Valorization of biodiesel derived glycerol as a carbon source to obtain added-value metabolites: Focus on polyunsaturated fatty acids.

The amount of glycerol derived from the biodiesel industry is exponentially increasing. The valorization of glycerol has acquired attention and resources with an obvious economic and environmental interest. Glycerol has the potential to improve the profitability of biodiesel in a biorefinery scenario. Added-value metabolites obtained from glycerol-based fermentations are the target of multiple research studies, primarily chemicals and biopolymers. Pigments and polyunsaturated fatty acids are exceptional examples as they have market presence as nutraceuticals. Most of the studies reviewed have been based on microalgae cultures. Depending on the strain and the engineering aspects of such cultures the final yield suffers notable variations. This is an emerging field which shows great potential from the perspective of a byproduct usage and the increasing yields (value) obtained from the bioprocess.