Assessing the wastewater treatment efficiency and bioproducts accumulation potentials of co-cultures of mixotrophic microalgae

Abstract

Utilization of microalgae for simultaneous wastewater treatment and bioproducts accumulation has been a subject of research interest for a while. However, in order to successfully turn this into reality, development of strategies to maximize the yield and performance of the deployed microalgae remains paramount. Herein, the performances and yield of different artificial microalgae consortia were evaluated in a synthetic municipal wastewater medium. The results revealed that the performance of the best monoculture (KL10) was more or less comparable to that of the best binary culture (CK). However, the general pattern of the result revealed that regardless of the species diversity in all the cultures, the average reduction of chemical oxygen demand and total phosphorus, as well as the accumulation of protein, chlorophyll a, chlorophyll b and carotenoids content remined comparable (p > 0.05). Furthermore, the average PO43--P reduction efficiency and biomass productivity of the monocultures was higher than (p < 0.05) those of the co-cultures. Conversely, average NH4-N reduction efficiency and lipid productivity of the binary cultures were superior (p < 0.05) to those of the other culture combinations. Finally, the fatty acids composition, which revealed similar fatty acids profile in all the cultures, suggests the suitability of all the cultures for utilization as feedstock for biodiesel production. In conclusion, the findings of the current study suggest that contrary to the popular notion, raising species diversity in microalgae cultures does not always guarantee increased yield and performance.