Potentiality of huge revenue drawn through Arthrospira (Spirulina sp.) platensis KAU02 (Cyanophyceae) cultivation in treated wastewater rather than discharge into sea

الملخص

Study on microalgae continues to increase due to its various usages such as live feed, feed supplements, food additives and colourization, ingredients of medicine, cosmetics and biofuels. Among microalgae, Spirulina (Arthrospira) is the most important and popular for cultivation, since it is an excellent source of high protein, polyunsaturated fatty acids (omega 3 and 6) and carotene. Its cultivation has advantages over typical traditional agriculture because of lacking of by-product and ability to grow in arid, semi-arid, and in fresh or in salt water. However, the shortage of freshwater is becoming a serious environmental problem globally, on the other hand Ca²⁺ and Mg²⁺ of natural seawater cause phosphate (PO₄^-) dilatation problem above pH of 7.10, create milky turbidity and nutrient precipitation in Spirulina culture medium. In the Kingdom of Saudi Arabia (KSA), the main source of freshwater is the desalination system. An alternative source for cultivation of Spirulina was explored by using treated waste water since there are several waste water treatment plants in KSA. Thus, the treated waste was examined for cultivation of Spirulina platensis KAU02 (GenBank accession number: OR723792) isolated from the Red Sea. Therefore, the objective was to use different concentration of plant’s nutrients with treated wastewater to determine the profuse growth and biochemical composition of S. platensis KAU02 in a newly formulated medium, naming Affan-Lafi-King AbdulAziz University-Spirulina (ALKAUS), and compared the biomass production and biochemical composition with standard Zarrouk’s (1966). The maximum specific growth rate (μ_max. day⁻¹), dry biomass production and chlorophyll a content of S. platensis KAU02 was 0.293 and 0.294 day⁻¹, 1.75 and 1.80 g L⁻¹ and 15.85 and 16.18 mg. L⁻¹ in culture media of ALKAUS and Zarrouk’s, respectively. The biochemical composition and phycocyanin content were similar in biomass of both cultures’ media. Therefore, S. platensis KAU02 can be produced in industrial scale by using treated waste water following our invented method.