Microalgae from domestic wastewater facility’s high rate algal pond: Lipids extraction, characterization and biodiesel production

• Published in: Bioresource technology Vol. 206; pp. 239 - 244
• Main Authors: Drira, Neila, Piras, Alessandra, Rosa, Antonella, Porcedda, Silvia, Dhaouadi, Hatem
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2016
• Subjects: Biodiesel; Biofuels - microbiology; Biomass; Biomass flocculation/coagulation; Biotechnology - methods; Calcium - analysis; carbon dioxide; Electric Conductivity; Esterification; fatty acid methyl esters; Fatty Acids - analysis; flocculation; fuel production; harvesting; Hydrogen-Ion Concentration; Lipid extraction; Lipids - isolation & purification; Magnesium - analysis; microalgae; Microalgae - metabolism; Microalgae - ultrastructure; Microwaves; municipal wastewater; neutralization; Ponds - microbiology; sewage treatment; solvents; stearic acid; ultrasonics; unsaturated fats; unsaturated fatty acids; Waste Water - microbiology; Wastewater; Lipid extraction; Biomass flocculation/coagulation; Wastewater; Biodiesel
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.01.082

[Display omitted] •Microalgae biomass recovery from a real-scale HRAP by pH increase.•Methods of Folch and Hara modified by ultrasounds irradiation for extraction of lipids.•Supercritical CO2 lipid extract has the highest unsaturated fatty acids content.•Microwave assisted extractive-transesterification of the HRAP’s biomass and micro-biodiesel production. In this study, the harvesting of a biomass from a high rate algal pond (HRAP) of a real-scale domestic wastewater treatment facility and its potential as a biomaterial for the production of biodiesel were investigated. Increasing the medium pH to 12 induced high flocculation efficiency of up to 96% of the biomass through both sweep flocculation and charge neutralization. Lipids extracted by ultrasounds from this biomass contained around 70% of fatty acids, with palmitic and stearic acids being the most abundant. The extract obtained by supercritical CO2 contained 86% of fatty acids. Both conventional solvents extracts contained only around 10% of unsaturated fats, whereas supercritical CO2 extract contained more than 40% of unsaturated fatty acids. This same biomass was also subject to direct extractive-transesterification in a microwave reactor to produce fatty acid methyl esters, also known as, raw biodiesel.