Microalgae for biofuel production and removal of heavy metals: a review

Removal of heavy metals from wastewaters using microalgae is gaining interest because microalgae also assimilate carbon, nitrogen and phosphorus. Here, we review algal metabolism and cultivation; algal biomass conversion to biodiesel, bioethanol, biohydrogen, methane, electricity and fertilizers; and removal of metals with microalgae. The mixotrophic approach enables the effective treatment of both organic and inorganic wastes in water. For cultivation, photobioreactors are found efficient due to the control of operational conditions. Bioremediation of heavy metals by physiochemical processes appears to be more efficient than algal uptake.