Plasmid design, cloning, and expression of Vitreoscilla hemoglobin in Streptomyces pilosus : a novel strategy to enhance desferrioxamine B production and yield

Streptomyces pilosus is the primary producer of desferrioxamine B (DFOB), to treat acute and chronic iron overload. Its growth and productivity depend on dissolved oxygen concentration. Vitreoscilla hemoglobin (VHb enhances oxygen transfer and metabolic efficiency under oxygen-limited conditions. In this study, the vgb gene was cloned into S. pilosus to enhance DFOB production. The shuttle vector pGM1192 was designed in SnapGene, synthesized, and propagated in E. coli TOP10. PCR and restriction digestion with NdeI and BamHI confirmed recombinant plasmids. The recombinant plasmid was subsequently transferred into S. pilosus via electroporation. Transformation was verified through colony PCR and electrophoresis on a 1% agarose gel. The kinetics of cell growth and DFOB production in the recombinant strain expressing VHb were analyzed and compared with those of the wild-type strain. The recombinant VHb-expressing strain showed improved growth and DFOB production relative to the wild-type strain, achieving an OD600 of approximately 11 and producing about 1.2 g/L DFOB within 24 h. In contrast, under identical conditions, the wild-type strain reached only an OD600 of about 5.5 and produced approximately 0.4 g/L DFOB. These results indicate that VHb-mediated oxygen enhancement represents an effective metabolic engineering strategy for boosting DFOB biosynthesis in S. pilosus.