(772d) Enhanced Autotrophic Growth of Nannochloris Sp. with Buffer Chemicals for Sustainable Carbon Recycle

In this study, a potential ability of buffer chemicals for CO₂ gas capture and the resultant solutions were investigated for the autotrophic growth of Nannochloris sp. in a modified Shuisheng-4 culture medium. Sodium-based buffer chemicals used in this study well dissolve in water due to their high solubility and the buffer solutions can be converted to sodium bicarbonate solution after absorbing CO₂(g). After absorbing CO₂(g), both total inorganic carbon (TIC=HCO₃^-, CO₃^2-, H₂CO₃, CO₂(aq)) and dissolved inorganic carbon (=DIC=HCO₃^-+CO₂(aq)) in the solution significantly increased and the pH of the solution is equilibrated at pH=8.3 suitable for the growth of Nannochloris sp. As a result, high DIC concentration dramatically increased the autotrophic growth rate of Nannochloris sp. when the Na⁺ concentration was less than 0.12 M. In addition, Nannochloris sp. was cultivated in the buffer chemicals system using simulated flue gas mixed with CO₂, N₂, SO₂, NO, and HCl gases. As a result, the buffer solutions could suppress the possible inhibition effect of acid gases such as SO₂, NO, and HCl on the growth of Nannchloris sp. This study suggests that the sodium-based buffer chemicals can be effectively used for biological CO₂ conversion and sustainable carbon recycle with pure CO₂ or flue gas from a coal-fired power plant.