Academic literature on the topic 'Desmodesmus sp'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Desmodesmus sp.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Desmodesmus sp"
1
Danilovic, Bojana, Jelena Cvetkovic-Rakic, Jovan Ciric, Jelica Simeunovic, Vlada Veljkovic, and Dragisa Savic. "The isolation and screening of microalgae for the production of oil." Chemical Industry 71, no. 1 (2017): 69–74. http://dx.doi.org/10.2298/hemind151127019d.
Full textAbstract:
The biodiesel production has gained increasing attention of the researches in recent years. Current commercial biodiesel production involves transesterification of oil derived from oil crops. Since this production is no more sustainable, the use of microalgae represents a good alternative. Microalgae have high growth rate, high oil content and can be cultured in the environment which are not suitable for agriculture. Additionally, microalgae cultivation improves the reduction of carbon dioxide in the atmosphere. Selection of microalgae for oil production must take into consider certain criteria which include growth rate, oil content, fatty acids profile and ease of separation. In order to analyze the possibility of the use of microalgae for the production of oil, isolation of freshwater microalgae was performed. The isolation was done by the use of traditional techniques from freshwaters near Leskovac. A total number of 6 microalgae strains were isolated and identified as the representatives of the genera Chlorococcum (1 isolate), Chlorella (1 isolate), Scenedesmus (1 isolate) and Desmodesmus (3 isolates). Isolates of microalgae were screened for the growth rate, biomass and oil productivity and oil content. The highest content of biomass was 1.5 g/l and it was observed in the strains Chlorococcum sp. and Desmodesmus sp. 1. The highest value of specific growth rate was calculated during the growth of microalgae Chlorella sp., Scenedesmus sp. and Desmodesmus sp.1, while the lowest value was observed for Chlorococcum sp. Oil productivity was the highest for Chlorella sp. and Desmodesmus sp.1 (0,4 g/l) and the lowest for Desmodesmus sp.2, Desmodesmus sp.3 and Chlorococcum sp. (0,2 g/l). The oil content was in the range from 15.8% (Chlorococcum sp.) to 33% (Chlorella sp). Since the microalgae isolates Chlorella sp. and Scenedesmus sp. had the highest oil productivity, high growth rate and high oil content, these strains are the most suitable for further investigation in order to improve the oil yield and analyse the possibility of the use in the production of biodiesel.
2
Shrestha, Govinda, and Shiva Kumar Rai. "Algal flora of Rajarani Lake, Dhankuta and their seasonal distribution." Our Nature 15, no. 1-2 (2017): 44–54. http://dx.doi.org/10.3126/on.v15i1-2.18793.
Full textAbstract:
In this paper, a total 46 algae belonging to 34 genera and 3 classes (Chlorophyceae 54%, Bacillariophyceae 28%, Cyanophyceae 18%) have been reported from Rajarani Lake, Dhankuta, Nepal. Among these, 13 algae were reported as new to the country. Genera Ankistrodesmus, Closterium, and Desmodesmus had maximum number of species whereas 25 genera were represented by single species. Seasonal variation of algae showed that there was changing number and type of algae with physicochemical parameters in different seasons. Cyanophycean algae Microcystis flos-aque was dominant and observed in all sites in every collection of winter, summer and rainy seasons, and followed by bacillariophyceaean algae i.e., Aulacoseira granulata var. angustissima. The maximum number of algae was found in summer (59%) followed by winter (50%) and rainy (31%) seasons. There were 6 common algae found in all season’s viz. Ankistrodesmus falcatus, Aulacoseira granulata var. angustissima, Flagilaria tenera, Microcystis flos-aquae, Navicula radiosa and Oedogonium sp. Algae viz., Anabaena affinis, Cyclotella meneghiana, Pinnularia divergens, Pinnularia interrupta, Tetrastrum heteracanthum, and Ulothrix subtilissima were found only in winter season whereas, Aulacoseirsa granulata var. muzzanensis, Bolbochaete sp, Closterium striolatum, Cylindrospermum muscicola, Desmodesmus abundans, Desmodesmous quadricauda var.bicaudatus, Eunotia bilunaris, Gomphonema lacusrankaloides and Gomphonema pseudoaugur were observed only in summer. Similarly, Aphanocapsa pulchra, Oscillatoria sancta and Pediastrum duplex var. gracillimum were reported only in rainy season.
3
Godinho, Luciana Rufino, Augusto A. Comas González, and Carlos Eduardo de Mattos Bicudo. "Criptógamos do Parque Estadual das Fontes do Ipiranga, São Paulo, SP: algas, 30: Chlorophyceae (família Scenedesmaceae)." Hoehnea 37, no. 3 (2010): 513–53. http://dx.doi.org/10.1590/s2236-89062010000300005.
Full textAbstract:
Levantamento florístico dos representantes da família Scenedesmaceae (Chlorophyceae) do Parque Estadual das Fontes do Ipiranga, São Paulo, Brasil. Doze gêneros (Crucigenia, Crucigeniella, Desmodesmus, Didymogenes, Dimorphococcus, Pseudodidymocystis, Pseudotetrastrum, Scenedesmus, Tetrachlorella, Tetrallantos, Tetrastrum e Westella), 47 espécies e 11 variedades que não são as típicas de suas respectivas espécies foram identificadas. O gênero representado pelo maior número de táxons foi Desmodesmus, com 16 espécies e sete variedades que não são as típicas de suas respectivas espécies. Vem a seguir Scenedesmus com 14 espécies e quatro variedades igualmente não típicas. As espécies que ocorreram no maior número de ambientes foram: Desmodesmus communis, D. denticulatus var. linearis, D. intermedius var. acutispinus, Pseudodidymocystis fina, Scenedesmus obliquus var. dimorphus, S. acunae e S. obtusus, por ocorrerem em três localidades cada uma.
4
Jesus, Helenice Silva de, Servio Tulio Alves Cassini, Marcos Vinicius Pereira, Aline Figueredo Dassoler, and Ricardo Franci Gonçalves. "Autochthonous microalgae cultivation with anaerobic effluent: isolation of strains, survivorship, and characterization of the produced biomass." Ambiente e Agua - An Interdisciplinary Journal of Applied Science 14, no. 4 (2019): 1. http://dx.doi.org/10.4136/ambi-agua.2362.
Full textAbstract:
Six Chlorophyta strains were isolated from the effluent of an anaerobic reactor treating municipal wastewater and identified as Desmodesmus sp. L02, Chlorococcum sp. L04, Coccomyxa sp. L05, Chlorella sp. L06, Scenedesmus sp. L08 and Tetradesmus sp. L09. The microalgae strains were cultivated in unsterilized wastewater under laboratory conditions to determine their potential to survive under non-sterile conditions. The strains were also cultivated in sterilized wastewater in order to analyze their nutrient removal potential and characterize the produced biomass. Amongst the isolated microalgae, Chlorella sp. L06 had the highest survivorship percentage (90%) for ten days of culture, whilst Desmodesmus sp. L02 had the lowest, not exceeding 1.8% after 24h of inoculation. The dried biomass of the isolates showed an average of 28.7% of protein, 15.4% of lipids and 14.8% of carbohydrates, with Chlorococcum sp. L04 reaching 29.3% of carbohydrates. In terms of nutrients, nitrogen removal varied from 59.2 to 93%, and phosphorus removal ranged from 79.1 to 95.4%, with Tetradesmus sp. L09 being the most efficient strain.
5
Braglia, Roberto, Lorenza Rugnini, Sara Malizia, et al. "Exploiting the Potential in Water Cleanup from Metals and Nutrients of Desmodesmus sp. and Ampelodesmos mauritanicus." Plants 10, no. 7 (2021): 1461. http://dx.doi.org/10.3390/plants10071461.
Full textAbstract:
Increasing levels of freshwater contaminants, mainly due to anthropogenic activities, have resulted in a great deal of interest in finding new eco-friendly, cost-effective and efficient methods for remediating polluted waters. The aim of this work was to assess the feasibility of using a green microalga Desmodesmus sp., a cyanobacterium Nostoc sp. and a hemicryptophyte Ampelodesmos mauritanicus to bioremediate a water polluted with an excess of nutrients (nitrogen and phosphorus) and heavy metals (copper and nickel). We immediately determined that Nostoc sp. was sensitive to metal toxicity, and thus Desmodesmus sp. was chosen for sequential tests with A. mauritanicus. First, A. mauritanicus plants were grown in the ‘polluted’ culture medium for seven days and were, then, substituted by Desmodesmus sp. for a further seven days (14 days in total). Heavy metals were shown to negatively affect both the growth rates and nutrient removal capacity. The sequential approach resulted in high metal removal rates in the single metal solutions up to 74% for Cu and 85% for Ni, while, in the bi-metal solutions, the removal rates were lower and showed a bias for Cu uptake. Single species controls showed better outcomes; however, further studies are necessary to investigate the behavior of new species.
6
Morales, Ever, Verónica Luna, Lucía Navarro, Vismeli Santana, Ana Gordillo, and Andrés Arévalo. "Diversidad de microalgas y cianobacterias en muestras provenientes de diferentes provincias del Ecuador, destinadas a una colección de cultivos." Revista Ecuatoriana de Medicina y Ciencias Biológicas 34, no. 1-2 (2017): 129–49. http://dx.doi.org/10.26807/remcb.v34i1-2.240.
Full textAbstract:
El presente trabajo conforma un estudio sobre diversidad, identificación y aislamiento de microalgas y cianobacterias a partir de muestras de aguas continentales, termales, salobres y lodos; colectadas en 74 sitios de 25 sectores de las provincias del Carchi, Guayas, Imbabura, Pichincha y Santa Elena (Ecuador), entre octubre 2011 y abril 2012, con la finalidad de poder determinar en dichas muestras, su diversidad inicial, sucesión de estos microorganismos y la estabilidad de los consorcios entre microalgas y cianobacterias durante la fase de selección de muestras y de aislamiento para el establecimiento de una colección in vitro de cultivos de microorganismos fotosintéticos para la Escuela de Bioanálisis de la Pontificia Universidad Católica del Ecuador. De 194 muestras evaluadas, fueron aislados el 43.81 % de microalgas y cianobacterias; donde los taxones más susceptibles de ser aislados son: Chlorella, Desmodesmus y Leptolyngbya. En cambio, se mantuvo el 56.19 % como consorcios o cultivos mixtos de microalgas y cianobacterias. De estos, se cuantificaron 14 cultivos solo con cianobacterias; 40 solo entre microalgas y 55 mixtos (31 y 18, taxa de microalgas y cianobacterias; respectivamente). Los tax más frecuentes en los consorcios microalga-microalga fueron: Chlorella sp.>Desmodesmus sp. >Navicula sp.; en los cianobacteria-cianobacteria: Leptolyngbya sp.> Calothrix sp.> Nostoc sp. y en los microalga-cianobacteria: Leptolyngbya sp.>Navicula sp.> Chlorella sp.> Desmodesmus sp.> Calothrix sp. Las muestras obtenidas en la laguna “El Salado”, San Gabriel, Carchi presentaron la mayor diversidad. Mientras que, las colectadas en “Aguas Hediondas”, Tufiño, Carchi mostraron exclusividad de Dictyosphaerium sp., Microspora sp., y Mougeotia sp. La cianobacteria Leptolyngbya sp., refleja ser altamente competitiva en cultivos envejecidos y deficientes en nutrientes. Se recomienda ingresar todos los consorcios a las colecciones, dada su importancia como fuentes de biodiversidad y para estudios de fisioecología, biotecnología ambiental y agrícola.
7
Do, Jeong-Mi, Seung-Woo Jo, Il-Sup Kim, et al. "A Feasibility Study of Wastewater Treatment Using Domestic Microalgae and Analysis of Biomass for Potential Applications." Water 11, no. 11 (2019): 2294. http://dx.doi.org/10.3390/w11112294.
Full textAbstract:
Water scarcity and emerging demands for renewable energy have increased concerns about energy security and advanced wastewater treatment, and microalgae have emerged as promising candidates to solve these problems. This study assesses the feasibility of microalgal wastewater treatment, and the utilization of the resulting microalgal biomass, as a renewable energy source. We cultured four selected microalgal species in filtered wastewater collected from the municipal treatment facility in Daegu, Republic of Korea. We measured nutrient consumption, growth rate, and physicochemical properties during cultivation, then analyzed the biomass for biochemical composition, ultimate analysis, proximate analysis, and biodiesel and lubricant properties, to estimate its potential applications. Desmodesmus sp. KNUA024 emerged as the most promising strain, removing 99.10% of ammonia nitrogen, 91.31% of total nitrogen, and 95.67% of total phosphate. Its biomass had a calorific value of 19.5 MJ kg−1, similar to terrestrial plants. α-linolenic acid was the most abundant polyunsaturated fatty acid (PUFA; 54.83%). Due to its PUFA content, Desmodesmus sp. KNUA024 also had a high iodine value, indicating its potential for use as a bio-lubricant. Therefore, Desmodesmus sp. KNUA024 shows promise for wastewater treatment, energy, and industrial applications.
8
Oviedo-Montiel, Harold, Edwin Herrera-Cruz, Jenny Hoya-Florez, Martha Prieto-Guevara, Ana Estrada-Posada, and Jonny Andrés Yepes Blandón. "Crecimiento y viabilidad celular de microalgas: efecto del medio de cultivo." Intropica 15, no. 2 (2020): 126–36. http://dx.doi.org/10.21676/23897864.3633.
Full textAbstract:
En acuicultura, el uso de microalgas es fundamental en la primera alimentación de especies nativas de peces, pues su óptimo nivel nutricional favorece la sobrevivencia. El éxito de la producción de microalgas depende, entre otras, del medio de cultivo empleado. Los fertilizantes agrícolas usados como medio de cultivo son una alternativa de bajo costo que favorece el crecimiento celular y la criopreservación. El objetivo fue evaluar el efecto de dos medios de cultivo sobre el crecimiento poblacional (CP) y la viabilidad celular post-descongelación (VCP) de microalgas Chlorella sp., Desmodesmus sp., y Ankistrodesmus sp. Se evaluó el CP y VCP los medios de cultivo F/2 Guillard, y Nutrifoliar®. Para el CP en ambos tratamientos se determinó: crecimiento (k), tiempo de duplicación (td), rendimiento (r) y densidad máxima (dm). Para VCP se empleó metanol al 5 y 10 %, en seis tratamientos. La VCP se clasificó: sin daño celular (SDC), daño celular (DC) y lesiones marcadas (LM). El crecimiento poblacional fue igual para las tres microalgas (p>0,05). El T1 tuvo el menor td para Desmodesmus sp. (p<0,05). El T2 presentó el mayor r y dm para las tres microalgas (p <0,05). En la viabilidad celular post-descongelación, el mayor porcentaje SDC para Chlorella sp., al día (d) cero, fue similar en T3 y T4 y al d cinco fue en T6; para Desmodesmus sp, al d cero fue en T6 y al d cinco fue similar en T6 y T1; mientras que, para Ankistrodesmus sp, al d cero y cinco se presentó en T3. Se concluye que el medio de cultivo Nutrifoliar®, es una alternativa viable y de bajo costo para el cultivo y la criopreservación de microalgas de agua dulce.
9
Rosini, Edna Ferreira, Célia Leite Sant'Anna, and Andréa Tucci. "Scenedesmaceae (Chlorococcales, Chlorophyceae) de pesqueiros da Região Metropolitana de São Paulo, SP, Brasil: levantamento florístico." Hoehnea 40, no. 4 (2013): 661–78. http://dx.doi.org/10.1590/s2236-89062013000400008.
Full textAbstract:
Foi realizado o levantamento das Scenedesmaceae em 10 pesqueiros da Região Metropolitana de São Paulo (RMSP). As amostras foram coletadas na sub-superfície por meio de arrasto horizontal com rede de plâncton (20 μm), em dois períodos: setembro-outubro de 2001 (estiagem) e fevereiro-março de 2002 (chuvoso), totalizando 20 amostras. As amostras foram preservadas em formol a 4-5% e estudadas ao microscópio fotônico. Foram identificados 26 táxons de Scenedesmaceae, distribuídos em 10 gêneros, 23 espécies, duas variedades e uma forma taxonômica. Desmodesmus lefevrei (Deflandre) An, Friedl & Hegewald, Dicloster acuatus Jao, Wei& Hu e Scenedesmus baculiformis Chodat são citadas pela primeira vez para o Estado de São Paulo. Scenedesmus e Desmodesmus foram os gêneros mais bem representados, com nove e oito espécies, respectivamente.
10
Wu, Y. C., Y. Xiao, HY Fu, and F. Zhao. "Light Affects Electrochemical Characterization of Electrogenic Microalgae Desmodesmus sp. A8." IOP Conference Series: Earth and Environmental Science 146 (May 2018): 012044. http://dx.doi.org/10.1088/1755-1315/146/1/012044.
Full textDissertations / Theses on the topic "Desmodesmus sp"
1
Al-Mousawi, Adnan Abdulah Hamad. "Investigation of neutral lipid production in Desmodesmus armatus and Synechocystis sp. PCC6803." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18537/.
Full textAbstract:
Microalgae has been introduced in the last decades to be an optimum source for biofuel production that can be utilised efficiently to replace the conventional fossil fuels as a source of energy. In our study, a local strain of green microalgae was isolated from the Weston Park pond (Sheffield, UK) and identified, using different molecular markers including 18S rDNA, ITS1, ITS2, and 5.8S rDNA, as Desmosdesmus armatus. The neutral lipid content (as the basis of renewable biodiesel production) of both D. armatus and the model cyanobacterium Synechocystis sp. was measured using the lipophilic fluorescent dye Nile Red. The two strains were grown in normal BG11 medium and under stress conditions including high salinity (0.2, 0.4 M NaCl), different concentrations of sodium nitrate in the BG11 media (10% NaNO3, N-free), and different sources of nitrogen (NH4Cl, urea). The results showed that N-free BG11 medium was the best stress conditions in both strains for inducing a significant (p < 0.05) increase in neutral lipid content. Further work concentrated on D. armatus and the Fatty Acid Methyl Esters (FAME) conversion yield was examined using a direct transesterification method and the composition of fatty acids was investigated using GC-MS. Desmodesmus armatus grown in N-free BG11 medium showed the highest yield and the contents of C16 and C18 fatty acids (useful for biodiesel production) increased significantly under this stress condition. Further analysis of D. armatus lipid content was conducted using 1H NMR and the results confirmed that the fatty acid content is much higher in the N free grown cells. The final set of experiments focused on random mutation of D. armatus cells using Ultra Violet light (254 nm) to generate new strains with high neutral lipid content. The high lipid containing cells were isolated using Nile Red staining and automated fluorescence assisted cell sorting (FACS) flow cytometry technique. A mutant strain was isolated with 5 times greater yield of neutral lipid than the wild type strain based on the median of the Nile Red fluorescence of the wild type and the mutant cells. This significant increase in the lipid yield using UV-induced random mutation, Nile Red staining and FACS has paved the way for further investigation of the molecular and genetic approaches to identify the key genes that control neutral lipid biosynthesis in microalga.
2
Ríos, Pinto Luisa Fernanda 1981. "Estudo do crescimento da microalga Desmodesmus sp. visando a produção de biodiesel." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266120.
Full textAbstract:
Orientadores: Maria Regina Wolf Maciel, Luiz Fernando de Lima Luz JuniorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
Made available in DSpace on 2018-08-24T13:41:08Z (GMT). No. of bitstreams: 1 RiosPinto_LuisaFernanda_D.pdf: 4599056 bytes, checksum: 80a3191a923471837068d7b5f547c19e (MD5) Previous issue date: 2014
Resumo: Atualmente, a destruição ambiental devido à exploração inapropriada dos recursos naturais não renováveis, o aquecimento global, e a contaminação da biosfera causada, principalmente, pela globalização e um crescimento tecnológico acelerado, tem levado ao desenvolvimento de diversos combustíveis de fontes de energia renováveis, que sejam capazes de manter ou superar a eficiência dos hidrocarbonetos fósseis. Neste cenário, se deu o desenvolvimento do biodiesel, um combustível biodegradável derivado de fontes renováveis, o qual, na sua combustão, libera menos gases tóxicos, como são os óxidos de enxofre e nitrogênio. O biodiesel pode ser produzido a partir de gorduras animais, óleos vegetais ou biomassa. A fim de reduzir os custos da produção do biodiesel, matérias primas como os lipídios vêm sendo estudadas. Neste contexto, as microalgas oferecem uma série de vantagens como fonte de lipídios, como por exemplo, altas taxas fotossintetizantes, alta produção de biomassa e um rápido crescimento, se comparado, principalmente, com outras fontes de óleo vegetal. Neste trabalho, foi realizado o estudo do crescimento da microalga Desmodesmus sp. sob condição autotrófica, mixotrófica e heterotrófica com o objetivo de obter maior teor de lipídios na célula da microalga, visando a produção de biodiesel. Nas condições autotróficas, se obteve um crescimento de 53,1 Mcélulas mL-1. No cultivo mixotrófico, conseguiram-se 181 Mcélulas mL-1 e no heteretrófico atingiu-se 298 Mcélulas mL-1, todos no sexto dia de cultivo. As porcentagens de lipídios foram de 23%, 25% e 17% (m/m) da biomassa para o cultivo autotrófico, mixotrófico e heterotrófico, respectivamente. O óleo extraído do cultivo autotrófico, foi caracterizado via cromatografia gasosa e, a partir desta análise, produziu-se um óleo sintético (mistura de óleos vegetais e animais) com as características semelhantes da microalga para realizar a cinética da reação de transesterificação, num reator em batelada. A produção de biodiesel foi feita por transesterificação ácida, com excesso de etanol. O tempo de reação foi de 24 horas e obteve-se 90% de ésteres produzidos
Abstract: Currently, environmental destruction caused by inappropriate exploitation of non-renewable natural resources, global warming, and pollution of the biosphere caused mainly by globalization and accelerated technological growth has led to the development of various fuels from renewable source, which are able to maintain or exceed the effectiveness of fossil hydrocarbons. Biodiesel, a biodegradable fuel derived from renewable source, which releases less toxic gases such as sulfur and nitrogen oxides in its combustion. Biodiesel can be obtained from animal fats, vegetable oils or biomass. In order to reduce the cost of biodiesel production, raw materials such as lipids have been studied. In this context, microalgae offer a number of advantages as a source of fat, such as high photosynthetic rates, high biomass, and fast growth rate, compared to other sources of vegetable oil. The objective of this work was to study the autotrophic, mixotrophic and heterotrophic growths of microalgae Desmodesmus sp in order to optimize the levels of lipids in the microalgae cell to produce biodiesel. In autotrophic conditions, it was observed 5.31x107 cells ml-1; in mixotrophic were achieved 1.81x108 cells ml-1; and in heterotrophic reached 2.98x108 cells ml-1 were reached after sixth day of cultivation. The percentages of lipids of biomass for autotrophic, heterotrophic mixotrophic cultivation were 23%, 25% and 17% (m/m) respectively. Oil extracted from autotrophic cultivation was characterized via gas chromatography. A synthetic oil (mixture of vegetable and animal oils) with similar characteristics to the microalgae was used to perform the transesterification kinetics in a batch reactor. The production of such biodiesel was performed under acid conditions with excess of ethanol for 24 hours yielding 90% product
Doutorado
Desenvolvimento de Processos Químicos
Doutora em Engenharia Quimica
3
Fontes, Luiza Moura. "BIODEGRADAÇÃO DE EMULSÃO DE ÓLEO RESIDUAL PESADO EM CULTIVO DE DESMODESMUS SP." Escola Politécnica, 2017. http://repositorio.ufba.br/ri/handle/ri/24618.
Full textAbstract:
Submitted by Luiza Fontes (luimf@yahoo.com.br) on 2017-11-17T22:01:25Z
No. of bitstreams: 1
dissertacao_mestrado_pei_Luiza_Fontes_final.pdf: 2354845 bytes, checksum: 20aedd4de1231ce14dd1ce159439415d (MD5)Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-11-20T14:45:54Z (GMT) No. of bitstreams: 1 dissertacao_mestrado_pei_Luiza_Fontes_final.pdf: 2354845 bytes, checksum: 20aedd4de1231ce14dd1ce159439415d (MD5)
Made available in DSpace on 2017-11-20T14:45:54Z (GMT). No. of bitstreams: 1 dissertacao_mestrado_pei_Luiza_Fontes_final.pdf: 2354845 bytes, checksum: 20aedd4de1231ce14dd1ce159439415d (MD5)
CNPq e Fapesb
Os impactos ambientais provenientes do refino do petróleo são inúmeros e entre estes está a geração de grande quantidade de resíduos pesados contendo uma variedade de compostos orgânicos policíclicos, aromáticos e tóxicos ao homem e ao meio ambiente. É sabido que as microalgas utilizam compostos de carbono como o CO2 como fonte de nutrientes para produção de carboidratos, proteínas, lipídeos e pigmentos. Neste trabalho foi realizado um estudo sobre a capacidade das microalgas da espécie Desmodesmus sp.de biodegradar emulsões de óleo residual pesado de petróleo (BPF) em água. Com esta finalidade foram preparadas emulsões com tensoativos aniônicos e não iônicos biodegradáveis permitindo o acesso das microalgas em cultivo aquoso ao óleo residual e a seus componentes tóxicos, hidrocarbonetos policiclicos aromáticos (HPAs). O preparo das emulsões priorizou ativos biodegradáveis provenientes de fontes de carbono renováveis. Com o objetivo de preparar uma solução emulsionante utilizando quantidades mínimas de tensoativos para foi realizado um planejamento estatístico dos experimentos. Inicialmente foi cultivado o inoculo mãe; uma vez alcançada a fase estacionária, o cultivo foi reiniciado com 30%(v/v) do inoculo mãe e 1%(v/v) das emulsões contendo o óleo BPFem condição restrita de nutrientes, forçando assim a utilização da emulsão como fonte carbônica de nutrientes. Ao longo de cada experimento foi avaliado o crescimento celular das microalgas e acompanhados os teores de carotenoides dos cultivos através de espectroscopia Raman. Ao final, foi avaliada a presença de HPAs no meio de cultivo através de técnica cromatográfica gasosa. A espécie Desmodesmus sp. apresentou curva de crescimento atípica na presença do óleo BPF emulsionado, bem como alterações no metabolismo de produção de β-caroteno. Conclui-se que as microalgas da espécie Desmodesmus sp. foram capazes de biodegradar em 90 dias, nas condições utilizadas nos experimentos, os componentes orgânicos presentes no óleo BPF, incluindo a maior parte dos HPAs presentes.
The environmental impacts from the refining of petroleum are numerous and among these is the generation of large quantities of heavy residues containing a variety of polycyclic organic compounds, aromatic and toxic to humans and the environment. It is known that microalgae use carbon compounds such as CO2 as a source of nutrients for the production of carbohydrates, proteins, lipids and pigments. In this work a study on the ability of the microalgae of the species Desmodesmus sp. to biodegrade heavy oil residual oil (BPF) emulsions in water was carried out. For this purpose, emulsions containingbiodegradable anionic and nonionic surfactants were prepared, allowing the microalgae in aqueous culture to reach the residual oil and its toxic components, aromatic polycyclic hydrocarbons (PAHs). The preparation of the emulsions prioritized biodegradable assets from renewable carbon sources. In order to use minimum amounts of surfactants, a statistical design of experiments was carried out to prepare the ideal emulsifier solution. Initially the mother inoculum was cultivated; The culture was restarted with 30% (v / v) of the mother inoculum and 1% (v / v) of the emulsions containing the BPF oil in a nutrient restricted condition, thus forcing the emulsion to be source of nutrients. Throughout each experiment the cell growth of the microalgae was evaluated and the carotenoid contents of the cultures were monitored through Raman spectroscopy. At the end, the presence of PAHs in the culture medium was evaluated by gas chromatographic technique. The species Desmodesmus sp. presented an atypical growth curve in the presence of emulsified BPF oil, as well as changes in the metabolism of β-carotene production. It is concluded that the microalgae of the species Desmodesmus sp. were able to biodegrade in 90 days, under the conditions used in the experiments, the organic components present in the BPF oil, including most of the HPAs present.
4
Yen-YingLai and 賴彥頴. "Optimizing lipid production with an indigenous thermo-tolerant microalga Desmodesmus sp." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/882kcr.
Full textAbstract:
碩士國立成功大學
化學工程學系碩博士班
101
Nowadays, rapid industrial development and the overuse of fossil fuels have caused some severe problems, such as environmental pollutions, climate change, and even the species extinctions. Therefore, using alternative energy (such as biomass energy) has been recognized as one of the strategies to solve these problems. Among the options of biomass energy, microalgae-based biodiesel is consider a promising one since microalgae have high growth rate, high lipid content, can be cultivated on non-arable. In this study, standard criteria (i.e., oil/lipid production performance, lipid quality, and auto-sedimentation ability) were established as a platform technology for screening potential microalgal strains suitable for the use as the oil feedstock for biodiesel production. Based on the aforementioned criteria, the strain with the highest potential as microalgal oil producer was selected from four indigenous thermo-tolerant Desmodesmus sp. isolates (i.e., F2, F32, F44, and F51) obtained from southern coast of Taiwan. Under the same cultivation conditions (light intensity, 100 μmol m-2 s-1; temperature, 35 oC), Desmodesmus sp. F2 appeared to have higher lipid content (52.86 % w/w), higher lipid productivity (113 mg L-1 d-1), proper fatty acid profile, and great auto-sedimentation ability (61.97 % hour-1). Therefore, the F2 strain was chosen as the target strain for further oil production studies. Next, the effects of environmental factors (i.e., light intensity, temperature, nitrogen source, nitrogen concentration, and duration of nitrogen depletion) on cell growth and lipid accumulation of Desmodesmus sp. F2 were examined. Response surface methodology (i.e., RSM) was used to determine the optimal conditions for batch microalgal oil production. Under the optimal conditions (i.e., light intensity, 700 μmol m-2 s-1; temperature, 35 oC; nitrogen concentration, 6.6 mM; 6-day nitrogen depletion), the maximum lipid productivity and lipid content was about 263 mg L-1 d-1 and 67.57 % w/w, respectively. This lipid productivity is 2 folds higher than that obtained from original conditions before the RSM optimization. Different cultivation strategies (i.e., fed-batch and semi-continuous cultivation systems) were also applied to improve the microalgal oil production performance. For fed-batch cultivation system, different feeding intervals (i.e., 2, 4, and 6-day nitrogen depletion) were explored. The best results were obtained with 6-day nitrogen depletion feeding, giving a final biomass concentration of 9.33 g L-1, which is 3-fold higher than that obtained in batch cultivation system. Nevertheless, the lipid content (49.16 % w/w) and lipid productivity (213 mg L-1 d-1) were lower than those from batch cultivation. On the other hand, semi-continuous cultivation system was conducted using different replacement ratio of culture broth and fresh medium. Using the semi-batch operation with 90 % replacement ratio, the maximum lipid productivity was 302 mg L-1 d-1, which is higher than using batch cultivation system, whereas the lipid content (45.57%(w/w)) was lower. Thus, the selection of cultivation systems has to depend on different requirements. Moreover, the 50 L outdoor batch cultivation of Desmodesmus sp. F2 was also investigated. The results show that the biomass productivity, lipid content, and lipid productivity was 84 mg L-1 d-1, 33.0 % w/w, and 22 mg L-1 d-1, respectively under the light intensity and high temperature in outdoor environment. The results discussed above suggest that D. sp. F2 seems to be a feasible candidate of oil producer for large-scale biodiesel production.
5
Diale, Palesa Promise. "The biosorption of heavy metals by immobilised green microalgae Desmodesmus sp. biosmass." Thesis, 2016. http://hdl.handle.net/10539/20029.
Full textAbstract:
Gold mining had a prominent place in the South African economy since its discovery in 1886. However, its fall in production and imminent resource exhaustion over the years has come with extensive environmental problems. This therefore calls for sustainable and cost-effective technologies that can reduce toxic levels of heavy metal concentrations in water streams to environmentally acceptable levels. A green microalgae such as Desmodesmus sp. has a potential to be a sustainable and cost-effective solution, due to its proficient capability of heavy metal sequestration in aqueous solutions. This study is therefore governed by two key complimentary components: (i) in-depth optimization study of Ca-alginate matrix composition for the purpose of immobilizing Desmodesmus sp. and (ii) the immobilized Desmodesmus sp. being used for biosorption of heavy metals from aqueous solutions. Following the preliminary optimization studies, bead diameter of 3 mm; calcium chloride concentration of 9 % w/v; sodium alginate concentration of 6 % w/v and biomass loading of 8 % w/v were used for subsequent biosorption experiments. High correlation coefficients was found for the Freundlich model indicating that it can be used to best describe the sorption of Fe (II) and other heavy metals on immobilized algal biomass. The correlation coefficient study showed the R2 value of Fe (II) sorption kinetics for pseudo-second order kinetic equation was close to 1, making it a better fit to the experimental data compared to pseudo-first order where R2 values were 0.18; 0.38; 0.76; 0.41; 0.48 and 0.76 for 5; 60; 120; 240; 480 and 1000 mg / L. The trend in binding of heavy metal ions is as follows: Ni (II) > Mn (II) >Cr (III) > Fe (II). The increase in loading capacity as a function to time when Fe (II), Ni (II), Mn (II) and Cr (III) are adsorbed by the immobilized microalgae Desmodesms sp. is an indication that microalgae cells are tolerant of toxic heavy metals in aqueous solutions. According to this study a flow rate of 4 mL/min with a packing height of 82 cm (Co = 120 mg / L) seems to be the most effective combination, which has a potential to increase the metal removal rate significantly. Further work will be required to develop models that will best describe the biosorption of heavy metals in a continuous flow system, packed bed column. From this study the immobilized green microalgae Desmodesmus sp. has shown to have a high loading capacity for Fe (II), it has a potential to be re-used and regenerated for multiple cycles of heavy metal uptake.
Conference papers on the topic "Desmodesmus sp"
1
Hosseini, Hoda Ali, Samir Jaoua, and Imen Saadaoui. "Assessment of anti-proliferative and anti-bacterial Activity of a Desert Microalgal Strain Desmodesmus sp." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0036.
Full textAbstract:
Microalgae are believed to be a promising source of different high value products (HVP). HVP are metabolites which are produced during the growth of microalgae and their production is triggered by the physiochemical growth conditions of the microalgae. The present project is aimed at exploring the presence of bioactive compounds in desert microalgae Desmodesmus sp. and to assess its ability to support and improve health care in Qatar. The isolate was cultivated under conventional conditions as a control, and under 3 different stress conditions to enhance the production of high value products. Then crude algal extracts were used to assess the biological activity. Results of the study suggest that Desmodesmus sp. produces high value products that exhibit great anti-oxidant, anti-proliferative and anti-bacterial activity when cultivated under conventional conditions and under continuous light stress.
2
VIEIRA, B., P. BITTENCOURT, L. MARTINS, A. OLIVEIRA, R. SUPERBI, and M. AREDES. "ANÁLISE REOLÓGICA DE SUSPENSÕES IN NATURA DA MICROALGA Desmodesmus sp." In XXII Congresso Brasileiro de Engenharia Química. Editora Blucher, 2018. http://dx.doi.org/10.5151/cobeq2018-pt.0011.
Full text
3
Vieira, Vinícius, Leonardo Fregolente, Luisa Pinto, and Gabriela Ferreira. "Study of the variables that influence in situ transesterification reaction of desmodesmus SP." In Congresso de Iniciação Científica UNICAMP. Universidade Estadual de Campinas, 2019. http://dx.doi.org/10.20396/revpibic2720191637.
Full text
4
Souza, Ana, Danielle Bessa, Rosane Castro, Roberto Derner, and Marisa Fernandes Mendes. "AVALIAÇÃO DA COMPOSIÇÃO DO ÓLEO EXTRAÍDO DA MICROALGA Desmodesmus sp. UTILIZANDO FLUIDO SUPERCRÍTICO." In Simpósio Nacional de Bioprocessos e Simpósio de Hidrólise Enzimática de Biomassa. Galoá, 2015. http://dx.doi.org/10.17648/sinaferm-2015-33857.
Full text
5
VIEIRA, VINÍCIUS DE FRANÇA, LEONARDO VASCONCELOS FREGOLENTE, LUISA FERNANDA RIOS PINTO, and GABRIELA FILIPINI FERREIRA. "ESTUDO DAS VARIÁVEIS QUE INFLUENCIAM NA REAÇÃO DE TRANSTERIFICAÇÃO IN SITU DA DESMODESMUS SP." In XIII Congresso Brasileiro de Engenharia Química em Iniciação Científica. Editora Blucher, 2019. http://dx.doi.org/10.5151/cobecic2019-erc36.
Full text
6
"Lipid accumulation of Desmodesmus sp. EJ 8-10 in digested and undigested piggery effluents." In 2014 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers, 2014. http://dx.doi.org/10.13031/aim.20141900309.
Full text
7
"Effects of different pre-treatments of piggery wastewater on Desmodesmus sp. cultivation and nutrient removal." In 2014 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers, 2014. http://dx.doi.org/10.13031/aim.20141900275.
Full text
8
Maduwanthi, Chathurika, Chathumini Nuwanthika, Piyuminil Withanage, Paramitha Sandani, and Thilini Ariyadasa. "Effect of Different Pretreatment Methods on Lipid Yield and Biodiesel Quality of Desmodesmus sp. Isolated from Sri Lanka." In 2019 Moratuwa Engineering Research Conference (MERCon). IEEE, 2019. http://dx.doi.org/10.1109/mercon.2019.8818823.
Full text
9
"The investigation of two stage cultivation on biomass, lipid content and FAME profiles composition capacity of microalgae: Desmodesmus sp. EJ 8-10 in anaerobic digestion wastewater." In 2014 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers, 2014. http://dx.doi.org/10.13031/aim.20141900295.
Full text