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1
Scholz, Matthew John. "Microbial Cogeneration of Biofuels". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145446.
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The fields of biodiesel and bioethanol research and development have largely developed independently of one another. Opportunities exist for greater integration of these processes that may result in decreased costs of production for both fuels.To that end, this work addresses the use of the starches and glycerol from processed algal biomass as substrates for fermentation by the yeasts
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King, P. M. "The use of ultrasound on the extraction of microalgal lipids". Thesis, Coventry University, 2014. http://curve.coventry.ac.uk/open/items/4aabbd22-686a-4284-a18d-23de6bcff203/1.
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Microalgae synthesize and store large volumes of lipids (potentially over 25% of dry weight) which could provide a renewable source of biodiesel. Traditional extraction techniques often produce poor lipid yields particularly from microalgae with robust cell walls. This project investigated the role of power ultrasound as a cell disruption step in lipid extraction from four microalgal species. Nile Red staining was used to assess the time when ultrasound induced increased membrane permeability in each species and lipids were extracted using an ultrasound assisted Bligh and Dyer extraction method. A 20 kHz probe system (40% amplitude, 0.086 W/cm3) caused increased lipid recovery from dry biomass in all cases; D. salina (no cell wall) from 15 to 22.5% of dry biomass after 1 minute (26% when stressed with 35 g/L NaCl). C. concordia (thin cell wall) from 7.5 to 10.5% of dry biomass after 2 minutes (27% with 25% nitrogen reduction in growth media). N. oculata (thick cell wall) from 6.5 to 10% of dry biomass after 16 minutes (31.5% when stressed with 30 g/L NaCl). The stressed cultures yield could be improved to 35% when ultrasound was combined with S070 beating beads. Chlorella sp. (thick cell wall) from 6.3 to 8.7% of dry biomass, after 16 minutes (44% was achieved when harvested at day 9 instead of 15). A Dual Frequency Reactor (16 and 20 kHz, 0.01 W/cm3) flow system with S070 beads demonstrated that high lipid extraction yields could be achieved on a larger level with N. oculata. After 4:48 minutes sonication 24% lipid recovery was achieved. This system could theoretically increase daily microalgal oil production from 3.96 to 5.76 L per day when compared to conventional techniques, at an extra production cost of only 2.9 p/litre (1.5% increase). D. salina, N. oculata and C. concordia resumed normal growth following sonication at 20 kHz after 1-20 days (8 minutes treatment for D. salina, 60 minutes treatment for N. oculata and 16 minutes treatment for C. concordia). It was found that the supernatant of sonicated D. salina and C. concordia when added to established cultures were able to boost their growth.
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Griffiths, Erick W. "Removal and Utilization of Wastewater Nutrients for Algae Biomass and Biofuels". DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/631.
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The Logan City Environmental Department operates a facility that consists of 460 acres of fairly shallow lagoons (~ 5'deep) for biological wastewater treatment that meets targets for primary and secondary treatments (solids, biological oxygen demand (BOD), and pathogen removal). Significant natural algal growth occurs in these lagoons, which improves BOD removal through oxygenation and also facilitates N removal through volatilization as ammonia under high pH conditions created by algal growth. Phosphorus, however, is non-volatile and stays in the water and likely cycles in and out of algal cells as they grow and die in the lagoons. In the near future, the regulatory limits on phosphorus released from the Logan wastewater treatment facility are likely to become significantly lower to counter potential downstream eutrophication. One way to potentially lower phosphorus levels in the wastewater effluent is through management of algal growth in the lagoons. As mentioned above, algae growth naturally occurs in the treatment lagoons and if the algal biomass is harvested when growth yields are highest, the phosphorus contained in the cells could be removed to obtain phosphorus-free water. The algal biomass could then be used for production of biofuels. This research focuses on laboratory and pilot assessments to show the ability of algae indigenous to the Logan lagoons to uptake phosphorus and produce biomass that can be used for biofuel production.
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Moulin, Solène. "Synthesis of hydrocarbons in algae : from biodiversity to biotechnology". Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0429.
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Les hydrocarbures (HCs) sont prédominants dans notre économie actuelle (carburants, cosmétiques, chimie, etc.) mais sont quasi-exclusivement issus des ressources fossiles. Les problématiques de changement climatique et d’épuisement des ressources poussent les recherches vers l’étude et la domestication des voies de synthèse naturelles d’HCs. Lorsque j’ai commencé ma thèse, une enzyme de biosynthèse d’HC, l’acide gras photodécarboxylase (FAP) venait d’être découverte chez la microalgue Chlorella. J’ai d’abord caractérisé son homologue chez la microalgue modèle Chlamydomonas. Une étude phylogénétique de la famille des GMC oxidoréductases à laquelle appartient la FAP a permis d’identifier un large réservoir de de 200 FAPs putatives. La caractérisation biochimique de plusieurs d’entre elles a permis de montrer qu’une FAP fonctionnelle a été conservée lors des endosymbioses secondaires. Cela suggère que la FAP joue un rôle important chez les algues. Ce rôle a été étudié par une approche de génétique inverse chez Chlamydomonas. La caractérisation physiologique de mutants knockout a permis de démontrer le rôle de la FAP dans la synthèse d’HCs dans le chloroplaste et de mettre en évidence des modifications physiologiques transitoires. Des mécanismes de compensation à l’absence d’HCs restent donc à découvrir. Dans une dernière partie, j’ai développé une souche d’E. coli exprimant la FAP et une thioestérase. Cette souche produit en continu des HCs dans la phase gaz des cultures, ce qui permet une récolte facilitée du produit d’intérêt sous forme pure. Cette étude constitue une preuve de concept que la FAP pourrait être utilisée pour la production biosourcée d’HCsHydrocarbons (HCs) are predominant in our current economy (fuels, cosmetics, chemicals, etc.) but are almost exclusively derived from fossil resources. Climate change and resource depletion concerns are pushing research towards the study and domestication of natural HC synthesis pathways. When I started my thesis, a HC forming enzyme, the fatty acid photodecarboxylase (FAP) had just been discovered in the microalgae Chlorella. I first characterised its homolog in the model microalgae Chlamydomonas. A phylogenetic study of the GMC oxidoreductase family to which the FAP belongs has allowed identification of a large reservoir of 200 putative FAPs. Biochemical characterisation of several of them showed that a functional FAP was maintained during secondary endosymbiosis. This suggests that FAP plays an important role in algae. This role has been studied by a reverse genetic approach in Chlamydomonas. The physiological characterisation of knockout mutants demonstrated the role of FAP in the synthesis of HCs in chloroplasts as well as transient physiological changes. Mechanisms to compensate for the absence of HCs therefore remain to be discovered. In a last part, I developed a strain of E. coli expressing the FAP and a thioesterase. This strain continuously produces HCs in the gas phase of the cultures, which allows an easier harvesting of the product of interest in a pure form. This study is a proof of concept that FAP could be used for the biobased production of HCs
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Jeffrey, Bargiel. "Commercialization of Lateral Displacement Array for the Dewatering of Microalgae". Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1238702010.
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Christenson, Logan. "Algal Biofilm Production and Harvesting System for Wastewater Treatment with Biofuels By-Products". DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/994.
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Excess nitrogen and phosphorus in discharged wastewaters can lead to downstream eutrophication, ecosystem damage, and impaired water quality that may affect human health. Chemical-based and physical-based technologies are available to remove these nutrients; however, they often consume significant amounts of energy and chemicals, greatly increasing treatment costs. Algae are capable of removing these pollutants through biomass assimilation, and if harvested, can be utilized as a feedstock for biomethane or biodiesel production. Currently, difficulties in harvesting, concentrating, and dewatering algae have limited the development of an economically feasible treatment and production process. When algae are grown as surface-attached biofilms, the biomass is naturally concentrated and more easily harvested, leading to less expensive removal from treated water, and less expensive downstream processing for biofuel production. In this study, a novel algal biofilm production and harvesting system was designed, built, and tested. Key growth parameters were optimized in order to maximize biomass production and nutrient uptake from wastewater. Compared to suspended algae systems, the attached algal biofilm design of this study led to increased biomass production and greater treatment of domestic wastewater. An efficient and inexpensive algal biofilm harvesting technique was also developed in order to obtain a concentrated biosolids product, resulting in improved water quality and a feedstock suitable for further processing in the production of biofuels.
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Woertz, Ian C. "Lipid Productivity of Algae Grown on Dairy Wastewater as a Possible Feedstock for Biodiesel". DigitalCommons@CalPoly, 2008. https://digitalcommons.calpoly.edu/theses/183.
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The objective of this thesis is to develop a biological wastewater treatment system that utilizes algal growth to simultaneously create renewable energy in the form of biodiesel and digester biogas, remove polluting nutrients, and abate greenhouse gases. Research under the Department of Energy Aquatic Species Program during 1978-1996 concluded that cultivating algae for biofuels was cost prohibitive at that time and that an integrated approach should be studied that combined wastewater treatment with algal biofuel production. Nutrient removal, in particular nitrogen and phosphorus, from wastewater is a growing regulatory need and the use of algae cultivation could create a unique marriage between waste treatment and biofuel production. To investigate this possible synergy, bench-scale tests were conducted to determine potential algal lipid productivity with mixed-cultures of algae grown on anaerobically-pretreated dairy wastewater in batch mode. The total lipid content of the algae ranged from 8% to 29% of algal mass. Maximum biomass concentration reached 920 mg/L, measured as volatile suspended solids, on Day 13 of incubation. In contrast, maximum total lipid content was reached at Day 6, corresponding to a lipid productivity of 2.8 g/m^2/day, or 1,200 gallons/acre/year if scaled up. Nutrient removal over 12 days of incubation was nearly complete. Total ammonia (NH3+NH4+) was reduced 96% to 1.1 mg/L as N, and phosphate (PO4^3-) was reduced >99% from an initial concentration of 2.5 mg/L PO4 as P.
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Bajhaiya, Amit. "Metabolite analysis of Chlamydomonas reinhardtii and transcriptional engineering for biofuel production". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/metabolite-analysis-of-chlamydomonas-reinhardtii-and-transcriptional-engineering-for-biofuel-production(185995ba-d1be-44ff-a87a-140c19655d31).html.
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It has been long known that algae have the potential to produce a diverse range of metabolic products including lipid and starch, which could be utilized as a fuel feedstock. Despite the capacity of algae to synthesize and store large amounts of lipids and starch, algae are not currently a commercially viable feedstock for biofuel. The metabolite storage in algae can depend on the availability of nutrients such that nutrient starvation can boost the storage of lipid and carbohydrate. These nutrient-status-induced changes in lipid and starch are underpinned by altered expression of several metabolite-related genes. However, many aspects of fatty acid and carbohydrate biosynthesis are not well understood. Furthermore, the genetic regulators of nutrient starvation-induced carbohydrate and lipid accumulation are unknown in microalgae. Therefore, this PhD focused on screening cultivation conditions, in particular Phosphorus (P) and Nitrogen (N) limited conditions that induce metabolic changes, evaluated a rapid microalgal screening method, which was used to identify putative metabolism regulators, and characterized in detail the role of one P-starvation regulator, called PSR1 (Phosphorus starvation response 1). For establishing suitable culture conditions, the microalga Chlamydomonas reinhardtii was cultured in five different P and N-limited conditions and screened for metabolic changes using Fourier transform infrared spectroscopy (FT-IR) at different phases of growth. The FT-IR spectral changes were visualized by multivariate statistical tools such as principal component analysis (PCA) and principal component-discriminant function analysis (PC-DFA). Clear clustering based on nutrient availability and metabolic changes demonstrates the potential and sensitivity of FT-IR in screening multiple culture conditions. The potential of FT-IR was further tested by screening mutant strains of C. reinhardtii that were defective in response to nutrient starvation. Nine lines with mutation in one or more of the PSR1, SNRK2.1 or SNRK2.2 genes and a wild type were screened by FT-IR for P and N starvation-induced metabolic changes. PCA, PC-DFA and predictive partial least squares discriminant analysis (PLS-DA) of FT-IR spectra, clearly distinguished wild type from mutant strains and clustered mutants with similar genetic backgrounds, demonstrating the potential of FT-IR to detect and differentiate specific genetic traits. The changes in lipid and carbohydrate profile under nutrient stress and in the different strains were validated by biochemical analysis and liquid chromatography-mass spectrometry (LC-MS).This thesis demonstrated that PSR1 is an important regulator of neutral lipid and starch biosynthesis. Transcriptomic analysis on wild type and psr1 mutant under P-starvation was performed to identify transcripts induced by P-starvation that were mis-regulated in psr1. Mainly transcripts encoding starch and triacylglycerol enzymes were affected. To further evaluate the role of PSR1 in regulating lipid and starch metabolism, complementation of psr1 and overexpression by PSR1 was performed. The P-starvation phenotype was clearly rescued in the complementation lines, and overexpression lines showed increased expression of P homeostasis genes and increased Pi accumulation in cells, with an increase in total starch content and number of starch granules. Clear increases in expression of key starch biosynthesis genes such as soluble starch synthase (SSS1, SSS5) and starch phosphorylase (SP1) was observed, which correlated with increased starch content in the overexpression lines. A carbon shift was observed as a decrease in neutral lipid was coupled with the increase in starch content. All together these findings suggest that PSR1 is a key transcriptional regulator of global metabolism, and demonstrated successful transcriptional engineering of microalgae.
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Cook, Charlotte. "Sequencing and analysis of the diel transcriptome of Botryococcus braunii". Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/17075.
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Microalgae are widely viewed as a potential source of renewable biofuels. Microalgae are highly productive and can be cultured in recycled water on margial or non-agricultural land. Despite their advantages, the industrial scale deployment of microalgae faces numerous challenges including relatively little knowledge of the algae themselves and the comparatively expensive infrastructures required for culture. The green microalga, Botryococcus braunii is particularly interesting because it synthesizes long-chain (C30- C40) hydrocarbons that can be converted to liquid fuel by hydrogenation and catalytic cracking. Moreover, B. braunii is the major fossil present in the Ordovician oil shales and kerogen deposits. Although studied since the 1970s, very little is known regarding critical aspects of B. braunii, notably its molecular biology. In higher plants molecular clocks have been well defined and transcript profiling has revealed a sophisticated network of circadian scheduling of metabolic processes. Characterization of temporal controls over hydrocarbon synthesis is therefore of importance to optimization of biofuel production from B. braunii. In this project B. braunii (Race B, strain Guadeloupe) were cultured in a 12-hour photoperiod and either maintained in that regime or transferred to constant light. Algae were sampled every 4 hours, during a 28-hour time-course and mRNA extracted. mRNA was reverse-transcribed to cDNA and sequenced using a paired-end protocol on an Illumina HiSeq 2000 platform. Over 2 billion sequence reads of 100 bp were generated and assembled de novo, into a complete transcriptome for B. braunii. The transcriptome was comprehensively annotated using global and targeted protocols and differential expression and co-expression analyses were performed. Metabolic pathway analysis confirmed the presence, and photoperiodic regulation of the MEP/DOXP Terpenoid Backbone synthesis pathway. Targeted annotation and expression analysis revealed two predicted B. braunii circadian clock components, which were incorporated into a B. braunii circadian clock model. In non-hierarchical cluster analysis, contigs of the B. braunii transcriptome clustered under four distinct patterns of diel expression. Networks of co- and anti-expressed contigs were elucidated by hierarchical clustering. These results demonstrate the exquisite control over metabolism in B. braunii. Such knowledge is essential for the industrial applications of B. braunii, either directly or through the engineering of selected B. braunii genes or molecular pathways into alternative chassis.
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De, la Rosa Nina N. "Exploring the Use of Everglades Agricultural Area Canal Water as Base Medium for the Mass Production of Algae for Biofuels". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1689.
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Freshwater use is a major concern in the mass production of algae for biofuels. This project examined the use of canal water obtained from the Everglades Agricultural Area as a base medium for the mass production of algae. This water is not suitable for human consumption, and it is currently used for crop irrigation. A variety of canals were found to be suitable for water collection. Comparison of two methods for algal production showed no significant difference in biomass accumulation. It was discovered that synthetic reticulated foam can be used for algal biomass collection and harvest, and there is potential for its application in large-scale operations. Finally, it was determined that high alkaline conditions may help limit contaminants and competing organisms in growing algae cultures.
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Bowden, Dustin D. "Evaluation of the Performance of a Downward Flow Inclined Gravity Settler for Algae Dewatering". Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1431545628.
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De, Mill Chad R. "Integrated Life Cycle and Techno-economic Assessment of the Conversion of High Productivity, Low Lipid Algae to Renewable Fuels". DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5262.
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The production of alternative transportation fuels is imperative to meet future energy demands without contributing to global climate change. Advances in alternative processing techniques that have emerged due to interest in microalgae as a feedstock have led to a variety of potential processing pathways for the production of bio-based fuels. A major hurdle in the algal production process is maintaining a fast and stable algae culture. Monocultures, developed for their high lipid content, suffer from low productivity, are susceptible to crashes and require a constant supply of carbon dioxide to maintain productivity. In an effort to circumvent these obstacles, algal turf scrubber systems (ATS) are now being targeted not only for water purification, but as a means of producing algae feedstocks for fuel conversion. The resulting algae are capable of being harvested at a much higher density, requiring less energy for dewatering purposes. ATS systems do present other drawbacks that downstream technologies need to account for to make this system a viable means for fuel conversion. While polyculture algae species display great growth characteristics, they contain high percentages of nitrogen containing proteins and low lipid content. If not removed this nitrogen pollutes any resulting biocrude making it unacceptable for diesel fuel blends. This study investigates a processing method which reduces the nitrogen content of the resulting fuel by fermenting both carbohydrates and proteins into intermediate compounds. By tuning the E. coli fermentation stain it is hoped that the process will yield higher value co-products than those investigated in this study. The research contained herein incorporates laboratory experimentation with engineering systems modeling to assess the economic feasibility and environmental impacts of generating biofuels from ATS cultivated algae. Results show a minimum fuel selling price of $5.93 per gasoline gallon equivalent and greenhouse gas emissions of -0.0185 kg CO2eq per MJ fuel. Discussion points include process optimization in terms of minimum fuel selling price and global warming potential.
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Janecka, Remigijus. "Organinių medžiagų skaidymo ultragarsiniame lauke tyrimas". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140722_103215-76861.
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Baigiamajame darbe apžvelgiamos organinių medžiagų skaidymo ultragarsu sistemos. Didžiausias dėmesys skiriamas dumblių skaidymo ultragarsu sistemoms. Apžvelgiamos dumblių pritaikymo, jų auginimo ir išgavimo tendencijos. Nagrinėjama išilginių virpesių ultragarsinė dumblių skaidymo sistema „UIP 1000hd”.
Darbo tikslas - Standartinio ultragarsinio įrenginio(UIP1000hd Set ) pagalba ištirti botanikos institute auginamų dumblių (augalinių bioląstelių) skaidymo galimybę.
Darbo uždaviniai:
1. Įsisavinti naują ultragarsinę įrangą, išmokti naudoti įvairius titaninius koncentratorius, nustatyti reikiamus augalinių bioląstelių skaidymo režimus, išmokti registruoti ultragarsinės sistemos elektrinius ir mechaninius parametrus.
2. Susipažinti su pramoninių dumblių auginimo specifika. Kartu su Botanikos instituto mokslininkais organizuoti tyrimo objekto - dumblių(augalinių bioląstelių) bandomosios partijos užauginimą.
3. Išdirbti dumblių skaidymo lygio vertinimo (tyrimo) metodiką.
4. Išdirbti dumblių skaidymo tyrimo įrenginiu UIP1000hd Set metodiką.
5. Atlikti ultragarsinės sistemos ir kavituojamo skysčio su organine medžiaga virpesių pasiskirstymo analizę ( sistemos kompiuterinis modeliavimas turimomis laboratorijoje programomis).
6. Iš elektrinės ir mechaninės pusės ištirti ultragarsinę sistemą : nustatyti varžines - dažnumines ir amplitudines – dažnumines charakteristikas esant įvairioms elektrin4ms galioms, laisvame ir apkrautame režime.
7. Atlikti 2-3 rūšių pramoninių dumblių... [toliau žr. visą tekstą]The Master’s Thesis provides an overview on the systems of organic matter decomposition by ultrasound. The focus is on the systems of algal ultrasound decomposition. The tendencies of algae adaptation, cultivation and extraction were reviewed. The ultrasonic algae decomposition system of longitudinal oscillation named “UIP 1000hd” was analyzed. The aims and objectives of the thesis: The aim - is to examine the decomposition possibility of algae (bio cells) growing in the Botanical Institute with the help of standard ultrasound device (UIP1000hd Set). Objectives: 1. To learn about the new ultrasound equipment, learn to use a variety of titanium concentrators, set the required decomposition modes of bio cells, learn to record electrical and mechanical parameters of the ultrasound system. 2. To familiarize with the specifics of industrial algae cultivation. To organize the experimental batch cultivation of the object of the research - algae (plant bio cells) - together with scientists of the Botanical Institute. 3. To master the assessment (research) methodology of the level of algae division. 4. To master the methodology of the algae decomposition equipment UIP1000hd Set. 5. To carry out the distribution of vibration analysis of the ultrasound system and the cativating with the organic matter (the system modeling by computer using programs that are in the Laboratory). 6. To investigate the electrical and mechanical sides of the ultrasound system: to set... [to full text]
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Willis, Robert M. "ncreased Production and Extraction Efficiency of Triacylglycerides from Microorganisms and an Enhanced Understanding of the Pathways Involved in the Production of Triacylglycerides and Fatty Alcohols". DigitalCommons@USU, 2013. http://digitalcommons.usu.edu/etd/1530.
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The continued increase in the demand for fossil fuels combined with their ever dwindling supply has prompted the search for a suitable alternative fuel. The research contained within this dissertation seeks to increase the lipid content of cellular feedstocks, improve extraction efficiencies of lipids, and understand the pathways involved in the production of fatty alcohols and triacylglycerides from microbial feedstocks. As part of this research the diatom, Cheatoceros gracilis, was grown at small and large scale to determine optimal growing conditions. No apparent nutrient stress trigger was required to initiate the accumulation of the biodiesel precursor triacylglyceride, unlike other documented algal strains. A follow-up to this project demonstrated that the microalga C. gracilis may utilize light intensity as a trigger for lipid production. A major difficulty in the production of biofuels from microorganisms is the expensive process of dewatering, drying, and extracting the lipid compounds from the cells. As part of this research, a process has been developed that allows for lipid extraction to occur in the presence of water at a point as low as 2 percent solids or 98 percent water. This process utilizes a single organic solvent that mixes well with microbial lipids, but poorly with water allowing for efficient extraction of lipids and fast solvent to water separation. This process greatly decreases the cost of the microbial biofuels production associated with the removal of water from cell slurries. Triacylglycerides and fatty alcohols are oleochemicals that are commonly used in industrial, pharmaceutical, and consumable processes. A predicted fatty acyl CoA reductase enzyme was cloned into an E. coli vector, expressed, characterized and shown to be active as a dual reductive enzyme reducing a fatty acyl CoA to its respective fatty alcohol, constituting the first enzyme of this type discovered in a bacterium. The process of triacylglyceride production in microbes is fairly well understood; however, the process that regulates this production has not yet been fully explored. As part of this research, the model yeast organism, Yarrowea lipolytica, is utilized to identify essential genes for citrate transport that if removed could result in increasing triacylglyceride production in vivo.
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Willis, Robert M. "Increased Production and Extraction Efficiency of Triacylglycerides from Microorganisms and an Enhanced Understanding of the Pathways Involved in the Production of Triacylglycerides and Fatty Alcohols". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1530.
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The continued increase in the demand for fossil fuels combined with their ever dwindling supply has prompted the search for a suitable alternative fuel. The research contained within this dissertation seeks to increase the lipid content of cellular feedstocks, improve extraction efficiencies of lipids, and understand the pathways involved in the production of fatty alcohols and triacylglycerides from microbial feedstocks. As part of this research the diatom, Cheatoceros gracilis, was grown at small and large scale to determine optimal growing conditions. No apparent nutrient stress trigger was required to initiate the accumulation of the biodiesel precursor triacylglyceride, unlike other documented algal strains. A follow-up to this project demonstrated that the microalga C. gracilis may utilize light intensity as a trigger for lipid production. A major difficulty in the production of biofuels from microorganisms is the expensive process of dewatering, drying, and extracting the lipid compounds from the cells. As part of this research, a process has been developed that allows for lipid extraction to occur in the presence of water at a point as low as 2 percent solids or 98 percent water. This process utilizes a single organic solvent that mixes well with microbial lipids, but poorly with water allowing for efficient extraction of lipids and fast solvent to water separation. This process greatly decreases the cost of the microbial biofuels production associated with the removal of water from cell slurries. Triacylglycerides and fatty alcohols are oleochemicals that are commonly used in industrial, pharmaceutical, and consumable processes. A predicted fatty acyl CoA reductase enzyme was cloned into an E. coli vector, expressed, characterized and shown to be active as a dual reductive enzyme reducing a fatty acyl CoA to its respective fatty alcohol, constituting the first enzyme of this type discovered in a bacterium. The process of triacylglyceride production in microbes is fairly well understood; however, the process that regulates this production has not yet been fully explored. As part of this research, the model yeast organism, Yarrowea lipolytica, is utilized to identify essential genes for citrate transport that if removed could result in increasing triacylglyceride production in vivo.
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Pinilla, Maria Juliana. "Comparative Life Cycle Assessments of Lignocellulosic and Algae Biomass Conversion to Various Energy Products through Different Pathways". Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3740.
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Bioenergy has the potential to reduce the world's dependence on fossil fuels, and to decrease the CO2 emissions due to fossil combustion. Lignocellulosic and algae biomass have been presented as promising feedstocks for bioenergy production.
In this study, a comparative Life Cycle Assessment (LCA) has been developed to evaluate the environmental impacts associated with different energy products via different routes across the whole life of algal and lignocellulosic bioenergy. Results were compared per energy basis, the production of 1 million BTU of energy products.
For the development of the comparative algae biomass conversion LCA, algal biomass was converted to liquid biofuels via a thermochemical gasification and Fisher-Tropsch Synthesis (FTS) process; and to electricity and heat via anaerobic digestion and combined heat and power (CHP) process. Overall results from the algae biomass conversion LCA showed that the process that converts algae biomass through anaerobic digestion and CHP process to electricity and heat had the highest overall environmental impact. Results also showed that the impact categories that appear to contribute the most to the overall impacts are ecotoxicity, human health non-cancer, and human health cancer.
For the development of the comparative lignocellulosic biomass conversion LCA, lignocellulosic biomass was converted to ethanol and higher alcohols through thermochemical gasification and alcohol synthesis process, to liquid biofuels via thermochemical gasification and FTS process, and to liquid biofuels via a thermochemical gasification and FTS process that uses methane. Overall results from the lignocellulosic biomass conversion LCA showed that the process that converts lignocellulosic biomass into alcohols has the highest overall environmental impact. Results also showed that the impact categories that appear to contribute the most to the overall impacts are ecotoxicity, human health non-cancer, human health cancer, and global warming.
This study determined that cultivated algae biomass feedstock has much higher environmental impacts compared with lignocellulosic biomass feedstock from forestation and agriculture byproducts. It was also concluded that thermochemical gasification and FTS process showed higher efficiency when converting biomass to bioenergy.
In addition, the five biomass to bioenergy conversion pathways used in the development of this LCA study were compared. Results showed that the pathway with lignocellulosic biomass (feedstock), thermochemical gasification and alcohol synthesis process (conversion process), and ethanol and higher alcohols (energy products) has the largest environmental impact.
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Shirvani, Tara. "The role of catalysts and algae in forming a sustainable solution for a global food and fuel crisis". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:30af0957-1ed6-4ea7-949b-f120606ab22e.
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This thesis undertakes three separate lifecycle analyses to determine the emissions and fossil energy demand required to process algae biomass into renewable fuel and animal feed. A complete well-to-wheel fuel-cycle analysis is conducted for the production of biodiesel and jet biofuel from algae biomass. The environmental impacts of algae-based fuels for the road transportation and aviation industry are benchmarked against analogue conventional fossil fuels. This thesis demonstrates that algae biofuel production can only realize its inherent environmental advantage of reduced GHG emissions, once every step of the production chain is fully optimized and decarbonized. This includes smart co-product utilization, offsetting fertilizers through wastewater recycling, reusing exhaust gases as additional CO2 source and using decarbonized electricity, heat and indirect energy. The definition of a Catalyst Sensitivity Index (CSI) demonstrates how catalytic efficiency increases can impact the fossil energy consumption and the greenhouse gas emissions balance of catalyst-dependent processes. The CSI will allow the industry to highlight 'best practice catalysts' and draw conclusions for what efficiency gains one could anticipate with higher performance catalysts. For countries where a decarbonized electricity and heat grid is not available to guarantee low-carbon algae fuel production and the looming resource scarcity around marine feed production has become more pressing, the alternative use of algae for aquafeed production is recommended. This thesis analyses major routes towards the future cost-competitive production of microbial biomass as sustainable fish meal and oil source to meet a global demand for depleting fish feed supplies. A comprehensive economic cost analysis and lifecycle assessment demonstrates the feasibility of replacing global fish meal and fish oil supplies with low-carbon and affordable algae feed by the year 2030. This research reveals how algae feed production has the potential to transform a pressing resource tipping point into a turning point.
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Berthold, Erwin David. "Enhancing Algal Biomass and Lipid Production through Bacterial and Fungal Co-Culture". FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2563.
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This thesis investigates the effects of co-culturing microorganisms including 37 yeast, 38 bacteria, nine diazotrophic cyanobacteria, and three fungi on biomass and lipid production in fresh- and saltwater algae. Algal lipid content was measured using Nile Red method and gravimetric techniques. Among the algal strains tested, freshwater Coelastrum sp. 46-4, and saltwater Cricosphaera sp. 146-2-9, showed enhanced biomass yield and lipid content in response to co-culture with bacteria, cyanobacteria, and fungi. While co-culture with yeast caused inhibition of algal productivity, no difference in algal productivity was observed between nitrogen-free diazotrophic cyanobacterial co-culture and nitrogen-replete monoalgal culture. Results indicated that extracellular compounds from the freshwater bacteria Pseudomonas stutzeri and marine fungus Fusarium sp. significantly account for stimulation of lipid accumulation within algal cells, while co-cultivation with live microorganism cells stimulated biomass production in algae.
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Kaloudis, Dimitrios. "Improving microalgae for biofuel production". Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665443.
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Microalgae are a diverse group of oxygenic photosynthetic microorganisms which show great promise as a source of biofuel. However, significant challenges still remain before microalgae can be considered a viable source of biofuel. The main current challenges are nutrient sourcing and recycling as well as downstream processing. The algal cell wall and especially the presence of an algaenan cell wall in some Chlorophyte algae could be an important variable in determining downstream processing costs but not much comparative research has been done to elucidate this. The first part of the present study focuses on the recently isolated alga Pseudochoricystis ellipsoidea (Trebouxiophyceae) and its improvement and assessment for biofuel production. Random mutagenesis and FACS screening protocols were developed for the isolation of pigment and cell wall mutants but despite considerable efforts no suitable mutants could be identified in the first half of this project. Two 500 L raceway ponds as well as an algal growth room and bubble column bioreactors were set up to facilitate algal research at the University of Bath and assess the performance of P. ellipsoidea in realistic culture conditions. P. ellipsoidea showed a maximum growth of 1.53 divisions day-1 in semi-open raceway ponds, resistance to contamination and a 30% lipid content, making it particularly suitable for raceway pond cultures. In the second part of this project six species of Chlorophyte (“green”) algae, three of which produced algaenan, were compared for suitability to growth in anaerobic digestate and municipal wastewater as well as cell wall strength, permeability and suitability to hydrothermal liquefaction. We found that anaerobic digestate was a good medium for the growth of all species independently of autoclaving and that non-autoclaved wastewater was a very challenging medium. Algaenan production did not affect cell disruption by ultrasonication but growth stage and cell wall thickness did. Lipid extraction kinetics by chloroform/methanol were greatly affected by algaenan, meaning that this material is relatively impermeable to organic solvents. Cell wall thickness, cell volume and lipid content also had an effect on lipid extraction kinetics but this was only measurable after 180 minutes of extraction. 8 Hydrothermal liquefaction showed high solid and low oil yields, very low sulphur (≤0.1 %) as well as a 1.1 % -1.8 % nitrogen content which is significantly lower than most algal HTL studies to date. This suggests that stationary stage algae are more difficult to process but give a cleaner biocrude and reduce the loss of nitrogen through incorporation in the oil. Significant opportunities for optimisation still exist in the HTL process.
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Hiatt, Michael John. "Synergetic Algal Infrastructure: Investigating the Benefits of Algae Production in an Airport Environment". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366241697.
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Shellcock, Carole. "Molecular aspects of algal biofuels". Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=217886.
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The ability of micro–algae to respond to diverse and often rapidly changing habitats has been attributed to the versatility of their cellular lipids. Amongst these the energy rich triacylglycerols (TAG) have attracted considerable attention due to their potential use as feedstock for renewable biofuel. Although micro-algae have considerable advantages over other biofuel sources there are constraints to their utilisation. Improvements are required in certain areas including efficiencies in production and enhanced lipid yields if micro-algal biofuels are to become commercially feasible. To achieve this, genetic and metabolic manipulation will be essential and therefore a greater understanding of the lipid biosynthetic pathways is required. In this study the expression of genes putatively involved in TAG biosynthesis in the diatom Phaeodactylum tricornutum was investigated, for the first time, with CO2 supplementation and low pH stress over the entire growth cycle. This molecular analysis was combined with physiochemical examination of the lipid accumulation in the micro-algal model. The results indicated that TAG accumulation was enhanced by CO2 supplementation and occurred predominantly during the stationary growth phase. The molecular analysis revealed increased expression for three genes of interest, encoding enzymes involved in the acyl dependent pathway: Glycerol-3-phosphate acyl transferase (GPAT) -7198728 (Phatrdraft_50031), lysophosphatidic acyl transferase (LPAAT) -7196550 (Phatrdraft_42446) and phosphotidic acid phosphatase (PAP) -7195747 (Phatrdraft_40261) in cultures supplemented with CO2. Under the same conditions up-regulation of a gene involved in the first committed step of fatty acid biosynthesis, Acetyl CoA carboxylase (ACC) -7194806 (Phatrdraft_54926) was also observed. Overall, this study provides further insight on the specific genes linked with increased TAG production in P. tricornutum and the identification of references genes suitable for normalisation of qPCR data across the growth cycle and under CO2 supplementation, thus providing the tools needed for future molecular studies of P. tricornutum lipid production.
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Affandy, Gabriel, Donald Bridges, Quinn Daniels, Drew Janicek, Julia Martin, Edward Poling, Jordan Schmalz et al. "HAWAII ALGAL BIOFUEL". Monterey, California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/32891.
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This report investigates the feasibility and affordability of producing algae-derived biofuel in Hawaii for military aviation. The authors evaluated methods for cultivation of algae, investigated the processes necessary to locally refine bio-oil into bio-kerosene, researched the environmental impacts of cultivation and refinement facilities in Hawaii, and studied the resultant cost per gallon of bio-kerosene production. Based on the current state of technology and the proposed system of systems architecture, this report estimates that bio-kerosene can be produced for $8.00 - 22.87/gal, indicating that although this system is technically feasible, it is unlikely to be affordable at current fuel prices without ongoing subsidy or further technical innovation.
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Patel, Bhavish. "Wet algae processing for biofuel production". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/62984.
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Microalgae is seen as a sustainable source of chemicals and biofuels, but its processing to low value fuels is expensive, particularly due to drying, and thus the feasibility of a wet processing route is necessary. This thesis presents experimental research and life cycle assessment on the conversion of microalgal biomass to liquid biofuel (precursor) using high temperature and pressure processing technologies. The bulk of the work is related to Hydrothermal Liquefaction of algal biomass at various residence time (0.5 - 60 min) and temperatures within the Hydrothermal regime (275 - 380°C), using both batch and novel in-house built continuous flow reactor systems. Several analytical tools were deployed to assist with analysis of the formed biocrude to help understand the effect of the reaction conditions on the formed products. Having analysed the biocrude, it became apparent that the aqueous phase contained substantial matter and as such an investigation to quantitate the inorganics in the aqueous phase was conducted. As for the biocrude, detailed analysis showed that further treatment was necessary to make it amenable for utility directly or as a blended fuel and thus, Hydrotreatment using commercially available catalyst under H2 in a batch reactor was conducted. Lastly, the conversion of algal lipids to biodiesel as well as other constituents was investigated under Hydrothermal conditions in presence of methanol, leading to in situ Supercritical Transesterification. The reaction conditions used were found to be too severe for stable yield of methyl esters and consequently degradation kinetics of methyl esters was calculated. Lastly, to understand the environmental profile of the investigated processes, a life cycle assessment was conducted based on experimental data combined with literature values for a conceptual biorefinery in 5 different countries with differing energy mixture. The thesis ends with concluding remarks on the investigation and potential direction for future work.
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Balch, Brian Palmer. "Industrial Transesterification of Cultivated Algae for Biofuel". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/612548.
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The objective of our design was to create a chemical plant that uses cultivated algae grown on site in order to produce a biofuel as an alternative energy source. Currently there is a push for sustainable energy sources and biologically produced fuels are attractive due to their near net-zero carbon emissions. Algae provides a valuable source of energy due to its growth rate and sustainability. Chemical engineering principles were utilized in design; a supercritical carbon dioxide extractor for the triglycerides in the algae cells, base catalyzed transesterification reaction in continuously stirred reactors in series and separation processes at the end in order to produce a high grade biofuel for consumer applications. Emphasis on environmental consideration also went into the design, such as the use of carbon dioxide for both the growth of the algae and solid extraction process and methanol used for the transesterification and liquid extraction, allowing for easy recycle and further reducing the environmental footprint the product fuel will have.
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LaRue, Kate, Brian Balch, Chris Jabczynski y Connor Swensen. "INDUSTRIAL TRANSESTERIFICATION OF CULTIVATED ALGAE FOR BIOFUEL". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613238.
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Foltz, Garrett. "Algae Lysis with Pulsed Electric Fields". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/732.
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With growing interest in alternative fuels, algae lipid harvesting is seen as a possible source of biofuel. Algae species under consideration include Chlorella vulgaris, Chlamydomonas reinhardtii and Dunaliella salina due to lipid contents as high as 30% to 56% of their dry weight (depending on growth conditions) and availability [5], [6]. In order to harvest lipids from algae, the cells must first be lysed.
Lysing is achieved by breaking the algal cell wall or membrane to separate oil from the rest of the algae biomass. Current lysing procedures use enzymes, pressure homogenization, and/or sonication to lyse cells; however, these methods are costly and complicate oil extraction [9], [10].
This project examines a novel method of cell lysis through pulsed electric field (PEF) application that enables cost-effective extraction methods relative to current enzyme and sonication techniques.
A theoretical model for cell membrane potential in the presence of electric field was developed, and PEF chambers were manufactured on microscope slides to enable microscope viewing and cell lysis recording during PEF application. Additionally, larger static chambers were created for testing higher volumes of algal solution. Electric field characteristics, such as pulse width, pulse number and magnitude, sufficient for lysis of Dunaliella salina and Chlorella vulgaris were found.
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Almutairi, Adel. "Production of biofuels from the green alga Tetraselmis". Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/10720/.
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The research described in thesis deals with the production of biofuels and fine chemicals from the green alga Tetraselmis suecica. Firstly, the identity of the strain received from the culture collection was confirmed using molecular techniques (18S rDNA sequencing) and electron microscopy. Secondly, a fully defined artificial seawater medium was developed to grow T. suecica and then the tolerance of this alga to salinity and pH changes was established. The neutral lipid (triacylglycerol) production was measured using Nile Red dye after stressing T. suecica cells with high salinity (up to 1 M NaCl) and pH values (pH 7 to 9). It was established that high salinity and high pH values tended to induce higher levels of triacylglycerol in the algal cells. Then fatty acid profiles of T. suecica cells were analyzed by gas chromatography–mass spectrometry (GC-MS) after direct transesterification with hydrochloric acid in methanol. Higher salinity grown cells showed higher levels of monounsaturated fatty acids, which are ideal for biodiesel production. The possibility of growing T. suecica on a larger scale was investigated using a 2 L airlift photobioreactor and the response to higher levels of CO2 was assessed in the airlift bioreactor. The effect of reusing the medium on the growth of T. suecica was examined with the aim of developing anintegrated algal biorefinery process using T. suecica as the feedstock.
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Mokebo, Kirsty R. "Ultrahigh productivity photobioreactors for algal biofuel production". Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589640.
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Algal biodiesel is a biodegradable and sustainable alternative to traditional petroleum fuels. Algal biodiesel is synthesised from algal lipids via transesterification and has many desirable physical properties for fuel use. Current photobioreactors are inefficient. This thesis looks to increase efficiency and reduce energetic running costs. This was undertaken by the design, construction and trialling of an LED photobioreactor. The controlled growth of the algae, specifically Chlorella emersonii, using pulsed monochromatic or bi-chromatic light conditions with comparison to continuous white light to improve light economy is explored in this thesis. The prediction of biodiesel profile from the growth conditions is also investigated for Chlorella emersonii. Chapter 1 is a general introduction to the area of algal biodiesel. This introductory chapter reviews the current literature regarding microalgae growth conditions and control, processing microalgae to produce biodiesel and photobioreactor designs for the controlled growth of algae. The known effects of different light sources and types on algal growth are also reviewed. Chapter 2 concerns the pulsing-LED vertical airlift photobioreactor design, construction and testing, including an overview of the system constructed and the process of design to combat specific issues. Results from the testing of the photobioreactor are reported in this chapter which include analysis of the resultant fatty acid methyl ester (FAME) profile of algae grown under various pulsed mono-chromatic and bi-chromatic light conditions and the comparison to continuous white light. This chapter draws together the hypotheses and stand-alone observations reported in the current literature allowing direct comparisons for different light conditions and conclusions to be reported which include the effect on resultant FAME profile and not just lipid percentage. Chapter 3 explores the effect of environmental factors on the fatty acid methyl ester composition of the algal biodiesel. This chapter describes the effect of carbon dioxide, nitrate, phosphate and iron levels, length of culture and the effect of supplementary carbon sources on Chlorella emersonii growth and resultant FAME composition. The result of synergetic effects of nutrient levels and length of algal cultivation are analysed in addition to the stage of algal growth and its impact on FAME profile. Chapter 4 details the procedures used for the growth of algae, the production of the algal biodiesel and the development of techniques used for analysis of the resultant biodiesel. The techniques and conditions employed for the growth of the algae as well as the extraction and transesterification of the algal lipids are explained.
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Uttley, P. J. "Integration of biological wastewater treatment and algal growth for biofuels". Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6393/.
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This thesis is concerned with the production of biofuels from microalgae that can be grown in wastewater on marginal land. Algal-derived biodiesel is a promising alternative to both the finite reserves of fossil fuels and also the current biofuel crops that take up agricultural land. The case for coupling biological wastewater treatment to the production of algal biodiesel is a compelling one that is explored in this research using a combination of mathematical modelling and laboratory experiments. Algae utilise by-products of the wastewater treatment process such as carbon dioxide, nitrate and ammonia. In this work, a mathematical model of an integrated wastewater treatment and algal cultivation system is presented. The model contains two units: an activated sludge unit for secondary wastewater treatment and a pond for the cultivation of algae. These units have both liquid phase and gas phase integration. For the liquid phase, the treated effluent from the activated sludge unit is transferred to the algal pond to provide nutrients for algal growth. The model also incorporates gas-phase integration whereby the CO2 rich off-gas from the activated sludge unit is captured and used to enhance the algal growth. In addition, the O2 enriched off-gas from the algal pond is recycled back to improve dissolved oxygen levels in the activated sludge unit. The mathematical model uses equations for algal growth that were developed using laboratory experiments to measure the effect of dissolved CO2, nitrate and ammonia on the growth kinetics of a typical strain of freshwater alga: Chlorella sp. The model includes the industry standard Activated Sludge Model No. 3 for wastewater treatment. An economic profit function is used in the model to find the optimal pattern of gas phase integration to maximise Net Present Value over a specified project lifetime. For the case considered, the model predicts that integration using the gas and liquid exchange described above is necessary for a profitable outcome. This is a general approach that can be used to retrofit biofuel production onto an existing wastewater site, or design a new integrated system from first principles.
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Archbold, Brad. "Using algae to capture CO₂ and as a feedstock for biofuel". Online pdf file accessible through the World Wide Web, 2007. http://archives.evergreen.edu/masterstheses/Accession86-10MES/Archbold_%20B%20MESThesis%202007.pdf.
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Venkatagiri, Avinash. "Materials and Methods for Algae Preconcentration". Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1406313094.
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Wyss, Sarah Christine. "Design of a Cross-Domain Quorum Sensing Pathway for Algae Biofuel Applications". Ohio University Honors Tutorial College / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1367239424.
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Kazamia, Elena. "Synthetic ecology : a way forward for sustainable algal biofuel production". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607904.
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Barnard, Anro. "Extraction of oil from algae for biofuel production by thermochemical liquefaction / Anro Barnard". Thesis, North-West University, 2009. http://hdl.handle.net/10394/3979.
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The extraction of oil from microalgae was investigated. The study focused on the
hydrothermal liquefaction of the microalgae Microcystis aeruginosa, Cyclotella
meneghinia and Nitzschia pusilla. M. aeruginosa was collected from the
Hartebeespoort dam, while C. meneghinia and N. pusilla were cultured in the
laboratory.
The experiments were conducted in a high pressure autoclave with an inert
atmosphere. Sodium carbonate was studied as a potential catalyst. The
hydrothermal liquefaction of M. aeruginosa, C. meneghinia and N. pusilla was carried
out at various reaction temperatures and catalyst loads. For the liquefaction of M.
aeruginosa the residence times were also varied. The reaction temperatures ranged
from 260 to 340 °C, while the catalyst loads varied between 0 and 10 wt% Na2CO3.
The residence time was varied between 15 and 45 minutes.
The study showed that hydrothermal liquefaction of M. aeruginosa produced a
maximum oil yield of 15.60 wt% at 300 °C, whereas the thermochemical liquefaction
of C. meneghinia and N. pusilla produced maximum yields of 16.03 wt% and 15.33
wt%, respectively, at 340 °C. The residence time did not influence thermochemical
liquefaction of the algae, while an increase in the catalyst load reduced the oil yield.
The reaction conditions had no effect on the elemental composition or the calorific
value of the thermochemical liquefaction oil. The calorific value of the hydrothermal
liquefaction oils ranged from 28.57 to 35.90 MJ.kg
-1
.
Hydrothermal liquefaction of microalgae produced oil that can be used as substitute
for coal in simple gasification processes. The study showed that microalgal blooms,
such as the M. aeruginosa blooms of the Hartebeespoort dam, can be used for the
extraction of oil through hydrothermal liquefaction.Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2010.
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Kerns, Kristen, Hopkins, Kevin Neaves, Jonathan Hopkins, Patrick Knowles, Michael Lisella, Judith Young y Joseph Villucci. "ALGAE-BASED BIOFUEL DISTRIBUTION SYSTEM TO SERVICE THE DEPARTMENT OF DEFENSE IN HAWAII". Monterey, California. Naval Postgraduate School, 2013. http://hdl.handle.net/10945/32893.
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The most effective distribution system, capable of delivering 42.9 million gallons of biofuel annually to the Department of Defense aviation assets in the state of Hawaii, consists of the combination of pipeline and trucks. A tailored system engineering process using Analytical Hierarchy Process assessed stakeholders requirements into quantifiable metrics, and used CORE to develop a functional architecture to trace these needs. The modeling software ExtendSim was used to simulate various alternatives of a distribution system comprised of pipeline and/or trucks to deliver a required capacity of the pre-mixed biofuel blend. Environmental risks of the system were assessed, and a Master Logic Diagram was used to identify ways to manage risk. Based on this analysis the capabilities and benefits of this combination system outweigh the potential risks associated with its operation. An analysis of alternatives confirmed that in terms of performance and cost, the most efficient distribution system takes part in two stages. First is the transportation of biofuel from the refinery to the Red Hill Storage Facility via the pipeline that is currently in place. From this point, trucks load the biofuel at the pumping station to continue delivery to the customers.
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Ghasemi, Nodooshan Keivan. "A Multi-Objective Robust Algal Biofuel Supply Chain Under Uncertainty". Thesis, Northern Illinois University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10603441.
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Energy has historically been of great importance to the world. Depletion of fossil fuels, growing demand, global warming, and etc. have even accentuated this importance more. Amongst the biomass for production of biofuel which is one of the most promising renewable energy options, algae have been gaining a lot of attention in recent years. This thesis will propose a Biofuel Supply Chain Network Design for the development of algal biofuels. In order to do so, a Mixed Integer Linear Program will be created to design and optimize a biofuel supply chain from raw material procurement to biofuel distribution. Furthermore, a robust optimization method will be utilized to enable the model to cope with uncertainties of the biofuel supply chain. In addition, an environmental objective would be considered alongside an economic objective both of which are optimized by augmented &egr;-Constraint method to address issues such as global warming.
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Johnson, Daniel. "Investigation of the Physiology of Hydrogen Production in the Green Alga Chlamydomonas reinhardtii Using Spectral-Selective Photosystem I Light". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311581.
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With increasing global populations and demand for energy, greater strain is placed on the limited supply of fossil derived fuels, which in turn drives the need for development of alternative energy sources. The discovery of biophotolysis in Chlamydomonas reinhardtii and the development of a spectral-selective photosystem I activating/photosystem II deactivating light (PSI-light) method provides a promising platform for commercial hydrogen production systems. The PSI-light method allows electrons to pass through the photosynthetic electron transport chain while reducing radiation available for photosynthetic oxygen evolution that inactivates hydrogenase. Exploring the physiology of photohydrogen production using the PSI-light method can provide insight on how to optimize conditions for maximum hydrogen production. Through the use of photosynthetic mutant strains of C. reinhardtii, it was possible to suppress photosynthetic oxygen evolution further than using photosystem I light alone to extend photohydrogen production longevity and total yield. A preliminary investigation of an iterating light treatment revealed that longevity and yield could be increased further by providing a period of darkness to allow cells to consume evolved oxygen and resynthesize hydrogenase. Work with these mutants provided understanding that a balance of radiation was required to provide electrons to hydrogenase while limiting oxygen evolution, and that when no light was provided, fermentation of stored starch was the major contributor of electrons to hydrogen production. To determine the role of starch during hydrogen production, wild type cells were exposed to different media and light treatments and monitored for starch consumption and hydrogen production. The results indicated that starch was required for hydrogen production in the dark, but for photohydrogen production, starch likely played a minor role in contributing electrons to hydrogenase. The experiments also showed the importance of acetate in the medium during the hydrogen production phase to allow any significant photohydrogen production. The role of acetate was further investigated as a growth medium constituent that stimulates metabolic activity while reducing photosynthetic oxygen evolution when added to cells grown auto- or mixotrophically. By exposing cells to CO₂ during growth, photohydrogen production was significantly increased over cells grown only in the presence of acetate.
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Wissinger, Joshua Clinton. "Hydrothermal Treatment of Algal Feedstocks". University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1370954774.
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CARVALHO, VICTOR CABRAL DA HORA A. DE. "EVALUATION OF THE IMPLEMENTATION OF A BIOFUEL PRODUCING ALGAE FARM IN AN ETHANOL PLANT". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=35665@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCom a crescente demanda – nacional e internacional – por biocombustíveis e a pressão internacional para redução da emissão de gases de efeito estufa, o Brasil teria muito a ganhar, do ponto de vista econômico e ambiental, com um aumento na eficiência e oferta de biocombustíveis. O advento da produção de biocombustíveis produzidos em fazendas de alga possibilita uma relação de simbiose com usinas de cana-de-açúcar. Tais algas se alimentam, entre outras substâncias, de dióxido de carbono, e a abundante biomassa de cana queimada em caldeiras, aliada à incidência solar privilegiada no Brasil, fazem da utilização de algas em usinas de cana uma possibilidade de conversão de emissões de gás de efeito estufa em biocombustível. Essa dissertação tem como objetivo estimar o resultado da implantação de uma fazenda de algas em uma usina de cana-de-açúcar. A usina em questão sofreu vistoria e fez-se o levantamento da produção de energia renovável e as emissões atmosféricas dos principais gases de efeito estufa (CH4, N2O e CO2), através da metodologia de Avaliação de Ciclo de Vida (ACV). A meta, a partir desta análise e com o uso de dados primário de uma empresa que instala fazendas de alga, é estimar o acréscimo de biocombustível gerado por algas e o decréscimo das emissões de GEE no processo produtivo. Os resultados obtidos na Usina Estudada mostram que caso a mesma implantasse uma fazenda de algas em seu parque industrial, sua eficiência energética na produção de energia através do etanol quase triplicaria ao passo em que emitiria quatro vezes menos poluentes em sua cadeia de produção. Caso a usina optasse por gerar exclusivamente Biodiesel, produziria Biodiesel (B100) para 19 anos de subsistência com um combustível 78,4 por cento menos poluente em termos de GEE. Aproximações mostram que caso a totalidade da lavoura de cana implante fazendas de algas no Brasil, apenas o Biodiesel gerado neste processo seria equivalente à quase 70 por cento da produção Brasileira de diesel de 2012.
With the demand for Biofuels growing – in Brazil and abroad – and with worldwide efforts to reduce greenhouse gas (GHG) emissions, Brazil would have much to gain, from an environmental and economic point of view, from increasing the efficiency and offer of biofuels. The advent of biofuels produced in algae farms enabled a symbiotic relationship with ethanol plants. Such algae feeds off, among other things, Carbon Dioxide, and the abundant biomass burned in ethanol plants boilers, along with Brazil s privileged solar incidence, and this regime permits such farms to convert GHG to biofuel. The objective of this study was to investigate an ethanol plant as a productive system to understand how the addition of an algae farm could change the status quo of energy efficiency and emission of pollutant gases. The system analyzed includes the sugarcane sowing, the plantation handling, the harvesting, the industrial activities, and the Ethanol distribution. The goal, from this analysis and using primary data from a company that installs algae farms, is to estimate the increase of biofuel generated by algae and decrease GHG emissions in the production process. The results obtained in Plant Studied show that an algae farm in its industrial grounds would better its energy efficiency in almost threefold, while generating four times less atmospheric pollution in their production chain. If the plant chose to produce exclusively Biodiesel, production of B100 Biodiesel would be enough for the industry s diesel needs for 19 years, with a 78.4 percent cleaner fuel in terms of GHG emissions. Approximations show that if all the sugar cane fields implant algae farms in Brazil, the Biodiesel generated in this process would be equivalent to almost 70 percent of the Brazilian production of diesel from 2012.
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Voleti, Ram Sudheer. "Experimental Studies of Vertical Mixing in an Open Channel Raceway for Algae Biofuel Production". DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1307.
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Turbulent mixing plays an important role in the distribution of sunlight, carbon dioxide, and nutrients for algae in the raceway ponds. For large-scale raceway ponds the choice of mixing technology still needs to be evaluated in order to prevent algae sedimentation and to enhance light utilization efficiency. In open ponds, mixing the algae culture is of great significance in terms of input energy costs and particularly productivity. A very small amount of research has been performed previously using different vortex generators in the algal raceway ponds, but the quantification of mixing depth relationships is not defined well. By accepting the premise from the literature review that mixing increases algal production, delta wings were selected to study mixing characteristics in the raceway. The main objective of this research was to study algae-raceway hydrodynamics with an emphasis on increasing vertical mixing. A clear acrylic raceway was designed and constructed for flow visualization studies. Experimental investigations were performed to quantify the vertical mixing with and without delta wings in a lab-scale raceway at approximately the same power input to the paddle wheel. Velocity vector profiles and turbulence parameters were measured using an Acoustic Doppler Velocimeter (ADV) at various locations along the entire length of the raceway. The results indicated that the addition of delta wings increases the vertical mixing intensity or circulation of algae cells over the raceway depth. Vortices were observed in the raceway up to a distance of around 3 m downstream of the delta wing. This sort of systematic vertical mixing plays an important role to produce the flashing light effect (light-dark cycles) on algae mass culture. In addition, turbulence dissipation rates were evaluated to compare them with the published literature and to estimate the microscales using the Kolmogorov hypothesis. Also, an energy model was developed to operate the paddlewheel-driven raceway with the delta wing.
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Almohsen, Jasem Saleh H. "Isolation and characterisation of halotolerant bacteria and algae and their potential for biofuel production". Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6406/.
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The first aim of the project was to isolate, identify and characterize salt tolerant bacteria from river and pond water. This aim was achieved by the isolation of the salt tolerant bacterium Enterococcus amnigenus from water samples taken from Weston Park pond and by the isolation of the salt tolerant bacterium Pseudomonas fluorescens from a dew pond in the Derbyshire Peak District. E. amnigenus in common with many enterococci, is a potential pathogen, but it also has uses in industry as a producer of bacterial cellulose. P. fluorescens is a ubiquitous organism found in marine and soil environments and has been well characterized as an important biofilm-forming organism and as a rhizobacterium. The second aim of the project was to isolate salt-tolerant microalgae from the fresh water Weston Park pond and this was successfully achieved by isolating and identifying two algal species - the diatom Navicula pelliculosa and the green alga Chlorella sp. Initial work measuring total lipid concentrations suggested that Navicula was the most promising organism for biofuel production due to having a total lipid concentration of around 20%. Further characterization of Navicula was undertaken to investigate its suitability for biofuel production. It was shown to grow under conditions of high pH and high salinity, making it a candidate species for growth in outdoor raceway ponds. Experiments using Nile Red fluorescence to measure neutral lipid production indicated that stress conditions (high salinity or high pH) could increase the neutral lipid accumulation by Navicula cells. To grow in high salinity (up to 0.8 M NaCl), Navicula cells must balance the external osmotic potential by accumulating a compatible solute within the cells. NMR analysis showed that the compatible solute accumulated by Navicula is glucosylglycerol, which is not normally found in diatoms.
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Nguyen, Thi Hong Minh y Van Hanh Vu. "Bioethanol production from marine algae biomass: prospect and troubles". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-99282.
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The increase of petroleum cost as well as global warming and climate change result in investigation to discover new renewable energy resources. Bioenergy is one of the most important sources that is concerning the scientists and industrial sector. Although bioethanol had to be known as one of the most important renewable energy sources in order to reduce greenhouse gases and global warming, there is a limited number of publications reporting on them. In this review, a brief overview is offered about bioethanol production from algae. It can be given a deeper insight in dificulties and promising potential of bioethanol from algaeSự gia tăng giá nhiên liệu hóa thạch cùng với cảnh báo toàn cầu về biến đổi khí hậu hướng đến việc nghiên cứu tìm ra những nguồn năng lượng có thể tái tạo. Năng lượng sinh học là một trong những nguồn quan trọng được các nhà khoa học và doanh nghiệp quan tâm. Mặc dù ethanol sinh học đã được biết đến như là một trong những dạng năng lượng tái tạo quan trọng nhất để giảm thiểu các khí nhà kính và cảnh báo toàn cầu, nhưng chỉ có một số ít bài báo về nó. Trong bài tổng quan này, chúng tôi giới thiệu vắn tắt việc sản xuất ethanol sinh học từ tảo. Nó đưa ra cái nhìn sâu hơn về những khó khăn và tiềm năng hứa hẹn của sản xuất ethanol sinh học từ tảo
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Cormier, Ivy. "A STELLA Model for Integrated Algal Biofuel Production and Wastewater Treatment". Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3562.
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Based on a municipal wastewater treatment plant (WWTP) in Tampa, FL, a dynamic multiple-systems model was developed on the STELLA software platform to explore algae biomass production in wastewater by incorporating two photobioreactors into the WWTP‟s treatment train. Using a mass balance approach, the model examined the synergy through algal growth and substrate removal kinetics, as well as macroeconomic-level analyses of algal biomass conversion to biodiesel, biogas, or fertilizer. A sensitivity analysis showed that biomass production is highly dependent on Monod variables and harvesting regime, and profitability was sensitive to processing costs, market prices of products, and energy environment. The model demonstrated that adequate nutrients and carbon dioxide are available in the plant‟s influent to sustain algal growth. Biogas and fertilizer production were found to be profitable, but biodiesel was not, due to high processing costs under current technologies. Useful in determining the growth potential on a macro-level, the model is a tool for identifying focus areas for bench and pilot scale testing.
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Milledge, J. J. "Energy balance and techno-economic assessment of algal biofuel production systems". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/357074/.
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There has been considerable discussion in recent years about the potential of micro-algae for the production of sustainable and renewable biofuels. Unfortunately the scientific studies are accompanied by a multitude of semi-technical and commercial literature in which the claims made are difficult to substantiate or validate on the basis of theoretical considerations. To determine whether biofuel from micro-algae is a viable source of renewable energy three questions must be answered : a. How much energy can be produced by the micro-algae? b. How much energy is used in the production of micro-algae? c. Is more energy produced than used? A simple approach has been developed that allows calculation of maximum theoretical dry algal biomass and oil yields which can be used to counter some of the extreme yield values suggested in the 'grey' literature. No ready made platform was found that was capable of producing an energy balance model for micro-algal biofuel. A mechanistic energy balance model was successfully developed for the production of biogas from the anaerobic digestion of micro-algal biomass from raceways. Preliminary calculations had suggested this was the most promising approach. The energy balance model was used to consider the energetic viability of a number of production scenarios, and to identify the most critical parameters affecting net energy production. These were: a. Favourable climatic conditions. The production of micro-algal biofuel in UK would be energetically challenging at best. b. Achievement of ‘reasonable yields’ equivalent to ~3 % photosynthetic efficiency (25 g m-2 day-1) c. Low or no cost and embodied energy sources of CO2 and nutrients from flue gas and wastewater d. Mesophilic rather than thermophilic digestion e. Adequate conversion of the organic carbon to biogas (≥ 60 %) f. A low dose and low embodied energy organic flocculant that is readily digested, or micro-algal communities that settle readily g. Additional concentration after flocculation or sedimentation h. Exploitation of the heat produced from parasitic combustion of micro-algal biogas in CHP units i. Minimisation of pumping of dilute micro-algal suspension It was concluded that the production of only biodiesel from micro-algae is not economically or energetically viable using current commercial technology, however, the production of micro-algal biogas is energetically viable, but is dependent on the exploitation of the heat generated by the combustion of biogas in combined heat and power units to show a positive balance. Two novel concepts are briefly examined and proposed for further research: a. The co-production of Dunaliella in open pan salt pans. b. A 'Horizontal biorefinery' where micro-algae species and useful products vary with salt concentration driven by solar evaporation.
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Neto, Antonio Alves da Silva. "Alga marinha vermelha Hypnea musciformis (wulfen) como fonte potencial de carboidratos para a produÃÃo de etanol". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10625.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorAlta demanda de energia e mudanÃas climÃticas globais tÃm gerado interesse dos governantes mundiais para investir em pesquisas de fontes alternativas e renovÃveis de combustÃveis. Nessa perspectiva, as macroalgas vÃm ganhando ampla atenÃÃo por parte de pesquisadores do mundo inteiro como fonte alternativa renovÃvel de biomassa para a produÃÃo de bioetanol, o qual à denominado atualmente de combustÃvel de âterceira geraÃÃoâ. A utilizaÃÃo das algas marinhas como matÃria-prima para produÃÃo de bioetanol apresenta vantagens, tais como (1) nÃo competiÃÃo com a produÃÃo de alimentos, (2) alto conteÃdo de carboidratos, (3) baixo conteÃdo de lignina e (4) alta produtividade. O potencial da alga marinha vermelha Hypnea musciformis em fornecer carboidratos fermentescÃveis para a produÃÃo de bioetanol foi avaliado no presente trabalho. A alga foi obtida de cultivo comercial, localizado na praia de Flecheiras, municÃpio de Trairi, Cearà e apÃs lavagem, secagem e trituraÃÃo, 5 g foram adicionados a 100 mL de HCl (0,2; 0,5 e 1,0 M) em erlenmeyers, autoclavados a 121 ÂC (10, 20 e 30 min). Foi observada a presenÃa de galactose (7,4 â 10,8 g.L-1) e glucose (3,4 â 4,7 g.L-1) em todos os hidrolisados e a condiÃÃo de hidrÃlise 0,5/20, apresentando uma concentraÃÃo de glicose + galactose de 14,8 g.L-1, foi selecionada para os ensaios de fermentaÃÃo dos monossacarÃdeos por Saccharomyces cerevisiae a 30ÂC. Os resultados mostraram que a glicose e a galactose, foram consumidas simultaneamente, no entanto esse consumo sà foi iniciado apÃs 7 h de fermentaÃÃo e apÃs 52 h, 82,5 % da glicose e 72% da galactose tinham sido consumidas, com uma produÃÃo mÃxima de 5,3 g.L-1 de bioetanol, representando uma eficiÃncia fermentativa de 50% do teÃrico e evidenciando a habilidade da S. cerevisiae em fermentar a galactose proveniente de matÃria-prima algÃcea com um rendimento de 0,1 g de bioetanol/g de alga seca. Observou-se, na condiÃÃo de hidrÃlise selecionada, uma maior velocidade especÃfica de consumo de substrato acompanhado da velocidade de produÃÃo de etanol. Os rendimentos de etanol baseados no consumo de substrato (glucose + galactose) e biomassa foram 0,315 e 0,08 (g/g), respectivamente. As produtividades de biomassa e etanol foram 0,008 g.L-1.h-1 e 0,100 g.L-1.h-1, respectivamente. Com os dados obtidos pode-se concluir que a alga marinha H. musciformis se mostrou uma potencial fonte renovÃvel de biomassa para a produÃÃo de etanol. No entanto, sÃo necessÃrios mais estudos para otimizar o processo produtivo de bioetanol a partir desses organismos.
High energy demand and global climate changes have generated interest in world leaders to invest in research on alternative and renewable fuels. In this perspective, the macroalgae are gaining wide attention from researchers around the world as an alternative source of renewable biomass for bioethanol production, which is currently called fuel "third generation". The use of seaweed as a feedstock for bioethanol production has advantages such as (1) no competition with food production, (2) high carbohydrates content, (3) low lignin content and (4) high productivity. The potential of the red seaweed Hypnea musciformis to provide fermentable carbohydrates for bioethanol production was evaluated in this study. The algae was obtained from a commercial cultivation, located on the Flecheiras beach, Trairi, Cearà and after washing, drying and grinding 5 g were added to 100 mL HCl (0.2, 0.5 and 1.0 M) in Erlenmeyer flasks, autoclaved at 121 ÂC (10, 20 and 30 min). It was observed the presence of galactose (7.4 to 10.8 g.L-1) and glucose (3.4 to 4.7 g.L-1) in all hydrolyzed and the hydrolysis condition 0.5/20, with a concentration of glucose + galactose 14.8 g.L-1, was selected for testing fermentation of monosaccharides by Saccharomyces cerevisiae at 30  C. The results showed that glucose and galactose were consumed simultaneously, however this consumption only started after 7 h of fermentation and after 52 h, 82.5% of glucose and 72% galactose had been consumed, with a maximum yield of 5.3 g.L-1 of ethanol, it represents a fermentation efficiency of 50% theory and showing the ability of S. cerevisiae ferment galactose from algal feedstock with a yield of 0.1 g ethanol/g dry seaweed. It was observed in the hydrolysis condition selected, a higher specific rate of the substrate consumption accompanied by the rate of ethanol production. The ethanol yields based on consumption of substrates (glucose + galactose) and biomass were 0.315 and 0.08 (g/g) respectively. The biomass and ethanol productivity were 0.008 g.L-1.h-1 and 0.100 g.L-1.h-1, respectively. With the date obtained it can be conclude that the red seaweed H. musciformis showed be a potential renewable source of biomass for the production of bioethanol. However, other studies are needed to optimize the production process of bioethanol from these organisms.
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Adesanya, Victoria Oluwatosin. "Investigation into the sustainability and feasibility of potential algal-based biofuel production". Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708126.
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Meï, Coline. "Etude des relations entre division cellulaire et métabolisme des triglycérides chez les plantes et les microalgues". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV043/document.
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Trouver des solutions aux carburants fossiles est un des grands challenges du XXIème siècle. Les plantes et les microalgues sont capables de produire de l’huile, facilement convertible en biodiésel. Afin d’optimiser la production de biocarburant, il est essentiel de connaitre les mécanismes cellulaires menant à la formation de ces lipides de réserve aussi appelés TAG (Triacylglycérides). En condition physiologique, le flux de lipide est naturellement orienté vers la synthèse de lipides membranaires qui permettent de créer de nouvelles membranes lors de la division cellulaire. Le manque de nutriments disponibles est une condition souvent rencontrée par les végétaux terrestres et les microalgues. Chez ces dernières, lors d’une en carence d’azote, la croissance cellulaire est ralentie et les TAG s’accumulent. Le flux de lipides, normalement orienté vers la synthèse de nouvelles membranes, est-il alors basculé vers la synthèse des lipides de réserve ? Pour vérifier cette hypothèse, une gamme de composés connus pour arrêter la croissance cellulaire a été testée sur la plante supérieure Arabidopsis thaliana selon une stratégie de génétique chimique. Quel que soit le traitement, l’inhibition de la croissance est toujours accompagnée par une augmentation de la teneur en TAG. Parmi les inhibiteurs, le méthotrexate, qui réprime l’enzyme dihydrofolate réductase impliquée dans le métabolisme C1, induit une augmentation des lipides de réserve jusqu’à 15 fois la valeur du contrôle. Ce traitement a été comparé à une carence en azote, qui dans nos conditions expérimentales, ralentie la croissance cellulaire et augmente d’un facteur 60 la teneur en TAG. L’analyse des profils lipidiques révèle que la déficience en azote engendre une diminution des classes de lipides membranaires -phospholipides et galactolipides, au profit des TAG, tandis que le traitement méthotrexate n’est pas associé à un remaniement membranaire. Néanmoins, les deux conditions partagent des similitudes, comme le taux d’insaturation des acides gras et l’expression des gènes des désaturases qui sont modifiés. La forte expression des gènes codant pour les Non Spécific Phospholipases C (NPC4/5), ainsi que des expériences de pulse-chase avec de la phosphatidylcholine (PC) marquée, ont mis en évidence que ce phospholipide est plus utilisé pour produire des TAG dans les deux traitements, qu’en condition contrôle. Afin d’évaluer plus finement l’importance des enzymes NPC4 et 5 dans le métabolisme d’accumulation des lipides de réserve, la construction de lignées mutantes d’A. thaliana (surexpresseur ou knock-out) a été amorcée. Les microalgues sont des modèles puissants pour les biocarburants de 3ème génération. Pour cette raison nous avons testé l’effet d’une déficience minérale et l’impact de différents inhibiteurs de croissance sur l’accumulation de TAG chez la microalgue Phaeodactylum tricornutum. Les résultats préliminaires suggèrent que la sensibilité aux inhibiteurs peut être différente chez les diatomées et les plantes supérieuresAlternatives to fossil fuel are one of the biggest challenges of the 21st century. Plants and microalgae are able to produce oil which is easily convertible in biodiesel. In order to optimise the biofuel production it is necessary to know the cellular mechanisms leading to the setting up of these storage lipids or TAG (Triacylglycerides). In its physiological condition, the lipid flux is naturally orientated towards the membrane lipid synthesis, which allows the creation of new membranes which occurs during the cell division. Nitrogen deficiency, a condition often encountered by plants and algae, is known to induce cell growth to slow down and an accumulation of TAG in microalgae models. Is the lipid flux, which is conventionally orientated towards new membrane synthesis, tipped over the storage lipid synthesis? To check this hypothesis, a range of compounds known to stop the cell growth was tested on the higher plant model Arabidopsis thaliana, according to a chemical genetic strategy. All treatments showed a rise of the TAG content associated to a cell growth inhibition. Among them, the methotrexate inhibit the dihydrofolate reductase enzyme involved in the C1 metabolism and induced a TAG accumulation up to 15 times the control. This treatment was compared to a nitrogen starvation condition, which in our experiments slowed down the cell growth and induced an increase of 60 times to the TAG content. The lipid profile analysis revealed that the nitrogen deficiency led to a decrease of membrane lipids -phospholipids and galactolipids, in favour to TAG, whereas the methotrexate treatment was not associated to any membrane remodelling. Nevertheless, both conditions shared similarities, as the modifications of the fatty acid insaturation profile and the expression of desaturase genes. The strong gene expression of Non Specific phospholipases C (NPC4/5) and pulse-chase experiments performed with a labelled phosphatidylcholine (PC), highlighted the predominant involvement of this phospholipid in the TAG production which occurs during the two treatments. In order to evaluate the NPC role in the storage lipid metabolism more closely, A. thaliana mutant lines for NPC4 and NPC5 (over-expressers and knock-out) were initiated. Microalgae are powerful models for the third generation of biofuels. For this reason we tested the impact of a nutrient deficiency as well as the effect of different growth inhibitors on the TAG accumulation in the marine microalgae Phaeodactylum tricornutum. Preliminary results suggested that the inhibitor sensibility can be different between diatoms and higher plants
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Steichen, Seth A. y Seth A. Steichen. "Tracking an Algal Predator: Monitoring the Dynamics of Vampirovibrio Chlorellavorus in Outdoor Culture". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/622836.
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The environmental conditions created in the Southwestern deserts of the United States are conducive to the production of green microalgae biomass, for use as a feedstock intended for conversion to carbon neutral liquid biodiesel. One promising heat-tolerant, rapidly-growing, high lipid content species is the chlorophyte, Chlorella sorokiniana (Shihira and Krauss, 1965) (isolate DOE 1412), which has been selected for pilot-scale production as part of a larger algal biofuels project to assess its potential for long-term productivity in open, outdoor monoculture production systems. Molecular analysis exposed the presence of the pathogenic bacterium, Vampirovibrio chlorellavorus (Gromov & Mamkaeva, 1972) causing infection and death of DOE 1412, which occurred most rapidly at air temperatures exceeding 34 °C. This Gram-negative bacterium has been reported to attach to and utilize the cellular contents of several Chlorella species, leading to yellowing and flocculation of algal cells, and death of the host. A quantitative PCR assay was developed to monitor pathogen accumulation using the 16S ribosomal RNA gene, in addition to the algal 18S ribosomal RNA gene for normalization. The assay is highly sensitive, with limits of quantification for the 16S and 18S gene targets calculated to be 19 and 131 copies, respectively. The qPCR assay was used to monitor several outdoor reactors inoculated with the DOE1412, throughout the warm season growth-to-harvest cycle to understand the disease cycle and inform disease management decisions. Further, the bacterium was monitored in paddlewheel DOE 1412 cultures treated with benzalkonium chloride (BAC), a biocide tested for the ability V. chlorellavorus attack of DOE 1412. The treatment resulted in a reduced growth rate for DOE 1412, but prolonged the duration of the production cycle resulting in increased total harvestable yield, compared to untreated control cultures.
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Smith-Baedorf, Holly D. "Microalgae for the biochemical conversion of CO2 and production of biodiesel". Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.564010.
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As the global population rises to an estimated 9.4bn by 2050, the pressure for food, fuel and freshwater will continue to increase. Current renewable energy technologies are not widely applicable to the transport sector, which requires energy dense liquid fuels that drop into our existing infrastructure. Algal biofuels promise significantly higher yields than plants, without the displacement of valuable agricultural resources and have the potential to meet the global demand for transport fuel. Fossil fuel energy is largely ‘a legacy of algal photosynthesis’, with algae accounting for ~50% of global CO2 fixation today. In addition, these curious organisms show remarkable diversity in form, behaviour and composition. Recently there has been a global resurgence of interest in microalgae as a resource of biomass and novel products. With the present level of technology, knowledge and experience in commercial scale aquaculture, the capital cost and energy investment for algal biomass production is high. Culturing, harvesting and disrupting microalgal cells account for the largest energy inputs with more positive energy balances requiring low energy designs for culture, dewatering and extraction, efficient water and nutrient recycling with minimal waste. Little is known about the variable cell wall of microalgae, which presents a formidable barrier to the extraction of microalgal products. Staining, transmission electron microscopy (TEM) and enzymatic digestion were all utilised in an attempt to visualise, digest and characterise the cell wall of stock strains of Chlorella spp. and Pseudochoricystis ellipsoidea. The presence of algaenan, a highly resistant biopolymer, rendered staining and enzymatic digestion techniques ineffective. TEM revealed that algaenan is present in the outer walls of microalgae in a variety of conformations which appeared to impart strength to cells. A preliminary investigation utilising Fusarium oxysporum f.sp. elaeidis as a novel source of enzymes for the digestion of algaenan has also been described. Methods were developed for the mutagenesis of Chlorella emersonii and P. ellipsoidea using EMS and UV with the intent of generating cell-wall mutants. Although no viable cell wall mutants were produced, a viable pale mutant of C. emersonii was recovered 5 from UV mutagenesis. Growth rates of the pale mutant were significantly slower than the wild type, yet FAME profile was largely unaffected. Fluorescence activated cell sorting (FACS) was also investigated as a means for the rapid screening of mutagenized cells for cell wall mutants. In an attempt to reduce cooling costs of closed-culture systems, temperature tolerant species of microalgae were sought by bioprospecting the thermal waters of the Roman Baths. Numerous methods for isolation and purification of microalgae from the Baths were employed, ultimately yielding seven diverse isolates including cyanobacterial, eukaryotic, filamentous and single celled species. Despite some species possessing an increased tolerance to higher temperatures, none showed marked temperature tolerance coupled with high productivity. Further improvements to the culture conditions may have improved the productivity at higher temperatures. All seven isolates were deposited to the Culture Collection of Algae and Protozoa (CCAP). A variety of extraction methods including soxhlet, beadbeating, sonication and microwaving was investigated for efficacy of extracting fatty acid methyl esters (FAMEs) from C. emersonii. Beadbeating proved most effective in the extraction of FAMEs from C. emersonii. Microwaving showed potential as a rapid method of extraction yet was coupled with degradation of FAMEs, requiring further method development to resolve this issue. Method development has been a significant component of the work described in this thesis.
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Eustance, Everett O'Brien. "Biofuel potential, nitrogen utilization, and growth rates of two green algae isolated from a wastewater treatment facility". Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/eustance/EustanceE0811.pdf.
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Nitrogen removal from wastewater by algae provides the additional benefit of producing lipids for biofuel and biomass for anaerobic digestion. As ammonium is the renewable form of nitrogen produced during anaerobic digestion and one of the main nitrogen sources associated with wastewater, experiments focused on the optimization of growth and lipid production when grown on ammonium were evaluated. Scenedesmus sp. 131 and Kirchneriella sp. 92 were grown in a 14:10 light/dark cycle on ammonium, nitrate or urea in the presence of 5% CO ₂ and ammonium and nitrate in the presence of air. Growth on nitrate and urea showed similar growth rates, and provided knowledge on the target growth rate for optimizing growth on ammonium. Results showed the pH decreased during exponential growth on ammonium in both 5% CO ₂ and air, causing chlorophyll degradation. Growth on nitrate and air increased the pH of the medium and produced an increase in Nile Red fluorescence and biofuel potential for strain 131, but not for strain 92. Biological buffers were implemented to counteract the change in pH to prevent growth inhibition. Cultures were grown on 5% CO ₂ or air, which showed that increased levels of CO ₂ are required for increased growth, biofuel potential, and ammonium utilization. This increased the growth rates from 0.26 d -¹ to 1.04 d -¹ for strain 131 and 0.45 d -¹ to 1.31 d -¹ for strain 92. pH-controllers using 0.1 M KOH were used in experiments with 5% CO ₂ with the understanding that buffers are limited to lab scale experiments and pH control would bridge the gap to industrial processes. The growth rate while utilizing pH-controllers showed similar growth rates to buffered experiments. Growth on nitrate, urea, and buffered ammonium with 5% CO ₂ showed an increase in the biofuel potential for strain 92 in comparison to growth with air. Strain 131 had a decrease in biofuel potential when grown on ammonium compared to growth on nitrate or urea. Both strains showed increased levels of CO ₂ is required to increase biofuel productivity.