Adaptation and Growth of Botryococcus braunii on Acid Mine Drainage

Phycoremediation of acid mine drainage (AMD) is an alternative to AMD treatment but has limited applications. The obstacle in the application of AMD phycoremediation is that the characteristic of wastewater which limits the growth of microalgae, where AMD has a high metal content and low pH. In this study, Botryococcus braunii was cultured on media with variations in the addition of AMD of (v/v) 0%, 2.5%, 3%, 3.5%, 4% and had a pH of 7.2, 5.6, 5.1, 4.8, 4.3, respectively, on the photobioreactor. Botryococcus braunii growth rate was analyzed, as well as the effect of metal exposure and pH variations on the growth of Botryococcus braunii. Botryococcus braunii showed different growth rates, sequentially from the highest rate in the media with addition of AMD (v/v) 2.5%, 3%, 0%, 3.5%, 4% is 1.403 d-1 ,1.374 d-1 ,0.0862 d-1 ,0.0738 d-1 , and 0.0616 d-1 . It is known that the highest growth rate of Botryococcus braunii is obtained in media with 2.5% (v/v) AMD with an initial pH of 5.6, and Fe and Mn concentrations of 2.15 mg.L-1 and 0.62 mg.L-1 , respectively. It is also known the ability of Botryococcus braunii to adapt to acidic conditions with Fe and Mn content, where Botryococcus braunii plays a role in increasing media pH and is able to remove Fe and Mn with the highest values of 84.28% and 98%, respectively.