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Teece, Mark A. "Biodegradation of algal lipids and significance for sediment studies." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239071.
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Chiodza, Kudzai Godknows. "Desulphurisation of fine coal waste tailings using algal lipids." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29892.
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The South African economy is an energy-driven economy which relies on coal to meet most of its energy demands. Coal mining has resulted in the generation of coal waste over 60 million tonnes, annually. Apart from the huge footprint of this waste, the sulphide minerals contained in the waste have resulted in the generation of acid rock drainage (ARD). A lot of techniques have been developed to prevent and mitigate ARD, however most of these techniques have fallen short in terms of meeting their desired objectives due to the long-term nature of ARD generation which can persist for hundreds of years after mine closure. This has resulted in emphasis being put on long-term prevention techniques that remove ARD risk over treatment techniques. One prevention technique which has shown good technical potential is the two-stage flotation method developed for desulphurisation of hard rock tailings and coal fines, developed at the University of Cape Town. On desulphurising coal, the first stage produces an upgraded coal product that may be sold, with the second stage used to separate the tailings from the first stage into targeted high-sulphide and low-sulphide fractions which may then be appropriately used or disposed of. An economic assessment of the process showed across a wide range of coal wastes the high cost of oleic acid used in the first stage of the process as a collector was a major contributor to the operating costs. The investigation undertaken in this thesis looked at the potential of algal lipids and their derivatives as biocollectors to replace the oleic acid collector in the desulphurisation process at the laboratory scale. A review of cost was carried out for a process that used raw algal lipids (RALs) or fatty acid methyl esters (FAMEs), which are derived from RALs through transesterification. Batch flotation experiments were used to assess the performance of the two bioflotation reagents in comparison to oleic acid and dodecane, an alternative but less successful chemical collector. The algal lipids cost review was a desktop study which was done by adapting literature data from Davis et al. (2014) which focused on economic evaluation of algal lipid biofuels production pathways. Results from laboratory experiments for two different coal waste feed samples showed that the performance of RALs and FAMEs was similar to that of oleic acid for the sample that was high in ash and sulphur, and better than oleic acid for the sample that was low in ash and sulphur. For example, the product from Site 1 discards from Waterberg had 24.37% ash and 2.76% sulphur using FAMEs, 26.13% ash and 2.56% sulphur with RALs, and 23.48% ash and 2.41% using oleic acid, at a reagent dose of 2.8 kg/t for all reagents. For Site 2 waste tailings from the Witbank area, the product had 23.17% ash and 0.72% sulphur when FAMEs were used as collector, 22.75% ash and 0.75% sulphur with RALs, and 20.18% ash and 0.74% sulphur using oleic acid, at the same reagent dose. Discards from Site 1 had an initial ash and sulphur content of 47.61% and 5.71%, respectively. Site 2 waste tailings had 25.56% ash and 0.91% sulphur before flotation. Increasing biocollector dosage resulted in higher yields with a compromise on the upgraded coal quality. The pH tests showed that the performance of the two bioflotation reagents was best at pH 4 in terms of yield. However, increasing the pH of the process from the natural pH of the sample (pH 2.7) to 7 resulted in collection of more ash and sulphur, thus reducing the product quality. The algal lipids cost review showed that RALs and FAMEs were potentially 20 to 21% cheaper than oleic acid, with more room for improvement. Both the laboratory experiments and the technical evaluation showed that algal lipids and their derivatives have the potential to replace oleic acid in the two-stage desulphurisation process for coal waste to obtain a saleable quality coal product while simultaneously decreasing the impact of ARD from coal waste.
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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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Olsen, Rebecca Lynn. "Modification of plant and yeast lipids by heterologous expression of protist, algal, and animal desaturases." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/Fall2006/r_olsen_011907.pdf.
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Johnson, Michael Ben. "Microalgal Biodiesel Production through a Novel Attached Culture System and Conversion Parameters." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/32034.
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Due to a number of factors, the biodiesel industry in the United States is surging in growth. Traditionally, oil seed crops such as soybean are used as the feedstock to create biodiesel. However, the crop production can no longer safely keep up with the demand for the growing biodiesel industry.
Using algae as a feedstock has been considered for a number of years, but it has always had limitations. These limitations were mainly due to the production methods used to grow and harvest the algae, rather than the reaction methods of creating the biodiesel, which are the same as when using traditional crops. Algae is a promising alternative to other crops for a number of reasons: it can be grown on non arable land, is not a food crop, and produces much more oil than other crops. In this project, we propose a novel attached growth method to produce the algae while recycling dairy farm wastewater using the microalga Chlorella sp.
The first part of the study provided a feasibility study as the attachment of the alga onto the supporting substrate as well as determining the pretreatment options necessary for the alga to grow on wastewater. The results showed that wastewater filtered through cheesecloth to remove large particles was feasible for production of Chlorella sp, with pure wastewater producing the highest biomass yield. Most importantly, the attached culture system largely exceeded suspended culture systems as a potentially feasible and practical method to produce microalgae. The algae grew quickly and were able to produce more than 3.2 g/m2-day with lipid contents of about 9% dry weight, while treating dairy farm wastewater and removing upwards of 90% of the total phosphorus and 79% of the nitrogen contained within the wastewater.
Once the â proof-of-conceptâ work was completed, we investigated the effects of repeat harvests and intervals on the biomass and lipid production of the microalgae. The alga, once established, was harvested every 6, 10, or 15 days, with the remaining algae on the substrate material functioning as inoculums for repeated growth. Using this method, a single alga colony produced biomass and lipids for well over six months time in a laboratory setting.
The second part of this study investigated another aspect of biodiesel production from algae. Rather than focus solely on biomass production, we looked into biodiesel creation methods as well. Biodiesel is created through a chemical reaction known as transesterification, alcoholysis, or commonly, methylation, when methanol is the alcohol used. There are several different transesterification methods. By simplifying the reaction conditions and examining the effects in terms of maximum fatty acid methyl esters (FAME) produced, we were able to determine that a direct transesterification with chloroform solvent was more effective than the traditional extraction-transesterification method first popularized by Bligh & Dyer in 1959 and widely used. This synergistic research helps to create a more complete picture of where algal biodiesel research and development is going in the future.<br>Master of Science
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Clemente, Ilaria. "Compartmentalized algal-based nanocarriers as vectors for antioxidants: structural and functional characterization." Doctoral thesis, Università di Siena, 2022. http://hdl.handle.net/11365/1193669.
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The delivery of poorly water-soluble natural drugs is a longtime challenge that has led to the development of several solubilizing and encapsulating carrier systems, to administrate hydrophobic molecules for biomedical, pharmaceutical, food and cosmetics applications. Among the most popular soft matter nanocarriers, lipid-based vectors are particularly favored thanks to the advantageous properties of lipids used as versatile and biocompatible building blocks. Indeed, lipids are the class of bio-macromolecules with the richest polymorphism and spontaneous self-assembly character, that result in a broad variety of hierarchical structures. Several aggregates with various interfacial curvatures and symmetries can be obtained, mainly depending on the lipid class and packing parameter, and they can be differentiated in lamellar and nonlamellar mesophases. Lamellar aggregates are characterized by the presence of one or multiple bilayers which possess vesicular morphology at larger scale (um). Nonlamellar mesophases with exotic symmetries, such as cubic and hexagonal, are lyotropic liquid crystalline systems with specific inner ordering, and among the most interesting nonlamellar structures are the bicontinuous cubic phases. When these systems are in excess water conditions, dispersed nanosystems are obtained and termed liposomes and cubosomes, respectively. The versatility and biodegradability of these nanosystems makes them particularly suitable as carriers for orally administered drugs. Moreover, lipids to be used for formulation development can be obtained from a variety of natural sources and biomasses, to obtain nanovectors for bioactive molecules with high carrier-cargo and carrier-target compatibility. In this thesis work, lipid nanovectors were designed and prepared as biocompatible and biodegradable drug carriers for a commercially valuable antioxidant drug i. e. curcumin, whose therapeutic application is typically hindered by its poor water solubility, that was chosen as the designated natural antioxidant of interest for this investigation. Two other antioxidants i. e. α-tocopherol and piperine were used as adjuvants for curcumin since they are known to facilitate incorporation and co-administration by acting synergistically as bio-enhancers. These three antioxidants were then encapsulated in newly formulated lipid nanocarriers to improve their biodistribution and bioavailability. The design strategy adopted for these formulations involved the use of natural-derived building blocks by lipid extraction from two biomasses of the marine microalga Nannochloropsis sp., containing mostly either phospholipids or triglycerides. Two dispersed nanovector series with different supramolecular structure were thus obtained i. e. liposomes and cubosomes, respectively. The high surface-to-volume ratio and loading efficiency granted successful encapsulation of the guest molecules. These nanoformulations were extensively characterized both from the physico-chemical and functional viewpoint. The structure and morphology was studied by combination of Dynamic Light Scattering, Small Angle X-Ray Scattering and Cryogenic Transmission Electron Microscopy. The guest-carrier and guest-guest interactions, stability and cargo entrapment were investigated by spectroscopic (UV–Vis, Nuclear Magnetic Resonance) and calorimetric (Isothermal Titration Calorimetry) techniques. Finally, the functionality was studied with both chemical and biological approaches, in an integrated structure-function perspective.
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Hamam, Fayez. "Lipase-catalyzed acidolysis of algal oils with a medium-chain fatty acid, capric acid /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,156236.
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Neto, Riamburgo Gomes de Carvalho. "Estudo dos mecanismos envolvidos na separaÃÃo e ruptura simultÃneas de biomassa algal pelo uso da tecnologia de eletroflotaÃÃo por corrente alternada." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10985.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico<br>Dentre as diversas etapas para a transformaÃÃo de microalgas em biodiesel, os processos de separaÃÃo e a ruptura celular dessa biomassa sÃo particularmente importantes, uma vez que as tecnologias disponÃveis para este fim apresentam elevados custos, comprometendo a viabilidade do aproveitamento energÃtico. Este trabalho teve como objetivo geral estudar os mecanismos envolvidos na separaÃÃo e ruptura simultÃneas de biomassa algal pelo uso da tecnologia de eletroflotaÃÃo por corrente alternada (EFCA), com objetivo principal de extrair o conteÃdo lipÃdico da biomassa algal, assim como verificar o potencial da tecnologia na remoÃÃo de nutrientes de efluentes de lagoas de estabilizaÃÃo. Foram realizados ensaios de coagulaÃÃo/floculaÃÃo em jar test com coagulantes sintÃticos (FeCl3 e Al2(SO4)3) e orgÃnicos (Tanfloc SG e SL) com o objetivo de avaliar a decantaÃÃo quimicamente assistida na separaÃÃo de biomassa algal. Foi desenvolvido um reator de EFCA para operar em batelada, utilizando-se eletrodos nÃo consumÃveis e baixa potÃncia elÃtrica. Foi avaliado o seu potencial de separaÃÃo com e sem o auxÃlio dos mesmos coagulantes utilizados nos testes de jarro e, em seguida, buscou-se variar as frequÃncias de operaÃÃo do conjunto de eletrodos com o objetivo de verificar a condiÃÃo Ãtima para separaÃÃo e rompimento celular das microalgas. Foi tambÃm avaliada a capacidade desta metodologia na remoÃÃo de nutrientes presentes nos efluentes e elucidar os mecanismos envolvidos. Foi possÃvel a remoÃÃo de biomassa algal tanto por meio da decantaÃÃo quimicamente assistida quanto pela EFCA, sendo que a segunda à mais atrativa nÃo somente pelas eficiÃncias de remoÃÃo de turbidez e clorofila-a encontradas, como tambÃm pela nÃo necessidade aparente de utilizaÃÃo de coagulantes, o que traz economia ao processo e facilita a reutilizaÃÃo da biomassa algal. A EFCA mostrou-se ainda capaz de promover com eficiÃncia o rompimento celular das microalgas e fazer com que os lipÃdeos liberados se aderissem à biomassa algal separada pelo processo. Foi possÃvel alcanÃar um rendimento lipÃdico de atà 14% em peso de massa seca, mesmo os estudos tendo sido realizados com uma matriz diversa de microalgas proveniente das lagoas de estabilizaÃÃo. O estudo dos mecanismos envolvidos revelou a boa capacidade do sistema em gerar gÃs hidrogÃnio, o qual alÃm de ajudar na separaÃÃo das microalgal pode tornar futuramente o processo energeticamente sustentÃvel. AlÃm disso, foi verificada a geraÃÃo de espÃcies oxidantes que ajudam tanto o processo de separaÃÃo quanto possivelmente de ruptura celular. O efeito de diferentes frequÃncias de vibraÃÃo nos rendimentos lipÃdicos encontrados nÃo foi aparente. Buscou-se ainda a elucidaÃÃo dos mecanismos de remoÃÃo de fÃsforo total, o que provavelmente se deu pela formaÃÃo de
ferro durante o processo, cujos valores ficaram na ordem de 2,5 mg/L depois de 70 minutos de batelada. JÃ para a remoÃÃo de amÃnia, possivelmente o mecanismo foi de oxidaÃÃo indireta da amÃnia atravÃs do excesso de Ãcido hipocloroso como a forma predominante de conversÃo da mesma em nitrogÃnio gasoso, o qual ajuda no processo de separaÃÃo. A utilizaÃÃo de microalgas diretamente de lagoas de estabilizaÃÃo mostrou-se uma potencial alternativa aos processos de obtenÃÃo de biomassa tradicionalmente utilizados (fotobiorreator e lagoas do tipo raceway), sendo que a tecnologia proposta se mostrou atrativa para todos processos que demandem separaÃÃo algal.<br>Among the various steps for microalgae transformation in biodiesel, the harvesting and cell disruption processes are particularly important, since technologies available for this purpose have usually high costs, undermining the energy recovery viability. This work studied the mechanisms involved in the simultaneous harvesting and cell disruption of microalgae using electroflotation by alternating current (EFCA), as well as to investigate the system capacity on nutrients removal from waste stabilization ponds effluents. Coagulation/flocculation tests were performed using synthetic (FeCl3 e Al2(SO4)3) and organic (Tanfloc SG e SL) coagulants to evaluate the chemically assisted sedimentation of the algal biomass. The EFCA reactor was designed to operate in batch, using non-consumable electrodes and low electrical power, and evaluated the harvesting potential in the presence and absence of coagulants. After this, experiments were performed varying the electrode frequency to verify the optima condition for simultaneous harvesting and cell disruption of microalgae. The system capacity in terms of nutrients removal was also investigated as well as the mechanisms involved. It was possible to remove algae biomass both using chemically assisted sedimentation and EFCA. However, the electrolytic technology is more attractive, not only for the turbidity and chlorophyll-a efficiencies founded, but also because there is no apparent need of coagulants, which makes the process cheaper and facilitates the microalgae biomass reuse. The EFCA was even able to promote the cell disruption of microalgae and the liberated lipids were able to attach to the algal biomass separated by the process. A lipid yield of 14 % in terms of dry matter was found, even when a complex matrix from waste stabilization ponds was used. The study of the mechanisms involved in EFCA revealed the good system ability to generate hydrogen gas, which contributes to microalgae harvesting and can make the process even more sustainable under an energetic perspective. Furthermore, the generation of oxidant species was found which helps the harvesting and cell disruption process. The effect of different vibration frequencies in the lipid yield was not apparent. We sought to elucidate the mechanisms involved on total phosphorus removal, and probably the removal was due to iron formation in the process, in which the concentrations were close to 2.5 mg/L after 70 minutes batch time. In terms of ammonia removal, possibly the mechanism was an indirect oxidation by excess of hypochlorous acid to form nitrogen gas, which helps the separation process. The use of microalgae from stabilization ponds showed a potential alternative for the processes traditionally used nowadays for
microalgae production (photobioreactor and raceway ponds), and showed to be attractive to all processes that demand microalgae harvesting.
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Wong, Yee Keung. "Feasibility of using Chlorella vulgaris for the production of algal lipids, for advancement towards a potential application in the manufacture of commodity chemicals and the treatment of wastewater." HKBU Institutional Repository, 2016. https://repository.hkbu.edu.hk/etd_oa/254.
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Driven by the increase in industrialization and population, the global demand of energy and material products is steadily growing. Microalgae have come into prominence in the past several decades due to their ability to utilize solar energy to fix atmospheric carbon dioxide, and produce biomass and lipids at productivities much higher than those possible with terrestrial biomass. The main objective of this research is to maximize the biomass and lipid production of Chlorella vulgaris by varying different external conditions so as to achieve the ideal feedstock for the production of commodity chemicals and implement wastewater treatment. The effects of various culture medium compositions on Chlorella vulgaris growth and lipid production were investigated using batch culture. Thirteen culture media: Modified Chu’s No. 10, Bold basal, BG-11, Modified BG-11, N-8, M-8, RM, Modified Spirulina, F-si, Fogg’s Nitrogen free, Fog, F/2, and Johnson medium were compared in terms of optical density, biomass production, specific growth rate and lipid production. Following a 10-day culture in a temperature controlled environment, Bold basal medium was found to have the highest average biomass productivity of 48.056 ± 2.097 mg L -1 day -1 , with overall specific growth rate of (d -1 ): 0.211 ± 0.003 and lipid productivity of 9.295 mg L -1 day -1 among the selected media. This is a basis for the optimization of different cultivating medium to enhance algal lipid production. In order to maximize the quality and quantity of the algal biomass and lipid content in Chlorella vulgaris, different strategies were used using different ratios of nitrogen and phosphorus source in the modified Bold basal medium (BBM). In the 12-day batch culture period, the highest biomass productivity obtained was 72.083 mg L -1 day -1 under Bold basal medium with Nitrogem control Phosphorus limited conditions. The highest lipid content, lipid concentration and lipid productivity obtained were 53.202%, 287.291 mg/L and 23.449 mg L -1 day -1 respectively, under Bold basal medium with Nitrogen Control Phosphorus Deprivation conditions. Nitrogen starvation was found to be the critical factor affecting the biomass production and lipid accumulation while the starvation of phosphorus induced a higher total lipid content and affected the lipid composition of Chlorella vulgaris cultures. Recently, as the demand for pure microalgae strains for the production of algal lipid as a feedstock of renewable energy has been increasing, the designation of an effective photobioreactor (PBR) for mass cultivation is essential to assure stability in the amount of feedstock. Various PBRs design such as bubbling, air-lift, porous air-lift was compared. In general, the bubbling design is a better PBR designs than the others, having the highest biomass concentration of 0.78 g/L during the culture time. Besides, it was observed that the 35 cm draft tube of the porous air-lift PBR had shorter mixing time (24.5 seconds) and higher biomass concentration (0.518 g/L) than the 50 cm air- lift design. The bubbling PBR with the highest gas flowrate of 2.7 L/min produced the highest biomass production of 0.74 g/L within the cultivation time. The information is shown to be a useful guide for determining the optimal condition of the PBRs. Light wavelengths and intensities were determinant factors in affecting the growth and lipid content of autotrophic organisms such as C. vulgaris. The experiment investigated the effect of algal lipid production by using LEDs (Light Emitting Diodes) with different wavelengths. C. vulgaris was grown in the effluent for 10 days under the photoperiod of 18:6 h Light/Dark cycles with different visible light sources (cool white, blue and red) and intensities (50 μmol m -2 s -1 ) at 25°C. The overall maximum dry biomass of 1353.33 mg/L was observed at 50 μmol m -2 s -1 cool white light during 10th culture day, with the highest overall productivity of dry biomass production (117.23 mg/L d -1 ) within cultivation time. The highest lipid content (34.06 %) was obtained with the blue color due to light efficiency and deep penetration to the photosynthetic pigments (chlorophyll) in C. vulgaris. However, the highest lipid productivity was observed in cool white light of 318.63 mg/L during the 10th culture day. The effect of light intensity toward the lipid productivity was further investigated by increasing the light intensity of cool white light. The highest lipid productivity was observed at 110 μmol m -2 s -1 in a light intensity of 658.99 mg/L during the 10th culture day. In high irradiance (110 μmol m -2 s -1 ), the proportion of poly unsaturated fatty acid (C18:1 and C18:2) contributed most of the fatty acid methyl ester (FAME) content in the collected sample, irrespective of all treatments. The next study optimized the harvesting rate of algae by using an electro- coagulation-flotation (ECF) harvester, which combines the electrochemical reaction in the electrodes and the dispersion of hydrogen gas to allow floatation of microalgae cell for surface harvesting. The response surface methodology model (RSM) was employed to optimize different ECF parameters: electrode plate material, electrode plate number, charge of electrode, electrolyte concentration and pH of the solution. The model revealed that aluminum was the best electrode material for the ECF process. It was also found that a three electrode plates setup with one anode and two cathodes had the best performance for harvesting. Additionally, sodium chloride (NaCl) at 8 g/L in harvesting medium could increase the flocculant concentration and reduce electric power consumption. Also, having the culture medium at pH 4 also had a significant effect on improving the flocculant production. Combining these optimal conditions, the highest flocculant concentration reached 2966 mg/L in 60 mins; a 79.8% increase in flocculant concentration, based on the tested conditions. The results of this study show the significance of different parameters affecting the coagulation and flocculation of C. vulgaris and provide a reference for the design of a large-scaled harvester for microalgae harvesting in the further study. To conclude, this research comprises a study on the use of indigenous algae for the production of algal lipid, which is used to produce commodity chemicals. Details on the use of nutrient sources, the techniques of cultivation and the optimization of cell harvesting were included so as to remove nutrients from effluents to minimize the occurrence of eutrophication in harbor, thereby providing economic advantages. Thus, the optimization of these processes is very adequate and offers significant advantages for the wastewater treatment. The developing of algal cell biotechnology is necessary to further enhance algal lipid production in an attempt to apply it commercially.
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Woolsey, Paul A. "Rotating Algal Biofilm Reactors: Mathematical Modeling and Lipid Production." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1107.
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Harvesting of algal biomass presents a large barrier to the success of biofuels made from algae feedstock. Small cell sizes coupled with dilute concentrations of biomass in lagoon systems make separation an expensive and energy intense-process. The rotating algal biofilm reactor (RABR) has been developed at USU to provide a sustainable technology solution to this issue. Algae cells grown as a biofilm are concentrated in one location for ease of harvesting of high density biomass. A mathematical model of this biofilm system was developed based on data generated from three pilot scale reactors at the City of Logan, Utah wastewater reclamation plant. The data were fit using nonlinear regression to a modified logistic growth equation. The logistic growth equation was used to estimate nitrogen and phosphorus removal from the system, and to find the best harvesting time for the reactors. These values were extrapolated to determine yields of methane and biodiesel from algae biomass that could be used to provide energy to the City of Logan if these reactors were implemented at full scale. For transesterification into biodiesel, algae need to have high lipid content. Algae biofilms have been relatively unexplored in terms of cell lipid composition accumulation and changes with regard to environmental stressors. Results indicated that biofilm biomass was largely unaffected by nutrient stresses. Neither nitrogen limitation nor excess inorganic carbon triggered a significant change in lipid content. Biofilm algae grown with indoor lighting produced an average of 4.2% lipid content by dry weight. Biofilm algae gown outdoors yielded an average of 6.2% lipid content by dry weight.
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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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Jones, Lisa A. "Bioadsorption of Copper (II) By Chlorella Sp. Biomass: Continuous Process with Cost Analysis and Comsol Model Simulations." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/307004.
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With the continuous improvement in knowledge and health risks associated with heavy metal expulsion, government environmental agencies are continuously reducing the legal disposal limits. However, the demand for items like IPods or energy-efficient appliances containing heavy metal like copper is on the rise. Whether from commercial or residential areas, heavy metals are known to have toxic effects on humans, animals, and/or ecosystems; hence, their removal is necessary part of preserving our environment. With the rising cost of natural resources, biological species have proven to be viable alternatives in the jet fuel and biodiesel industries. Algal biomass is widely considered economical because of its renewable, biodegradable, noncompetitive, and nontoxic properties. Currently, algae are being grown on waste water for the lipid; this research involves taking the left over or lipid-extracted algae (LEA) for utilization as a biosorbant to remove heavy metals from wastewater. Down selection via batch processes showed that Chlorella sorokianna and its associated lipid-extracted algae (LEA) demonstrated similar adsorption capacities of copper (II) as three current-in-use ion exchange resins. A feasibility study proved that the LEA was an economically realistic means to remove copper (II) from effluent. The LEA biomass is capable of a maximum adsorption of 14.36 ± 0.27 mg of copper (II) per gram of dry biomass for six regeneration, sorption-desorption, cycles with nitric acid. Using SEM and FTIR, the LEA is capable of ion exchange electrostatic interaction with various surface sites of carboxyl, hydroxyl, and metal groups. Next, the batch process was used to fabricate a lab-scale continuous column process much like ion exchange or activated carbon columns in a waste water treatment plant. Using the continuous systems' kinetics and cycle life, a cost analysis was performed on a plant scale column to reduce copper (II) in wastewater for recovery at a later date, which would yield cost saving over the life of columns. To install three LEA columns prior to ion exchange in a waste water treatment plant, the total capital expense is $1.03 million for a one year time line. The bidirectional flow columns are meant as pretreatment prior to ion exchange columns. The LEA columns provide a waste water treatment plant a sustainable, greener and cheaper alternative to offset costs associated with purifying waste water.
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Vít, Radek. "Analýza glukanů v rostlinných a mikrobiálních vzorcích." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-414130.
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The aim of the diploma thesis is study of glucans production in selected species of yeasts, algae and plants. Cultivation conditions for yeast strains were performed to gain increased production of glucans under different temperature conditions and in media of different composition. Into the set of tested yeasts species strains Saccharomyces cerevisiae (CCY 6646), Sporidiobolus pararoseus (CCY 19-9-6), Phaffia rhodozyma (CCY 77-1), Rhodotorula glutinis (CCY 20-78-26) and Cystofilobasidium infirmominiatum (CCY 17-18-4) were enrolled. Saccharomyces cerevisiae was cultivated as a control strain because of its verified production of -glucans. -glucans were determinated by the enzyme kit K-YBGL Megazyme. For comparison, algal strain Euglena gracilis (CCALA 349), some species of mushrooms (shiitake, oyster mushroom, garden champignon and Jew’s ear) and cereals (wheat, rye, oats, rice and barley) were analysed too. Further, fatty acid content in the yeast cells was determined by the GC/FID. The best producer of yeast -glucans was R. glutinis CCY 20-7-26, which showed the highest biomass production (12-14 g/l) and also a relatively high amount of -glucans (25-30 %), in cultivation at 15 °C in a medium containing yeast extract in combination with ammonium sulphate. The presence of -glucans has been demonstrated in the microalgae, Euglena gracilis CCALA 349, as well as in samples of higher fungi and cereals.
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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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Tillett, David McIlvain. "Lipid productivity and species competition in laboratory models of algal mass cultures." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/10274.
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Pettitt, T. R. "Lipid metabolism and membrane function in two species of marine red algae." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382614.
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Kanemoto, Fernando Takashi. "Otimização de sistema de cultivo de baixo custo de Nannochloropsis gaditana Lubián 1982 para produção de biodiesel." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-26092013-193937/.
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O desenvolvimento de fontes de energia renováveis tem se tornado cada vez mais necessário e, nesse contexto, os biocombustíveis têm um importante papel. Este trabalho teve como objetivo otimizar a produtividade de biomassa e de lipídios da microalga Nannochloropsis gaditana, em cultivos de baixo-custo visando à produção de biodiesel. Um sistema de cultivo foi concebido com materiais acessíveis e os experimentos testaram o efeito de diferentes exposições das células ao claro-escuro, sob irradiância de 800?E m-2 s-1. Foram testadas três profundidades de cultivo (2, 4 e 8 cm) e duas taxas de aeração (0,25 e 1,00 L min-1 por L de cultivo). A penetração de luz nos cultivos e o rendimento de biomassa seca foram monitorados diariamente. Altos rendimentos de biomassa e lipídios foram alcançados. Os valores máximos foram observados no experimento com 4 cm de profundidade e maior taxa de aeração: 13,83 g m-2 d-1 de produtividade de biomassa e 20,50% de teor lipídico, resultando em uma produtividade lipídica de 2,84 g m-2 d-1. Estes resultados indicam o potencial da utilização de N. gaditana para aplicação em cultivos de larga escala, uma vez que o rendimento lipídico observado foi superior ao da soja, principal matéria-prima vegetal para produção de biodiesel. O sistema de cultivo desenvolvido pode ser inserido em um processo de scaling up em cultivos abertos de grande escala.<br>The development of renewable energy sources has becoming an increasing necessity and, in this context, biofuels have an important role. This study aimed to optimize the productivity of biomass and lipids of the microalgae Nannochloropsis gaditana in a low-cost system, focusing biofuel production. A culture system was designed with low-cost and accessible materials and the experiments tested the effect of different degrees of exposition of cells to light-dark, under 800?E m-2 s-1 irradiance. Three different culture depths (2, 4 e 8 cm) and two aeration ratios (0.25 e 1.00 L min-1 per L of culture) were tested. Light penetration into the cultures and the dry biomass yield were monitored daily. High yields of biomass and lipids were attained in the experiment with 4 cm depth and the high aeration ratio: 13.83g m-2 d-1 of biomass productivity and 20.50% lipid content, resulting in a lipid productivity of 2.84 g m-2 d-1. These results indicate the potential of N. gaditana for application in large-scale cultivation, since its lipid yield is higher than the soybean, the main feedstock plant for biodiesel production. The culture system developed can be inserted in a process of biomass scaling up for large-scale open microalgae cultures.
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Segali, Alexandra Maria Donadon Lusser [UNESP]. "Desempenho de Ankistrodesmus gracilis (Reischi) Korsikov (Chlorophyta) cultivada em três meios de cultura em laboratório." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/116024.
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000804740.pdf: 427264 bytes, checksum: a59271f661e7ce490375621680ab8a3e (MD5)<br>A microalga A. gracilis é conhecida pela sua capacidade de ser usada em nutrição de organismos aquáticos. Alguns estudos relatam que a adição de vitamina junto ao meio de cultura promove uma melhora nas condições do cultivo. O objetivo deste estudo foi avaliar o desempenho da microalga Chlorophyceae, Ankistrodesmus gracilis, em condições controladas em três diferentes meios de cultura, sendo um comercial (CHU12) e dois alternativos (NPK (20:5:20) e Macrófita + NPK) durante o período de 28 dias de cultivo para cada meio. O experimento foi realizado em recipientes de 13L durante 28 dias, com luminosidade constante de 60 ?mol m-2 s-1 e para cada recipiente foram adicionados 20 mg de vitamina do complexo B. No meio CHU12 apresentou densidade celular máxima de 25,6 x 105 cel mL-1 e nos meios NPK e M+NPK foi de 25,5 e 24,2 x 105 cel mL-1 , respectivamente. As quantidades de lipídios obtidas no presente estudo foram, para o meio NPK o valor médio foi de 12,68% do peso seco e para os meios M + NPK e CHU12 os valores obtidos foram 9,85 e 2,82% do peso seco respectivamente. Em relação às proteínas a microalga A. gracilis apresentou valores significativos comprovando assim o seu grande potencial como nutriente na alimentação de organismos aquáticos, foram obtidos para o meio NPK valores de 41,26% do peso seco, e para os meios M + NPK e CHU12 valores de 37,71 e 31,76% do peso seco respectivamente. Através dos dados obtidos neste estudo, pode-se concluir que a utilização dos meios de cultura alternativos NPK (20:5:20) e macrófita + NPK apresentaram resultados satisfatórios no crescimento e desenvolvimento da microalga A. gracilis. Em relação à nutrição de organismos aquáticos pode ser uma grande ferramenta como alimento natural<br>The microalgae A. gracilis is known for its ability to be used in nutrition of aquatic organisms. Some studies report that the addition of vitamin on the culture medium promotes an improvement in the conditions of cultivation. The objective of this study was to evaluate the performance of microalgae Chlorophyceae, Ankistrodesmus gracilis, under controlled conditions in three different culture media, being a commercial (CHU12) and two alternatives (NPK (20:5:20) and Macrophyte+NPK) during the period of 28 days of cultivation for each half. The experiment was accomplished in 13L containers during 28 days, with constant brightness of 60 ?mol m-2 s-1 and for each container were added 20 mg of vitamin B complex. In the middle CHU12 has maximum cell density 25,6 x 105 cel mL-1 and NPK and M+NPK media was 25,5 and 24,2 x 105 cel mL-1, respectively. The quantities of lipid obtained in this study were, in the middle the average value was NPK 12,68% of the dry weight and the means M + NPK and the values obtained CHU12 were 9,85 and 2,82% of the dry weight respectively. In relation to protein microalgae A. gracilis presented significant values proving so its great potential as a nutrient in the feeding of aquatic organisms, were obtained for the NPK values of 41,26% of dry weight, and for the means CHU12 37,71 values and M+NPK and 31,76% of the dry weight respectively. Through the data obtained in this study, it can be concluded that the use of alternative culture media NPK (20:5:20) and macrophyte + NPK presented satisfactory results in the growth and development of microalgae A. gracilis. In relation to the nutrition of aquatic organisms can be a great tool as health food
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Bosley, Amber L. "Algae Characterization and Processing Techniques." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1321538296.
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Szotkowski, Martin. "Srovnání metabolické aktivity a potenciálního využití mikrořas a pigmentotvorných kvasinek." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-240805.
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Carotenoids are natural pigments occurring in plants and many microorganisms, such as algae, yeast and bacteria. They represent the most common group of antioxidants with significant biological effect. Lipids are an essential component of all living organisms. They are the source and the reservoir of energy for organisms, which can also be used in the petrochemical industry for the production of biofuels. This thesis deals with the production properties of carotenoids and lipids by selected strains of yeasts, algae, and canobacteria, in order to apply the acquired knowledge and find cheap suitable alternatives for microbial biotechnological production of these metabolites using waste substrates. Carotenoids, coenzyme Q, and ergosterol in cells were determined by liquid chromatography. The lipid content and fatty acid profile was analyzed by gas chromatography. Cell morphology and localization of selected metabolites were analyzed by fluorescence lifetime imaging microscopy. In this work yeast genera Sporobolomyces, Cystofilobasidium and Rhodotorula were used. As the representatives of the algae and cyanobacteria strains of Desmodesmus, Cyanothece, Chlamydomonas, Synechoccocus and Chlorella strains were studied. In the overall comparison, the yeast strains were more productive than algae and cyanobacteria. The highest carotenoid production was found in S. pararoseus, C. capitatum and R. mucilaginosa cells, while the highest lipid yield was observed in strains of C. infirmominiatum and S. metaroseus.
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Wang, Bei. "Microalgal Lipids Production and NitrogenPhosphorus Removal Using the Green Alga Neochloris oleoabundans." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28571.
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A Neochloris oleoabundans strain screened in our lab was demonstrated to have the ability to accumulate large quantities of triglycerides, the feedstock of biodiesel production, and to remove nitrogen and phosphorus from wastewater efficiently. Box-Behnken experimental design (BBD) and response surface method (RSM) were used to study the effects of a large number of nutrients on cell growth and lipid accumulation. The optimized medium supported a lipid concentration of 641.4 mg/l and a cell density of 2.54 g/l, which were 4.5-fold and 2.2-fold of that obtained with the basic medium, modified Bristol medium (MBM), respectively. The capacity of the strain for phosphorus removal and nitrogen removal was investigated using artificial wastewater and municipal wastewater effluents. It was demonstrated that the strain could achieve near-zero residual phosphate and nitrogen at the end of cultivation when artificial wastewater contained up to 140 mg N-NO 3-/l and 47 mg P-PO43-/l. The rates of the removal of N-NO3- and P-PO4 3-, are 27.5 mg/l·d, and 9.4 mg/l·d, respectively under optimal conditions. It was observed that the nitrogen content of the wastewater effluent was not sufficient and additional nitrogen source (e.g., NaNO 3) of 70 mg/l was required for optimal cell growth, CO2 fixation, and phosphate removal.
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Anthony, Renil J. "Solvent Extraction of Lipids from Microalgae." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1280854965.
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Chen, Guanqun. "Lipid and fatty acid composition and their biosyntheses in relation to carotenoid accumulation in the microalgae nitzschia laevis (Bacillariophyceae) and haematococcus pluvialis (chlorophyceae)." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39557364.
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Chen, Guanqun, and 陳冠群. "Lipid and fatty acid composition and their biosyntheses in relation tocarotenoid accumulation in the microalgae nitzschia laevis(Bacillariophyceae) and haematococcus pluvialis (chlorophyceae)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39557364.
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Nicolai, Eric Alexander. "Growth Media and Lipid Determination Comparison of High Rate Algae Ponds." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1351.
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Growth Media and Lipid Determination Comparison
of High Rate Algae Ponds
Eric Alexander Nicolai
The feasibility of algal biofuel production relies on the use of a non-potable water source. Municipal wastewater is nutrient-rich and a cost effective option as a growth media in algae ponds. However, this resource may be too valuable for algal biomass production, as reclaimed wastewater is needed for surface irrigation and groundwater recharge. This thesis compares the performance of 4.2 m2 high rate algal raceway ponds (HRAPs) to 33 m2 HRAPs grown on primary settled wastewater during a media recycling study and a growth media comparison study using wastewater and reclaimed water. The comparative metrics of performance for this study included: pond productivity, settling efficiency, and nutrient removal. This thesis also discusses the variability of algal lipid content from wastewater ponds using three different lipid determination methods. Six 4.2-m2, 0.3 m deep HRAPs were compared to nine 33-m2 HRAPs located at the San Luis Obispo Water Resource Recovery Facility (SLOWRRF). During the media recycling study, the first round of growth (Round 1) included ponds operating at 2-day and 3-day hydraulic retention times (HRTs) for both pond sizes. The pond arrangements for the second round of growth (Round 2) were the same with the exception of no 2-day HRT for the 33-m2 pond set. Net biomass productivity in the 4.2-m2 ponds under predicted the productivity of the 33-m2 ponds. Settling efficiency was comparable between the different rounds of growth for both pond sizes. Total soluble nitrogen removal was predicted using 4.2-m2 ponds. Of the three lipid determination methods, the fatty acid methyl esters (FAMEs) quantification was the most precise between replicates. However, this method determined the lowest lipid content because it quantifies a better representative lipid content by excluding other constituents not relevant to biofuel production.
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Gottumukala, Vasudev. "Evaluation of Lake Erie Algae as Bio-fuel Feedstock." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271194064.
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Hutton, Matthew W. "EXTRACTION AND CHARACTERIZATION OF LIPIDS FROM MICROALGAE GROWN ON MUNICIPAL WASTEWATER." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/214.
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Based on results of its Aquatic Species Program (1978-1996), which sought to develop algae-to-liquid fuel technology, the U.S. Department of Energy has suggested that algal wastewater treatment may be incorporated into biodiesel production schemes to reduce the operating costs of both processes. the purpose of the current research was to evaluate the triglycerides produced by wastewater-grown algae for their suitability as a fuel feedstock and to investigate the effectiveness of several solvent mixtures and extraction procedures at recovering lipids from fresh algae. The research involved two separate experiments. The first determined the quantity and quality of lipids produced over the lifetime of a batch culture of algae grown in a small outdoor high-rate pond. Transesterification of the algal triglycerides yielded mostly saturated and monounsaturated 16 and 18-carbon fatty acid methyl esters, together comprising approximately 8 to 30% of the biomass in the pond. The average triglyceride production rate during the grwoth phase of the culture was 0.97 grams per square meter of pond surface per day. The second experiment compared several industrially practicable extraction procedures to the Bligh and Dyer laboratory extraction method. The Bligh and Dyer laboratory extraction procedure provides excellent lipid recovery efficiency, but several factors limit its potential on an industrial scale. The Bligh and Dyer method requires a larger volume of solvents than other methods, uses the probable carcinogenic chemical chloroform, and involves a complex series of steps that are difficult to automate. A simple, low-energy extraction process using relatively non-toxic solvents was found to have an extraction efficiency comparable to that of the laboratory method.
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Ahmad, Kamaroddin Mohd Farizal. "In-situ disinfection and algal lipid extraction using ozonation in novel microbubble bioreactor for biofuel production." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/17194/.
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The scaling up and downstream processing costs of biodiesel from microalgae are major concerns. This study focuses on developing a new method by integrating ozone-rich microbubbles in both the production of microalgae and in downstream processes such as biomass harvesting and lipid extraction. A bacterial contaminant of a green algal (Dunaliella salina) culture was successfully screened, isolated and identified using 16S rRNA gene sequencing as a member of the Halomonas genus (gram-negative). Ozonation of mixed cultures of D. salina and Halomonas for 10 minutes at 8 mg/L reduced the bacterial contaminant without harming the microalgal cells. The sterilisation efficiency reached 66% after 5 minutes and increased to 93% after 10 minutes of ozonation. The algal cell growth performance (biomass concentration) was decreased by over 50% at 10% (v/v) contaminant concentration. Ozonation for 10 minutes at the beginning of the experiment resulted in a biomass reduction of 28.6%, which suggests that ozonation at the beginning of experiment can control the contamination. The optimum values for three parameters (culture media volume, ozone concentration and ozonation time) suggested by the statistical software were 30.63 mL, 8.20 mg/L and 37.7 min, respectively. Harvesting of D. salina cells through microflotation resulted in a 93.4% recovery efficiency. Ozonation of the harvested microalgae for 40 minutes produced three main saturated compounds [2-pentadecanone 6, 10, 14-trimethyl; n-hexadecanoic acid (palmitic acid); and octadecanoic acid (stearic acid)] that consist of 16 to 18 carbons. The main products increased significantly around 156%, 88.9% and 150% for 2-pentadecanone, 6, 10, 14-trimethyl; palmitic acid and stearic acid, respectively when the temperature was increased (60 ˚C), and smaller bubbles (generated by a fluidic oscillator) were introduced during the extraction process. By integrating microbubbles and ozonation into an airlift-loop bioreactor-processing system, this thesis describes a microbubble photobioreactor that delivers in-situ disinfection with microflotation harvesting and lipid extraction in an easily scalable and energy-efficient process.
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Csavina, Janae L. "The Optimization of Growth Rate and Lipid Content from Select Algae Strains." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1215529734.
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Sathish, Ashik. "Biodiesel Production from Mixed Culture Algae Via a Wet Lipid Extraction Procedure." DigitalCommons@USU, 2012. https://digitalcommons.usu.edu/etd/1372.
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With world crude oil reserves decreasing and energy prices continually increasing, interest in developing renewable alternatives to petroleum-based liquid fuels has increased. An alternative that has received consideration is the growth and harvest of microalgae for the production of biodiesel via extraction of the microalgal oil or lipids. However, costs related to the growth, harvesting and dewatering, and processing of algal biomass have limited commercial scale production of algal biodiesel. Coupling wastewater remediation to microalgal growth can lower costs associated with large scale growth of microalgae. Microalgae are capable of assimilating inorganic nitrogen and phosphorous from wastewater into the biomass. By harvesting the microalgal biomass these nutrients can be removed, thus remediating the wastewater. Standard methods of oil extraction require drying the harvested biomass, adding significant energetic cost to processing the algal biomass. Extracting algal lipids from wet microalgal biomass using traditional methods leads to drastic reductions in extraction efficiency, driving up processing costs. A wet lipid extraction procedure was developed that was capable of extracting 79% of the transesterifiable lipids from wet algal biomass (16% solids) without the use of organic solvents while using relatively mild conditions (90 °C and ambient pressures). Ultimately 77% of the extracted lipids were collected for biodiesel production. Furthermore, the procedure was capable of precipitating chlorophyll, allowing for the collection of algal lipids independently of chlorophyll. The capability of this procedure to extract lipids from wet algal biomass, to reduce chlorophyll contamination of the algal oil, and to generate feedstock material for the production of additional bio-products provides the basis for reducing scale-up costs associated with the production of algal biofuels and bioproducts.
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Moraes, Gisely Souza Campos. "Produção de biomassa algal e extração de óleo a partir da microalga Chlorella Vulgaris /." Guaratinguetá, 2018. http://hdl.handle.net/11449/180247.
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Orientador: Marcela Aparecida Guerreiro Machado<br>Resumo: A microalga Chlorella possui ácidos graxos poli-insaturados, vitaminas e alto conteúdo proteico. Desse modo, estudos recentes têm explorado o uso de microalgas para obtenção de lipídios, principalmente os de maior valor comercial como o ácido ɣ-linolênico. Estre trabalho objetivou propor um método de cultivo para a microalga Chlorella vulgaris e extração do óleo. Os experimentos foram realizados em duplicata de acordo com o arranjo ortogonal de Taguchi, a partir da qual foram organizadas duas etapas: na primeira foram viabilizados cultivos nos quais os fatores de interesse pudessem ser avaliados em dois níveis de operação: Aeração (1,67 e 3,33L/min), NO3 (0,25 e 0,50 g/L), PO4 -3 (0,35 e 0,65 g/L), NaHCO3 (0,25 e 0,50 g/L), intensidade de luz (0,85 e 14,50 K luz) e fotoperíodo (12 e 24 h). Em tal etapa correu também a colheita, floculação, secagem e moagem da biomassa. Na segunda etapa foram realizadas as extrações lipídicas de acordo com e uso de solventes como o clorofórmio e metanol, utilizou-se também o banho de ultrassom para as extrações dos teores lipídicos. Obteve melhor resultado a concentração de biomassa algal, a qual atingiu a concentração de nitrato (0,50 g/L), concentração de bicarbonato de sódio (0,50 g/L), fosfato (0,65 g/L) e fotoperíodo de 12 em 12hs. O melhor resultado para a extração lipídica ocorreu conforme a metodologia de Zorn (2017), com aproximadamente 2,5% mais eficiente e obteve o seguinte resultado para os fatores, no nível alto são: aeração (3,33... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The micro-algae Chlorella has polyunsaturated fatty acids, vitamins and high protein content. Thus, recent studies have explored the use of microalgae to obtain lipids, especially those with higher commercial value such as β-linolenic acid. The objective of this work was to propose a method of cultivation for the microalga Chlorella vulgaris and extraction of the oil. The experiments were carried out in duplicate according to Taguchi's orthogonal arrangement, from which two stages were organized: in the first, cultures were feasible in which the factors of interest could be evaluated at two levels of operation: aeration (1.67 e 3.33L/min), PO4 -3 (0.35 and 0.65 g / L), NaHCO 3 (0.25 and 0.50 g / L), NO 3 (0.25 and 0.50 g / L) , light intensity (0.85 and 14.50 K light) and photoperiod (12 and 24 h). In this stage also the harvest, flocculation, drying and milling of the biomass took place. In the second stage, the lipid extractions were performed according to the use of solvents such as chloroform and methanol, and the ultrasonic bath was used to extract the lipid contents. The best results were the algal biomass concentration, which reached the concentration of nitrate (0.50 g / L), sodium bicarbonate (0.50 g / L), phosphate (0.65 g / L) and photoperiod every 12 hours The best result for the lipid extraction occurred according to the Zorn (2017) methodology, with approximately 2.5% more efficient and obtained the following result for the factors, at the high level are: aerati... (Complete abstract click electronic access below)<br>Mestre
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Liu, Zhouyang. "Nitrogen Removal and Lipid Production from Secondary Wastewater Using Green Alga Chlorella vulgaris." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1329935203.
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Gigante, Bethany Marie. "SALINE ADAPTATION OF THE MICROALGA Scenedesmus dimorphus FROM FRESH WATER TO BRACKISH WATER." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1382355969.
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Goold, Hugh. "Décrypter le métabolisme des lipides dans les microalgues en utilisant des approches de génétique moléculaire." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4047.
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Dans notre contexte moderne, les besoins en carburant demandent une innovation constante en terme de sources d'énergie. La dominance actuelle des carburants d'origine fossile dans les modes de transport personnels tels que l'aviation peut être renversée à condition de disposer de carburants efficaces riches en molécules énergétiques comme les hydrocarbures long. Dans le cas où les marchés économiques augmentent le prix des énergies fossiles, une source d'énergie renouvellable seront les plantes. Les plantes qui semblent les plus prometteuses sont les algues. En effet, ces cellules vertes produisent des lipides et ne nécessitent pas l'utilisation de terres arables si fortement prisées dans d'autres secteurs de l'agriculture. Cette thèse examine donc les conditions requises pour la productionde lipides neutres par Chlamydomonas reinhardtii. Pour commencer, un mutant est caractérisé en comparaison avec le type sauvage: sa concentration en amidon et lipides neutres est plus elevée sous illumination forte et normale. La caractérisation genomique a mis en lumière 41 gènes manquants. A la place, cette étude présente les résultats liés à l'effet de l'exposition de la souche sauvage à une forte illumination d'une part, et à une carence en azote d'autre part. Pendant les périodes de luminosité intense, les niveaux de TAG sont d'abord élevés. Dans le cas de carence en azote, l'augmentation du niveau de TAG commence seulement après l'épuisement total d'azote. L'expression du MLDP est plus notable dans le cas d'une carence en azote que d'une forte luminosité. Afin de révéler l’effet de la forte lumière seule, les corps lipidiques ont été isolés et comparés<br>Neutral lipid accumulation by microalgae has recently regained considerable interest as these organisms are considered as a promising feedstock for the production of renewable biodiesel. Nitrogen deprivation is well described as a trigger for neutral lipid accumulation in various species of microalgae including Chlamydomonas. However nitrogen deprivation provokes a stop in protein synthesis and cell division, therefore limiting microalgal biomass productivity. In order to elucidate mechanisms of lipid accumulation in Chlamydomonas reinhardtii, a mutant exhibiting elevated TAG levels is characterized. The mutant exhibits reduced chlorophyll butelevated starch and neutral lipids under strong illumination in replete medium. Genomic characterization has revealed 41 missing genes. This mutant has highlighted the link between luminosity and TAG biosynthesis. To gain insights into the differences in molecular mechanisms behind oil accumulation processes under nitrogen starvation to that of high light, lipidomic changes in separate wildtype cultures were observed. Results showed that despite intracellular TAGs were found to accumulate to lower levels in response to high light in comparison to nitrogen deprivation; the TAGs productivity was higher due to a persistent biomass production. Furthermore differences in both the lipid and protein composition were observed in lipidomes and proteomes determined by pure extracts of lipid bodies isolated from both conditions revealing differences in lipid bodies isolated from different conditions
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COSTELLI, CRISTINA. "Genetic and phylogenetic characterization of microalgae strains in view of their exploitation for CO2 capture and biofuel production." Doctoral thesis, Università degli Studi di Cagliari, 2015. http://hdl.handle.net/11584/266805.
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In the light of for sustainable development, microalgal biodiesel, as a renewable and sustainable
energy type, has enjoyed a surge in popularity. In fact, differently from the first generation biofuels,
the use of microalgae to produce bioenergy does not involve the triggering of "food for fuel"
competitivity and thus represents a sustainable mean to face significant concerns, such as wars and
political instabilities deriving from oil reserves shortage. Morevoer, the high oil yields and less land
use are the main advantages of microalgae. However, in order to make the current technology
viable at the large-scale, several limitations should be overcome. In particular, biomass and lipid
productivities should be further increased and all the downstream processes, from harvesting to
lipid extraction, should be optimized. To these aims, high efforts involving high investments should
be done in order to implement an intensive multidisciplinary research activity both at the laboratory
and the industrial scale.
The microalgae cultivation is the base of biofuel development and suitable genetic engineering
strategies have to be developed in order to augment the microalgae oil content and their growth rate
so that biofuels production could performed in a sustainable way. In particular, the creation of new
microalgal strains intrinsically characterized by high lipid productivities as well as by a good
tolerance to high CO2 levels is an ambitious goal which might be achieved only once their genome
is known. The results presented in this thesis represent the first step needed to design a genetic
approache which may eventually facilitate large-scale production of algae. The use of transgenic
microalgae for the production of bioproducts represent an enormous economic and biotechnology
promise, because algal production combines the simplicity and speed of haploid, single-cell
genetics in an organism with elaborate biosynthetic potential, and with the associated economic
benefit of using photosynthesis to drive product formation.
As technology continues to be progressed and algae production industrialization continues to be
improved, microalgae energy as the third generation biofuel will contribute their own strength to
relieve the tense situation of resources.
The contribution of the present work, to this general target can be briefly summarized as follows.
The growth kinetics of C. sorokiniana has been investigated along with their corresponding lipid
content, both batch and helical photobioreactors. The main results achieved during this activity are
the knowledge of the effect of nitrogen concentration in solution on the growth rate and lipid
content of C. sorokiniana. These informations represent the first step towards the development of a
nitrogen based strategy for the optimization of lipid productivity of C. sorokiniana cultures.
As far as the genetic characterization activity, the chloroplast and mitochondrial DNAs of two
strains, i.e. C. sorokiniana and C. variabilis, respectively, have been sequenced for the first time in
the literature. The obtained results allowed to perform a phylogenetic assessment involving
different microalgae strains belonging to the Chlorella clade. Such results represent the first
important step towards the development of genetic engineering strategies aimed to improve the
current microalgae based systems for the production of biofuels and the capture of CO2.
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Halfhide, Trina Cassandra. "Algae: Opportunities for Biomass Feedstock Production, Wastewater Treatment and Educational Outreach." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5032.
Full textAbstract:
Algae are a diverse group of simple organisms that lack roots, stems or leaves and are able to use sunlight, carbon dioxide, and nutrients to produce complex compounds, such as carbohydrates, proteins and lipids. These compounds, especially lipids, are highly sought-after by agricultural, nutraceutical and energy interests. Although there is great potential for algae derived biofuels, there are technical and economic challenges associated with their cultivation. Relevant to this dissertation, the environmental impacts associated with algae cultivation can be reduced by using municipal and agricultural wastewaters as a water and nutrient source. This research was divided into three sections to address current challenges in the algal industry and science, technology, engineering and math (STEM) education. The sections were: 1) examination of the growth of indigenous algae on wastewater (centrate) produced from dewatering anaerobically digested municipal sludge, 2) examination of the effect of non-axenic conditions on the growth of three different algal cultures using wastewater from a recirculating aquaculture system (RAS), and 3) using wastewater treatment and algae to increase scientific inquiry in authentic science research with high school students. In the first section, indigenous algae were cultivated on centrate under natural light conditions in a semi-continuous photobioreactor. A non- linear bio-optical model was developed considering Michaelis-Menten photosynthesis-irradiance response. The bio-optical model was applied to fit the cumulative biomass data and had an R-squared value of 0.96. The second section examined the growth and accumulation of storage product. Higher calorific values were observed for all algae cultures when grown under non-axenic conditions, most likely due to significantly higher lipid contents. Significantly higher algal lipid contents under non-axenic conditions may be attributed to the stress of the presence of RAS microorganisms. Finally, having a university-based algal project with involvement of University of South Florida (USF) researchers, teachers and high school (HS) students facilitated increased scientific understanding and skills among HS students. Outcomes included graduate students gaining greater in-depth practical understanding as these students had to learn skills, such as designing a photobioreactor and then immediately had to teach HS students how to construct photobioreactors, design and conduct experiments, and gather scientific data. HS students gained a greater understanding of biological and chemical processes, such as photosynthesis. In addition, they learned important skills, such as calculating means and standard deviations using Excel, orally communicating scientific concepts and preparation of a PowerPoint presentation.
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Silva, Leonardo Guimarães. "Farinha de algas marinhas (schizochytrium sp.) e vitamina E na alimentação de cordeiros confinados." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153725.
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Previous issue date: 2018-03-02<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>O trabalho foi dividido em dois estudos. No estudo 1, objetivou-se avaliar o efeito da inclusão de farinha de algas marinhas Schizochytrium sp. associada ou não a vitamina E, na dieta de cordeiros Ile de France, sobre o consumo, digestibilidade, desempenho, balanço de nitrogênio, comportamento ingestivo e características quantitativas de carcaça, realizados no Laboratório de Produção Ovina pertencente ao Departamento de Zootecnia da FCAV, Unesp, Campus Jaboticabal, SP. Foram utilizados 32 cordeiros Ile de France, machos não castrados, com peso inicial de 20,0 ± 0,2 kg recebendo as dietas: CO = silagem de milho + concentrado; FA = silagem de milho + concentrado com 4% de farinha de algas marinhas; VE = silagem de milho + concentrado contendo 1000 mg de vitamina E e FAVE = silagem de milho + concentrado contendo 4% de farinha de algas marinhas e 1000 mg de vitamina E, com base na matéria seca (MS), e relação volumoso:concentrado 40:60, fornecidos às 7 e 17 h, até atingirem o peso de abate de 35,0 ± 0,2 kg. As avaliações de digestibilidade e balanço de nitrogênio foram realizadas em gaiolas de metabolismo quando os animais atingiram 27 kg de peso corporal, representando a média de peso de entrada e saída no confinamento. Os parâmetros quantitativos da carcaça foram obtidos após abate humanitário dos animais. No estudo 2, foram avaliados parâmetros ruminais in vitro, tendo como variáveis pH, nitrogênio amoniacal (N-NH3) e ácidos graxos de cadeia curta (AGCC), realizados na Unidade Animal de Estudos Digestivos e Metabólicos da mesma unidade universitária. Foram usados oito ovinos canulados adultos da raça Santa Inês, castrados, com peso corporal médio de 50,0 kg, como doadores do líquido ruminal, sendo dois animais por dieta. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro tratamentos e oito repetições para o estudo um e quatro tratamentos e seis repetições para o estudo dois, com auxílio do programa estatístico SAS versão 9.2, e comparações das médias pelo teste Tukey a 5% de significância. O consumo de nutrientes, desempenho, balanço aparente de nitrogênio, parâmetros quantitativos de carcaça, medidas no músculo Longissimus e tamanho de cortes não diferiram (P>0,05) entre as dietas. A inclusão de farinha de algas marinhas e vitamina E resultaram em maior (P<0,05) digestibilidade aparente do extrato etéreo (EE), fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA). O comportamento ingestivo diferiu para as variáveis ócio, número de bolos ruminados (NBR), número de mastigação (NM), tempo de mastigação (TM) e número de mastigação diária (NMD). Os parâmetros ruminais in vitro, pH, N-NH3 e AGCC variaram (P<0,05) segundo os tratamentos, com pH superior (<0,05) para o tratamento com inclusão de vitamina E (VE). O N-NH3, foi superior (<0,05) para o tratamento com inclusão de farinha de algas (FA). Quando avaliado o AGCC, o ácido acético foi superior (<0,05) no tratamento sem inclusão de farinha de algas ou vitamina E (CO), e o ácido propiônico superior (<0,05) no tratamento apenas com inclusão de farinha de algas (FA). A inclusão de farinha de algas marinhas associadas ou não a vitamina E, se mostrou alternativa para nutrição de cordeiros confinados, melhorando a digestibilidade aparente do EE, FDN e FDA, comportamento ingestivo e parâmetros ruminais in vitro.<br>The research was divided into two studies. In study 1, the aim was to evaluate the effect of feeding marine algae meal Schizochytrium sp. associated or not with vitamin E to Ile de France lambs, on intake, digestibility, performance, nitrogen balance, feeding behavior, and quantitative carcass traits. The study was performed at the Sheep Production Laboratory belonging to the Animal Science Department of FCAV, Unesp - Jaboticabal, SP. A total of 32 intact Ile de France male lambs with an initial weight of 20.0 ± 0.2 kg were fed the following diets: CO = corn silage + concentrate; SM = corn silage + concentrate with 4% marine algae meal; VE = corn silage + concentrate containing 1000 mg of vitamin E, and SMVE = corn silage + concentrate containing 4% marine algae meal and 1000 mg vitamin E, on a dry matter basis, at a forage:concentrate ratio of 40:60, supplied at 7 a.m. and 5 p.m., until the lambs reached the slaughter weight of 35.0 ± 0.2 kg. The digestibility and nitrogen balance evaluations were performed in metabolism cages when the animals reached 27 kg of body weight, representing the average weight at feedlot entry. The quantitative carcass parameters were obtained after humane slaughtering. In study 2, the following in vitro ruminal parameters were evaluated: pH, ammoniacal nitrogen (N-NH3) and short chain fatty acids (SCFA), performed at the Animal Unit of Digestive and Metabolic Studies belonging to the same university. Eight castrated Santa Inês adult sheep, cannulated, with a mean body weight of 50.0 kg were used as donors of ruminal fluid, being two animals per diet. The experimental design was completely randomized, with four treatments and eight replications for the study 1, and four treatments and six replications for the study 2, using the SAS statistical software version 9.2. The averages were compared by Tukey’s test 5% at significance. Nutrient intake, performance, apparent nitrogen balance, quantitative carcass parameters, measurements on Longissimus muscle, and the size of meat cuts did not differ (P>0.05) between diets. The inclusion of marine algae meal and vitamin E resulted in higher (P<0.05) apparent digestibility of ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Feeding behavior differed for the variables idleness, number of boli ruminated (NBR), chewing number (CN), chewing time (CT), and daily chewing number (DCN). The in vitro ruminal parameters pH, N-NH3, and SCFA varied (P<0.05) according to the treatment, with higher pH (<0.05) when vitamin E was used (VE). N-NH3 was higher (<0.05) for the treatment with inclusion of marine algae meal (SM). For the SCFA, acetic acid was higher (<0.05) for the treatment without inclusion of marine algae meal or vitamin E (CO), and propionic acid was higher (<0.05) for the treatment with inclusion of marine algae meal (SM). The inclusion of marine algae meal with or without vitamin E was shown to be an alternative for feeding feedlot lambs, improving the apparent digestibility of EE, NDF, and ADF, feeding behavior, and in vitro ruminal parameters.
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Adams, Curtis. "Studies on nitrogen and silicon deficiency in microalgal lipid production." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1955.
Full textAbstract:
Microalgae are a rich, largely untapped source of lipids. Algae are underutilized, in part, because lipid formation generally is stimulated by stress, such as nutrient deficiency. Nutrient deficiencies reduce growth, resulting in a tradeoff between elevated cellular lipids and abundant cell division. This tradeoff is not well understood. We also have a poor understanding of the physiological drivers for this lipid formation. Here we report on three sets of research: 1) Assessment of species differences in growth and lipid content tradeoffs with high and low level nitrogen deficiency; 2) Investigation of physiological drivers of lipid formation, by mass balance accounting of cellular nitrogen with progressing deficiency; 3) Examination of the effects of sodium chloride and silicon on lipid production in a marine diatom. 1) Nitrogen deficiency typically had disproportionate effects on growth and lipid content, with profound differences among species. Optimally balancing the tradeoff required a wide range in the rate of nitrogen supply to species. Some species grew first and then accumulated lipids, while other species grew and accumulated lipids concurrently--a characteristic that increased lipid productivity. High lipid content generally resulted from a response to minimal stress. 2) Commonalities among species in cellular nitrogen at the initiation of lipid accumulation provided insight into the physiological drivers for lipid accumulation in nitrogen deficient algae. Total nitrogen uptake and retention differed widely among species, but the ratio of minimum retained nitrogen to nitrogen at the initiation of lipid accumulation was consistent among species at 0.5 ± 0.04. This suggests that lipid accumulation was signaled by a common magnitude of nitrogen deficiency. Among the cellular pools of nitrogen at the initiation of lipid accumulation, the concentration of RNA and the protein to RNA ratio were most similar among species with averages of 3.2 ± 0.26 g L-1 (8.2% variation) and 16 ± 1.5 (9.2% variation), respectively. This implicates critical levels of these parameters as potential signals initiating the accumulation of lipids. 3) In a marine diatom, low levels of either sodium chloride or silicon resulted in at least 50% increases in lipid content. The synergy of simultaneous, moderate sodium chloride and silicon stress resulted in lipid content up to 73%. There was a strong sodium chloride/silicon interaction in total and ash-free dry mass densities that arose because low sodium chloride was inhibitory to growth, but the inhibition was overcome with excessive silicon supply. This suggests that low sodium chloride may have affected metabolism of silicon.
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Hodgson, Paul Andrew. "The effects of environmental variables upon the lipid class and fatty acyl composition of a marine microalga, Nannochloropsis oculata (Droop) Eustigmatophyceae (Hibberd)." Thesis, University of Stirling, 1990. http://hdl.handle.net/1893/25425.
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Detailed analyses of the lipid class and fatty acid composition were carried out for the marine microalgal species Nannoch/oropsis oculata (Droop) (CCAP strain no. 849/1) of the division Eustigmatophyceae (Hibberd). The alga was grown in batch and continuous culture using a novel culturing apparatus, the cage culture turbidostat, the construction of which is detailed in full. The total lipid extract yielded by the alga varied in a growth-phase dependent manner within the range 25 % to 80 % of the lyophilised cell mass. Of this between 40 % and 70 % was recovered as fatty acid methyl esters (FAME) upon transesterification. The total fatty acid composition of N. oculata consisted mainly of 16:0, 16:1 and 20:5(n-3), these three fatty acids often accounting for greater than 80 % of the total fatty acid mass. Between 9 % and 50 % of the mass of total FAME was accounted for by 20:5(n-3), the balance being accounted for by variations in the relative proportions of 16:0, 16:1, 18:1, 18:2 and 20:4. During periods of low cellular division rate, such as the lag- and stationary-phases, the proportion of polyunsaturated fatty acids (PUFA) (mainly 20:5(n-3» decreased. The total fatty acids became increasingly saturated as higher proportions of shorter chain length fatty acids accumulated, mainly in triacylglycerols (TAO). Increased cellular proportions of total lipid resulted from TAO accumulation which occurred on account of preferential partitioning of carbon into TAO biosynthesis whilst cellular division was suspended. The fatty acid composition of the TAO was more saturated at high synthesis rate and vice-versa at lower rates. The galactolipids, monogalactosyldiacylglycerol (MODO) and digalactosyldiacyl glycerol (DODO) were rich in 20:5(n-3) during exponential cell division containing up to 77 % and 53 % 20:5(n-3) respectively. Phosphatidylcholine (PC) was the only cl~s to contain significant proportions of CIS fatty acids during exponential growth, thus implicating its involvement in the acyl chain elongation reactions between the Cl6 and C20 fatty acids. Culture incubation temperature in the range 5 °C to 25°C did not influence the fatty acid composition of N. oculata. The effect of temperature upon culture dynamics at the lower culture incubation temperatures gave an apparent decrease in the PUFA content of the total fatty acid at a given point on the cultures growth curves. By expressing the data in tenns of culture doubling periods during the exponential-phases of growth it was found that temperature had no real effect upon fatty acid unsaturation or chain length. at either the total or the individual lipid class FAME level after the cells had passed through five doubling periods. Increasing the culture medium salinity from one quarter to one and a half times that of normal seawater decreased the un saturation and chain length of the fatty acids at both total and individual lipid class levels. The change resulted from the progressive accumulation of 18:1 and 18:2"at the expense of 20:5. Variation of salinity did not affect the dynamics of the cultures in the same respect as temperature in that a lag-phase was not observed on the cultures growth curves. However. such a phase was evident in the fatty acid profile of the cells in the period following inoculation. The 'effects of culture illumination intensity in the range 45 Jill m-2 sec-I to 170 Jill m 2 sec-! were examined under continuous culture conditions using the cage culture turbidostat Accumulation of saturated TAG by the cells at the higher illumination intensities gave an apparent decrease in the rate of PUFA biosynthesis. The polar lipid classes were found to be more highly unsaturated at higher illumination intensities. At lower illumination intensity TAG accumulation was reduced and the total fatty acid composition was accordingly more unsaturated. The fatty acid composition of the TAG component was more unsaturated but those of the polar lipid classes were less unsaturated than at higher illumination intensity. Increased illumination increased the degree of un saturation of the polar lipid cl~sses. Excess fixed carbon was partitioned into TAG biosynthesis. primarily as 16:0 and 16:1. The net accumulation of this lipid class even at high cell division rates resulted in a low overall unsaturation level. The effects of decreasing nitrate concentration in the range 1.0 mM N03 - to 0.001 mM N03 - had a similar basis to those of illumination in that the changes in the total fatty acid composition were largely governed by the rate of TAO accumulation. At high nitrate concentrations the cellular division rate was relatively high and the proportion of TAO in the total lipid extract was low. Consequently, both total and individual lipid classes contained high proportions of unsaturates, particularly 20:5(n-3). However, when the nitrate concentration was decreased, such that it began to limit the rate of cellular division, TAG accumulated Cursory analyses of the molecular species of the galactolipid classes, MODO and DODO, and phospholipid class PC are presented. The effects of environmental variables are discussed in tenns of the changes which may occur in the growth phase distribution of the cells in asynchronous culture, along with the concommitant changes in the lipid composition of the cells. The potential linkage of the elongation and desaturation reactions with both MODO and PC is also discussed briefly with reference to future research.
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Butler, Reece. "Effect of Heavy Metals Found in Flue Gas on Growth and Lipid Accumulation for Green Algae Scenedesmus obliquus." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1159.
Full textAbstract:
This study evaluated the effect of several heavy metals that are present in flue gases on the algae, focusing on the growth and accumulation of lipids in the algae that can be converted to biodiesel. Concentrations for the heavy metals were calculated based on literature and assumptions. Metals were tested individually first at the highest concentrations that might be present (reference concentrations). The metals and their reference concentrations were: arsenic at 1.56 mg/L, cadmium at 0.3 mg/L, chromium at 2.6 mg/L, cobalt at 0.32 mg/L, copper at 2.62 mg/L, lead at 1.09 mg/L, nickel at 5.08 mg/L, mercury at 0.2 mg/L, selenium at 0.2 mg/L, and zinc at 8.8 mg/L. At these concentrations, most of the metals had a negative effect on the growth and lipid content of the algae. All of the metals were then tested at lower concentrations. At 1/20 the reference concentrations, the metals enhanced growth as well as lipid accumulation in the algae. At higher concentrations there was a negative effect.
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Coogan, Melinda Ann La Point Thomas W. "Bioaccumulation of triclocarban, triclosan, and methyl-triclosan in a North Texas wastewater treatment plant receiving stream and effects of triclosan on algal lipid synthesis." [Denton, Tex.] : University of North Texas, 2007. http://digital.library.unt.edu/permalink/meta-dc-3986.
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Coogan, Melinda Ann. "Bioaccumulation of Triclocarban, Triclosan, and Methyl-triclosan in a North Texas Wastewater Treatment Plant Receiving Stream and Effects of Triclosan on Algal Lipid Synthesis." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3986/.
Full textAbstract:
Triclosan (TCS) and triclocarban (TCC), widely used antimicrobial agents found in numerous consumer products, are incompletely removed by wastewater treatment plant (WWTP) processing. Methyl-triclosan (M-TCS) is a more lipophilic metabolite of its parent compound, TCS. The focus of this study was to quantify bioaccumulation factors (BAFs) for TCS, M-TCS, and TCC in Pecan creek, the receiving stream for the City of Denton, Texas WWTP by using field samples mostly composed of the alga Cladophora sp. and the caged snail Helisoma trivolvis as test species. Additionally, TCS effects on E. coli and Arabidopsis have been shown to reduce fatty acid biosynthesis and total lipid content by inhibiting the trans-2 enoyl- ACP reductase. The lipid synthesis pathway effects of TCS on field samples of Cladophora spp. were also investigated in this study by using [2-14C]acetate radiolabeling procedures. Preliminary results indicate high TCS concentrations are toxic to lipid biosynthesis and reduce [2-14C]acetate incorporation into total lipids. These results have led to the concern that chronic exposure of algae in receiving streams to environmentally relevant TCS concentrations might affect their nutrient value. If consumer growth is limited, trophic cascade strength may be affected and serve to limit population growth and reproduction of herbivores in these riparian systems.
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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.
Full textAbstract:
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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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.
Full textAbstract:
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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Lingaraju, Bala P. "Removal of Nitrogen from Wastewater Using Microalgae." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1321888338.
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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.
Full textAbstract:
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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Yang, Ying. "Effects of Temperature, Light Intensity and Quality, Carbon Dioxide, and Culture Medium Nutrients on Growth and Lipid Production of Ettlia oleoabundans." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-dissertations/42.
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Ettlia oleoabundans, a freshwater green microalga, was grown under different environmental conditions to study its growth, lipid yield and quality for a better understanding of the fundamental physiology of this oleaginous species. E. oleoabundans showed steady increase in biomass under low temperature and low light intensity, and at high temperature lipid cell content significantly increased independent of nitrate depletion. Studies on light quality showed that red light treatment did not change the biomass concentration, but stimulated lipid yield especially oleic acid, the most desirable biodiesel precursor. Moreover, no photoreversibility in lipid production was observed when applying alternating short-term red and far-red lights, which left the phytochrome effect still an open question. In addition, carbon dioxide enrichment via an air sparging system significantly boosted exponential growth and increased carbon conversion efficiency. Finally, a practical study demonstrated the feasibility of growing E. oleoabundans for high lipid production using a diluted agricultural anaerobic waste effluent as the medium. Together, these studies showed the potential of E. oleoabundans as a promising high yield feedstock for the production of high quality biodiesel.
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Guha, Roy Aimee. "Microalgal growth and lipid production : trends, multiple regression models, and validation in a photobioreactor." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:282874c9-06d4-41bf-bdc9-fb4ff515f57c.
Full textAbstract:
Algae are a promising new source of oil for biodiesel. They are aquatic organisms that do not require cropland, and they can produce many useful side-products for bioenergy, aquaculture, and nutraceutical production. To be cost-effective, algae need high and reliable oil productivities; however, there is still a great deal to learn about the effects of culturing conditions on algae growth rates and lipid production. These culturing conditions include light intensity, gas flow, use of CO<sub>2</sub>, and culture volume. An extensive database of published research on algae growth rates and lipid contents under a wide variety of environmental conditions was prepared. By graphing data from 116 publications on 132 microalgae species, several key trends were identified relating to culturing parameters and algae biomass and lipid production. In addition, data from 131 publications on 128 microalgae species were graphed to look at presence of flagella, nutrient limitation, lipid productivity, and productivity tradeoffs. Moreover, cell size information was gathered for 146 species. The interactions between culture variables are complex, so it is difficult to quantify the degree to which each culture variable affects algae growth rates and lipid production. Therefore, several multivariate analyses were performed to generate a set of general and simple predictive models to assess specific growth rates, maximum lipid contents, and volumetric lipid productivities. These models were used to determine which culture parameters were significant predictors of algae growth rates and lipid production, and the contribution of each environmental parameter was quantified. In addition to models for algae in general, genera specific models were prepared for Chlorella, Isochrysis, Nannochloropsis, Phaeodactylum, and Tetraselmis. These models show high predictive capabilities, and they greatly extend the range of species-specific multiple regression models available. Furthermore, one Tetraselmis model was validated using Tetraselmis impellucida growth experiments in a large novel photobioreactor.
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DeMicco, Erik David. "Feasibility of Using Biofuel By-Products as a Sustainable Nutritional Resource for Aquaculture Production of Litopenaeus vannamei." NSUWorks, 2015. http://nsuworks.nova.edu/occ_stuetd/387.
Full textAbstract:
Many different algal species can provide an acceptable protein ingredient, with good digestibility, for shrimp feeds. Compared to fish meal, similar protein, carbohydrate, and lipid levels can be found in select algal species. Traditional shrimp diets in aquaculture rely on fish meal and fish oil from pelagic fish fisheries. A reduction or elimination of these ingredients would reduce the dependency of shrimp aquaculture on offshore fisheries and increase economic competiveness. Biofuel production produces algal by-products of potential use to aquaculturists that might reduce or eliminate the need for fisheries products in shrimp feed. Established uses for by-products from biofuel production include fertilizer for crops, fodder for swine and poultry, and production of methane and alcohol fuels. However, using biofuel production by-products as a protein and carbohydrate source for the Pacific white shrimp, Litopenaeus vannamei, has not been investigated. Therefore, a series of feeding experiments were conducted to evaluate if the algae used to produce biofuel could be a suitable main protein source in formulated diets for L. vannamei.
The feasibility of substituting biofuel algae by-product for fish meal in the juvenile L. vannamei (0.0306 ± 0.0011 g) diet was evaluated, and an adequate substitution ratio was determined. Eighteen experimental diets were evaluated using 60, 80, and 100% fish meal substitution levels. Chaetoceros calcitrans, Nannochloropsis salina, and Pavlova sp. were chosen as the algae sources as they have potentially high use in biodiesel production due to their high lipid content and each has been included in established larval shrimp aquaculture operations. Each diet varied the level of fish meal substitution (60, 80, or 100%) and either contained dried algal biomass or, alternatively, dried algal biomass with reduced lipid content to simulate algal biomass post-biodiesel production. The diets were compared, relative to their effect on weight gain in juvenile L. vannamei, to each other and to a commercially available diet (CONTROL) and a diet formulated using the ingredients used in all of the experimental diet formulations but without algal biomass (BASAL).
The shrimp were held individually in 355-ml Styrofoam cups filled with 200-ml seawater with a salinity of 32 parts per thousand (ppt) salinity under a 12:12 light:dark photoperiod. Water exchange was 90% per day for six days and 100% on the seventh day when weights were taken. Each of the twenty diets was presented daily to seven replicate cups, each cup containing a single shrimp, for six weeks. Food was presented once per day to satiation, which was determined by the shrimp refusing additional feed. Each animal was weighed weekly. After six weeks, the shrimp were harvested and final weights were taken.
The analysis of differences between strains, levels, and lipids indicated there was a significant difference between all of the algal-based diets and the control. Overall, significantly better growth rates were observed in the diets with less fish protein replacement. The 60% fish meal replaced diets outperformed the diets that had 80 or 100% fish meal replacement. There were no significant differences in nutritional value among the algal species. Survival rates, from an aquaculture perspective, were acceptable for all treatments (>71%).
Results from these studies demonstrated that formulated diets using algal biomass from biodiesel production can be the primary protein source for L. vannamei postlarvae.
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Šimanský, Samuel. "Optimalizace extrakce pigmentů z buněk kvasinek a řas." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-432694.
Full textAbstract:
The presented diploma thesis deals with the extraction and storage stability of lipophilic pigments produced by selected strains of yeasts and algae. In this thesis, there was studied the influence of the selected solvents on the efficiency of extraction, as well as the effect of ambient temperature on the stability of the pigments during storage. The work is divided into two main parts, theoretical and practical part. In the theoretical part knowledge about algae, yeasts and their cultivation parameters is summarized. Furthermore, some information regarding the selected lipid metabolites, their properties and possibilities of application in various branches of industry is mentioned. The practical part deals with the preparation of extracts and stability tests. Extracts were prepared from selected biomass samples in solvents suitable for applications in food industry or cosmetics (ethanol and hexane). Subsequently, the long-term stability tests lasting 4 months and short-term stability tests lasting a total of 28 days were performed on these extracts. The pigments were determined by HPLC and spectrophotometrically, the fatty acid content was determined by GC. For the extraction of pigments from biomass, in the most cases ethanol appears to be the optimal solvent. However, for lipid extraction from biomass, hexane appears to be the optimal solvent for a significant number of samples. In most samples, storage in the freezer showed the most favourable effect on pigment stability, but some samples showed comparable stability even when stored in the refrigerator.