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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 consortia under three concentrations of coal fired flue gas (1%, 3.0% and 5.5% CO2). Under 1% CO2 concentration (flue gas), the FAME content was 280.3 μg/mL, whereas the 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 reduced 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.

Laser stimulation effect on L. siceraria seed mucilage, biochemicals and enzymatic activities during early growth stages were investigated. The laser density power of 1mW/cm2 for 3 and 5min treatments were performed and various responses i.e., seedlings mucilage, biochemical and enzymatic activities were studied. Laser treatment of L. siceraria seeds enhanced the biochemical as well as the enzymatic activities. TPC (total phenolic contents),TFC (total flavonoids contents), TSS (total soluble sugar), reducing sugar, proline contents, total soluble protein and nitrogen contents were recorded higher in laser treated groups versus control. Mucilage from L. siceraria seed coat was also characterized. The pre-sowing seeds were treated with laser radiation for 3 and 5min. TPC, TFC, proline contents, total soluble protein and nitrogenous compounds contents, ascorbic acid contents were recorded higher at 3min. The laser irradiation effect on TSS, hydrogen peroxide (H2O2), malondialdehyde (MDA) was insignificant versus control. The SOD (superoxide dismutase) and POD (peroxidase), AMY (amylase), CAT (catalase) activities were recorded higher for 5min laser treatment. Results revealed that He-Ne continuous wave-laser pre-sowing seed irradiation affected the seed coat mucilage, biochemical and enzymatic activities positively and this treatment could possibly be used to enhance the L. siceraria productivity. Future study will be focused on growth at later stages and yield characteristics of L. siceraria.