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Search Results: 1 - 10 of 306 matches for " Microalgae "
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Morphological and chemical aspects of Chlorella pyrenoidosa, Dunaliella tertiolecta, Isochrysis galbana and Tetraselmis gracilis microalgae  [PDF]
Cristiane Mesquita da Silva Gorg?nio, Donato Alexandre Gomes Aranda, S?nia Couri
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.57094
Abstract:

This study evaluates the growth and chemical composition of the following marine microalgae: Dunaliella tertiolecta, Isochrysis galbana, and Tetraselmis gracilis and the chemical composition of Chlorella pyrenoidosa. Microalgae can produce a number of compounds of high commercial value for the industry, mainly for the food industry. The growth kinetics, cell volume, pigments, carbohydrates, proteins, lipids, and fatty acid and amino acid composition were evaluated. I. galbana had the largest number of cells per mL-1 (107), concentration of carotenoids (6.33 μg·mL-1), and carbohydrates (34.32%). D. tertiolecta and T. gracilis had the highest cell volume (560.6 and 592.7 μm3, respectively), the highest amount of total dry biomass. D. tertiolecta

Development and Characterization of Nanovesicles Containing Phenolic Compounds of Microalgae Spirulina Strain LEB-18 and Chlorella pyrenoidosa  [PDF]
Letícia Marques de Assis, Adriana Rodrigues Machado, Amanda de Souza da Motta, Jorge Alberto Vieira Costa, Leonor Almeida de Souza-Soares
Advances in Materials Physics and Chemistry (AMPC) , 2014, DOI: 10.4236/ampc.2014.41002
Abstract:

The objective of this study was to elaborate liposomes, through the lipid film hydration methodology, to nanoencapsulate phenolic compounds of Spirulina LEB-18 and Chlorella pyrenoidosa microalgae, and evaluate their physicochemical characteristics and storage stability for 21 days. The total phenolic compounds were evaluated using a calibration curve of gallic acid using methanol and ethanol as extraction solvents. The size and polydispersity index of nanovesicles were determined by light scattering and the percentage encapsulation efficiency was determined by a centrifugation process. The stability of the liposomes at storage time was measured by zeta potential for 21 days. The methanol extracts from Spirulina had a higher content of phenolic compounds (2.62 mg gallic acid·g-1 of microalgae) compared to the extracts of Chlorella. However, liposomes with ethanolic extracts of the two algae showed higher encapsulation efficiency. The value was higher (96.40%) for Chlorella. All samples obtained nanometric size, with the highest value obtained for the liposome containing ethanol extract of Chlorella (239 nm) differing significantly (p 0.05) from the others. The liposomes containing extracts of Spirulina were more stable during the 21 days of storage, whereas, those consisting of ethanol extract showed no significant difference

Cultivation of Microalgae Monoraphidium sp., in the Plant Pilot the Grand Valle Bio Energy, for Biodiesel Production  [PDF]
Gisel Chenard Díaz, Yordanka Reyes Cruz, René González Carliz, Rosa C. Vitorino de Paula, Donato A. Gomes Aranda, Marcellus A. G. Dario, Gustavo Saraiva Marass, Nelson C. Furtado
Natural Science (NS) , 2015, DOI: 10.4236/ns.2015.77040
Abstract: At present, Brazil imports approximately 11 billion liters/year of diesel. With the interruption of the works in the new Petrobras refineries, the projection is that by 2025 this volume will increase to 24.2 billion liters of diesel/year. In this sense, the biodiesel factory Grand Valle Bio Energy Ltda., located in the state of Rio de Janeiro, in conjunction with the FAPERJ makes some investments in technology development for the cultivation and use of microalgae as an alternative raw material in the production of biodiesel. Based on arguments previously said, this work presents the results of the microalgae cultivation Monoraphidium sp. in photobioreactors the pilot plant of the company. The installation with an area of 120 m2 is included with 2 open photobioreactors of type falling film (20 m × 1 m), with a cascade of 18mm and capacity of 4000 L. The lineage cultivated is selected from previous ecophysiological studies that are identified as promising for biodiesel production by having a high potential for the production of lipids. This lineage is maintained at collection of the stock of cultures Laboratory of Green Technologies of the School of Chemistry/ UFRJ. The cultivation was performed in means ASM-1 (Gorham et al., 1964), initial pH 8.0, with aeration and circulation average of 8 hours a day during 19 days. The culture was started with an inoculum of 1 × 107 cel/ml. The lipid production was determined in two phases of growth: on day 4 (exponential phase) and 15 day (stationary phase). For the determination and quantification of lipid content, two different methods were assessed for a sample of biomass, submitted to the same processes the separation and drying. The results showed the methodology of Bligh & Dyer with modifications as the most efficient in extracting lipids. The total lipid content of the biomass Monoraphidium sp. was 30.58%. The growth rate varied between 0.74 ± 0.01 and 0.68 ± 0.02.
Biodiesel Production Based in Microalgae: A Biorefinery Approach  [PDF]
Lauren Espinosa González, Gisel Chenard Díaz, Donato Alexandre Gomes Aranda, Yordanka Reyes Cruz, Mariana Monteiro Fortes
Natural Science (NS) , 2015, DOI: 10.4236/ns.2015.77039
Abstract: It is of great knowledge nowadays that the use of fossil fuels is responsible for the emission of gases that intensify the greenhouse effect, which threatens the survival of the humankind. The gravity of this fact could be mitigated through the indirect use of solar energy for fuels derived from vegetable that can be planted and cultivated by the world of renewable and non-polisher. Microalgae play an important role in this regard, as they have promising characteristics as potential raw material for the production of biofuels, able to absorb large amounts of CO2. Chlorophyll organisms convert these simple substances in the atmosphere, absorbing sunlight into chemical energy stored, that is, compounds with high energy, biomass can also be used to obtain biocompounds human nutritional supplement and food animal, however, have been found an important number of difficulties to economically viable production like high cost of production of dry biomass and oil extraction. Here, we review the main approaches of biorefinery concept appearing as an alternative to achieve economic viability of the production of bio-diesel based on microalgae. The major points are the following: 1) use of re-residual water, 2) marketing of Carbon Credits, and 3) development of co-products resulting from high value added.
Microalgae Lipid and Biodiesel Production: A Brazilian Challenge  [PDF]
Carolina T. Miranda, Roberta F. Pinto, Daniel V. N. de Lima, Carolina V. Viegas, Simone M. da Costa, Sandra M. F. O. Azevedo
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.615254
Abstract: Global increases in atmospheric CO2 and climate change are drawing considerable attention to identify sources of energy with lower environmental impact than those currently in use. Biodiesel production from microalgae lipids can, in the future, occupy a prominent place in energy generation because it represents a sustainable alternative to petroleum-based fuels. Several species of microalgae produce large amounts of lipids per biomass unit. Triacylglycerol is the fatty acid used for biodiesel production and the main source of energy reserves in microalgae. The current literature indicates that nutrient limitations can lead to triacylglycerol accumulation in different species of microalgae. Further efforts in microalgae screening for biodiesel production are needed to discover a native microalgae that will be feasible for biodiesel production in terms of biomass productivity and oil. This revision focuses in the biotechnological potential and viability of biodiesel production from microalgae. Brazil is located in a tropical region with high light rates and adequate average temperatures for the growth of microalgae. The wide availability of bodies of water and land will allow the country to produce renewable energy from microalgae.
Biosorption of Zn2+ and Ni2+, Cu2+ by Four Kinds of Active Microalgae  [PDF]
Fang Chen, Budan Chen, Guojuan Gan, Lin Zhang, Yan Liang, Sikai Wu
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.411002
Abstract: To investigate the affinity of the terrestrial microalgae to metal ions (Zn2+, Cu2+ and Ni2+) in aqueous solutions, four kinds of living algae (Oscillatoria, Botryococcus, Scenedesmus and Spirulina platensis Geitl, abbreviated as CZ, PTZ, SZ and LXZ) were chosen to biosorption experiment, and the mechanism of algae biosorption to metal ions were explored by fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results show that four kinds of algae have a good affinity for Cu, Zn, the removal rate could reach more than 95%; while for Ni, compared with CZ, SZ and PTZ, the adsorption rate of LXZ is weak. The results of FTIR and SEM experiments revealed that the function groups such as carboxyl, hydroxyl, amino, sulfonic groups and so on are the main groups which played important role in the procedure of absorbing metal ions from water aqueous. Specific algae have different affinity to different metals which will be great helpful in the field of biosorption.
Microalgae Tolerance to High Concentrations of Carbon Dioxide: A Review  [PDF]
Fadhil M. Salih
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.25074
Abstract: The increasing concentration of carbon dioxide (CO2) in the atmosphere is considered to be one of the main causes of the global warming problem. Moreover, there is an international movement to reduce the emission of CO2 by imposing different measures such as carbon tax. Biological CO2 fixation has been extensively investigated as part of efforts to solve the global warming problem. Microalgae are fast growing systems that can consume high quantities of CO2 to produce different types of biomass. The efficiency of microalgae is highly related to the concentration of CO2 in the growth atmosphere and the higher the concentration of CO2 the better is the growth and hence productivity. The present review aimed at shedding some light upon microalgal capability to sustain their viability and propagate under high CO2 concentration.
Biodiesel production by hydroesterification of microalgal biomass using heterogeneous catalyst  [PDF]
Yordanaka Reyes, Gisel Chenard, Donato Aranda, Cristiane Mesquita, Mariana Fortes, Rafael Jo?o, Leonardo Bacellar
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.410102
Abstract: This paper assesses the hydroesterification process for the production of Biodiesel from Monoraphidium contortum (MORF-1) microalgae biomass, as it is a sustainable alternative not only economically, but also environmentally and ecologically to replace petroleum diesel fuel. The Biodiesel studied in this work was obtained from fatty acid esterification, a product of microalgae and methanol biomass hydrolysis reaction. CBMM’s (HY-340) niobium oxide powder was used as catalyst. The reactions were carried out in a properly closed autoclave reactor (batch), where the reagents were mixed under constant stirring at 500 rpm for hydrolysis and esterification. The products generated were submitted to gas chromatography and oxidative stability analysis. The hydroesterification process showed itself to be a promising alternative to the conventional biodiesel production process (transesterification) as it favors the use of feedstocks with any acidity and moisture content and may be performed with acid catalyst, which favors high conversions in a small range of time (30 minutes).
Modeling of Biomass Production of Haematococcus pluvialis  [PDF]
Rosana M. Galv?o, Tarlen S. Santana, Cristiano H. O. Fontes, Emerson A. Sales
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.48A008
Abstract:

Microalgae cultivation is justified by the production of high-value fine chemicals and biofuels, essential to reduce the emissions of gases that cause global warming. This paper presents a study of the growth of microalgae Haematococcus pluvialis considering light conditions from 2000 to 10,000 lux, temperature 22?C and pH in the 6.5-12.5 range. The experiments were performed in 4 liter flat plate photobioreactors using the Rudic culture medium. The biomass growth was measured by counting cells in a Neubauer chamber. Both the light intensity and the pH of the medium influenced the rate of growth of the microalgae. A model with exponential behavior was proposed to describe the production of microalgae biomass over time. A nonlinear autoregressive model based on an Artificial Neural Network was used to predict the dynamic behavior of the pH during the growth of the microalgae at different light intensities. Simulations were carried out to analyze the behavior of biomass production at other light intensities within the range considered.

New Bio-Flocculatious Effect and Its Examination  [PDF]
Zoltán Hodai, Dóra Rippel-Peth?, Géza Horváth, Laszló Hanák, Róbert Bocsi
World Journal of Engineering and Technology (WJET) , 2014, DOI: 10.4236/wjet.2014.22013
Abstract: Algaetechnology is a significant scope of the international research and developmental work because it’s a green technology that reduces the utterance of impurities and works as a renewing energy source. The CO2 from stack gases of the various flows of manufacturing and the nitrogen from certain technical wastewater are necessary for the plants even as algae. The transaction of CO2 with this object and the utilization stand a good chance by hungarian clime with the teamwork from the technical environment. The technology is a new solution in Hungary which eases utterance of the impurities. As a result of our research we expanded alga polities which utilize the CO2 from refinery’s stack gas and they grow intensively in the continental clime, too. The critical points of the technology are the concentration of the algae suspension and the extraction because of the high investment and operating costs and high operational time. The algae technology in this direction depends on this step. Our aim is to separate the algae mass faster and more economical from the starter solution. The optimization of the separating operations and technologies takes notice of the environmental and economic aspects.
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