Biodiesel production from microalgae and a cyanobacteria grown in different qualities of water.

The biodiesel production from photosynthetic microorganisms, is a topic of increasing research. However, the implications of nutrient removal and lipid accumulation capacity are unknown, when microorganisms grown in municipal wastewater with respect to be grown in a rich medium. In the present study the potential of two species of microalgae Chlorella vulgaris and Scenedesmus acutus and a cyanobacterium, Arthrospira maxima were evaluated to remove nutrients and accumulate lipids, useful for producing biodiesel, when growing into two wastewater qualities, raw (RWW) and treated (TWW), compared with an enriched medium (EM) with commercial fertilizer. The cultures were performed in volumes of 1 L, with photoperiods of light:dark of 12 h:12 h. With the results an ANOVA was performed and treatment means were compared with Tukey's test (p 0.05). The cultures in RWW showed: 1) the higher biomass productivity (p 0.05) with S. acutus (1.28 g L-1) and C. vulgaris (1.15 g LI, for A. maxima values were similar to RWW (0.93 g L-1) and EM (0.96 g L-1) (p >0.05), the highest rate of biomass increase corresponded to C. vulgaris (0.20 to 0.27 4:1-1) for the three culture media (p 0.001), and for S. acutus and A. maxima was between 0.06 and 0.14 d-1; 2) the higher efficiency of nutrient removal, over 60 % of phosphorus and 90 % of organic nitrogen (p 0.05) for all microorganisms; 3) higher lipid accumulation (p 0.05) for S. acutus, 28.3 %, C. vulgaris 22.4 % and A. maximum 13.8 %; 4) the higher production of biodiesel (between 109.4 and 244.6 mg L-1) for the three microorganisms.