Maximizing unsaturated fatty acids production by using sugarcane agroindustry wastes in cultivation of Desmodesmus sp. in a flat plate photobioreactor

• Published in: Journal of biotechnology 2022-12, Vol.360, p.117-124
• Main Authors: Ferreira, Gabriela Filipini, Pinto, Luisa Fernanda Ríos, Filho, Rubens Maciel, Fregolente, Leonardo Vasconcelos
• Format: Article
• Language: English
• Subjects: CO2; Cultivation; Flat plate photobioreactor; Light intensity; Microalgae; Stress
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2022.11.007

Microalgae lipid accumulation can be accomplished by different strategies rather than naturally reaching the stationary phase. Many studies employ nitrogen (N) depletion to improve lipid production; however, this approach might not be a suitable alternative when growth in wastewater is attempted. Agro-industry effluents in particular can have high concentrations of N, so nutrient removal is also required. This study evaluated two possibilities of achieving stress conditions in Desmodesmus sp. cultivation: light intensity and CO2 concentration. The culture medium also included liquid and solid residues from the sugarcane agro-industry: vinasse and a biofertilizer produced from bagasse biochar. Optimization of growth in a flat plate photobioreactor was conducted by combining a two-level factorial design and simplex methodology. Both the highest biomass and polyunsaturated fatty acid productivities (150.2 and 21.4 mg L−1 day−1, respectively) were achieved near the central points (5% CO2 in air and 1000 μmol m−2 s−1 light intensity). These results show the possibility of microalgae growth in a sustainable medium coupled with high-value lipid production, e.g., omegas-3, − 6, and − 9. [Display omitted] •High light intensity and CO2 concentration are efficient stress inducers.•Lipid accumulation increased in detriment to biomass production.•Desmodesmus sp. could be cultivated using sugarcane agro-industry residues.•Mixotrophic growth was efficient, employing CO2, vinasse, and biofertilizer.•Highest PUFAs productivity was achieved using 3% CO2 and high light intensity.