Littérature scientifique sur le sujet « Algal lipids »
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Articles de revues sur le sujet "Algal lipids"
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Loria, Mark H., James S. Griffin, George F. Wells et Kurt R. Rhoads. « Effects of feast-famine nutrient regimes on wastewater algal biofuel communities ». PLOS ONE 18, no 1 (4 janvier 2023) : e0279943. http://dx.doi.org/10.1371/journal.pone.0279943.
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Microalgae accumulate lipids in response to nutrient deprivation, and these lipids are a biodiesel fuel stock. Algal cultivation with secondary wastewater effluent is one proposed platform for biofuel production, which provides nutrients to algae while further polishing wastewater effluent. Algal bioreactors were tested using a feast-famine feeding regiment in simulated secondary wastewater effluent to evaluate the effects on lipid content and algal community structure. Algal polycultures were inoculated into reactors fed with synthetic secondary wastewater effluent at pH 7.5 and 9 and operated under a feast-famine nutrient (N, P, and BOD) supply regime in sequencing batch reactors. Fatty acid methyl ester contents of the reactors were assessed, which showed a decrease in lipid content after the feast-famine cycling (from 12.2% initially to 5.2% after four cycles at pH 9). This decrease in lipid content was not correlated with an increase in carbohydrate storage within biomass, nor an increase in bacterial biomass abundance relative to algal biomass in the reactors. The eukaryotic microbial communities from reactors operated at pH 9 diverged from reactors operated at pH 7.5 during cycling, with the pH 9 reactors becoming dominated by a single Operational Taxonomic Unit aligning to the Scenedesmus genus. These results suggest that high pH and feast-famine nutrient cycling may select for a less diverse algal community with a lower lipid content within a secondary wastewater polishing scheme.
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Czerwik-Marcinkowska, Joanna, Katarzyna Gałczyńska, Jerzy Oszczudłowski, Andrzej Massalski, Jacek Semaniak et Michał Arabski. « Fatty Acid Methyl Esters of the Aerophytic Cave Alga Coccomyxa subglobosa as a Source for Biodiesel Production ». Energies 13, no 24 (9 décembre 2020) : 6494. http://dx.doi.org/10.3390/en13246494.
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The microscopic alga Coccomyxa subglobosa, collected from the Głowoniowa Nyża Cave (Tatra Mountains, Poland), is a source of fatty acids (FAs) that could be used for biodiesel production. FAs from subaerial algae have unlimited availability because of the ubiquity of algae in nature. Algal culture was carried out under laboratory conditions and algal biomass was measured during growth phase, resulting in 5 g of dry weight (32% oil). The fatty acid methyl ester (FAME) profile was analyzed by means of gas chromatography–mass spectrometry (GC–MS). The presence of lipids and chloroplasts in C. subglobosa was demonstrated using GC–MS and confocal laser microscopy. Naturally occurring FAMEs contained C12–C24 compounds, and methyl palmitate (28.5%) and methyl stearate (45%) were the predominant lipid species. Aerophytic algae could be an important component of biodiesel production, as they are omnipresent and environmentally friendly, contain more methyl esters than seaweed, and can be easily produced on a large scale.
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K., Santhoshkumar, Prasanthkumar S. et J. G. Ray. « Chlorococcum humicola (Nageli) Rabenhorst as a Renewable Source of Bioproducts and Biofuel ». Journal of Plant Studies 5, no 1 (29 février 2016) : 48. http://dx.doi.org/10.5539/jps.v5n1p48.
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Among the diverse new generation biomass yielding species, green algae are the most promising organisms. Compared to biomass production of other organisms, production of algae is less laborious, quite fast, and more economical. Moreover, eutrophicated waters get naturally purified in the cultivation process of algae. Algal biomass from monoculture of specific species, which are rich in carbohydrates, proteins and lipids, is considered a good source of diverse bio-products and feed-stock for food, feeds and bio-fuels. Quantity and quality of algal biomass for specific products depend on the species and strains as well as environmental conditions of cultivation. In this connection, biomass productivity and oil-yield of a local strain of <em>Chlorococcum humicola </em>(Nageli) Rabenhorst was assessed in Bold’s Basal Medium. Long-term storage capacity of the alga was tried by entrapping the algal cells in sodium alginate beads, which showed viability up to 14 months. Estimation of total carbohydrate, protein, lipid and chemical characterization of oil as well as the feasibility of its conversion to biodiesel revealed the industrial potential of this local strain as a source of food and biofuel. Fatty acid profiling of the extracted oil showed that 70% are mono-saturated and 12.2 % are nutritionally important polyunsaturated fatty acids. The oil could be effectively trans-esterified to methyl esters and the conversion was confirmed by FTIR spectroscopy. Further standardization of the mass production of the alga in natural environmental conditions for biomass and oil is progressing to optimize its value as globally competent food, nutraceutical and biofuel resource.
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Zachleder, Vilém, Veronika Kselíková, Ivan N. Ivanov, Vitali Bialevich, Milada Vítová, Shuhei Ota, Tsuyoshi Takeshita, Shigeyuki Kawano et Kateřina Bišová. « Supra-Optimal Temperature : An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri ». Cells 10, no 7 (16 juillet 2021) : 1806. http://dx.doi.org/10.3390/cells10071806.
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Green algae are fast-growing microorganisms that are considered promising for the production of starch and neutral lipids, and the chlorococcal green alga Parachlorella kessleri is a favorable model, as it can produce both starch and neutral lipids. P. kessleri commonly divides into more than two daughter cells by a specific mechanism—multiple fission. Here, we used synchronized cultures of the alga to study the effects of supra-optimal temperature. Synchronized cultures were grown at optimal (30 °C) and supra-optimal (40 °C) temperatures and incident light intensities of 110 and 500 μmol photons m−2 s−1. The time course of cell reproduction (DNA replication, cellular division), growth (total RNA, protein, cell dry matter, cell size), and synthesis of energy reserves (net starch, neutral lipid) was studied. At 40 °C, cell reproduction was arrested, but growth and accumulation of energy reserves continued; this led to the production of giant cells enriched in protein, starch, and neutral lipids. Furthermore, we examined whether the increased temperature could alleviate the effects of deuterated water on Parachlorella kessleri growth and division; results show that supra-optimal temperature can be used in algal biotechnology for the production of protein, (deuterated) starch, and neutral lipids.
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Hasnain, Maria, Neelma Munir, Zainul Abideen, Heather Macdonald, Maria Hamid, Zaheer Abbas, Ali El-Keblawy, Roberto Mancinelli et Emanuele Radicetti. « Prospects for Biodiesel Production from Emerging Algal Resource : Process Optimization and Characterization of Biodiesel Properties ». Agriculture 13, no 2 (9 février 2023) : 407. http://dx.doi.org/10.3390/agriculture13020407.
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The present work focuses on the optimization of the energy conversion process and the use of algal resources for biodiesel production with ultrasound and microwave techniques in Oedogonium, Oscillatoria, Ulothrix, Chlorella, Cladophora, and Spirogyra for the first time. The fuel properties are investigated to optimize the efficiency of the newly emerging algal energy feedstock. The study indicates that the optimized microwave technique improves the lipid extraction efficiency in Oedogonium, Oscillatoria, Ulothrix, Chlorella, Cladophora, and Spirogyra (38.5, 34, 55, 48, 40, and 33%, respectively). Moreover, the ultrasonic technique was also effective in extracting more lipids from Oedogonium sp., Oscillatoria sp., Ulothrix sp., Chlorella, Cladophora sp., and Spirogyra sp. (32, 21, 51, 40, and 36%, respectively) than from controls, using an ultra-sonication power of 80 kHz with an 8-min extraction time. The fatty acid composition, especially the contents of C16:0 and C18:1, were also enhanced after the microwave and sonication pretreatments in algal species. Enhancement of the lipids extracted from algal species improved the cetane number, high heating value, cold filter plugging point, and oxidative stability as compared to controls. Our results indicate that the conversion of biofuels from algae could be increased by the ultrasound and microwave techniques, to develop an eco-green and sustainable environment.
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Udiharto, M., Rino Nirwawan et Sri Astuti Rahayu. « The Superiority Of Micro-Algae As A Potential Feedstock For Alternative Energy ». Scientific Contributions Oil and Gas 32, no 1 (17 mars 2022) : 21–26. http://dx.doi.org/10.29017/scog.32.1.829.
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Micro-algae are plant like organisms belong to Thallophytic group, they have no true roots, stems, and leaves. They can easy to grow in fresh, saline, and brackish water. Like plants, micro-algae can conduct photosynthetic process to manufacture carbohydrates for their own food. Algal cell generally contains high concentration of proteins, carbohydrates, and lipids. Micro-algae grow very rapidly, and their biomass is commonly double within 24 hours. The algal are the highest potential energy yield agricultural oil crop. In accordance with capability of their lives, micro-algae have potential as feedstuff for alternative energy. Other capabilities of algal are as carbon dioxide reduction, animal feed, livestock feed, fertilizer, supplement for human health, etc.
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Bocanegra, Aránzazu, Adrián Macho-González, Alba Garcimartín, Juana Benedí et Francisco José Sánchez-Muniz. « Whole Alga, Algal Extracts, and Compounds as Ingredients of Functional Foods : Composition and Action Mechanism Relationships in the Prevention and Treatment of Type-2 Diabetes Mellitus ». International Journal of Molecular Sciences 22, no 8 (7 avril 2021) : 3816. http://dx.doi.org/10.3390/ijms22083816.
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Type-2 diabetes mellitus (T2DM) is a major systemic disease which involves impaired pancreatic function and currently affects half a billion people worldwide. Diet is considered the cornerstone to reduce incidence and prevalence of this disease. Algae contains fiber, polyphenols, ω-3 PUFAs, and bioactive molecules with potential antidiabetic activity. This review delves into the applications of algae and their components in T2DM, as well as to ascertain the mechanism involved (e.g., glucose absorption, lipids metabolism, antioxidant properties, etc.). PubMed, and Google Scholar databases were used. Papers in which whole alga, algal extracts, or their isolated compounds were studied in in vitro conditions, T2DM experimental models, and humans were selected and discussed. This review also focuses on meat matrices or protein concentrate-based products in which different types of alga were included, aimed to modulate carbohydrate digestion and absorption, blood glucose, gastrointestinal neurohormones secretion, glycosylation products, and insulin resistance. As microbiota dysbiosis in T2DM and metabolic alterations in different organs are related, the review also delves on the effects of several bioactive algal compounds on the colon/microbiota-liver-pancreas-brain axis. As the responses to therapeutic diets vary dramatically among individuals due to genetic components, it seems a priority to identify major gene polymorphisms affecting potential positive effects of algal compounds on T2DM treatment.
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Cheban, Larysa, Oleksii Khudyi, Maja Prusińska, Arkadiusz Duda, Lidiia Khuda, Grzegorz Wiszniewski, Olha Kushniryk et Andrzej Kapusta. « Survival, proximate composition, and proteolytic activity of Artemia salina bioencapsulated with different algal monocultures ». Fisheries & ; Aquatic Life 28, no 4 (1 décembre 2020) : 205–15. http://dx.doi.org/10.2478/aopf-2020-0025.
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Abstract This study focused on testing Artemia sp. zooplankton saturation with freshwater microalgae biomass and then using this method to correct the nutritional composition of Artemia. Accordingly, the influence of three species of microalgal monocultures was analyzed (2 freshwater – Desmodesmus armatus (Chod.) Hegew. and Chlorella vulgaris Veijerinck; one halophilous – Dunaliella viridis Teodor.). The algal monocultures were applied once in a quantity of 2-3 × 106 cells × l−1 for each 200,000 Artemia individuals hatched. The control group Artemia did not receive algae. The enrichment process lasted 24 h, and control measurements were performed every 6 h. The survival of Artemia nauplii, their proteolytic activity, and the content of proteins, lipids, and carotenoids were analyzed. The choice of algae species for Artemia enrichment was guided by the size of the algal cells and their biochemical composition. Selected algae contained about 50% protein, 20% lipid, and 12 mg of carotenoids per g of dry weight. Using algae to saturate the Artemia nauplii permitted reducing their mortality during the 24 h enrichment regime. The introduction of C. vulgaris biomass halved this value. The use of algae also increased the proteolytic activity in Artemia nauplii and the content of proteins, lipids, and carotenoids in their biomass. The best results of the bioencapsulation of Artemia nauplii with algae was with the C. vulgaris biomass.
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Ameka, G. K., L. K. Doamekpor, A. A. Amadu et A. P. Amamoo. « Production of Biodiesel from Marine Macroalgae occurring in the Gulf of Guinea, off the Coast of Ghana ». Ghana Journal of Science 60, no 1 (31 juillet 2019) : 50–58. http://dx.doi.org/10.4314/gjs.v60i1.5.
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The purpose of this study was to determine the suitability of marine macroalgae (also known as seaweeds), from the Gulf of Guinea, off the coast of Ghana, for the production of biodiesel as an alternative to liquid fuels like gasoil and gasoline. Five green marine macroalgae species: Caulerpa taxifolia, Chaetomorpha antennina, Chaetomorpha linum, Ulva fasciata, and Ulva flexuosa, were collected from the coastal waters of Ghana at West Tema Rocks during low tide. Algal lipids were extracted from dried algae biomass with hexane and diethyl ether. Biodiesel was produced from algal lipids by base-catalysed transesterification, with alcohol. The lipid content of samples was highest in C. linum (1.13 g; 5.65% dry wt.) and lowest in C. antennina (0.54 g; 2.70% dry wt.). Similarly, the quantity of biodiesel produced from the lipids was highest in C. linum (0.97 g; 4.85% dry wt.) and lowest in C. antennina (0.48 g; 2.40% dry wt.). The quantity of biodiesel produced from samples of the five species fell well within the range obtained for such species worldwide. The implications of the yield of biodiesel for commercial production and future work on marine macroalgae from Ghana as source of biofuel are discussed.
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Kent, Robert A., et Pierre-Yves Caux. « Sublethal effects of the insecticide fenitrothion on freshwater phytopiankton ». Canadian Journal of Botany 73, no 1 (1 janvier 1995) : 45–53. http://dx.doi.org/10.1139/b95-006.
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The effects of the insecticide fenitrothion (O,O-dimethyl-O-(3-methyl-4-nitrophenyl)phosphorothioate) were investigated on the unicellular phytoplankton Ankistrodesmus falcatus, Chlamydomonas reinhardtii, Chlamydomonas segnis, Chlorella pyrenoidosa, Navicula sp., Scenedesmus obliquus, Selenastrum capricornutum, and Staurastrum sp. at concentrations of 0.1, 1.0, and 10 mg∙L−1. Following a 24-h exposure, total lipids, fatty acid profiles, and bioaccumulation of fenitrothion into algal cells were determined for the above species. Total lipids may play an important role in determining sensitivity of phytoplankton to fenitrothion stress over 96-h exposures. A saturation occurred in A. falcatus membranes represented by the 5.4 and 4.3% increases in palmitic (16:0) and oleic (18:1) acids, respectively, and 1.8 and 7.6% decreases in linoleic (18:2) and linolenic (18:3) acids, respectively. This resulted in a shift from a profile dominated by linolenic (18:3) acid to one dominated by the more saturated oleic (18:1) acid. Bioconcentration factors (BCF), or the ratio of the total radiocarbon associated with algae, calculated for viable Chlamydomonas reinhardtii and Chlamydomonas segnis cells were 293 and 124, respectively. BCFs for dead cells were 1261 and 1025 for the same species, respectively. These investigations showed differential insecticide bioaccumulation between species. This bioaccumulation was shown to be correlated with the total lipid content of algal cells. Key words: algae, fatty acids, fenitrothion, lipids, pesticide.
Thèses sur le sujet "Algal lipids"
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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.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.
Texte intégralRésumé :
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoDentre 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. Jà 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.
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.
Texte intégralRésumé :
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.
Texte intégralRésumé :
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.
Livres sur le sujet "Algal lipids"
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D, Cohen Zvi Ph, et Ratledge Colin, dir. Single cell oils : Microbial and algal oils. 2e éd. Urbana, Ill : AOCS Press, 2010.
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Karel, Marcus. Utilization of non-conventional systems for conversion of biomass to food components : Recovery optimization and characterization of algal proteins and lipids ; status report (March 1985 to June 1986). Cambridge, MA : Dept. of Applied Biological Sciences, Massachusetts Institute of Technology, 1986.
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Z, Nakhost, et United States. National Aeronautics and Space Administration, dir. Utilization of non-conventional systems for conversion of biomass to food components : Recovery optimization and characterization of algal proteins and lipids ; status report (March 1985 to June 1986). Cambridge, MA : Dept. of Applied Biological Sciences, Massachusetts Institute of Technology, 1986.
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Nakamura, Yuki, et Yonghua Li-Beisson, dir. Lipids in Plant and Algae Development. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-25979-6.
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M, Tillett David, Solar Energy Research Institute, Georgia Institute of Technology. School of Applied Biology et Georgia Institute of Technology. School of Chemical Engineering, dir. Effects of fluctuating environments on the selection of high yielding microalgae. Golden, Colo : Solar Energy Research Institute, 1987.
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Khotimchenko, S. V. Lipidy morskikh vodorosleĭ-makrofitov i trav : Struktura, raspredelenie, analiz. Vladivostok : Dalʹnauka, 2003.
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Knoshaug, Eric P. Current status of the Department of Energy's Aquatic Species Program lipid-focused algae collection. Golden, CO : National Renewable Energy Laboratory, 2009.
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Ratledge, Colin, et Zvi Cohen. Single Cell Oils : Microbial and Algal Oils. AOCS, 2015.
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Algae Biofuels : Algal Fuel Producers, High Lipid Content Microalgae, Chevron Corporation, List of Algal Fuel Producers, Botryococcus Braunii. Books LLC, 2010.
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Nakamura, Yuki, et Yonghua Li-Beisson. Lipids in Plant and Algae Development. Springer London, Limited, 2016.
Trouver le texte intégralChapitres de livres sur le sujet "Algal lipids"
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Kannan, Dheeban Chakravarthi, et Vikram M. Pattarkine. « Recovery of Lipids from Algae ». Dans Algal Biorefineries, 297–310. Dordrecht : Springer Netherlands, 2013. http://dx.doi.org/10.1007/978-94-007-7494-0_12.
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Guldhe, Abhishek, Krishan Ramluckan, Poonam Singh, Ismail Rawat, Suresh Kumar Mahalingam et Faizal Bux. « Catalytic Conversion of Microalgal Lipids to Biodiesel : Overview and Recent Advances ». Dans Algal Biofuels, 315–29. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51010-1_15.
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Guschina, Irina A., et John L. Harwood. « Algal Lipids and Their Metabolism ». Dans Algae for Biofuels and Energy, 17–36. Dordrecht : Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-5479-9_2.
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Wainman, Bruce C., Ralph E. H. Smith, Hakumat Rai et John A. Furgal. « Irradiance and Lipid Production in Natural Algal Populations ». Dans Lipids in Freshwater Ecosystems, 45–70. New York, NY : Springer New York, 1999. http://dx.doi.org/10.1007/978-1-4612-0547-0_4.
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Guschina, Irina A., et John L. Harwood. « Algal lipids and effect of the environment on their biochemistry ». Dans Lipids in Aquatic Ecosystems, 1–24. New York, NY : Springer New York, 2009. http://dx.doi.org/10.1007/978-0-387-89366-2_1.
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Gupta, Adarsha, Avinesh R. Byreddy et Munish Puri. « Extraction of Lipids and Carotenoids from Algal Sources ». Dans Food Bioactives, 137–52. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51639-4_6.
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Patterson, Glenn W. « Sterol Synthesis and Distribution and Algal Phylogeny ». Dans The Metabolism, Structure, and Function of Plant Lipids, 631–36. Boston, MA : Springer New York, 1987. http://dx.doi.org/10.1007/978-1-4684-5263-1_111.
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Abdullah, Mohd Azmuddin, Hann Ling Wong, Syed Muhammad Usman Shah et Pek Chin Loh. « Algal Pathways and Metabolic Engineering for Enhanced Production of Lipids, Carbohydrates, and Bioactive Compounds ». Dans Phycobiotechnology, 363–430. Series statement : Innovations in biotechnology ; volume 3 : Apple Academic Press, 2020. http://dx.doi.org/10.1201/9781003019510-14.
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Guldhe, Abhishek, Bhaskar Singh, Faiz Ahmad Ansari, Yogesh Sharma et Faizal Bux. « Extraction and Conversion of Microalgal Lipids ». Dans Algae Biotechnology, 91–110. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-12334-9_6.
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Ravindran, B., Mayur B. Kurade, Akhil N. Kabra, Byong-Hun Jeon et Sanjay Kumar Gupta. « Recent Advances and Future Prospects of Microalgal Lipid Biotechnology ». Dans Algal Biofuels, 1–37. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51010-1_1.
Texte intégralActes de conférences sur le sujet "Algal lipids"
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Samek, O., Z. Pilát, J. Ježek, M. Šerý, S. Bernatová, P. Zemánek, L. Nedbal et M. Trtílek. « Raman microspectroscopy monitoring of lipids in algal cells ». Dans Frontiers in Optics. Washington, D.C. : OSA, 2011. http://dx.doi.org/10.1364/fio.2011.ftua6.
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Beal, Colin M., Robert E. Hebner, Michael E. Webber, Rodney S. Ruoff et A. Frank Seibert. « The Energy Return on Investment for Algal Biocrude : Results for a Research Production Facility ». Dans ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38244.
Texte intégralRésumé :
This study is an experimental determination of the energy return on investment (EROI) for algal biocrude production at a research facility at the University of Texas at Austin (UT). During the period of this assessment, algae were grown at several cultivation scales and processed using centrifugation for harvesting, electromechanical cell lysing, and lipid separation in an enhanced coalescence membrane. The separated algal lipids represent a biocrude product that could be refined into fuel. To determine the EROI, a second order analysis was conducted, which includes direct and indirect energy flows, but does not consider capital energy expenses. At the time that the data in this study was collected, the research program was focused on improving biomass and lipid productivity. As a result, some higher efficiency processing steps were replaced by lower efficiency ones to permit other experiments. Although the production process evaluated here was energy negative, the majority of the energy consumption resulted from non-optimized growth conditions. Therefore, the experimental results do not represent an expected typical case EROI for algal fuels, but rather outline the important parameters to consider in such an analysis. The results are the first known experimental energy balance for an integrated algal biocrude production facility. A Reduced Case is presented that speculates the energy use for a similar system in commercial-scale production. In addition, an analytical model that is populated with data that have been reported in the literature is presented. For the experiments, the Reduced Case, and Literature Model, the estimated EROI was 1.3 × 10−3, 0.13, and 0.57, respectively (refining energy requirements are not included in the experimental or Reduced Case EROI value). These results were dominated by growth inputs (96.59%, 94.15%, and 76.32% of the total energy requirement, respectively). For the experiments and Literature Model, lipid separation was the most energy intensive processing step (2.47% and 10.06%, respectively), followed by harvesting, refining, and then electromechanical cell lysing.
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Wogan, David M., Michael Webber et Alexandre K. da Silva. « A Resource-Limited Approach to Estimating Algal Biomass Production With Geographical Fidelity ». Dans ASME 2010 4th International Conference on Energy Sustainability. ASMEDC, 2010. http://dx.doi.org/10.1115/es2010-90154.
Texte intégralRésumé :
This paper discusses the potential for algal biofuel production under resource-limited conditions in Texas. Algal biomass and lipid production quantities are estimated using a fully integrated biological and engineering model that incorporates primary resources required for growth, such as carbon dioxide, sunlight and water. The biomass and lipid production are estimated at the county resolution in Texas, which accounts for geographic variation in primary resources from the Eastern half of the state, which has moderate solar resources and abundant water resources, to the Western half of the state, which has abundant solar resources and moderate water resources. Two resource-limited scenarios are analyzed in this paper: the variation in algal biomass production as a function of carbon dioxide concentration and as a function of water availability. The initial carbon dioxide concentration, ranging from low concentrations in ambient air to higher concentrations found in power plant flue gas streams, affects the growth rate and production of algal biomass. The model compares biomass production using carbon dioxide available from flue gas or refinery activities, which are present only in a limited number of counties, with ambient concentrations found in the atmosphere. Biomass production is also estimated first for counties containing terrestrial sources of water such as wastewater and/or saline aquifers, and compared with those with additional water available from the Gulf of Mexico. The results of these analyses are presented on a series of maps depicting algal biomass and lipid production in gallons per year under each of the resource-limited scenarios. Based on the analysis, between 13.9 and 154.1 thousand tons of algal biomass and 1.0 and 11.1 million gallons of lipids can be produced annually.
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Bucy, Harrison, et Anthony J. Marchese. « Oxidative Stability of Algae Derived Methyl Esters Containing Varying Levels of Methyl Eicosapentaenoate and Methyl Docosahexaenoate ». Dans ASME 2011 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/icef2011-60047.
Texte intégralRésumé :
Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. biodiesel), renewable diesel, renewable gasoline or synthetic paraffinic aviation kerosene. For algal methyl ester biodiesel, fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chain-polyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is well known that oxidative stability decreases with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability of algal methyl esters with varying levels of EPA and DHA. Tests were conducted using a Metrohm 743 Rancimat with automatic induction period determination following ASTM D6751 and EN 14214 standards, which call for induction periods of at least 3 hours and 6 hours, respectively. Tests were conducted at a temperature of 110°C and airflow of 10 L/h with model algal methyl ester compounds synthesized from various sources to match the fatty acid compositions of several algae strains subjected to varying removal amounts of roughly 0 to 100 percent LC-PUFA. In addition, tests were also conducted with real algal methyl esters produced from multiple sources. The bis-allylic position equivalent (BAPE) was calculated for each fuel sample to quantify the level of unsaturation. The induction period was then plotted as a function of BAPE, which showed that the oxidative stability varied exponentially with the amount of LC-PUFA. The results suggest that removal of 45 to 65 percent of the LC-PUFA from Nannochloropsis-based algal methyl esters would be sufficient for meeting existing ASTM specifications for oxidative stability.
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Wogan, David M., Alexandre K. da Silva et Michael Webber. « Assessing the Potential for Algal Biofuels Production in Texas ». Dans ASME 2009 3rd International Conference on Energy Sustainability collocated with the Heat Transfer and InterPACK09 Conferences. ASMEDC, 2009. http://dx.doi.org/10.1115/es2009-90235.
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This paper describes a unique analytical model created to assess the maximum potential for algae production in Texas. The model, which merges engineering, biology and geosciences into a singular analysis, aims to identify suitable growth locations and estimate the quantity of algae-based oils that can be potentially produced in Texas. The model incorporates geographically- and temporally-resolved data on sunlight, anthropogenic CO2 emissions, and saline or brackish water availability. These data are then overlaid with first-order biological approximations for algae growth calculations in order to create maps of algae growth potential. Solar insolation data were obtained from measurement locations throughout the state for varying time scales spanning many years from the Texas Solar Radiation Database (TSRDB). CO2 emissions were compiled from area and point sources (such as natural gas and coal-fired power plants) from the Energy Information Administration and Environmental Protection Agency. Water data for wastewater treatment plants and saline aquifers were obtained from the Texas Commission on Environmental Quality and the Texas Water Development Board. A home-built MATLAB code uses these data, along with engineering approximations and the ability to manipulate different assumptions to calculate algae growth by location and time period. For each location, the model calculates potential oil yield, biomass produced, growth rates, water and CO2 consumed and land used. Standard pond and tubular photobioreactor dimensions have been used to model real world production facilities. Realistic limits for growth rates, photosynthetic efficiencies, photosynthetic flux tolerances and oil content are also incorporated. These parameters can be varied to approximate different algae strains and growth conditions. The model assumes reactors to have ideal mixing, optimal pH and temperature controls in place. This preliminary resource assessment estimates that Texas receives an average of 375 W/m2 annually, produces 409 million tons per year of CO2 from the industrial and electrical power sectors and has approximately 1.4 trillion gallons per year of available water on a sustainable basis. The computational model estimates that between 44 and 167 million tons of algal biomass and 3.1 to 12 billion gallons of lipids can be produced annually in Texas based on the combination and availability of these resources.
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Mahapatra, Durga Madhab, H. N. Chanakya et T. V. Ramachandra. « Bioenergy generation from components of a Continuous algal bioreactor : Analysis of lipids, spectroscopic and thermal properties ». Dans 2013 Annual IEEE India Conference (INDICON). IEEE, 2013. http://dx.doi.org/10.1109/indcon.2013.6725886.
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Bandhu, Sheetal, et Debashish Ghosh. « Genetic modification to enhance single cell oil production in the oleagineous yeast Rhodotorula mucilaginosa ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/bdpk2930.
Texte intégralRésumé :
Liquid fuels derived from non-fossil resources are considered feasible alternatives as global fuel demand rises. Yeast single cell oil is gaining ground as feedstock for biofuels and oleochemicals over plant-borne or algal oil due to its short lifespan and invariable quality under different seasonal or geographical conditions. In the present work, oleaginous yeast Rhodotorula mucilaginosa IIPL32 was genetically modified to improve its oil-producing capacity by overexpressing malic enzyme, a reductant providing enzyme active in several oleaginous yeasts. Intracellular Malic enzyme was purified and characterized to validate its presence and determine its involvement in lipid synthesis and NADPH+ supply in the yeast R mucilaginosa. Apart from the pentose phosphate route, it was found that malic enzymes also provided reductants for lipid biosynthesis in this yeast. A linear expression cassette was created for selective integration of the malic enzyme under a strong promoter into the yeast genome. The lipid output was increased 1.18-fold along with significant alteration in its fatty acid profile. Estimating fuel properties revealed that the total monounsaturated fatty acids improved from 49% to 66%. The lipid produced by transformed yeast complies with fuel properties (Density, Viscosity, Cetane number, Cloud point, Pour point) as per the EU, Indian, and US standards. We conclude that genetically modified yeast lipids could be a sustainable alternative to using plant-borne oil in biofuel generation. The yeast's ability to assimilate pentose sugars generated from biomass hydrolysis makes it an efficient oil platform.
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Khot, Mahesh Balwant. « Life cycle assessment (LCA) of microbial oil-derived fuels and other non-fuel products ». Dans 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/imol9786.
Texte intégralRésumé :
Much literature is available on fungal lipids and their capability as a renewable oil platform for alternate fuels, chemicals, and food products. Microbial oils will not displace all edible oils soon, given techno-economical hurdles in commercialization. However, continued research & development can flatten the curve of deforestation and land-use impacts associated with cultivating these crops. To better understand how oleaginous yeasts and fungi could alleviate the challenges related to the energy-environment-food nexus, it becomes critical to investigate their potential environmental impacts quantitively compared to other feedstocks. Life cycle analysis or assessment (LCA) is a standard tool used for this purpose. LCA studies are not being conducted on a broader scale for fungus-derived oils than their phototrophic algal counterparts. The different stages in the life cycle of fungal lipid production that can be analyzed for environmental implications include cultivation and fermentation, oil extraction; further downstream processing; and end-use. The LCA method for fungal lipid-derived biofuel production systems should cover the main sustainability concerns of biofuel production systems: energy efficiency, climate change, and land occupation. With the scope of microbial oil applications expanding beyond non-fuel encompassing food, supplements, and medicines, their subsequent environmental implications need to be investigated. Further work is required in this area. There are significant knowledge gaps in life cycle inventory and impact assessment information for non-fuel applications.
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Urmanova, Dilyara. « Petroleum Systems Modeling and Hydrocarbon Migration and Oil Potential Assessment of the Southern Side of Pre-Caspian Basin, Kazakhstan ». Dans SPE Annual Caspian Technical Conference. SPE, 2021. http://dx.doi.org/10.2118/207036-ms.
Texte intégralRésumé :
Abstract An active oil system is recognized from the data in the Tengiz-Primorsky uplift zone of the southern edge of the Pre-Caspian Basin in stratigraphic ascending and structural traps of the Famennian carbonate reservoir. This area is considered one of the most high-yeilding gas provinces in Kazakhstan. However, the timing of the displacement and migration of hydrocarbons depending on the formation of traps remains unclear. To reduce this uncertainty, an attempt was made to analyze a cross-sectional model that takes into account seismic structural interpretation and data from the Ansagan 1 well to simulate history, temperature, sourcerock maturity and pressure regimes over geological time. The displacement of hydrocarbons from the original rocks and further HC migration were modeled using 2D reservoir fluid flow modeling based on the Darcy flow equation. The main blocks of the source rocks correspond to the Devonian complex with the influence of algal lipids or organic matter enriched in lipids (type I kerogen). The maturity trend increases from east to west due to higher burial. The general objectives of this article were to set goals and determine the level of detalization of the research; selection and preparation of input data, filling the model with information, restoring the basin immersion history, calculating the thermal model, and determining the maturity of source deposits, calibrating the thermal model, calculating HC emigration; assessment of migration routes.
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Urmanova, Dilyara. « Petroleum Systems Modeling and Hydrocarbon Migration and Oil Potential Assessment of the Southern Side of Pre-Caspian Basin, Kazakhstan ». Dans SPE Annual Caspian Technical Conference. SPE, 2021. http://dx.doi.org/10.2118/207036-ms.
Texte intégralRésumé :
Abstract An active oil system is recognized from the data in the Tengiz-Primorsky uplift zone of the southern edge of the Pre-Caspian Basin in stratigraphic ascending and structural traps of the Famennian carbonate reservoir. This area is considered one of the most high-yeilding gas provinces in Kazakhstan. However, the timing of the displacement and migration of hydrocarbons depending on the formation of traps remains unclear. To reduce this uncertainty, an attempt was made to analyze a cross-sectional model that takes into account seismic structural interpretation and data from the Ansagan 1 well to simulate history, temperature, sourcerock maturity and pressure regimes over geological time. The displacement of hydrocarbons from the original rocks and further HC migration were modeled using 2D reservoir fluid flow modeling based on the Darcy flow equation. The main blocks of the source rocks correspond to the Devonian complex with the influence of algal lipids or organic matter enriched in lipids (type I kerogen). The maturity trend increases from east to west due to higher burial. The general objectives of this article were to set goals and determine the level of detalization of the research; selection and preparation of input data, filling the model with information, restoring the basin immersion history, calculating the thermal model, and determining the maturity of source deposits, calibrating the thermal model, calculating HC emigration; assessment of migration routes.
Rapports d'organisations sur le sujet "Algal lipids"
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Sukenik, Assaf, Paul Roessler et John Ohlrogge. Biochemical and Physiological Regulation of Lipid Synthesis in Unicellular Algae with Special Emphasis on W-3 Very Long Chain Lipids. United States Department of Agriculture, janvier 1995. http://dx.doi.org/10.32747/1995.7604932.bard.
Texte intégralRésumé :
Various unicellular algae produce omega-3 (w3) very-long-chain polyunsaturated fatty acids (VLC-PUFA), which are rarely found in higher plants. In this research and other studies from our laboratories, it has been demonstrated that the marine unicellular alga Nannochloropsis (Eustigmatophyceae) can be used as a reliable and high quality source for the w3 VLC-PUFA eicosapentaenoic acid (EPA). This alga is widely used in mariculture systems as the primary component of the artificial food chain in fish larvae production, mainly due to its high EPA content. Furthermore, w3 fatty acids are essential for humans as dietary supplements and may have therapeutic benefits. The goal of this research proposal was to understand the physiological and biochemical mechanisms which regulate the synthesis and accumulation of glycerolipids enriched with w3 VLC-PUFA in Nannochloropsis. The results of our studies demonstrate various aspects of lipid synthesis and its regulation in the alga: 1. Variations in lipid class composition imposed by various environmental conditions were determined with special emphasis on the relative abundance of the molecular species of triacylglycerol (TAG) and monogalactosyl diacylglycerol (MGDG). 2. The relationships between the cellular content of major glycerolipids (TAG and MGDG) and the enzymes involved in their synthesis were studied. The results suggested the importance of UDP-galactose diacylglycerol galactosyl (UDGT) in regulation of the cellular level of MGDG. In a current effort we have purified UDGT several hundredfold from Nannochloropsis. It is our aim to purify this enzyme to near homogeneity and to produce antibodies against this enzyme in order to provide the tools for elucidation of the biochemical mechanisms that regulate this enzyme and carbon allocation into galactolipids. 3. Our in vitro and in vivo labeling studies indicated the possibility that phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are associated with desaturation of the structural lipids, whereas shorter chain saturated fatty acids are more likely to be incorporated into TAG. 4. Isolation of several putative mutants of Nannochloropsis which appear to have different lipid and fatty acid compositions than the wild type; a mutant of a special importance that is devoid of EPA was fully characterized. In addition, we could demonstrate the feasibility of Nannochloropsis biomass production for aquaculture and human health: 1) We demonstrated in semi-industrial scale the feasibility of mass production of Nannochloropsis biomass in collaboration with the algae plant NBT in Eilat; 2) Nutritional studies verified the importance algal w3 fatty acids for the development of rats and demonstrated that Nannochloropsis biomass fed to pregnant and lactating rats can benefit their offspring.
2
Davis, Ryan, Daniel Fishman, Edward D. Frank, Mark S. Wigmosta, Andy Aden, Andre M. Coleman, Philip T. Pienkos, Ricahrd J. Skaggs, Erik R. Venteris et Michael Q. Wang. Renewable Diesel from Algal Lipids : An Integrated Baseline for Cost, Emissions, and Resource Potential from a Harmonized Model. Office of Scientific and Technical Information (OSTI), juin 2012. http://dx.doi.org/10.2172/1044475.
Texte intégral
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Davis, Ryan, Mary J. Biddy et Susanne B. Jones. Algal Lipid Extraction and Upgrading to Hydrocarbons Technology Pathway. Office of Scientific and Technical Information (OSTI), mars 2013. http://dx.doi.org/10.2172/1073585.
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Davis, R., M. Biddy et S. Jones. Algal Lipid Extraction and Upgrading to Hydrocarbons Technology Pathway. Office of Scientific and Technical Information (OSTI), mars 2013. http://dx.doi.org/10.2172/1076625.
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Davis, R., C. Kinchin, J. Markham, E. C. D. Tan, L. M. L. Laurens, D. Sexton, D. Knorr, P. Schoen et J. Lukas. Process Design and Economics for the Conversion of Algal Biomass to Biofuels : Algal Biomass Fractionation to Lipid-and Carbohydrate-Derived Fuel Products. Office of Scientific and Technical Information (OSTI), septembre 2014. http://dx.doi.org/10.2172/1271650.
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Davis, R., C. Kinchin, J. Markham, E. Tan, L. Laurens, D. Sexton, D. Knorr, P. Schoen et J. Lukas. Process Design and Economics for the Conversion of Algal Biomass to Biofuels : Algal Biomass Fractionation to Lipid- and Carbohydrate-Derived Fuel Products. Office of Scientific and Technical Information (OSTI), septembre 2014. http://dx.doi.org/10.2172/1159351.
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Goodenough, Ursula. Systems Biology of Lipid Body Formation in the Green Alga Chlamydomonas reinhardtii. Office of Scientific and Technical Information (OSTI), novembre 2017. http://dx.doi.org/10.2172/1408918.
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