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Atualmente é fundamental a busca por novos cenários e soluções mais sustentáveis, novas ideias mais limpas e inovadoras de forma a privilegiar o que é natural suprindo assim as nossas necessidades como espécie humana obtendo produtos que não acarretem um peso que não podemos pagar. De encontro com esta premissa surgem as microalgas, seres que através das suas características nos permitem através da sua exploração obter produtos de alto valor energético e comercial. Assim, o presente trabalho teve como objetivo avaliar a influência das condições de cultivo no potencial bioenergético e em biocompostos de valor de uma microalga. Para o efeito, foi avaliado o comportamento da microalga Chlorella vulgaris, selecionada entre três espécies por ser a de crescimento mais rápido, uniforme e estável, em cenários de stress diferentes e analisada a forma como a composição do meio de cultura e as condições de cultivo influenciam a produção de biomassa e de outros compostos de interesse como os pigmentos e os lípidos. A Chlorella vulgaris foi submetida a três cenários de stress nutricional com três concentrações diferentes para cada uma: com adição de glicose (0,5; 1,0 e 1,5 g/L), ferro (0,5; 1,0; 10 e 50 mg/L) e nitrato (28,4; 56,9; 170,7; 569 mg/L). Foi possível observar que a utilização de meios ricos em nitrato a partir dos 170,7 mg/L favorece a obtenção de um crescimento mais rápido da biomassa atingindo valores acima das 800mg/L biomassa, assim como maiores concentrações de pigmentos com mais enfase para as culturas com uma concentração de nitrato de 569 mg/L onde a clorofila a e carotenoides atingiram concentrações máximas de 6 mg/L e 2 mg/L respetivamente. No que respeita ao teor lipídico, verifica-se que a limitação de nitrato (<28,4 mg/L) favorece a acumulação de lípidos pelas microalgas (cerca de 42%). Meios com concentrações inferiores de ferro (0,5 mg/L) revelaram-se favoráveis para a obtenção de biomassa com concentrações superiores de clorofila a numa fase inicial contando com valores que variam desde 0,2 a 0,6 mg/L. Nos ensaios realizados em condições mixotróficas (com adição de glicose), ocorreu contaminação em todas as culturas, possivelmente devido à elevada concentração de fonte de carbono que contou com valores entre os 0,5 e 1,5 g/L de glicose. Adicionalmente, foi também observado decréscimo do crescimento da biomassa microalgal.
Nowadays, it is fundamental to search for new scenarios and solutions that are more sustainable, new green and innovative ideas, to give priority to what is natural, thus supplying our needs as a human species, obtaining products that do not carry a weight that we cannot afford. In line with this premise, microalgae appear because of their characteristics allow us through their exploitation to obtain products of high energy and commercial value. Thus, the present study aimed to evaluate the influence of cultivation conditions on bioenergy and biocompounds of value potential of a microalgae. For this purpose, the behavior of the microalgae Chlorella vulgaris, selected among three species because of its faster, uniform and stable growth, was evaluated in different stress scenarios and analyzed the way the composition of the culture medium and the cultivation conditions influence the production of biomass and other compounds of interest such as pigments and lipids. Chlorella vulgaris was subjected to three stress scenarios with three different concentrations for each one: with addition of glucose (0.5, 1.0 and 1.5 g/L), iron (0.5, 1.0, 10 and 50 mg/L) and nitrate (28.4, 56.9, 170.7, 569 mg/L). It was possible to observe that the use of nitrate rich media from 170.7 mg/L favors a faster growth of the biomass reaching values above 800 mg/L biomass, as well as higher concentrations of pigments with more emphasis for the cultures with a nitrate concentration of 569 mg/L where chlorophyll-a and carotenoids reached maximum concentrations of 6 mg/L and 2 mg/L respectively. As regards lipid content, nitrate limitation ((<28.4 mg/L) favors the accumulation of lipid content by microalgae (around 42%). The use of media with lower concentrations of iron (0.5 mg/L) was favorable for obtaining biomass with higher concentrations of chlorophyll-a at an initial stage, with values varying from 0.2 to 0.6 mg/L. In the tests carried out under mixotrophic conditions (addition of glucose), it was observed that contamination occurred in all the cultures, possibly due to the high concentration of carbon source that had values between 0.5 and 1.5 g/L glucose. In addition, growth decrease was also observed.
Nowadays, it is fundamental to search for new scenarios and solutions that are more sustainable, new green and innovative ideas, to give priority to what is natural, thus supplying our needs as a human species, obtaining products that do not carry a weight that we cannot afford. In line with this premise, microalgae appear because of their characteristics allow us through their exploitation to obtain products of high energy and commercial value. Thus, the present study aimed to evaluate the influence of cultivation conditions on bioenergy and biocompounds of value potential of a microalgae. For this purpose, the behavior of the microalgae Chlorella vulgaris, selected among three species because of its faster, uniform and stable growth, was evaluated in different stress scenarios and analyzed the way the composition of the culture medium and the cultivation conditions influence the production of biomass and other compounds of interest such as pigments and lipids. Chlorella vulgaris was subjected to three stress scenarios with three different concentrations for each one: with addition of glucose (0.5, 1.0 and 1.5 g/L), iron (0.5, 1.0, 10 and 50 mg/L) and nitrate (28.4, 56.9, 170.7, 569 mg/L). It was possible to observe that the use of nitrate rich media from 170.7 mg/L favors a faster growth of the biomass reaching values above 800 mg/L biomass, as well as higher concentrations of pigments with more emphasis for the cultures with a nitrate concentration of 569 mg/L where chlorophyll-a and carotenoids reached maximum concentrations of 6 mg/L and 2 mg/L respectively. As regards lipid content, nitrate limitation ((<28.4 mg/L) favors the accumulation of lipid content by microalgae (around 42%). The use of media with lower concentrations of iron (0.5 mg/L) was favorable for obtaining biomass with higher concentrations of chlorophyll-a at an initial stage, with values varying from 0.2 to 0.6 mg/L. In the tests carried out under mixotrophic conditions (addition of glucose), it was observed that contamination occurred in all the cultures, possibly due to the high concentration of carbon source that had values between 0.5 and 1.5 g/L glucose. In addition, growth decrease was also observed.
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Keywords
Biomassa Chlorella vulgaris Clorofila Lípidos Pigmentos Stress nutricional Biomass Chlorophyll-a Lipids Nutritional stress Pigments