Investigando o crescimento e a composição bioquímica de Chlorolobion lunulatum em escalas de 20 e 200 L

Abstract

Green microalgae have attracted biotechnological interest due to their ability to accumulate value-added biomolecules, such as proteins, lipids, carbohydrates, and photosynthetic pigments. In addition to being efficient in converting CO2 and sunlight into biomass, Chlorophyta species can present high productivity per area and versatility in different environmental conditions. Among the promising species, Chlorolobion lunulatum stands out, still little studied, but with potential for expanded cultivation already demonstrated in the Laboratory of Algae Biotechnology, where this study was carried out. Our main objective was to evaluate aspects of the physiology of C. lunulatum in two cultivation systems of different scales: in a 20 L tubular photobioreactor and in 200 L raceway ponds. While in 20 L, the cultivations had controlled light intensity, in 200 L shade nets were used to mitigate the intensity of incident sunlight. At the end of the cultivation period, the contents of lipids, proteins and carbohydrates, and photosynthetic pigments in the biomass were determined. Growth rates were used to compare the crops, which were grown for ten days. The 200 L crops showed a higher specific growth rate (1.14 d-1), higher biomass production and higher levels of proteins (up to 23% DW), lipids (28% DW) and carbohydrates (16% DW), evidencing the viability of cultivation in larger-scale systems. On the other hand, the 20 L cultures showed significantly higher concentrations of chlorophyll a (10.51 mg L-1) and chlorophyll b (8.15 mg L-1), while the carotenoid concentration in the biomass did not show significant variation between 20 and 200 L. The data indicate that the tubular photobioreactor favored the synthesis of photosynthetic pigments, while the raceway favored the accumulation of biomolecules, such as proteins and lipids. Therefore, C. lunulatum presents biochemical characteristics that make it a promising candidate for industrial applications, especially in the energetic sector.