Enhancing Desferrioxamine B production by <i>Streptomyces pilosus</i> through morphological and process optimization using statistical design methods

In this study, <i>Streptomyces pilosus</i> was used to produce Desferrioxamine B (DFOB). To increase DFOB yield, the effects of-yeast extract, MgSO4·7H2O concentration, and different buffer molarities-were assessed using Response Surface Methodology (RSM). The Statistical analysis indicated that all factors significantly influenced DFOB production. Under optimal conditions-yeast extract 15 g/L, MgSO4·7H2O 0.6 g/L, and phosphate buffer 0.0215 M-a maximum yield of 1.55 g/L was achieved, with a productivity of 0.63 g/L·day, the highest DFOB productivity reported in a flask to date. Since oxygen transfer, pH, and medium composition are crucial for improving production, the effects of glucose, yeast extract concentration, and oxygen transfer were studied in a 2-L bioreactor using the Taguchi method (L₉ orthogonal array), with pH maintained at 7.3. Under optimal conditions-glucose 25 g/L, yeast extract 20 g/L, and agitation at 200 rpm with aeration-resulted in 2.35 g/L DFOB, and 0.235 g/L.h productivity, the highest reported in a bioreactor. Field emission scanning electron microscopy (FESEM) analysis revealed that higher agitation rates caused extensive fragmentation of <i>S. pilosus</i> mycelia, reducing DFOB production. This study demonstrates that combining medium optimization and process control can achieve the highest reported DFOB yields, providing insights for industrial-scale production.