标题：Potential Applications of Native Cyanobacterium Isolate (<i>Arthrospira platensis</i> NIOF17/003) for Biodiesel Production and Utilization of Its Byproduct in Marine Rotifer (<i>Brachionus plicatilis</i>) Production
摘要：To achieve strong, successful and commercial aqua-biotechnological microalgae applications, screening, isolation, molecular identification, and physiological characterizations are needed. In the current study, a native cyanobacteria strain <i>Arthrospira platensis</i> NIOF17/003 was isolated from the surface water of El-Khadra Lake, a saline-alkaline lake located in Wadi El-Natrun, Egypt. The cyanobacterium was phylogenetically identified by 16S rRNA molecular marker and deposited in the GenBank database (accession number MW396472). The late exponential phase of <i>A. platensis</i> NIOF17/003 was reached at the 8th day of growth using Zarrouk medium, with a recorded dry weight (DW) of 0.845 g L<sup>−1</sup>. The isolated strain showed 52% of protein, 14% of carbohydrate, biomass productivity of 143.83 mg L<sup>−1</sup> day<sup>−1</sup>, 8.5% of lipid, and lipid productivity of 14.37 mg L<sup>−1</sup> day<sup>−1</sup>. In general, the values of cetane number, iodine value, cold filter plugging point (52.9, 85.5 g I2/100 g oil, and −2.2 °C, respectively) of the isolated fatty acid methyl esters are in accordance with those suggested by international standards. Besides, applying algal-free lipid (FL) as biodiesel byproduct in the production of rotifer (<i>Brachionus plicatilis</i>) revealed that a 0.6 g L<sup>−1</sup> FL significantly increased the rotifer population females carrying eggs, confirming that FL can be used efficiently for <i>B. plicatilis</i> production. The current study concluded that the new isolate <i>A. platensis</i> NIOF17/003 is a promising strain for double sustainable use in biodiesel production and aquaculture feed.
