Mixed microalgae consortia growth under higher concentration of CO2 from unfiltered coal fired flue gas: Fatty acid profiling and biodiesel production

Publication date: Available online 11 January 2018
Source:Journal of Photochemistry and Photobiology B: Biology
Author(s): Ambreen Aslam, Skye R. Thomas-Hall, Maleeha Manzoor, Faiza Jabeen, Munawar Iqbal, Qamar uz Zaman, Peer M. Schenk, M. Asif Tahir
Biodiesel is produced by transesterification of fatty acid methyl esters (FAME) from oleaginous microalgae feedstock. Biodiesel fuel properties were studied and compared with biodiesel standards. Qualitative analysis of FAME was done while cultivating mixed microalgae consortian under three concentrations of coal fired flue gas (1%, 3.0% and 5.5% CO2). Under 1% CO2 concentration (flue gas), the FAME content were 280.3 μg/mL, whereas lipid content was 14.03 μg/mL/D (day). Both FAMEs and lipid contents were low at other CO2 concentrations (3.0 and 5.5%). However, mixed consortia in the presence of phosphate buffer and flue gas (PB + FG) showed higher saturated fatty acids (SFA) (36.28%) and unsaturated fatty acids (UFA) (63.72%) versus 5.5% CO2 concentration, which might be responsible for oxidative stability of biodiesel. Subsequently, higher cetane number (52) and low iodine value (136.3 gI2/100 g) biodiesel produced from mixed consortia (PB + FG) under 5.5% CO2 along with 50 mM phosphate buffer were found in accordance with European (EN 14214) standard. Results revealed that phosphate buffer significantly enhanced the biodiesel quality, but reduce the FAME yield. This study intended to develop an integrated approach for significant improvement in biodiesel quality under surplus phosphorus by utilizing waste flue gas (as CO2 source) using microalgae. The CO2 sequestration from industrial flue gas not only reduced greenhouse gases, but may also ensure the sustainable and eco-benign production of biodiesel.

Graphical abstract