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Otimização da composição nutricional do meio de crescimento de microalgas
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Os organismos marinhos são conhecidos por produzirem uma grande diversidade de compostos com aplicabilidades na área da medicina, cosmética, indústria agroalimentar, biocombustíveis e aquacultura, principalmente por estarem sujeitos a condições físicas e químicas diferentes. As microalgas são um dos recursos de eleição, devido à capacidade de operarem em autotrofia, heterotrofia ou mixotrofia.
O objetivo deste estudo foi otimizar a composição nutricional do meio ALGAL e do meio TAP, de forma a maximizar o rendimento e a produtividade de biomassa das microalgas Tetraselmis sp. CTP4 e Chlorella sorokiniana. Para a otimização do meio ALGAL utilizou-se a glucose como fonte de carbono, foram testadas três concentrações. O carbono é um nutriente vital para o desenvolvimento da microalga, para além de ser o seu principal constituinte é também a sua fonte de energia, e em alguns casos a sua limitação pode inibir ou estimular a produtividade da estirpe em estudo. A otimização do meio TAP dividiu-se em duas fases, na primeira otimizou-se a concentração de fósforo e na segunda a concentração de enxofre. O fósforo é um elemento que desempenha um papel importante na produção lipídica e proteica. E o enxofre está presente no processo de divisão celular e no metabolismo proteico, além de ser um elemento estrutural das proteínas e vitaminas.
Com a microalga Tetraselmis sp. CTP4 em meio ALGAL realizam-se ensaios em condições de hetero e de mixotrofia. Em condições mixotróficas, a microalga CTP4 cultivada em meio ALGAL com 10 g/L de glucose produziu cerca de 7 g/L de biomassa, enquanto que em heterotrofia, foram obtidas apenas 3 g/L.
Na otimização do meio TAP, a microalga Chlorella sorokiniana apresentou as melhores condições de crescimento para a concentração de 3 mM de fósforo e 1 mM de enxofre, onde se registaram produtividades máximas de 0,233 gbiomassa/L.d e 0,227 gbiomassa/L.d, respetivamente. Usando o meio otimizado no crescimento desta microalga, foi atingida uma produtividade máxima foi 0,393 gbiomassa/L.d.
Os resultados obtidos na otimização do meio ALGAL sugerem que a CTP4 consegue ativar o sistema mixotrófico, aliando o consumo de uma fonte de carbono orgânico (glucose) e o efeito da luz na fixação do dióxido de carbono (CO2). Os ensaios de otimização do meio TAP para o aumento da produtividade da microalga Chlorella sorokiniana apresentaram resultados promissores, revelando assim a importância de definir as concentrações ótimas dos constituintes do meio de forma a estimular a produção dos produtos de interesse.
Marine organisms are known to produce a vast diversity of compounds with applications in medicine, cosmetics, agro-food industry, biofuel, and aquaculture, mainly because they are exposed to different physical and chemical conditions. Microalgae are one of the resources of choice due to the ability to grow in autotrophy, heterotrophy or mixotrophy. The aim of this study was to optimize the nutritional composition of the ALGAL medium and TAP medium, to maximize yield and biomass productivity of the Tetraselmis sp. CTP4 and Chlorella sorokiniana. For the optimization of the ALGAL medium, glucose was used as the carbon source, three concentrations were tested. Carbon is a vital nutrient for the development of microalgae. In addition, to be its main constituent, it is also its source of energy, in some cases, its limitation may inhibit or stimulate the productivity of the strain. The optimization of the TAP medium was divided into two phases, in the first one the phosphorus concentration was optimized and in the second the sulfur concentration, for which several concentrations were tested. Phosphorus plays an essential role in lipid and protein production. Sulfur, in addition to being a structural element of proteins, vitamins and amino acids, it is also present in the process of cell division and protein metabolism. With Tetraselmis sp. CTP4 in ALGAL tests were performed in hetero and mixotrophic conditions. In mixotrophy, the microalgae cultivated in ALGAL medium with 10 g/L of glucose produced about 7 g/L of biomass, whereas in heterotrophy 3 g/L were obtained. In the optimization of the TAP medium with Chlorella sorokiniana the best results were obtained for the concentration of 3 mM of phosphorus and 1 mM of sulfur, where the maximum productivity was 0,233 gbiomass/L.d e 0,227 gbiomass/L.d, respectively. For the final assay, the conditions described above were added and the maximum productivity obtained was 0,393 gbiomass/L.d. The results obtained from the Tetraselmis sp. CTP4 suggest that it can activate the mixotrophic system, combining the consumption of an organic carbon source (glucose) and the effect of light in the carbon dioxide (CO2) fixation. The optimization tests of the TAP medium to increase the productivity of Chlorella sorokiniana presented promising results, thus revealing the importance of defining the optimal concentrations of the constituents of the medium to stimulate the production of the products of interest.
Marine organisms are known to produce a vast diversity of compounds with applications in medicine, cosmetics, agro-food industry, biofuel, and aquaculture, mainly because they are exposed to different physical and chemical conditions. Microalgae are one of the resources of choice due to the ability to grow in autotrophy, heterotrophy or mixotrophy. The aim of this study was to optimize the nutritional composition of the ALGAL medium and TAP medium, to maximize yield and biomass productivity of the Tetraselmis sp. CTP4 and Chlorella sorokiniana. For the optimization of the ALGAL medium, glucose was used as the carbon source, three concentrations were tested. Carbon is a vital nutrient for the development of microalgae. In addition, to be its main constituent, it is also its source of energy, in some cases, its limitation may inhibit or stimulate the productivity of the strain. The optimization of the TAP medium was divided into two phases, in the first one the phosphorus concentration was optimized and in the second the sulfur concentration, for which several concentrations were tested. Phosphorus plays an essential role in lipid and protein production. Sulfur, in addition to being a structural element of proteins, vitamins and amino acids, it is also present in the process of cell division and protein metabolism. With Tetraselmis sp. CTP4 in ALGAL tests were performed in hetero and mixotrophic conditions. In mixotrophy, the microalgae cultivated in ALGAL medium with 10 g/L of glucose produced about 7 g/L of biomass, whereas in heterotrophy 3 g/L were obtained. In the optimization of the TAP medium with Chlorella sorokiniana the best results were obtained for the concentration of 3 mM of phosphorus and 1 mM of sulfur, where the maximum productivity was 0,233 gbiomass/L.d e 0,227 gbiomass/L.d, respectively. For the final assay, the conditions described above were added and the maximum productivity obtained was 0,393 gbiomass/L.d. The results obtained from the Tetraselmis sp. CTP4 suggest that it can activate the mixotrophic system, combining the consumption of an organic carbon source (glucose) and the effect of light in the carbon dioxide (CO2) fixation. The optimization tests of the TAP medium to increase the productivity of Chlorella sorokiniana presented promising results, thus revealing the importance of defining the optimal concentrations of the constituents of the medium to stimulate the production of the products of interest.
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Keywords
Microalgas Otimização Tetraselmissp. CTP4 Chlorella sorokiniana Heterotrofia Mixotrofia Produtividade