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Researchers from Brazil's State University of Campinas (UNICAMP) have cultivated microalgae in a laboratory setting under carefully controlled conditions. Their primary aim was to harness the metabolites, particularly lipids, produced by these microorganisms to create biofuels. The findings of the study have been published in the journal Biomass Conversion and Biorefinery.
Luisa Fernanda Ríos, the second author of the article, explained that besides utilizing the microalgae's lipids for biofuel production, it's also feasible to extract protein and carbohydrates from them to be used as food. Furthermore, valuable compounds such as beta-carotene and phycocyanin, a natural blue pigment used in cosmetics, can also be obtained from microalgae. Ríos also pointed out that microalgae can give color to the sea and rivers, which can vary from blue, green to brown, depending on the microalgae species present.
All of the authors of the article are associated with the Laboratory for Optimization, Design and Advanced Control (LOPCA) at UNICAMP's School of Chemical Engineering (FEQ). The last author of the article is Leonardo Vasconcelos Fregolente, while the first author is Bianca Ramos Estevam. The remaining co-author is Rubens Maciel Filho.
The research, which received support from FAPESP, focused on studying the growth and productivity of the microalga Botryococcus terribilis. The study involved analyzing the behavior of the microalgae in both open and closed systems. Closed systems, which can maintain strict control over the conditions, involve photobioreactors where there is no exchange of air with the environment. On the other hand, open systems, such as raceways, are shallow artificial ponds or channels that allow for the circulation of microalgae, water, and nutrients. In open systems, air is exchanged with the environment.
The article reports that the researchers were able to extract and quantify proteins, carbohydrates, lipids, pigments, and hydrocarbons from B. terribilis. It was the first time that the hydrocarbons extracted from B. terribilis were characterized. The authors highlighted the economic and environmental significance of studying the cultivation of B. terribilis, which has been infrequently addressed in the literature.
As Luisa Fernanda Ríos pointed out, "microalgae are the most ancient microorganisms and are responsible for producing up to 50% of the oxygen that we breathe." She also noted that microalgae and fungi played a crucial role in creating the organic matter that eventually evolved into the plants we know today.
Similar to plants, microalgae grow through photosynthesis, where they use atmospheric carbon dioxide, water, and sunlight to generate energy and produce oxygen as a byproduct. As a result of this process, microalgae produce metabolites such as proteins, carbohydrates, and lipids, as well as other substances like carotenoids, chlorophyll, and vitamins in smaller quantities.
It is worth noting that petroleum contains microalgae that have been deposited on the seabed and deep underground over millions of years. Luisa Fernanda Ríos, who holds a PhD in chemical engineering from UNICAMP, highlighted the importance of the substances found within the cells of these microorganisms.
Stress
Microalgae are unicellular organisms that reproduce through mitosis, where each cell divides into two identical daughter cells, leading to exponential multiplication. According to Luisa Fernanda Ríos, microalgae are grown in laboratories to extract and utilize the biocompounds present in their cells. She further explained that the microalgae need to be killed to extract these compounds, but this is not a concern since they grow rapidly and are always abundant.
The oils derived from B. terribilis have potential for biofuel production, as they consist of long-chain hydrocarbons and larger amounts of saturated and mono-unsaturated fatty acids. The study conducted by the researchers helps to address the information gap on the cultivation, stress response, and composition of B. terribilis microalgae, thereby supporting decisions related to cultivation parameters and biorefinery applications.
In this context, stress refers to the lack of essential growth nutrients, such as nitrogen or phosphorus. According to Luisa Fernanda Ríos, when microalgae sense a shortage of these nutrients, they tend to accumulate lipids as a survival strategy. The researchers employed this ability as a technique to increase the accumulation of the desired metabolite. By depriving the microalgae of essential nutrients, the growth rate slowed down, causing a decrease in the proportion of other metabolites such as proteins and carbohydrates. Ríos emphasized the importance of identifying the target compound and achieving the appropriate balance for the study.
About São Paulo Research Foundation (FAPESP)
The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.
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