Comparative optimization of macronutrient removal from a cyanobacterium and a microalga grown in synthetic wastewater for potential use as a biodiesel source

Microalgae can grow in alternative media, such as wastewater, since they can consume the nutrients present in it, generating high productivity of biomass and high-value compounds, such as fatty acids, carbohydrates, and pigments. This research aimed to optimize the concentration of ammonium, phosphates, and luminosity for the cultivation of the microalgae Leptolyngbya sp. and Chlorella sp. in synthetic wastewater, to study the consumption of nutrients and their influence on the biomass and lipids yield, which can be used for the biodiesel production. Different culture conditions were tested, such as: nutrient stress, photo-stress, excess nutrients, as well as under heterotrophic and mixotrophic conditions. The results indicated an optimal point for the consumption of ammonium and phosphates of Chlorella sp., In the concentration of 58.82 mg L-1, ammonium, 30.17 mg L-1, phosphates and 3645.54 lux of illumination: while for Leptolyngbya sp., in the concentrations of 58.82 mg L-1, ammonium, 30.17 mg L-1, phosphates and 3645.54 lux of illumination. Leptolyngbya sp. presented the highest lipid and biomass concentrations.