Harvesting of microalgae by means of flocculation

The large-scale production of microalgae for biofuels is still facing several major challenges to become competitive with other forms of renewable and non- renewable energy. A major challenge is harvesting, which requires the separation of a low amount of biomass consisting of small individual cells from a large volume of culture medium. Flocculation is seen as a promising low-cost harvesting method for microalgae biomass. The advantages and challenges of flocculation, such as interference of algal organic matter, will be highlighted for several methods including metal coagulants, tannin biopolymers, cellulose nanocrystals and alkaline flocculation. Novel approaches and recent advances will be overviewed and discussed in the framework of separation efficiency, impact on up and downstream processes including medium recycling and toxicity.status: publishe