BIOFIJACIÓN DE CO2 POR DOS ESPECIES DE MICROALGAS CULTIVADAS EN FOTOBIORREACTORES.

The biofixation capacity of carbon dioxide by the Chlorella vulgaris and Scenedesmus obliquus species cultivated in photobioreactors was evaluated in a 12:12 h photoperiod. A completely randomized experimental design was used, whose sources of variation were: microalgal species and CO2 dosage (0.36, 11.44 and 22.62 g.d-1). The photobioreactors were plastic units with 3.8 L of culture medium (NPK solution + micronutrients), and artificial lighting with a 4400 lumens fluorescent lamp. The following variables were estimated: biomass productivity using the dry weight methodology, CO2 biofixation by numerical method and CO2 removal efficiency in percentage. The results were subjected to the analysis of variance and Tukey's mean tests (p <0.05). Higher biomass productivity and CO2 biofixation were recorded in C. vulgaris compared to S. obliquus. The highest biofixation of CO2 by C. vulgaris and S. obliquus was recorded at the dose of 11.44 gd-1 with 161.79 ± 4.72 and 55.31 ± 0.73 mg.L-1d-1, respectively. The CO2 removal efficiency was significantly higher with the 0.36 g.d-1 dose, registering values of 49.80 ± 3.16 and 39.13 ± 0.57 % for C. vulgaris and S. obliquus respectively. These results suggest the possibility of scaling up low-cost photobioreactors for biofixation of CO2 emissions in industrial fixed fonts, thus contributing to the mitigation of greenhouse gases. [ABSTRACT FROM AUTHOR]