Carbon biofixation and lipid composition of an acidophilic microalga cultivated on treated wastewater supplied with different CO levels.

This study evaluated productivity, CO biofixation, and lipid content in biomass of the acidophilic microalga LAFIC-004 cultivated with five different carbon dioxide concentrations. The influence of carbon dioxide concentration on nutrient removal and pH was also investigated. Treated wastewater (secondary effluent) was used as culture medium. Five experimental setups were tested: T-0% - injection of atmospheric air (0.038% CO), T-5% (5% CO), T-10% (10% CO), T-15% (15% CO) and T-20% (20% CO). The T-5% and T-10% experiments showed the highest values of productivity and CO biofixation, and maximum biomass dry weight was 0.48 ± 0.02 and 0.51 ± 0.03 g L, respectively. This acidophilic microalga proved to be suitable for carbon biofixation and removal of nutrients from secondary effluent of wastewater treatment plants with high CO concentration. All assays were performed without pH control. This microalga species presented high lipid content. However, fatty acid methyl esters (FAME) are not suitable for biodiesel use.