The Feasibility of Using Inland Desalination Concentrate (DC) as an Alternative Substrate for Spirulina platensis Mass Cultivation

Abstract

The chemical composition of inland desalination concentrate (DC) contains several microelements necessary for metabolism in microalgae. This study investigated the biomass concentration and biochemical composition of Spirulina platensis cultivated in DC under indoor (laboratory) and outdoor (raceway ponds) units. Initially, S. platensis was cultivated indoor testing different concentrations 0-, 20-, 40-, 60-, 80-, 100-% of DC, and results showed that mixing 60% DC with 40% Paoletti Synthetic Medium (PSM) is a suitable medium for S. platensis. After that, the optimum 60% DC to cultivate S. platensis under outdoor raceway pond was utilized. In parallel, a control assay using 100% PSM constituents was performed. S. platensis cultured in optimum DC, under outdoor conditions, exhibited biomass productivity (~ 10 g m−2 day−1) and protein content (45.0%) comparable to literature data. In addition, S. platensis cultivated in optimum DC was also able to synthesize carbohydrates, amino acids, fatty acids, and phycocyanin, which could be potentially used as biofertilizer and supplement in animal and aquaculture feed. Our results demonstrated the valorization of brine management through S. platensis cultivation, which can be considered as a step forward of reducing freshwater and conventional nutrients for algal mass cultivation.