*2.2. Growth Conditions of Cyanobacteria*

This study uses three isolates related to cyanobacteria: *Desmonostoc muscorum* HSSASE1 KT277784, *Anabaena oryzae* HSSASE6 KT277789, and *Arthrospira platensis* HSSASE5 KT277788. Cyanobacterial samples were obtained from the botany and microbiology department, science faculty, Cairo University, Egypt. These strains were previously isolated from Egyptian

soil, showing a significant antifungal activity and recording elevated levels of phenolics and flavonoids in vitro. The axenic cultures of the tested isolates were identified and deposited in GenBank under accession numbers according to [32]. Cyanobacterial strains were cultured in BG11 medium [33], but *Arthrospira platensis* was cultivated in Zarrouk medium [34]. A shaker incubator was used to grow all the cyanobacterial strains, which have been maintained in highly controlled growth conditions. Cyanobacterial cultures were incubated under constant illumination of (150 ± <sup>10</sup> <sup>μ</sup>mol photons m−<sup>2</sup> <sup>s</sup>−1) at 27 ± <sup>2</sup> ◦C, pH = 7 for *Desmonostoc muscorum*, *Anabaena oryzae*, and at 34 ± 2 ◦C, pH = 8.7 for *Arthrospira platensis* and a continuous 5% CO2 airflow was provided via an air pump. After 14 days, total biomass was harvested at the end of the growth stationary phase by centrifugation at 4200× *g* for 10 min, and then pellets were rinsed with water and lyophilized.

#### *2.3. Preparation of Cyanobacteria Extracts*

After 14 days of cultivation, freeze-dried cyanobacteria biomass was exposed to aqueous extraction [35]. After washing 100 mg of the cyanobacterial dry biomass in sterile distilled water, the amount was dissolved in 12.5 mL phosphate buffer (0.1 M pH 6.0) for 10 min before sonication (5 s pulses of 8 W over 30 s, on ice). The phosphate buffer solution did not affect extract nutrient composition because it was employed to control and maintain system pH. In addition, the extraction tubes were kept at 4 ◦C for 24 h. Aqueous extracts were obtained by centrifugation at 8000× *g* for 10 min and then freeze-dried.
