Factors affecting the fatty acid profile of wastewater-grown-algae oil as feedstock for biodiesel

• Published in: Fuel (Guildford) Vol. 304; p. 121367
• Main Authors: Moreno-Garcia, L., Gariépy, Y., Barnabé, S., Raghavan, V.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.11.2021; Elsevier BV
• Subjects: Algae; Ammonia; Aquatic microorganisms; Biodiesel; Biodiesel fuels; Biofuels; Carbon content; Carbon dioxide; Composition; Design factors; Diesel; Environmental conditions; Factorial design; Fatty acids; Light intensity; Lipids; Luminous intensity; Microalgae; Nutrients; Organic carbon; Principal component analysis; Raw materials; Wastewater; Wastewaters; Wastewaters; Microalgae; Biodiesel; Fatty acids; Principal component analysis
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.121367

•High light intensities decreased monounsaturated fatty acids contents.•High light intensities reduced 16- and 18-carbon chain-length fatty acids contents.•High organic carbon contents increased the oxidative stability of the biodiesel.•Ammonia nitrogen uptake by cells enhanced monounsaturated fatty acids production.•Lipids properties complied to American and European standards for biodiesel. This study analyzes the influence that the environmental conditions and media composition have on the quality of wastewater-grown-microalgae lipids as a feedstock for biodiesel. A two-level full factorial design with three factors (organic carbon content, CO2 supply, and light intensity), followed by a PCA were utilized to explore relations among the variables. The content of SFAs, MUFAs, and PUFAs in the algal lipids ranged between 30.9 and 56.6%, 16.4–62.1%, and 4.7–27.9%, respectively. Light intensity was the major factor affecting lipids composition, followed by CO2. Experimental conditions at the lowest light intensity and the highest CO2 content tested in the study (40 μmol·m−2·d-1 and 10% CO2) were related to enhanced productions of MUFAs and increased C16 and C18 contents, which are desirable compounds in the lipids targeted to biodiesel production. Among the components derived from the wastewater mixture used as source of nutrients to microalgae, NH3-N was related to increased MUFAs productions by the cells. Higher contents of organic carbon reduced the unsaturation value, increasing the oxidative stability of the biodiesel. Biodiesel properties of the algal lipids grown under all experimental conditions tested in this study were found to comply with ASTM D6751 and EN 14214 standards.