Healthy specimens of the Egyptian sponge Aplysina fistularis were collected from Sharm El-Sheikh from January to February 2008. Induction of mutation by UV irradiation: Spores of Hedaya48 were gently scraped from the surface of ISP-2 agar plates, washed with sterile normal saline (0.90%) and filtered through glass wool. Spore suspensions were checked microscopically and diluted to have a count of 10⁴ spore/ml. Three milliliters of spore suspension was exposed to UV light (Philips TUV 30-W lamp) for different exposure times (5, 10, 15, 20, 25, 30, 35 and 40 min) placed about 25 cm above the liquid surface and gently swirled in a petri dish. After incubation in the dark, spores were plated on ISP-2 agar, incubated at 28 ℃ and observed after 72 h. Mutation, survival rates and antibiotic production were determined. Optimization of saadamycin production: The optimization of production of the anti-mycotic antibiotic, saadamycin, was carried out in 250-ml Erlenmeyer flasks containing 50 ml of starch nitrate medium and monitored in terms of mcg/ml. Duplicate flasks were pooled for analysis, and each result was an average of triplicate assays. Each parameter optimized earlier was incorporated in subsequent experiments. Optimized medium: Finally, production medium containing (g/l) starch, 10; glucose, 10; NaNO₃,1.0; valine, 0.5; alanine, 0.25; phenylalanine, 0.25; KH₂PO₄, 1.0; MgSO₄, 0.5; CaCO₃, 2.0; NaCl, 1.0; FeSO₄, 0.2; seawater 1 l; and pH 6.5 at 35 ℃ was recommended for saadamycin production by mutant Ah22.

Healthy specimens of the Egyptian sponge Aplysina fistularis were collected from Sharm El-Sheikh from January to February 2008. Induction of mutation by UV irradiation: Spores of Hedaya48 were gently scraped from the surface of ISP-2 agar plates, washed with sterile normal saline (0.90%) and filtered through glass wool. Spore suspensions were checked microscopically and diluted to have a count of 10⁴ spore/ml. Three milliliters of spore suspension was exposed to UV light (Philips TUV 30-W lamp) for different exposure times (5, 10, 15, 20, 25, 30, 35 and 40 min) placed about 25 cm above the liquid surface and gently swirled in a petri dish. After incubation in the dark, spores were plated on ISP-2 agar, incubated at 28 ℃ and observed after 72 h. Mutation, survival rates and antibiotic production were determined. Optimization of saadamycin production: The optimization of production of the anti-mycotic antibiotic, saadamycin, was carried out in 250-ml Erlenmeyer flasks containing 50 ml of starch nitrate medium and monitored in terms of mcg/ml. Duplicate flasks were pooled for analysis, and each result was an average of triplicate assays. Each parameter optimized earlier was incorporated in subsequent experiments. Optimized medium: Finally, production medium containing (g/l) starch, 10; glucose, 10; NaNO₃,1.0; valine, 0.5; alanine, 0.25; phenylalanine, 0.25; KH₂PO₄, 1.0; MgSO₄, 0.5; CaCO₃, 2.0; NaCl, 1.0; FeSO₄, 0.2; seawater 1 l; and pH 6.5 at 35 ℃ was recommended for saadamycin production by mutant Ah22.