Articoli di riviste: "Algal lipids"

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Loria, Mark H., James S. Griffin, George F. Wells e Kurt R. Rhoads. "Effects of feast-famine nutrient regimes on wastewater algal biofuel communities". PLOS ONE 18, n. 1 (4 gennaio 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 e Michał Arabski. "Fatty Acid Methyl Esters of the Aerophytic Cave Alga Coccomyxa subglobosa as a Source for Biodiesel Production". Energies 13, n. 24 (9 dicembre 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. e J. G. Ray. "Chlorococcum humicola (Nageli) Rabenhorst as a Renewable Source of Bioproducts and Biofuel". Journal of Plant Studies 5, n. 1 (29 febbraio 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 Chlorococcum humicola (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 e Kateřina Bišová. "Supra-Optimal Temperature: An Efficient Approach for Overaccumulation of Starch in the Green Alga Parachlorella kessleri". Cells 10, n. 7 (16 luglio 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 e Emanuele Radicetti. "Prospects for Biodiesel Production from Emerging Algal Resource: Process Optimization and Characterization of Biodiesel Properties". Agriculture 13, n. 2 (9 febbraio 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 e Sri Astuti Rahayu. "The Superiority Of Micro-Algae As A Potential Feedstock For Alternative Energy". Scientific Contributions Oil and Gas 32, n. 1 (17 marzo 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 e 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, n. 8 (7 aprile 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 e Andrzej Kapusta. "Survival, proximate composition, and proteolytic activity of Artemia salina bioencapsulated with different algal monocultures". Fisheries & Aquatic Life 28, n. 4 (1 dicembre 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 e 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, n. 1 (31 luglio 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., e Pierre-Yves Caux. "Sublethal effects of the insecticide fenitrothion on freshwater phytopiankton". Canadian Journal of Botany 73, n. 1 (1 gennaio 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.

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Maat, D. S., N. J. Bale, E. C. Hopmans, A. C. Baudoux, J. S. Sinninghe Damsté, S. Schouten e C. P. D. Brussaard. "Acquisition of intact polar lipids from the prymnesiophyte Phaeocystis globosa by its lytic virus PgV-07T". Biogeosciences 11, n. 1 (14 gennaio 2014): 185–94. http://dx.doi.org/10.5194/bg-11-185-2014.

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Abstract. Recent studies showed changes in phytoplankton lipid composition during viral infection and have indicated roles for specific lipids in the mechanisms of algal virus-host interaction. To investigate the generality of these findings and obtain a better understanding of the allocation of specific lipids to viruses, we studied the intact polar lipid (IPL) composition of virally infected and non-infected cultures of the prymnesiophyte Phaeocystis globosa G(A) and its lytic virus PgV-07T. The P. globosa IPL composition was relatively stable over a diel cycle and not strongly affected by viral infection. Glycolipids, phospholipids and betaine lipids were present in both the host and virus, although specific groups such as the diacylglyceryl-hydroxymethyltrimethyl-β-alanines and the sulfoquinovosyldiacylglycerols, were present in a lower proportion or were not detected in the virus. Viral glycosphingolipids (vGSLs), which have been shown to play a role in the infection strategy of the virus EhV-86, infecting the prymnesiophyte Emiliania huxleyi CCMP374, were not encountered. Our results show that the involvement of lipids in virus–algal host interactions can be very different amongst virus–algal host systems.

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Maat, D. S., N. J. Bale, E. C. Hopmans, A. C. Baudoux, J. S. Sinninghe Damsté, S. Schouten e C. P. D. Brussaard. "Acquisition of intact polar lipids from the Prymnesiophyte Phaeocystis globosa by its lytic virus PgV-07T". Biogeosciences Discussions 10, n. 7 (12 luglio 2013): 11705–27. http://dx.doi.org/10.5194/bgd-10-11705-2013.

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Abstract. Recent studies showed changes in phytoplankton lipid composition during viral infection and have indicated roles for specific lipids in the mechanisms of algal virus-host interaction. To investigate the generality of these findings and obtain a better understanding of the allocation of specific lipids to viruses, we studied the intact polar lipid (IPL) composition of virally infected and non-infected cultures of the Prymnesiophyte Phaeocystis globosa G(A) and its lytic virus PgV-07T. The P. globosa IPL composition was relatively stable over a diel cycle and not strongly affected by viral infection. Glycolipids, phospholipids and betaine lipids were present in both the host and virus, although specific groups such as the diacylglyceryl-hydroxymethyltrimethyl-β-alanines and the sulfoquinovosyldiacylglycerols, were present in a lower proportion or were not detected in the virus. Viral glycosphingolipids (vGSLs), which have been shown to play a role in the infection strategy of the virus EhV-86, infecting the Prymnesiophyte Emiliania huxleyi CCMP374, were not encountered. Our results show that the involvement of lipids in virus-algal host interactions can be very different amongst virus-algal host systems.

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Smertina, E. S., L. N. Fedyanina, V. A. Lyakh e K. F. Kurapova. "Prospects for the development of bakery products enriched with seaweed lipid fractions". Khleboproducty 31, n. 9 (2022): 52–56. http://dx.doi.org/10.32462/0235-2508-2022-31-9-52-56.

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The paper presents the results of studying the lipid composition of bakery products (HBI) with the addition of new ingredients to its formulation - water-ethanol extracts, four types of seaweed: green algae – Ulva lactuca; two types of brown algae – Sargassum pallidum and Japanese saccharin; red algae – Anfeltia tobuchinskaya, containing the main lipids – neutral lipids and glycolipids. The data obtained showed a change in the lipid composition of the developed bread. A statistically significant increase in all fractions of neutral lipids was registered in the developed CBI, a decrease in the amount of cholesterol and its cholesterol esters, compared with those in control samples. An increase in the amount of phosphatidylcholine (lecithin) in bread with the addition of kelp and anfeltia extracts was noted; a significant increase in phosphatidylethanolamine in bread with the introduction of all algal extracts. The revealed facts demonstrate the stability of lipid fractions in the composition of CBI with the addition of algae extracts and are positive in terms of giving them preventive properties. Particularly indicative is the appearance of the phosphatidylglycerol fraction in bread, which is the basis for the synthesis of other phospholipid compounds from it, which are essential substances that enter the human body exclusively through food, reducing the risks and consequences of adverse environmental factors affecting the body.

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Cheban, Larysa. "The use of Chlorella vulgaris beijer in bioremediation activities". Biolohichni systemy 12, n. 1 (25 giugno 2020): 26–30. http://dx.doi.org/10.31861/biosystems2020.01.026.

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The article focuses on the possibility of applying the green alga Chlorella vulgaris Beijer. culture to bioremediation activities. Two types of wastewater were simulated, agricultural (ACW) and domestic (DW). The experiment was conducted under laboratory conditions in 500-ml Erlenmeyer flasks. The ratio of the amount of the algal culture and the wastewater volume was 1:10. The content of NO3-, NO2-and NH4+ in the composition of the wastewater was tested before and after cultivating the alga; during cultivation, the pH of the culture medium and the optical density of the Ch. vulgaris culture were monitored. The indicators of the amount of various forms of nitrogen and the pH level show that simulated domestic and agricultural wastewater can serve as an alternative nutrient medium for growing green algae. The use of Ch. vulgaris for the treatment of domestic and agricultural effluents allows avoiding almost completely their nitrate and ammonia pollution. The amount of biomass obtained within 25 days of cultivating Ch. vulgaris on agricultural sewage was two times higher than in the control Tamiya medium. Resulting Ch. vulgaris algal mass with the proteins content of 55% and lipids reaching 30% can match various needs being used a source of protein or lipids.

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Moudříková, Šárka, Ivan Nedyalkov Ivanov, Milada Vítová, Ladislav Nedbal, Vilém Zachleder, Peter Mojzeš e Kateřina Bišová. "Comparing Biochemical and Raman Microscopy Analyses of Starch, Lipids, Polyphosphate, and Guanine Pools during the Cell Cycle of Desmodesmus quadricauda". Cells 10, n. 1 (3 gennaio 2021): 62. http://dx.doi.org/10.3390/cells10010062.

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Photosynthetic energy conversion and the resulting photoautotrophic growth of green algae can only occur in daylight, but DNA replication, nuclear and cellular divisions occur often during the night. With such a light/dark regime, an algal culture becomes synchronized. In this study, using synchronized cultures of the green alga Desmodesmus quadricauda, the dynamics of starch, lipid, polyphosphate, and guanine pools were investigated during the cell cycle by two independent methodologies; conventional biochemical analyzes of cell suspensions and confocal Raman microscopy of single algal cells. Raman microscopy reports not only on mean concentrations, but also on the distribution of pools within cells. This is more sensitive in detecting lipids than biochemical analysis, but both methods—as well as conventional fluorescence microscopy—were comparable in detecting polyphosphates. Discrepancies in the detection of starch by Raman microscopy are discussed. The power of Raman microscopy was proven to be particularly valuable in the detection of guanine, which was traceable by its unique vibrational signature. Guanine microcrystals occurred specifically at around the time of DNA replication and prior to nuclear division. Interestingly, guanine crystals co-localized with polyphosphates in the vicinity of nuclei around the time of nuclear division.

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Galal Shams El-Din, Nihal, Nayrah A. Shaltout, Mustafa A. Ghazal, Alaa E. Ali e Doha M. Beltagy. "PHYSICAL PRETREATMENT OF ULVA FASCIATA FOR ENHANCINGBIODIESEL PRODUCTION AND QUALITY". International Journal of Advanced Research 9, n. 03 (31 marzo 2021): 347–63. http://dx.doi.org/10.21474/ijar01/12591.

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The green algae Ulva faciata was subjected to different physical pretreatments comprising thermal and mechanical techniques at different experimental conditions to state the most appropriate method of cell disruption for increasing the quantity of the extracted lipid and hence improve the quality of the produced biodiesel with low cost. Thermal pretreatment was autoclaving of either wet or dry algal biomass, while mechanical pretreatments include microwave and ultrasonication at different time intervals. The control was the alga without pretreatment extracted at optimum conditions: 60 min, 55oC, shaking speed at 250 rpm, < 0.16 mm particle size with 25:1 v/w solvent to solid ratio. The results showed that the quantity of extracted lipids in case of using all physical pretreatments increased the Total fatty acids yield significantly by about 2-folds of the control for wet algae in hydrothermal treatment with optimum time of treatment 40 minutes, and 1.4 folds for dry algae in thermal pretreatment of the dried alga for 60minutes autoclaving period. The sharp increase by 2.2 folds of extracted lipids was recorded by microwave pretreatment for radiation period (5 min), while ultrasonication showed 2.1-fold increase in lipid yield at 15minutes ultrasound exposure time. Concerning the physical properties of the produced biodiesel after all physical pretreatments, the results indicated that the produced biodiesel had very high quality as all its properties are almost complied with the ASTM D6751 and EN14214 standards. These results were confirmed statistically where all physical pretreatments had high significant effect on fatty acids yield and Biodiesel properties.

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McConnell, Michael D., David Lowry, Troy N. Rowan, Karin van Dijk e Kevin E. Redding. "Purification and photobiochemical profile of photosystem 1 from a high-salt tolerant, oleaginous Chlorella (Trebouxiophycaea, Chlorophyta)". Biochemistry and Cell Biology 93, n. 3 (giugno 2015): 199–209. http://dx.doi.org/10.1139/bcb-2014-0144.

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The eukaryotic green alga Chlamydomonas reinhardtii has been studied extensively within the biofuel industry as a model organism, as researchers look towards algae to provide chemical feedstocks (i.e., lipids) for the production of liquid transportation fuels. C. reinhardtii, however, is unsuitable for high-level production of such precursors due to its relatively poor lipid accumulation and fresh-water demand. In this study we offer insight into the primary light harvesting and electron transfer reactions that occur during phototropic growth in a high-salt tolerant strain of Chlorella (a novel strain introduced here as NE1401), a single-celled eukaryotic algae also in the phylum Chlorophyta. Under nutrient starvation many eukaryotic algae increase dramatically the amount of lipids stored in lipid bodies within their cell interiors. Microscopy and lipid analyses indicate that Chlorella sp. NE1401 may become a superior candidate for algal biofuels production. We have purified highly active Photosystem 1 (PS1) complexes to study in vitro, so that we may understand further the photobiochemisty of this promising biofuel producer and how its characteristics compare and contrast with that of the better understood C. reinhardtii. Our findings suggest that the PS1 complex from Chlorella sp. NE1401 demonstrates similar characteristics to that of C. reinhardtii with respect to light-harvesting and electron transfer reactions. We also illustrate that the relative extent of the light state transition performed by Chlorella sp. NE1401 is smaller compared to C. reinhardtii, although they are triggered by the same dynamic light stresses.

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Arts, Michael T., Richard D. Robarts e Marlene S. Evans. "Energy Reserve Lipids of Zooplanktonic Crustaceans from an Oligotrophic Saline Lake In Relation to Food Resources and Temperature". Canadian Journal of Fisheries and Aquatic Sciences 50, n. 11 (1 novembre 1993): 2404–20. http://dx.doi.org/10.1139/f93-265.

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In three zooplankton species examined over a 2-yr period in an oligotrophic saline (22 g∙L−1) lake, triacylglycerols (energy reserve lipids) were the most abundant lipid class followed by phospholipids and sterols. Marked seasonal differences in patterns of total and energy reserve lipid content in the herbivorous calanoid Leptodiaptomus sicilis were correlated with temporal patterns in edible algal biomass and temperature. The appearance of particular algal species, or groups of similar-sized species, occurred synchronously with changes in lipid content of both L. sicilis and Daphnia pulex. These periods of changing lipid content were used to infer nutritional suitability or inadequacy (unavailability) of specific algae for wild populations of zooplankton. Energy transfer from phytoplankton to the carnivorous calanoid Hesperodiaptomus nevadensis through L. sicilis involved a time lag of approximately 1–2 mo; this was hypothesized to result from a feeding dependency on L. sicilis copepodites due to a gape limitation of the predator. Demographics of D. pulex in this lake were unusual because the species was consistently absent during spring. In addition, total lipids and triacylglycerols were low (<15% and <4.5 μg∙animal−1, respectively), suggesting that D. pulex had been pushed into a subsistence niche by the rising salinity levels.

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Yang, Wenchao, Zhaowei Wang, Jianbo Han, Shuang Song, Yong Zhang e Weimin Gong. "The role of polysaccharides and proteins in bio-oil production during the hydrothermal liquefaction of algae species". RSC Advances 9, n. 71 (2019): 41962–69. http://dx.doi.org/10.1039/c9ra07150d.

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In order to understand the effects of the major algal components-carbohydrates and proteins on the hydrothermal liquefaction (HTL) process of algae, the HTL of polysaccharides or proteins with lipids was performed at 220, 260, 300 °C, respectively.

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A, Aarthy, Smita Kumari, Prachi Turkar e Sangeetha Subramanian. "AN INSIGHT ON ALGAL CELL DISRUPTION FOR BIODIESEL PRODUCTION". Asian Journal of Pharmaceutical and Clinical Research 11, n. 2 (1 febbraio 2018): 21. http://dx.doi.org/10.22159/ajpcr.2018.v11i2.22481.

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Abstract (sommario):

Objective: This review article deals with the effect that various cell disruption techniques have on the efficiency of lipid extraction. We have reviewed existing algal cell disruption techniques that aid the biodiesel production process.Methods: Current rise in demand for energy has led the researcher to focus on the production of sustainable fuels, among which biodiesel has received greater attention. This is due to its larger lipid content, higher growth rate, larger biomass production, and lower land use. Extraction of lipid from algae (micro and macro) for the production of biodiesel involves numerous downstream processing steps, of which cell wall disruption is a crucial step. Bead milling, high-pressure homogenization, ultra-sonication, freeze-drying, acid treatment, and enzymatic lysis are some methods of cell disruption. The cell disruption technique needs to be optimized based on the structure and biochemical composition of algae.Result: The lipid extraction efficiency varies depending on the algal species and the cell disruption technique used.Conclusion: In-depth research and development of new techniques are required to further enhance the cell disruption of the algal cell wall for the enhanced recovery of lipids. In addition, the operating costs and energy consumption should also be optimized for the cost-effective recovery.

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Assemany, Paula Peixoto, Maria Lúcia Calijuri, Eduardo de Aguiar do Couto, Fernanda Pereira da Silva e Mauro Henrique Batalha de Souza. "Energy recovery in high rate algal pond used for domestic wastewater treatment". Water Science and Technology 78, n. 1 (14 novembre 2017): 12–19. http://dx.doi.org/10.2166/wst.2017.570.

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Abstract High rate algal pond (HRAP) was evaluated according to its energy potential and productivity by two rates, net energy ratio (NER) and specific biomass productivity. All energy inputs were calculated according to one HRAP with pre-ultraviolet disinfection treating anaerobic domestic sewage. The outputs were calculated for two energetic pathways: lipid and biogas production for the raw biomass (RB) and biomass after lipid extraction. The non-polar lipid content in dry biomass was 7.6%, reaching a daily lipid productivity of 0.2 g/m2·day and the biogas production potential was 0.20 m3/kg solids. For the biomass after lipid extraction, the biogas production reached 2.6 m3/kg solids. NER values of 10−3 for the RB were similar for lipids and biogas routes. The specific biomass productivity was 0.7 mg/kJ. For the residual biomass, after lipid extraction, NER value was 10−2 for the integrated route (lipids + biogas) and the specific biomass productivity of the extracted biomass was 0.4 mg/kJ. The best energetic pathway was to integrate both lipids and biogas route.

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Hasnain, Maria, Neelma Munir, Zainul Abideen, Daniel Anthony Dias, Farheen Aslam e Roberto Mancinelli. "Applying Silver Nanoparticles to Enhance Metabolite Accumulation and Biodiesel Production in New Algal Resources". Agriculture 13, n. 1 (26 dicembre 2022): 73. http://dx.doi.org/10.3390/agriculture13010073.

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Biofuel generation from algae can be increased by using nanotechnology. The present study emphasizes the use of silver nanoparticles on algae for algal fuel generation along with the impact of nanoparticles on biomass, metabolites and lipid profile. Silver ion amassing was enhanced in each algal species, but maximum phytoremediation was found in Ulothrix sp. Carbohydrates increased 3.2 times in Oedogonium sp., 3.3 times in Ulothrix sp., 3 times in Cladophora sp. and 2.7 times in Spirogyra sp. Additionally, the application of nanoparticles enhanced by 2 times the production of proteins in Oedogonium sp., 1.9 times in Ulothrix sp., 1.9 times in Cladophora sp. and 2.1 times in Spirogyra sp. Finally, the total lipid yield increased 60% DCW in Oedogonium sp., 56% DCW in Ulothrix sp., 58% DCW in Cladophora sp. and 63% DCW in Spirogyra sp. using 0.08 mg/L silver nanoparticle application. The lipids and fatty acid fractions from algae containing high concentrations of C16:0, C18:0 and C18:1 enhanced with silver nanoparticle addition were comparable with EN 14214 and ASTM 6751 biodiesel standards. This study indicates that the uptake of AgNPs can enhance the production of fatty acids and be commercialized as sustainable biodiesel. The algae Ulothrix sp. is evidenced as the best competent feedstock for biofuel production.

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23

Vargas-Perez, Magda, Gerardo Sierra-García, Hugo Luna Olvera, Abelardo Chavez-Montes e Azucena Gonzalez-Horta. "Impact of Melittin on Microalgae Cell Wall: A Monolayer Study". Natural Product Communications 13, n. 8 (agosto 2018): 1934578X1801300. http://dx.doi.org/10.1177/1934578x1801300822.

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Abstract (sommario):

The cell wall of microalgae presents a formidable barrier necessary for survival in aquatic environments. Unfortunately, this barrier affects certain processes of interest in algal biotechnology such as oil extraction. Thus, assessing the impact of lytic peptides or enzymes on algal cell wall degradation is a critical first step to utilizing algal biomass more efficiently. Galactolipids are the main structural component of plant chloroplastic membranes and blue-green algae cell membranes. The predominant lipids in this class are monogalactosyl-diacylglycerol (MGDG) and digalactosyl-diacylglycerol (DGDG). Here using de Langmuir monolayer technique, we have demonstrated that melittin, a lytic peptide, has an intrinsic propensity to interact and perturb interfacial monolayers made of MGDG or DGDG that mimic microalgae cell wall.

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24

Cho, Seok-Cheol, Woon-Yong Choi, Sung-Ho Oh, Choon-Geun Lee, Yong-Chang Seo, Ji-Seon Kim, Chi-Ho Song et al. "Enhancement of Lipid Extraction from Marine Microalga,ScenedesmusAssociated with High-Pressure Homogenization Process". Journal of Biomedicine and Biotechnology 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/359432.

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Abstract (sommario):

Marine microalga,Scenedesmussp., which is known to be suitable for biodiesel production because of its high lipid content, was subjected to the conventional Folch method of lipid extraction combined with high-pressure homogenization pretreatment process at 1200 psi and 35°C. Algal lipid yield was about 24.9% through this process, whereas only 19.8% lipid can be obtained by following a conventional lipid extraction procedure using the solvent, chloroform : methanol (2 : 1, v/v). Present approach requires 30 min process time and a moderate working temperature of 35°C as compared to the conventional extraction method which usually requires >5 hrs and 65°C temperature. It was found that this combined extraction process followed second-order reaction kinetics, which means most of the cellular lipids were extracted during initial periods of extraction, mostly within 30 min. In contrast, during the conventional extraction process, the cellular lipids were slowly and continuously extracted for >5 hrs by following first-order kinetics. Confocal and scanning electron microscopy revealed altered texture of algal biomass pretreated with high-pressure homogenization. These results clearly demonstrate that the Folch method coupled with high-pressure homogenization pretreatment can easily destruct the rigid cell walls of microalgae and release the intact lipids, with minimized extraction time and temperature, both of which are essential for maintaining good quality of the lipids for biodiesel production.

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25

Vasileva, Iv, e J. Ivanova. "BIOCHEMICAL PROFILE OF GREEN AND RED ALGAE – A KEY FOR UNDERSTANDING THEIR POTENTIAL APPLICATION AS FOOD ADDITIVES". Trakia Journal of Sciences 17, n. 1 (2019): 1–7. http://dx.doi.org/10.15547/tjs.2019.01.001.

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Abstract (sommario):

PURPOSE: With the improvements of the microalgal cultivation industry, it became possible to add algal biomass and its metabolites in foods in order to create a balanced and health-food. METHODS: By determining the growth and the biochemical composition (lipids, carbohydrates and proteins), two algal strains were evaluated as a potential source of food additives – the newly isolated strain of the green algae Scenedesmus sp. and the red algae Porphyridium cruentum). RESULTS: It turned out that in Scenedesmus sp. BGP the most abundant component were the proteins (up tp 45 %), which makes this alga an excellent unconventional protein producer. As opposed to it, the biochemical composition of Porphyridium cruentum was dominated by carbohydrates (up to 57%), but there was also a high content of some essential polyunsaturated fatty acids: arachidonic (AA, 20:4; 13-29%) and eicosapentaenoic acid (EPA, 20:5, 24-25%). CONCLUSIONS: Microalgae are a really remarkable source of biomass and a wide range of substances, but this area is poorly explored. Both of the microalgal strains proved to be important sources of functional ingredients that could be successfully used as food additives together or separately.

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26

Harwood, John. "Algae: Critical Sources of Very Long-Chain Polyunsaturated Fatty Acids". Biomolecules 9, n. 11 (6 novembre 2019): 708. http://dx.doi.org/10.3390/biom9110708.

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Abstract (sommario):

Polyunsaturated fatty acids (PUFAs), which are divided into n-3 and n-6 classes, are essential for good health in humans and many animals. They are metabolised to lipid mediators, such as eicosanoids, resolvins and protectins. Increasing interest has been paid to the 20 or 22 carbon very long chain PUFAs, since these compounds can be used to form lipid mediators and, thus, avoid inefficient formation of dietary plant PUFAs. The ultimate sources of very long chain PUFAs are algae, which are consumed by fish and then by humans. In this review, I describe the biosynthesis of very long chain PUFAs by algae and how this synthesis can be manipulated for commercial purposes. Ultimately, the production of algal oils is critical for ecosystems worldwide, as well as for human dietary lipids.

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27

Reis, Marcello, Maria Elisa Marciano Martinez e Alexandre Guimarães Vasconcellos. "PROSPECTIVE ANALYSIS OF ALGAL BIODIESEL PRODUCTION". Journal of Mechatronics Engineering 4, n. 2 (21 settembre 2021): 12–18. http://dx.doi.org/10.21439/jme.v4i2.97.

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Abstract (sommario):

This article aims to carry out an initial patent mapping of algal biodiesel. The production of algal biodiesel is one of the forms of third generation biodiesel; it is an environmentally friendly alternative energy whose main advantage is that it does not compete with food, as the algal biodiesel is produced from synthesized lipids by algae in growth using sunlight. The methodology used was the patent mapping by activity having as search criteria: the Espacenet database (“worldwide”); and, the keyword: biodiesel and algae and algal biodiesel. It was observed that about 80% of the family of patent documents referring to this technology were applied between 2007 and 2016 and that these documents were published mainly in China (34% of patent documents), followed by the United States (25% of patent documents) and thirdly, the World Intellectual Property Organization (WO), that is, the PCT's international patent application, which indicates an interest in protection in several countries (15% of patent documents). Concluding that China and the United States are the countries that invest the most in the development and protection of technologies related to the production of algal biodiesel, however, the interest in protection goes beyond these countries, since the interest in alternative energies is worldwide.

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Sydney, Thomas, Jo-Ann Marshall-Thompson, Rahul Kapoore, Seetharaman Vaidyanathan, Jagroop Pandhal e J. Fairclough. "The Effect of High-Intensity Ultraviolet Light to Elicit Microalgal Cell Lysis and Enhance Lipid Extraction". Metabolites 8, n. 4 (15 ottobre 2018): 65. http://dx.doi.org/10.3390/metabo8040065.

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Abstract (sommario):

Currently, the energy required to produce biofuel from algae is 1.38 times the energy available from the fuel. Current methods do not deliver scalable, commercially viable cell wall disruption, which creates a bottleneck on downstream processing. This is primarily due to the methods depositing energy within the water as opposed to within the algae. This study investigates ultraviolet B (UVB) as a disruption method for the green algae Chlamydomonas reinhardtii, Dunaliella salina and Micractinium inermum to enhance solvent lipid extraction. After 232 seconds of UVB exposure at 1.5 W/cm2, cultures of C. reinhardtii (culture density 0.7 mg/mL) showed 90% disruption, measured using cell counting, correlating to an energy consumption of 5.6 MJ/L algae. Small-scale laboratory tests on C. reinhardtii showed bead beating achieving 45.3 mg/L fatty acid methyl esters (FAME) and UV irradiation achieving 79.9 mg/L (lipids solvent extracted and converted to FAME for measurement). The alga M. inermum required a larger dosage of UVB due to its thicker cell wall, achieving a FAME yield of 226 mg/L, compared with 208 mg/L for bead beating. This indicates that UV disruption had a higher efficiency when used for solvent lipid extraction. This study serves as a proof of concept for UV irradiation as a method for algal cell disruption.

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29

Mateescu, C., A. Dima e D. Marin. "Sustainable solution for alien algae management to reduce the environmental consequences of sea and river transport". Technium: Romanian Journal of Applied Sciences and Technology 2, n. 1 (16 gennaio 2020): 97–103. http://dx.doi.org/10.47577/technium.v2i1.67.

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The accelerated development of sea and river transport over the past few decades has led to a negative phenomenon regarding the invasion and development of alien algal species, threating to modify the ecosystem functions. Algae are an attractive feedstock for biofuels production due to many advantages such as rapid growth, chemical composition rich in lipids, carbohydrates and proteins, but also because algae do not require farmland and do not create controversy in using arable land for energy purpose to the detriment of food-intended crops. Indigenous or alien algal biomass has been excessively developed in the Black Sea basin and areas affected by eutrophication, causing environmental problems. This paper presents a sustainable management solution for mitigating the negative impact of alien algae by exploiting their energy potential for producing biogas. An innovative concept of tubular bioreactor for biogas production was developed within INCDIE ICPE-CA and could be successfully applied to harness algal biomass and produce biogas for domestic and industrial use, while simultaneously ensuring sanitation of sea shore and fresh water streams.

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Assemany, Paula Peixoto, Maria Lucia Calijuri, Eduardo de Aguiar do Couto, Aníbal Fonseca Santiago e Alberto José Delgado dos Reis. "Biodiesel from wastewater: lipid production in high rate algal pond receiving disinfected effluent". Water Science and Technology 71, n. 8 (3 marzo 2015): 1229–34. http://dx.doi.org/10.2166/wst.2015.087.

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Abstract (sommario):

The production of different species of microalgae in consortium with other micro-organisms from wastewaters may represent an alternative process, to reduce the costs, for obtaining biofuels. The aim of this study was to evaluate the influence of pre-ultraviolet disinfection (UV) in the production of lipids from biomass produced in high rate ponds. Two high rate algal ponds were evaluated: a pond that received domestic sewage without disinfection and the other receiving domestic sewage previously disinfected by UV radiation (uvHRAP). The UV disinfection did not lead to significant differences in fatty acid profile and total lipid productivities, although it increased algal biomass concentration and productivity as well as lipid content. Moreover, the overall biomass concentrations and productivities decreased with the UV disinfection, mostly as a consequence of a loss in bacterial load. We thus conclude that uvHRAP disinfection may represent a potential strategy to promote the cleaner and safer growth of algal biomass when cultivated in consortium with other micro-organisms. Mainly regarding the use of wastewater as culture medium, together with a cheaper production of lipids for biodiesel, pre-disinfection may represent an advance since extraction costs could be significantly trimmed due to the increase in lipid content.

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Nguyen, Hoang SH, Päivi Mäki-Arvela, Uliana Akhmetzyanova, Zdeněk Tišler, Imane Hachemi, Andre Rudnäs, Annika Smeds et al. "Direct hydrodeoxygenation of algal lipids extracted fromChlorellaalga". Journal of Chemical Technology & Biotechnology 92, n. 4 (23 gennaio 2017): 741–48. http://dx.doi.org/10.1002/jctb.5158.

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32

Takáčová, Alžbeta, Miriama Bajuszová, Alexandra Šimonovičová, Štefan Šutý e Sanja Nosalj. "Biocoagulation of Dried Algae Chlorella sp. and Pellets of Aspergillus Niger in Decontamination Process of Wastewater, as a Presumed Source of Biofuel". Journal of Fungi 8, n. 12 (7 dicembre 2022): 1282. http://dx.doi.org/10.3390/jof8121282.

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Abstract (sommario):

The removal of microalgae represents a problematic part of the water decontamination process, in which most techniques are expensive and non-ecological. In the paper, we focus on the synergistic relationship between microscopic filamentous fungi and algal culture. In the process of decontamination of a model sample containing ammonium ions, efficient biocoagulation, resp. co-pelletization of dried algae Chlorella sp. and Aspergillus niger sensu stricto are shown. The microscopic filamentous fungus species A. niger was added to a culture of an algal suspension of Chlorella sp., where the adhesion of the algal cells to the fungi subsequently occurred due to the electrostatic effect of the interaction, while the flocculation activity was approximately 70 to 80%. The algal cells adhered to the surface of the A. niger pellets, making them easily removable from the solution. The ability of filamentous fungi to capture organisms represents a great potential for the biological isolation of microalgae (biocoagulation) from production solutions because microalgae are considered to be a promising renewable source of oil and fermentables for bioenergy. This form of algae removal, or its harvesting, also represents a great low-cost method for collecting algae not only as a way of removing unnecessary material but also for the purpose of producing biofuels. Algae are a robust bioabsorbent for absorbing lipids from the environment, which after treatment can be used as a component of biodiesel. Chemical analyses also presented potential ecological innovation in the area of biofuel production. Energy-efficient and eco-friendly harvesting techniques are crucial to improving the economic viability of algal biofuel production.

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33

Puri, Munish. "Algal biotechnology for pursuing omega-3 fatty acid (bioactive) production". Microbiology Australia 38, n. 2 (2017): 85. http://dx.doi.org/10.1071/ma17036.

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Abstract (sommario):

Algae are spread in diversified ecosystems that include marine, freshwater, desert and hot springs and even snow and ice environments. Algae are classified as multicellular large sea weeds (macroalgae) or unicellular microalgae. Macroalgae are targeted for mining of natural biologically active components, which include proteins, linear peptides, cyclic peptides, and amino acids1. Recently, microalgae have been exploited for the production of high-value compounds such as lipids (omega-3 fatty acids), enzymes, polymers, toxins, antioxidants, and pigments (carotenoids)2. Thus, algal biotechnology is defined as ‘the technology developed using algae (macro or micro) to make or modify bioactive compounds, or products (nutritional supplements, fine chemicals) and renewable fuels for specific use’.

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34

Cagliari, Alexandro, Rogerio Margis, Felipe Dos Santos Maraschin, Andreia Carina Turchetto-Zolet, Guilherme Loss e Marcia Margis-Pinheiro. "Biosynthesis of Triacylglycerols (TAGs) in plants and algae". International Journal of Plant Biology 2, n. 1 (22 dicembre 2011): 10. http://dx.doi.org/10.4081/pb.2011.e10.

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Abstract (sommario):

Triacylglycerols (TAGs), which consist of three fatty acids bound to a glycerol backbone, are major storage lipids that accumulate in developing seeds, flower petals, pollen grains, and fruits of innumerous plant species. These storage lipids are of great nutritional and nutraceutical value and, thus, are a common source of edible oils for human consumption and industrial purposes. Two metabolic pathways for the production of TAGs have been clarified: an acyl¬ CoA-dependent pathway and an acyl-CoA-independent pathway. Lipid metabolism, specially the pathways to fatty acids and TAG biosynthesis, is relatively well understood in plants, but poorly known in algae. It is generally accepted that the basic pathways of fatty acid and TAG biosynthesis in algae are analogous to those of higher plants. However, unlike higher plants where individual classes of lipids may be synthesized and localized in a specific cell, tissue or organ, the complete pathway, from carbon dioxide fixation to TAG synthesis and sequestration, takes place within a single algal cell. Another distinguishing feature of some algae is the large amounts of very long-chain polyunsaturated fatty acids (VLC- PUFAs) as major fatty acid components. Nowadays, the focus of attention in biotechnology is the isolation of novel fatty acid metabolizing genes, especially elongases and desaturases that are responsible for PUFAs synthesis, from different species of algae, and its transfer to plants. The aim is to boost the seed oil content and to generate desirable fatty acids in oilseed crops through genetic engineering approaches. This paper presents the current knowledge of the neutral storage lipids in plants and algae from fatty acid biosynthesis to TAG accumulation.

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35

Oprescu, Elena Emilia, Cristina Emanuela Enascuta, Ana Maria Galan, Mihaela Bombos, Gabriel Vasilievici, Gabriela Isopencu, Vasile Lavric e Sanda Velea. "Evaluation of Porphyridium purpureum and Nannochloropsis sp. for Carbohydrates and Lipids Production". Revista de Chimie 70, n. 9 (15 ottobre 2019): 3305–8. http://dx.doi.org/10.37358/rc.19.9.7539.

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Abstract (sommario):

This study was aimed to evaluate the growth conditions of Porphyridium purpureum and Nannochloropsis sp. microalgae for carbohydrates and lipids productivity increase. The cultivation experiments for both microalgae strains were done in triplicates using the artificial seawater (ASW) as culture media. The lipids were separated from the algal biomass and the exo-polysaccharides content from the supernatant. The results showed that the highest carbohydrate content is found in Porphyridium purpureum while the highest lipid content was found in biomass.

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Maltsev, Yevhen I., Nataliya A. Shkurina e Maxim S. Kulikovskiy. "The use of diatoms to improve the efficiency of feed for aquaculture". Issues of modern algology (Вопросы современной альгологии), n. 2(20) (2019): 303–7. http://dx.doi.org/10.33624/2311-0147-2019-2(20)-303-307.

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Abstract (sommario):

Comparison of the using efficiency of agricultural crops, livestock products and algal biomass shows that algae are a promising source of lipids for creating feed for aquaculture. We evaluated the productivity of biomass accumulation and fatty acid composition for nine strains of diatoms. It was shown that Nitzschia pusilla strains are the most promising both in terms of biomass accumulation and the amount of polyunsaturated fatty acids.

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Eloka-Eboka, Andrew C., e Freddie L. Inambao. "Performance and Emission Profile of Micro-Algal Biodiesel in Compression Ignition Engine". International Journal of Engineering Research in Africa 30 (maggio 2017): 110–24. http://dx.doi.org/10.4028/www.scientific.net/jera.30.110.

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Abstract (sommario):

Micro-algae are a large and diverse group of simple typically autotrophic organisms which have the potential to produce greater amounts of non-polar lipids and biomass than most terrestrial biodiesel feedstocks. Having emerged as one of the most promising sources for biodiesel production, they are gaining research interests in the current energy scenario due to their phenomenal growth potential (< 21 days log phase) in addition to relatively high lipids production which are also excellent source of biodiesel. In this study, engine performance and emission profile was performed using biodiesel fuels and blends from micro-algal technology in a compression ignition engine. The technology of micro-algae involved open pond cultivation and the use of photo-bioreactor model BF-115 Bioflo/celli Gen made in the US of 14 litre capacity (200 Lux light intensity) and flowrate of 2.5L/min. The micro-algal species used were Chlorella vulgaris and Scenedesmus spp. The biodiesel produced were blended with conventional diesel (AGO) at different proportions. The performance parameters evaluated include: engine power, torque, brake specific fuel consumption (BSFC), smoke opacity, thermal gravimetry, thermal efficiency, exhaust gas temperatures and lubricity while the varying effects of emission pollutants during combustion were also studied. Results showed that viscosity, density and lubricity have significant effects on engine output power and torque than when throttled with AGO which was used as control. Combustion efficiency and emission profile were better than the AGO due to the oxygenated nature of the micro-algal biodiesel which brought about complete combustion. A striking deduction arrived is that oxygen content of the algal biodiesel had direct influence on smoke opacity and emissions in the engine and also thermo-gravimetrically stable for other thermal applications. The engine tests (BSFC, BTE, ThE, MechE, EGT) and overall emissions (CO2, CO, VOCs, HC, SOx, NOx) were within acceptable limits and comparable with AGO. The implication of the study is that Micro-algal technology is feasible and can revolutionise development in biodiesel industry.

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38

Larida, Alvin Q., e Jaeven B. Bañaga. "Extraction and characterization of algal oil from Lake Sebu, South Cotabato". Journal of Science and Science Education 5, n. 1 (28 settembre 2021): 12–25. http://dx.doi.org/10.24246/josse.v5i1p12-25.

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Abstract (sommario):

Algae is rich in storage lipids and fats that can be converted into biodiesel. This study determined the algal oil from Lake Sebu, South Cotabato as biodiesel source. Samples were prepared at varying treatments and ratio with n-Hexane. The algal oil was extracted and efficiency % were determined. FFA% and Acid Number of the oil extract were identified using chemical titration. FTIR was used for Chemical characterization while GC-MS identified fatty acid and other organics. With the constant volume of solvent and by changing the mass of dried algae, the percent yield of oil increases as the solvent to algae ratio increases. Therefore, biomass ratio with n-Hexane should be 1:3. The IR spectra of the oil extract indicated the presence of functional groups such as amine and carbonyl group of amides, methylene, methyl, and alkene. While, GC-MS showed that the fatty acids found can be a potential biodiesel.

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Babu, Swathi Somaiyan, Rashmi Gondi, Godvin Sharmila Vincent, Godwin Christopher JohnSamuel e Rajesh Banu Jeyakumar. "Microalgae Biomass and Lipids as Feedstock for Biofuels: Sustainable Biotechnology Strategies". Sustainability 14, n. 22 (14 novembre 2022): 15070. http://dx.doi.org/10.3390/su142215070.

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Abstract (sommario):

Microalgae exhibit remarkable potential as a feedstock for biofuel production compared with other sources, owing to their high areal productivity, low environmental effect, and negligible influence on food security. However, the primary obstacle to the commercialization of algae-based biofuels is the high economic cost due to the low-yield lipid content in the microalgae biomass. Maximizing biomass and lipid production is crucial to improve the economic viability of microalgae for biofuels. Identifying appropriate algal strains, particularly from indigenous environments, and developing those ‘platform strains’ using mutagenesis and genetic-engineering techniques is preferable. The provided discussion of conventional methods to increase microalgae’s biomass and lipid productivity mostly entailed adjusting environmental (such as temperature, light, and salinity) and nutritional (such as nitrogen and phosphorus) parameters. This review illustrated a comprehensive overview of biotechnological approaches and the recent strategies to enhance the lipid productivity of microalgae. The research also emphasized the need to streamline engineering strategies with the aid of recent advancements in DNA-manipulation techniques to hinder the existing biological intricacies in lipogenesis. This review also discussed the current economic and commercialization of this algal biorefinery along with the drawbacks.

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40

Greenwell, H. C., L. M. L. Laurens, R. J. Shields, R. W. Lovitt e K. J. Flynn. "Placing microalgae on the biofuels priority list: a review of the technological challenges". Journal of The Royal Society Interface 7, n. 46 (23 dicembre 2009): 703–26. http://dx.doi.org/10.1098/rsif.2009.0322.

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Abstract (sommario):

Microalgae provide various potential advantages for biofuel production when compared with ‘traditional’ crops. Specifically, large-scale microalgal culture need not compete for arable land, while in theory their productivity is greater. In consequence, there has been resurgence in interest and a proliferation of algae fuel projects. However, while on a theoretical basis, microalgae may produce between 10- and 100-fold more oil per acre, such capacities have not been validated on a commercial scale. We critically review current designs of algal culture facilities, including photobioreactors and open ponds, with regards to photosynthetic productivity and associated biomass and oil production and include an analysis of alternative approaches using models, balancing space needs, productivity and biomass concentrations, together with nutrient requirements. In the light of the current interest in synthetic genomics and genetic modifications, we also evaluate the options for potential metabolic engineering of the lipid biosynthesis pathways of microalgae. We conclude that although significant literature exists on microalgal growth and biochemistry, significantly more work needs to be undertaken to understand and potentially manipulate algal lipid metabolism. Furthermore, with regards to chemical upgrading of algal lipids and biomass, we describe alternative fuel synthesis routes, and discuss and evaluate the application of catalysts traditionally used for plant oils. Simulations that incorporate financial elements, along with fluid dynamics and algae growth models, are likely to be increasingly useful for predicting reactor design efficiency and life cycle analysis to determine the viability of the various options for large-scale culture. The greatest potential for cost reduction and increased yields most probably lies within closed or hybrid closed–open production systems.

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DZIOSA, Karolina, e Monika MAKOWSKA. "A METHOD FOR THE PREPARATION OF LUBRICATING OIL FROM MICROALGAE BIOMASS". Tribologia 270, n. 6 (31 dicembre 2016): 33–44. http://dx.doi.org/10.5604/01.3001.0010.6706.

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Abstract (sommario):

The paper presents a method for the preparation of lubricating oil from the biomass of single-cell green algae Chlorella sp. The microalgae were grown in a synthetic nutrient medium under laboratory conditions. The biomass, which was obtained from the culture, was subjected to the process of dehydration, freeze-drying, and solvent extraction, in order to separate lipids that may be a feedstock for eco-friendly lubricants. The chemical structure of obtained bioproducts (biomass and algal oil) was investigated by means of Fourier Transform Infrared Spectrophotometry. Moreover, rheological characteristics (kinematic viscosity at 40 and 100°C, dynamic viscosity at 0–100oC) of the algal oil were determined. The results of the laboratory tests show that the oil has the chemical structure and viscosity-temperature properties similar to the rapeseed oil. This creates a potential opportunity to replace used vegetable lubricants or additives by algal oil in many technical areas.

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Kim, Kwanwoo, Sun-Yong Ha, Bo Kyung Kim, C. J. Mundy, Kathleen M. Gough, Nicole M. Pogorzelec e Sang Heon Lee. "Carbon and nitrogen uptake rates and macromolecular compositions of bottom-ice algae and phytoplankton at Cambridge Bay in Dease Strait, Canada". Annals of Glaciology 61, n. 82 (23 aprile 2020): 106–16. http://dx.doi.org/10.1017/aog.2020.17.

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AbstractOur understanding of ice algal responses to the recent changes in Arctic sea ice is impeded by limited field observations. In the present study, environmental characteristics of the landfast sea-ice zone as well as primary production and macromolecular composition of ice algae and phytoplankton were studied in the Kitikmeot Sea near Cambridge Bay in spring 2017. Averaged total chlorophyll-a (Chl-a) concentration was within the lower range reported previously for the same region, while daily carbon uptake rates of bottom-ice algae were significantly lower in this study than previously reported for the Arctic. Based on various indicators, the region's low nutrient concentrations appear to limit carbon uptake rates and associated accumulation of bottom-ice algal biomass. Furthermore, the lipids-dominant biochemical composition of bottom-ice algae suggests strong nutrient limitation relative to the distinctly different carbohydrates-dominant composition of phytoplankton. Together, the results confirm strong nitrate limitation of the local marine system.

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Khandelwal, Amitap, Ankisha Vijay, Ambesh Dixit e Meenu Chhabra. "Microbial fuel cell powered by lipid extracted algae: A promising system for algal lipids and power generation". Bioresource Technology 247 (gennaio 2018): 520–27. http://dx.doi.org/10.1016/j.biortech.2017.09.119.

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Laurens, Lieve M. L., e Edward J. Wolfrum. "Feasibility of Spectroscopic Characterization of Algal Lipids: Chemometric Correlation of NIR and FTIR Spectra with Exogenous Lipids in Algal Biomass". BioEnergy Research 4, n. 1 (27 luglio 2010): 22–35. http://dx.doi.org/10.1007/s12155-010-9098-y.

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45

Lambert, R., G. Sandmann e P. Böger. "Binding and Peroxidative Action of Oxyfluorfen in Sensitive and Tolerant Algal Species". Zeitschrift für Naturforschung C 42, n. 6 (1 giugno 1987): 819–23. http://dx.doi.org/10.1515/znc-1987-0630.

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Peroxidative activity of oxyfluorfen and binding of this nitrodiphenyl ether to cell fractions was investigated with the susceptible alga Scenedesrnus aeutus and the resistant alga Bumilleriopsis filiformis. Although a 10-fold higher concentration of oxyfluorfen was applied to Bumilleriopsis, the lag phase for initiation of peroxidative evolution of short-chain hydrocarbons from fatty acids was much longer than found with Seenedesmus. Oxyfluorfen was predominantly recovered after homogenization from the pellet which was separated into a lipid and a chloroform/methanol insoluble fraction. Parts of the oxyfluorfen which is present in the insoluble pellet fraction during the lag phase before the onset of peroxidation can be found in the lipid fraction when measurable peroxidative activities have started. This was observed with Seenedesmus as well as with Bumilleriopsis. During peroxidation initiated by oxyfluorfen acyl lipids are degradated as monitored by the disappearance of the plastidic sulfolipid. Analysis of bound fatty acids showed that they are targets for peroxidative reactions in acyl lipids. Destruction of polyunsaturated fatty acids was higher than for saturated ones.

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Lambert, R., G. Sandmann e P. Böger. "Binding and Peroxidative Action of Oxyfluorfen in Sensitive and Tolerant Algal Species". Zeitschrift für Naturforschung C 42, n. 7-8 (1 agosto 1987): 819–23. http://dx.doi.org/10.1515/znc-1987-7-813.

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Peroxidative activity of oxyfluorfen and binding of this nitrodiphenyl ether to cell fractions was investigated with the susceptible alga Scenedesmus acutus and the resistant alga Bumilleriopsis filiformis. Although a 10-fold higher concentration of oxyfluorfen was applied to Bumilleriopsis, the lag phase for initiation of peroxidative evolution of short-chain hydrocarbons from fatty acids was much longer than found with Scenedesmus. Oxyfluorfen was predominantly recovered after homogenization from the pellet which was separated into a lipid and a chloroform/methanol insoluble fraction. Parts of the oxyfluorfen which is present in the insoluble pellet fraction during the lag phase before the onset of peroxidation can be found in the lipid fraction when measurable peroxidative activities have started. This was observed with Scenedesmus as well as with Bumil-leriopsis. During peroxidation initiated by oxyfluorfen acyl lipids are degradated as monitored by the disappearance of the plastidic sulfolipid. Analysis of bound fatty acids showed that they are targets for peroxidative reactions in acyl lipids. Destruction of polyunsaturated fatty acids was higher than for saturated ones.

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Krespach, Mario K. C., María García-Altares, Michal Flak, Hanno Schoeler, Kirstin Scherlach, Tina Netzker, Anica Schmalzl et al. "Lichen-like association of Chlamydomonas reinhardtii and Aspergillus nidulans protects algal cells from bacteria". ISME Journal 14, n. 11 (4 agosto 2020): 2794–805. http://dx.doi.org/10.1038/s41396-020-0731-2.

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Abstract Organismal interactions within microbial consortia and their responses to harmful intruders remain largely understudied. An important step toward the goal of understanding functional ecological interactions and their evolutionary selection is the study of increasingly complex microbial interaction systems. Here, we discovered a tripartite biosystem consisting of the fungus Aspergillus nidulans, the unicellular green alga Chlamydomonas reinhardtii, and the algicidal bacterium Streptomyces iranensis. Genetic analyses and MALDI-IMS demonstrate that the bacterium secretes the algicidal compound azalomycin F upon contact with C. reinhardtii. In co-culture, A. nidulans attracts the motile alga C. reinhardtii, which becomes embedded and surrounded by fungal mycelium and is shielded from the algicide. The filamentous fungus Sordaria macrospora was susceptible to azalomycin F and failed to protect C. reinhardtii despite chemotactically attracting the alga. Because S. macrospora was susceptible to azalomycin F, this data imply that for protection the fungus needs to be resistant. Formation of the lichen-like association between C. reinhardtii and A. nidulans increased algal growth. The protection depends on the increased amounts of membrane lipids provided by resistant fungi, thereby generating a protective shelter against the bacterial toxin. Our findings reveal a strategy whereby algae survive lethal environmental algicides through cooperation with fungi.

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MACEDO, C. F., e R. M. PINTO-CORLHO. "Nutritional status response of Daphania laevis and Moina micura from a tropical reservoir to different algal diets: Scenedesmus quadricauda and Ankistrodesmus gracilis". Brazilian Journal of Biology 61, n. 4 (novembre 2001): 555–62. http://dx.doi.org/10.1590/s1519-69842001000400005.

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The accumulation of lipid reserves was investigated in two common cladoceran species typical of neotropical freshwaters. Experiments were performed in order to measure differential accumulation of lipid reserves in response to two algal diets, S. quadricauda and A. gracilis. The larger D. laevis fed with the Ankistrodesmus diet accumulated a higher amount of total lipids. The average lipid content for both diets was 11.1% and 22.1% dry weight for Scenedesmus and Ankistrodemsus, respectively. This difference was found to be highly significant. The superior nutritional quality of A. gracilis was confirmed by the experiments using the smaller Moina micrura. This cladoceran accumulated 11.4% and 19.9% of the average dry weight of lipids from Scenedesmus and Ankistrodesmus, respectively. The study also found that most lipid reserves are concentrated as triacylglycerols in both cladocerans. The relative contribution of this class of lipids also varied according to the diet. For Daphnia, for instance, the average triacylglycerol levels varied from 6.2 to 11.0 with the Scenedesmus and Ankistrodesmus diets, respectively.

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Tang, Yuting, Yue Zhang, Julian N. Rosenberg, Nadia Sharif, Michael J. Betenbaugh e Fei Wang. "Efficient lipid extraction and quantification of fatty acids from algal biomass using accelerated solvent extraction (ASE)". RSC Advances 6, n. 35 (2016): 29127–34. http://dx.doi.org/10.1039/c5ra23519g.

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50

Li, Da-Wei, Srinivasan Balamurugan, Yu-Feng Yang, Jian-Wei Zheng, Dan Huang, Li-Gong Zou, Wei-Dong Yang, Jie-Sheng Liu, Yuanfang Guan e Hong-Ye Li. "Transcriptional regulation of microalgae for concurrent lipid overproduction and secretion". Science Advances 5, n. 1 (gennaio 2019): eaau3795. http://dx.doi.org/10.1126/sciadv.aau3795.

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Commercialization of algal lipids and biofuels is still impractical owing to the unavailability of lipogenic strains and lack of economically viable oil extraction strategies. Because lipogenesis is governed by multiple factors, success in generating industrial-suitable algal strains using conventional strategies has been limited. We report the discovery of a novel bZIP1 transcription factor, NobZIP1, whose overexpression results in a remarkable elevation of lipid accumulation and lipid secretion in a model microalgaNannochloropsis oceanica, without impairing other physiological properties. Chromatin immunoprecipitation–quantitative PCR analysis revealed that the key genes up- and down-regulated by NobZIP1 are involved in lipogenesis and cell wall polymer synthesis, respectively, which, in turn, induce lipid overproduction and secretion. Among these regulated genes, UDP-glucose dehydrogenase was shown to alter cell wall composition, thus also boosting lipid secretion. In summary, these results offer a comprehensive strategy for concurrent lipid overproduction and secretion, strongly increasing the commercial potential of microalgae.

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