Growth and Metabolite Production in Chlorella sp.: Analysis of Cultivation System and Nutrient Reduction

• Published in: Bioenergy research 2023-09, Vol.16 (3), p.1829-1840
• Main Authors: Estevam, Bianca Ramos, Pinto, Luisa Fernanda Ríos, Filho, Rubens Maciel, Fregolente, Leonardo Vasconcelos
• Format: Article
• Language: English
• Subjects: Algae; Analysis; Aquatic microorganisms; Biomedical and Life Sciences; Carbohydrates; Carotenoids; Cell density; Chlorella; Chlorophyll; Cultivation; Decision making; Factorial design; Life Sciences; Lipids; Metabolites; Microalgae; Nitrogen; Nutrient concentrations; Nutrients; Phosphorus; Pigments; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Proteins; Reduction; Wood Science & Technology
• ISSN: 1939-1234; 1939-1242
• DOI: 10.1007/s12155-022-10532-z

Microalgae are a sustainable source for many bioproduct syntheses. This study shows how different cultivation systems and nutrient concentrations affect Chlorella sp. development. The cultivation was performed in open and closed lab-scale systems. A Tukey test was used to evaluate the significant differences between the microalgae growth and composition under the two systems analyzed. The effect of nitrogen and phosphorus concentration was analyzed with a 2 2 full factorial design. Lipids, carbohydrates, proteins, and pigments were extracted and quantified. The highest specific growth rate (0.52 1/day) was obtained in the open pond, with a cell density of 5.06 × 10 7 cells/mL and a biomass concentration of 1.30 mg/mL. In this condition, the higher concentration of pigments was obtained: 13 μg/mg of chlorophyll-a, 15 μg/mg of chlorophyll-b, and 2 μg/mg of carotenoids. An expressive increase in the lipid (from 17 to 35%) was obtained in low nitrogen and high phosphorus. Protein percentage increases with both nutrients at a higher level, reaching up to 60%. The percentage of carbohydrates decreases from 32 to 13% with phosphorus reduction. Thus, this study points out the conditions that benefit the accumulation of each Chlorella sp. metabolite, contributing to the decision-making for the cultivation and applications of this microalgae.