Phycoremediation potential of marine microalga Tetraselmis indica on secondary treated domestic sewage for nutrient removal and biodiesel production

Marine microalga Tetraselmis indica (T. indica) was cultivated in secondary treated domestic sewage (STDS) in batch mode. Optimization studies showed that after 14 days of cultivation period, highest biomass yield reached was 0.88 ± 0.04 g/L at the optimum temperature of 27 ± 1 °C and light intensity of 135 μmol m⁻² s⁻¹. T. indica removed about 60.93% phosphate, 78.46% nitrate, 72.94% chemical oxygen demand (COD), 73.17% biological oxygen demand (BOD), 98.90% total dissolved solids (TDS) and heavy metals (83.11% Cd, 55.67% Ca, 45.12% Cu, 13.67% Mn, 50.88% Pb, and 98.92% Al) from STDS. The level of electrical conductivity was reduced to 0.0974 ± 0.045 dS/m. The fatty acid methyl ester (FAME) profile showed the presence of palmitic acid (12.91%), oleic acid (35.94%), linoleic acid (14.89%) and eicosanoic acid (12.34%). This study indicates the potential of T. indica for removal of pollutants from STDS and also its capability of biodiesel production.