Sanitary Wastewater Supplemented with Glycerol to Obtain Lipid-Rich Microalgal Biomass

Introduction: Mixotrophic microalgae systems have great potential for bioenergy production and wastewater treatment. Anaerobic-treated wastewater supplemented with carbon can improve biomass yield and quality, as it presents low carbon content. Alternative carbon sources in microalgae cultivation, such as glycerol, are essential for minimizing the economic and environmental impacts caused by biomass production, and improving the profile of fatty acids. This study aimed to increase biomass production and the lipid content with glycerol as the carbon source for microalgae cultivation from sanitary wastewater. 
Materials and Methods: The microalgae behavior in the wastewater was pilot tested using glycerol supplementation at 7.5, 10.5, and 12.5 g L-1. 
Results: In all the experiments with sanitary wastewater, the microalgae production presented Chlorella sp. as the predominant species. The best biomass (3.78 ± 1.12 g L-1) and lipid (35.67 ± 0.80%) yields were found at 12.5 and 10.5 g L-1 of glycerol, respectively. 
Conclusion: The microalgae produced more lipids with glycerol supplementation. An attractive profile for biodiesel was found regarding the fatty acids in the biomass.