Quantitative Viability Assessment of Microalgae for Advanced Wastewater Treatment by Flow Cytometry

The nutrient uptake capacity of microalgae can be applied in advanced wastewater treatment processes. This study was set to develop a rapid and effective method for assessing the viability (i.e., live or dead) of microalgae applied for advanced wastewater treatment using a flow cytometry. Especially, a methodology to selectively evaluate the quantitative viability of only microalgae present in wastewaters having the co-culture of microalgae and bacteria was proposed. The live and dead cells of microalgae could be discriminated using chlorophyll autofluorescence and the SYTOX Green method developed in this study. Cell viability in live and dead conditions of microalgae showed about 90% accuracy, and about 40% viability ratio was derived in half-live and half-dead conditions. This result shows the potential to quantitatively evaluate the activity of microalgae in the wastewater environment.