Enhancement of carbon bio-fixation and lipid accumulation in Coccomyxa subellipsoidea with triethanolamine CO2 absorbent manipulation

The scenario probed carbon bio-fixation and lipid accumulation in Coccomyxa subellipsoidea with triethanolamine (TEA) CO2 absorbent manipulation. The results stated that CO2 bio-fixation (691.9 mg/L/d), CO2 utilization efficiency (57.84%), CO2 bio-fixation amount (3.86 g), biomass (2.58 g/L), and lipid accumulation (232.30 mg/ L/d) in C. subellipsoidea with 100 mg/L TEA batch manipulation were separately 1.28-, 1.28-, 1.26-, 1.26-, and 1.72-fold more than that without TEA management. TEA fed-batch manipulation further augmented carbon fixation and the fixed carbon conversion into lipid with the maximum instantaneous CO2 fixation rate (1065.9 mg/L/d) and lipid productivity (538.7 mg/L/d) that were 1.97-and 3.98-fold more than that without TEA manipulation case. TEA manipulation also heightened the proportions of C16-C18 fatty acids (over 89%) and mono-unsaturated C18:1 (approximate 40.85%) which were commendable for high-quality biofuels-making. Such virtues were attributed to that TEA balanced pH fluctuation, converted CO2 into purposive HCO3 - species, modulated glycolysis and TCA cycle to discharge appreciable energy, alleviated oxidative stress to block oxidative attack on lipids, and functioned as precursors to collectively boost CO2 sequestration and lipid accu-mulation in C. subellipsoidea. The outcomes were expected to provide exemplifications in developing win-win strategy for CO2 sequestration and lipid production by microalgae.