The potential use of natural coagulants for microalgae harvesting: a review

Microalgae cultivation has received much interest in foods and biofuel production and provides a significant potential option for cleaning the soil, water, and environment from several contaminants. Accordingly, microalgae harvesting becomes essential to separate the solid–liquid microalgae suspension for other green technologies and sustainable processes. Although several physical, chemical, and physiochemical methods have been widely used for microalgae harvesting, their cost, non-environmental residues, and harvesting efficiencies are still questionable. This review summarized and evaluated the performance of different natural coagulants used for harvesting cultivated microalgae. The operational factors and their effect on harvesting efficiency were discussed. Moreover, the current challenges in utilizing several natural coagulants in microalgae harvesting were considered.