings and thus make the process more energy efficient. Interestingly, the wavelength for maximum growth corresponded to one of the peaks in the absorption spectra but there was no increase in growth rate corresponding to any of the other peaks. To address the second aim, the author determined how well predictions on improving the growth of algae (Desmodesmus spp. for example), based on a theoretical model, would work when tested experimentally. What the researcher found was that the method improved algae production, using the same set of equipment. The production was improved by a factor of 1.28 and 1.26 (at product concentrations 1000 mg/L and 600 mg/L respectively) when retaining 40% of the algae suspension. The method may be particularly useful when large amounts of biomass are required as there is no extra cost of purchasing additional equipment. The same model was applied to a growth profile of duckweed (Spirodela polyrhiza 8483, which is convertible into biofuel or a source of food), and the author showed that the model could work if the duckweed was provided with an added carbon source. In order to find an economical and reliable alternative to bridge the scale gap between laboratory and industrial production, the author checked if duckweed species (Spirodela polyrhiza 8483, Spirodela polyrhiza 9509, Lemna gibba 8428, Lemna minor DWC 112, Wolffia cylindracea 7340 and Wolffia globosa 9527) could be cultivated in media less expensive than the basal laboratory medium (Schenk and Hildebrandt). The author found that duckweed can be cultivated more efficiently, and in a more cost-effective manner, in the alternative media types, while maintaining growth rates, RGR 0.09 day-1, and starch contents, 5– 17%(w/w), comparable with that obtained with the conventional laboratory media. Thus, by looking at the photosynthesis process thermodynamically and experimentally, it is shown to be possible to improve the process by using concepts presented in this thesis. / MT2017

Made available in DSpace on 2016-08-10T10:31:07Z (GMT). No. of bitstreams: 1 JOSE BENEDITO GIRARDELLO VENDRUSCOLO.pdf: 1476146 bytes, checksum: 5292fae7b7d577ba381792d84556d542 (MD5) Previous issue date: 2009-09-21 / O alimento originado do plâncton que chega ao peixe é o zooplancton e sua preferência alimentar na rede trófica são as microalgas, cuja autotrofia permite a riqueza de todos os sistemas aquáticos do mundo. Na produção aquícola os estudos de organismos como as microalgas, que possam permitir a produção sustentável na atividade, são necessários e relevantes. A microalga Scenedesmus quadricauda tem características especiais tais como digestibilidade, preferência de consumo, facilidade de cultivo. Objetivando a maximização da produção autotrófica e redução de custos no cultivo da microalga Scenedesmus quadricauda, dejetos biodigeridos de suínos e aves foram testados juntamente com meio de cultura Chu, tradicionalmente utilizado para essa finalidade. Esses produtos são disponíveis e de baixo custo na região do Sudoeste de Goiás, graças ao incremento regional da atividade de suinocultura e avicultura e ao seu potencial de crescimento nos últimos anos. Assim, o presente trabalho foi desenvolvido no Laboratório de Aquicultura do Departamento de Zootecnia da Universidade Católica de Goiás, atendendo às condições ambientais necessárias para cultivo da microalga Scnedesmus quadricauda em meio de cultivo tradicional. Durante quatorze dias foram avaliadas as quatro repetições dos três tratamentos: meios de cultura Chu, biodigerido de aves e biodigerido de suínos. Concluiu-se que o meio de cultivo Chu tradicional pode ser substituído pelos meios de cultivo biodigerido de suínos e aves sem perda na produção de células da microalga Scenedesmus quadricauda, uma vez que a comparação entre eles não apresentou diferença significativa ao nível de 5% de probabilidade. Os picos de crescimento que representam produtividade para os três meios de cultura diferiram entre si com superioridade para biodigerido de aves e suínos em relação ao meio Chu.

Com as descobertas das inúmeras aplicações potenciais da biomassa de microalgas é necessário o desenvolvimento de ferramentas que visem auxiliar o aumento da produtividade dos cultivos. A espectrometria por infravermelho com transformada de Fourier (FTIR) é uma técnica versátil e rápida utilizada na identificação, caracterização e quantificação de diversos compostos moleculares. Sua aplicação está definida de acordo com a região espectral a ser analisada. O objetivo deste trabalho é desenvolver uma metodologia que torne possível a utilização da espectroscopia FTIR na região do infravermelho médio (MIR) para quantificar os teores de lipídeos, proteínas, carboidratos e células de Scenedesmus sp. Para tanto, a biomassa de Scenedesmus sp. foi analisada diariamente por métodos tradicionais e através do espectro FTIR. Posteriormente os dados foram correlacionados com as bandas de absorção características de cada composto. O modelo gerado para lipídeos na região entre 3000-2800 cm-1 obteve o maior coeficiente de correlação (R2) de 0,8265. Para os carboidratos, a banda de absorção que melhor representou as ligações características foi entre 1200-950cm-1, com R2=0,8023. Já para proteínas, a escolha do método tradicional não mostrou boa relação com os resultados do FTIR. Quando a concentração celular foi correlacionada com a área total foi obtido R2=0,7900. Por fim, realizaram-se experimentos para validar os modelos preditos, obtendo bons resultados para a quantificação de lipídeos e carboidratos. O FTIR mostra ser uma ferramenta eficiente para estimar os conteúdos de lipídeos e carboidratos de Scenedesmus sp. Além disso, o FTIR permite análise simultânea de múltiplos metabolitos que permitirá o monitoramento mais detalhado do cultivo em um tempo de análise muito mais curto e com alta reprodutibilidade dos resultados. / With the discoveries of the numerous potential applications of microalgal biomass, it is necessary to develop tools to help increase the productivity of cultivation. Infrared spectrometry with Fourier transform (FTIR) is a versatile and fast technique used in the identification, characterization and quantification of several molecular compounds. Its application is defined according to the spectral region to be analyzed. The objective of this work is to develop a methodology that makes possible the use of FTIR spectroscopy in the medium infrared region (MIR) to quantify lipid, protein, carbohydrate and cells contents of Scenedesmus sp. For this, the Scenedesmus sp. biomass was analyzed daily by traditional methods and through the FTIR spectrum. Subsequently the data were correlated with the absorption bands characteristic of each compound. The model generated for lipids in the region between 3000-2800 cm-1 obtained the highest coefficient of correlation (R2) of 0.8265. For carbohydrates, the absorption band that best represented the characteristic bonds was between 1200-950cm-1, with R2=0.8023. For proteins, the choice of the traditional method did not show a good relation with the FTIR results. When the cell concentration was correlated whit the total area an R2=0.7900. Finally, experiments were carried out to validate the predicted models, obtaining good results for the quantification of lipids and carbohydrates. The FTIR shows to be an efficient tool to estimate lipid and carbohydrate contents of Scenedesmus sp. In addition, the FTIR allows simultaneous analysis of multiple metabolites that will enable more detailed monitoring of the cultivation in a much shorter analysis time and with high reproducibility of the results.

Las microalgas han demostrado ser la fuente de energía más económica. Además, reduce el dióxido de carbono, también tienen una mayor producción en un corto tiempo y menor espacio a diferencia de otros cultivos. Entre las más de 100 especies de microalgas, el Scenedesmus dimorphus es el que tiene mayor potencial. El objetivo de este trabajo de tesis fue determinar de qué manera con un medio de cultivo para Scenedesmus obliquus var. dimorphus (Turpin) se obtiene cantidad de biomasa y contenido de aceite. Inicialmente, el trabajo experimental consistió en la obtención de la cepa pura de Scenedesmus dimorphus (14 mL). Seguidamente, se realizó el escalamiento de cultivo desarrollándose de la siguiente manera: 100 mL, 250 mL, 500 mL, 1L, 2L y 5L, con el fin de determinar las curvas de crecimiento mediante el conteo celular de S. dimorphus con el uso de la cámara de Neubauer, obteniendo los siguientes resultados: 3’ 451,500 unidades celulares en 120 horas (Bayfolan Forte), 2’ 472,500 unidades celulares en 192 horas (BG-11) y 327,500 unidades celulares en 96 horas (Guillard). Concluyendo que el Bayfolan Forte se obtuvo un mejor resultado. A continuación, se realizó 5 cosechas, luego se usó el método de floculación mediante la utilización del sulfato de aluminio Al2(SO4)3 y posteriormente, para la extracción de aceites, se molió la biomasa seca (36.5 g) seguido por la extracción con disolvente en hexano/ isopropanol, y se obtuvo un total de 30 mL de lípidos. Finalmente, en la parte estadística se comprobó la validez de las hipótesis utilizando diferentes métodos, tales como: Anova, Tukey y T. Student.

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2017-08-21T17:48:06Z No. of bitstreams: 1 Cristiane Tomas 2016.pdf: 3290049 bytes, checksum: 1f383e6c83c3ca0a2b8d59aa65426c21 (MD5) / Made available in DSpace on 2017-08-21T17:48:06Z (GMT). No. of bitstreams: 1 Cristiane Tomas 2016.pdf: 3290049 bytes, checksum: 1f383e6c83c3ca0a2b8d59aa65426c21 (MD5) Previous issue date: 2016-08-29 / The search for renewable energy sources is a concern of the new generations in face of possible fossil fuel scarcity and climate change caused by greenhouse gas emissions. When compared with diesel derived from petroleum, the biodiesel can reduce 78% carbon dioxide emissions, considering plants reabsorption; also, it can reduce by 90% emissions of smoke and virtu ally eliminates sulfur oxide. The purpose of this research was to investigate the cultivation of microalgae Scenedesmus acuminatus in the substrate composed by corn steep liquor for biodiesel production purposes. Initially a preliminary test was carried out to verify the viability of growing the microalgae in the effluent; further, a central composite design was carried to study the influence of the effluent and inoculum concentration on the cell density biomass, production of biomass, chemical oxygen demand (COD) and maximum growth rate (μmax) of microalgae culture. Statistical analysis indicated that the percentage of inoculum and effluent had na influence on the cell density, COD and maximum specific growth rate and that the optimal cultivation conditions would be achieved with the use of 53.5 % of efluente and 5.2% of inoculum. The proposed model was validated through cultivation under the proposed conditions, achieving 0.30 g/L of dry biomass on the seventh day. The cultivation, together with the coagulation procedure, was efficient for the removal of organic matter, verified through the COD and pH reduction, reaching the appropriate level according the standard required by current legislation. HARA & RADIN (1978) was more efficient for extraction at 45ºC: achieved a yield of 44,50 ± 2,12 mg / L total lipids. The extraction temperature had influence on the yield of lipids: the procedure performed at 45 ° C was able to extract more lipids in both methods. / A busca por fontes renováveis de energia é uma preocupação das novas gerações em face da possível escassez dos combustíveis fósseis e das alterações climáticas causadas pelas emissões dos gases do efeito estufa. Comparado ao óleo diesel derivado de petróleo, o biodiesel pode reduzir em 78% as emissões de gás carbônico, considerando-se a reabsorção pelas plantas; também reduz em 90% as emissões de fumaça e praticamente elimina as emissões de óxido de enxofre. O objetivo desta pesquisa foi investigar o cultivo de microalgas Scenedesmus acuminatus em substrato composto por água de maceração do milho para fins de produção de biodiesel. Inicialmente realizou-se um teste preliminar para verificar a viabilidade de crescimento dessa microalga no efluente; posteriormente foi realizado um delineamento composto central rotacional para estudar a influência da concentração de efluente no meio e percentual inicial de células (inóculo) sobre a densidade celular, acúmulo de biomassa, DQO e velocidade máxima de crescimento (μmax) do cultivo. A análise estatística indicou que os percentuais de inóculo e efluente tiveram influência sobre a densidade celular, DQO e velocidade máxima específica de crescimento e que as condições ótimas do cultivo seriam alcançadas com a utilização de 53,5% de efluente e 5,2% de inóculo. O modelo proposto foi validado através de um cultivo nas condições propostas, cujo rendimento em biomassa seca foi de 0,30g/L ao sétimo dia. O cultivo, aliado ao procedimento de coagulação, foi eficiente para remoção de matéria orgânica do meio de cultura, observada através da redução dos valores de DQO e pH, que atingiram nível adequado ao padrão exigido pela legislação vigente. A metodologia HARA & RADIN (1978) foi a mais eficiente foi mais eficiente para extração de lipídeos totais à temperatura de 45ºC: obteve um rendimento de 44,50 ± 2,12 mg/L. A temperatura de extração teve influência sobre o rendimento em lipídeos: o procedimento realizado a 45°C foi capaz de extrair maior quantidade de lipídeos para ambos os métodos.

Coal-fired electricity production is the major emitter of CO2 and other greenhouse gases including NOx and SOx. Microalgae-based CO2 mitigation systems have been proposed to reduce the net CO2 emission from coal-fired power plants. This study focused on developing an optimum culture media and exploring the possibilities for recycling nutrients, which were added as commercial mineralized chemicals at the beginning of cultivation. In order to release the nutrients embedded in the cells so that they can be used as a nutrient source for new cells, Scenedesmus biomass was digested by anaerobic bacteria. Results showed that thermal pretreatment enhanced the methane production rate for the first 7 days of digestion. Three operational factors were tested: heating temperature, heating duration and NaOH dosage. The combination of 10 min heating with 3~6% NaOH at 50 °C gave the highest cell wall destruction for all samples except oven-dried algae. The anaerobic digestate, rich in mineralized nutrients including ammonium and phosphate, potassium and magnesium ions, was tested as a possible nutrient source for the algae cultivation. To cope with the high solid content of the digestates, the dosage of the digestates was reduced or the solid particles were removed prior to addition to the microalgae. Both approaches worked well in terms of providing nutrients with minimal effect on light penetration. Using digestates without any sterilization did not cause contamination or other deleterious effects on the Scenedesmus growth rate. Harvesting microalgae cells was critical to ensure a continuous and robust growth rate. The used media could be recycled at least four times without altering the algae growth. Nutrient replenishment was the key for a healthy culture when used media was incorporated. The combination of used media and digestates can sustain a normal algae growth. Life cycle assessment was conducted on the system including the photobioreactor, the anaerobic digester, the biomass settling and dewatering and used media and nutrient recycling. Considering methane as the energy source, the overall energy return of the system was 2.4. CO2 mitigation rate was about 39% under current mitigation system.