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

Abstract

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 accumulation in C. subellipsoidea. The outcomes were expected to provide exemplifications in developing win-win strategy for CO2 sequestration and lipid production by microalgae.