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Previous issue date: 2010-12-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Global warming due to Greenhouse Gases (GHG) emissions, especially CO2, has been identified as one of the major problems of the twenty-first century, considering the consequences that could represent to planet. Currently, biological processes have been mentioned as a possible solution, especially CO2 biofixation due to association microalgae growth. This strategy has been emphasized as in addition to CO2 mitigation, occurs the production of biomass rich in compounds of high added value. The Microalgae show high photosynthetic capacity and growth rate higher than the superior plants, doubling its biomass in one day. Its culture does not show seasons, they grow in salt water and do not require irrigation, herbicides or pesticides. The lipid content of these microorganisms, depending on the species, may range from 10 to 70% of its dry weight, reaching 90% under certain culture conditions. Studies indicate that the most effective method to promote increased production of lipids in microalgae is to induce stress by limiting nitrogen content in the culture medium. These evidences justify research continuing the production of biofuels from microalgae. In this paper, it was studied the strategy of increasing the production of lipids in microalgae I. galbana with programmed nutritional stress, due to nitrogen limitation. The physiological responses of microalgae, grown in f / 2 with different concentrations of nitrogen (N: P 15,0-control, N: 5,0 P and N: P 2,5) were monitored. During exponential phase, results showed invariability in the studied conditions. However the cultures subjected to stress in stationary phase, showed lower biomass yields. There was an increase of 32,5% in carbohydrate content and 87.68% in lipids content at N: P ratio of 5,0 and an average decrease of 65% in protein content at N: P ratios of 5, 0 and 2.5. There were no significant variations in ash content, independently of cultivation and growth phase. Despite the limitation of biomass production in cultures with N: P smaller ratios, the increase of lipid accumulation highest lipids yields were observed as compared to the control culture. Given the increased concentration of lipids associated to stress, this study suggests the use of microalgae Isochrysis galbana as an alternative raw material for biofuel production / O aquecimento global decorrente da emiss?o dos gases geradores do Efeito Estufa (GEE), em especial o CO2, ? um dos problemas mais graves do s?culo XXI, tendo em vista as conseq??ncias que esse agravante pode trazer ao planeta. Atualmente, os processos biol?gicos v?m sendo apontados como uma poss?vel solu??o, principalmente a biofixa??o do CO2 por microalgas. Essa estrat?gia tem sido ressaltada, uma vez que, paralelamente a mitiga??o do CO2 ocorre ? produ??o de biomassa rica em compostos de alto valor econ?mico agregado. As microalgas possuem alta capacidade fotossint?tica e taxa de crescimento superior aos vegetais superiores, duplicam a sua biomassa em um dia. O seu cultivo n?o segue regime de safras, s?o cultivadas em meio salino simples e n?o exigem irriga??o, herbicidas ou pesticidas. O teor de lip?dios destes microrganismos, dependendo da esp?cie, varia de 1 a 70% do seu peso seco, podendo chegar a 90% em certas condi??es de cultivo. Estudos indicam que ? poss?vel aumentar a produ??o de lip?dios pelas microalgas atrav?s de estresses fisiol?gicos induzidos pela restri??o do nitrog?nio no meio de cultura. Essas evid?ncias justificam pesquisas envolvendo a produ??o de biocombust?veis a partir de microalgas. No presente trabalho, estudou-se a estrat?gia de aumentar a produ??o de lip?dios pela microalga I. galbana atrav?s de um estresse nutricional programado, ocasionado pela restrin??o do nitrog?nio. Foram acompanhadas as respostas fisiol?gicas desta esp?cie, cultivada em meio f/2 com diferentes concentra??es de nitrog?nio (raz?es m?ssica N:P 15,0-controle, N:P 5,0 e N:P 2,5). Durante a fase exponencial, as an?lises mostraram uma invariabilidade para os cultivos estudados. Por?m, na fase estacion?ria, os cultivos submetidos ao estresse, indicaram menores rendimentos em biomassa. Observou-se um amento de 32,5% nos n?veis de carboidratos e de 87,68% no teor de lip?deos na raz?o N:P 5,0 e uma redu??o m?dia de 65% de prote?na nas raz?es N:P 5,0 ou 2,5. N?o houve varia??es significativas no teor de cinzas, independente das condi??es de cultivo e fase de crescimento. Apesar da limita??o de biomassa, o aumento do ac?mulo de lip?dios pelas culturas estressadas, proporcionou maiores produtividades de lip?dios, conseq?entemente este estudo sugere a utiliza??o da microalga Isochrysis galbana como fonte alternativa para a produ??o de biocombust?vel
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/15802 |
| Date | 21 December 2010 |
| Creators | Chagas, Bruna Maria Emerenciano das |
| Contributors | CPF:08580772800, http://lattes.cnpq.br/2621516646153655, Silva, Anita Ferreira da, CPF:07989454785, http://lattes.cnpq.br/2206935989496987, Lima, Anita Maria de, CPF:59763981468, http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4767606U6, Ara?jo, Of?lia de Queiroz Fernandes, Chiavone Filho, Osvaldo |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Engenharia Qu?mica, UFRN, BR, Pesquisa e Desenvolvimento de Tecnologias Regionais |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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