Upcycling glycerin and vinasse by means of microalgae cultivation.

In 2019, the biodiesel / ethanol biofuels sector generated glycerol and vinasse by-products in significant quantities (476 million and 466 billion liters, respectively). Therefore, it is necessary to reuse or treat these products to reduce their environmental impacts. Using them to support the cultivation of microalgae is a sustainable way of valuing and treating these residues. The objective of this work is to systematize the scientific articles that report their use for the cultivation of microalgae and, consequently, the type of algal bioproducts commonly obtained. Glycerol can be used as a source of carbon in algal mixotrophic growth and, therefore, it can increase algal biomass production. The same process can happen with several small molecular weight substances present in the vinasse, but the concentration of nitrogen and phosphorus is what makes such effluent attractive for the algal cultivation process. Although there are scientific studies describing the use of these substances for algal growth, this work highlights that they vary significantly according to the reports regarding the operation of such culturing system.