Condition Stabilization for Pseudomonas aeruginosa MTCC 5210 to Yield High Titers of Extra Cellular Antimicrobial Secondary Metabolite using Response Surface Methodology

The present study demonstrates statistic based experimental design for optimization of medium components for production of Secondary Metabolite (SM) from marine microbial isolate Pseudomonas aeruginosa MTCC 5210 in steady state condition. Significant effect of medium components (carbon, nitrogen, temperature and pH) on the production of secondary metabolite initially identified using one-factor-at-a-time approach. Peptone serves as optimum nitrogen source for microbial growth, while beef extract identified for high titers of secondary metabolite production. The optimum pH for growth is 7.5 and secondary metabolite production was at 7.0 and 7.5. Maximum growth was at 30°C and secondary metabolite production at 37°C. Using above results, Response Surface Methodology (RSM) employed to optimize the concentration of media components for production of SM and the quadratic model to fit the response. Response surface analysis revealed 1.4687 g L-1 of beef extract and 0.3 g L-1 of NaCl as optimum concentrations at pH 7.0 and temperature 37°C, which produces 3.857 g L-1 of secondary metabolite. This yield is 2.078-fold increase over the yield of un-optimized growth conditions. Antimicrobial activity of secondary metabolite evaluated against both gram positive and gram-negative strains and with Methicillin Resistant Staphylococcus aureus (MRSA) strains of local hospital origin emphasizes, secondary metabolite of MTCC 5210 acts as anti-MRSA agent.