CO2 supplementation to domestic wastewater enhances microalgae lipid accumulation under mixotrophic microenvironment: Effect of sparging period and interval

Abstract

Bio-sequestration of CO2 through microalgae cultivation is considered as a viable option for biofuel production as well as CO2 mitigation. Influence of CO2 sparging period and interval was evaluated on the growth and lipid accumulation of microalgae cultivated in domestic wastewater under mixotrophic microenvironment. Process performance was assessed in two phases viz., growth (GP) and starvation phases (SP) each with 8days of retention time. Experimental variations depicted marked influence on biomass growth and lipid accumulation of microalgae with the function of harvesting period. Sparging period of 120s documented maximum biomass growth (GP, 3.4mg/ml) and lipid productivity (SP, 27.3%) while in intervals, 4h (120s) condition showed maximum biomass (3.2mg/ml) and lipid productivity (27.8%). Total chlorophyll components documented higher concentrations of Chl b supporting the observed higher lipid productivity. Fatty acid composition varied with the experimental variations and represented higher degree of saturation indicating their utility as biodiesel.