Spirulina sp. LEB 18 cultivation in a raceway-type bioreactor using wastewater from desalination process: Production of carbohydrate-rich biomass

Abstract

This study aimed to evaluate the biomass production of Spirulina sp. LEB 18 cultivated in wastewater from the desalination process. The outdoor cultivations (210 L) were performed using as culture medium 100% wastewater supplemented with 25% of Zarrouk constituents (Tcs). In parallel, it was performed a control assay using 100% Zarrouk constituents. The biomass production in Tcs assay (1.14 g L^-1) was only 9% lower than the control assay (1.25 g L^-1). The Tcs assay showed a higher content of carbohydrates (52.29%), lipids (12.79%) and ash (2.69%) compared to the control assay (47.91; 7.59 and 1.29%, respectively). The biomass from the control and Tcs assays had mostly monounsaturated fatty acids C15:1 and C18:2n6t. The Spirulina sp. LEB 18 could use efficiently the nutrients from the wastewater, showing high removal efficiency of NO_3- (96.99%), PO₄ (83.11%) and Z (96.43%). At the same time, high added value biomolecules were produced for different purposes.

Keywords: Biomass composition; Bioremediation; Desalination process; Microalgae; Wastewater.