Regresar

Characterization of three algal strains used as a tertiary treatment for rural wastewater of ecuadorian littoral

Abstract:

Nine microalgae strains were collected, identified, isolated, and cultured under laboratory conditions in pretreated domestic wastewater (WW) at 30°C and 40°C using 12:12 photoperiod. The 3 strains with better growth rate, i.e., Chlorella sp. M2, Chlorella sp. M6 and Scenedesmus sp. R3 were selected to grow outdoors on partially aerobically treated WW in two types of photo-bioreactors: cylinder and panel. The cultures were harvested when they reached stationary phase and then dried. Chlorella sp. M2 presented the highest growth rate, moisture content, total lipids, carbohydrates, and total polyphenols. Chlorella sp. M6 showed the highest ash content and antioxidant capacity, while Scenedesmus sp. R3 had the highest protein content. There were significant differences among strains in terms of ashes, lipids, proteins, carbohydrates, total polyphenols, and antioxidant capacity. Additionally, the type of photobioreactor influenced the amount of lipids, proteins, carbohydrates, and the antioxidant capacity of algal strains. The strains presented absorbance in the wavelengths of the phytopigments astaxanthin, lutein, neoxanthin, ɑ-carotene, β-carotene, and δ-carotene. The native microalga Chlorella sp. M2, regardless of the method of cultivation, was the one with the best source of macronutrients and polyphenols; meanwhile, the panel-type photo bioreactor was the most effective for cultivating microalgae for phytopigments.