Replicative and integrative plasmids for production of human interferon gamma in Bacillus subtilis

Integrative and replicative plasmids for the expression driven by the P 43 promoter and secretion of recombinant proteins in Bacillus subtilis were constructed. The plasmids named pInt and pRep respectively were tested for the production of recombinant human interferon gamma (rhIFN-γ). A synthetic hIFN-γ gene employing the optimized B. subtilis codon usage was fused with the Bacillus licheniformis α-amylase signal peptide ( sp-amyL) encoding sequence. The integrative construct produced 2.5 ± 0.2 mg l −1 and the replicative system produced 20.3 ± 0.8 mg l −1 of total recombinant rhIFN-γ. The results showed that secretion of hIFN-γ was the bottleneck for the overexpression of mature rhIFN-γ by B. subtilis.