Optimization of Medium Composition for Antibacterial Substance Production by Aspergillus niger xj using Response Surface Methodology

To investigate the optimal medium composition for antibacterial substance production by,Aspergillus niger xj in liquid-state fermentation (LSF). The disc diffusion method was used to assay the production. Statistical methodologies, including the Plackett-Burman design (PBD) and the central composite design (CCD), were employed to investigate the individual crucial component of the medium that significantly affected the production. The optimum values of the critical components for the maximum antibacterial substance production were obtained as follows: x(1)(MgSO4)=-0.3417 (0.2982 g/L), x(2)(Tween-80)=-0.28878 (0.242245 ml/L) and the predicted diameter of the inhibitory zone value was 27.39847 mm. Using the optimized condition, the diameter of inhibitory zone reached 27.74 +/- 3.07 mm. By using PBD and CCD, we determined the optimal composition for antibacterial substance production by Aspergillus niger xj in LSF.