Isolamento, seleção e cultivo em meio sintético e vinhaça de microalgas com potencial para a produção de biodiesel
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Data
2017-08-03
Autores
Portilla Erazo, Róbinson Gerardo Trindade [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A biomassa derivada de microalgas apresenta um grande potencial devido a sua sustentabilidade e alta produtividade, sendo possível extrair lipídios para produção de biodiesel. Entretanto, desafios na cadeia de produção como um todo devem ser resolvidos para que o biodiesel de microalgas seja viável. Uma das etapas críticas é o cultivo, sendo o meio de cultura um elemento de alto custo. O objetivo principal deste trabalho é avaliar o crescimento de microalgas visando produção de lipídios para biodiesel, utilizando como fontes de nutrientes a vinhaça originada do processo produtivo de etanol no setor sucroalcooleiro. Foram isolados e indentificados três gêneros nativos de microalgas: uma cianobactéria Aphanocapsa sp., uma clorofícea Oocystis sp. e outra clorofícea Scenedesmus sp. O cultivo da microalga Scenedesmus sp. em fotobiorreator de placas planas com meio de cultivo MBM (Modified Bristol Medium) se mostrou modesta em termos de produtividade de biomassa (8 mg/l.dia) e em teor de lipídios na biomassa seca (1,5%). O cultivo dessa mesma microalga em tubos de ensaios com meio alternativo utilizando vinhaça (três diluições de 2%, 5% e 10% em volume) no meio de cultura mostrou desempenho comparável em relação ao meio sintético MBM, sendo que a partir do dia 6, os quatros cultivos se estabilizam em torno de uma concentração celular de 6×106 de células/ml, indicando que a vinhaça pode ser uma fonte de nutrientes de baixo custo para o cultivo de microalgas. Deste modo, é possível reduzir custos em uma importante etapa do processo global de produção de biodiesel de microalgas, viabilizando economicamente esta alternativa energética.
The biomass derived from microalgae presents great potential due to its sustainability and high productivity, it being possible to extract lipids to produce biodiesel. However, challenges in the production chain as a whole must be solved to make microalgae biodiesel viable. One of the critical steps is cultivation, with the culture medium being a costly element. The main purpose of this work is to evaluate the microalgae growth focusing in lipid production for biodiesel using as sources of nutrients the vinasse originated from the sugar-alcohol production process. Three natives microalgae genres have been isolated and identified: cyanobacteria Aphanocapsa sp., chlorophycea Oocystis sp. and other chlorophycea Scenedesmus sp. The cultivation of the microalgae Scenedesmus sp. in flat plate photobioreactor with Modified Bristol Medium (MBM) was modest in terms of biomass yield (8 mg/l.day) and lipid content in dry biomass (1.5%). The cultivation of this same microalga in test tubes in an alternative medium using vinasse (three dilutions of 2%, 5% and 10% in volume) in the culture medium showed a comparable performance in relation to the MBM, starting in the 6th day the stabilization of the cell concentration in 6×106 cells/ml for the four cultives, indicating that the vinasse can be a source of low cost nutrients for the cultivation of microalgae. In this way, it is possible to reduce costs at an important stage in the overall process of microalgae biodiesel production, making this energy alternative economically viable.
The biomass derived from microalgae presents great potential due to its sustainability and high productivity, it being possible to extract lipids to produce biodiesel. However, challenges in the production chain as a whole must be solved to make microalgae biodiesel viable. One of the critical steps is cultivation, with the culture medium being a costly element. The main purpose of this work is to evaluate the microalgae growth focusing in lipid production for biodiesel using as sources of nutrients the vinasse originated from the sugar-alcohol production process. Three natives microalgae genres have been isolated and identified: cyanobacteria Aphanocapsa sp., chlorophycea Oocystis sp. and other chlorophycea Scenedesmus sp. The cultivation of the microalgae Scenedesmus sp. in flat plate photobioreactor with Modified Bristol Medium (MBM) was modest in terms of biomass yield (8 mg/l.day) and lipid content in dry biomass (1.5%). The cultivation of this same microalga in test tubes in an alternative medium using vinasse (three dilutions of 2%, 5% and 10% in volume) in the culture medium showed a comparable performance in relation to the MBM, starting in the 6th day the stabilization of the cell concentration in 6×106 cells/ml for the four cultives, indicating that the vinasse can be a source of low cost nutrients for the cultivation of microalgae. In this way, it is possible to reduce costs at an important stage in the overall process of microalgae biodiesel production, making this energy alternative economically viable.
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Palavras-chave
Microalgas, Biodiesel, Vinhaça, Meio de cultura alternativo, Microalgae, Stillage, Alternative culture medium