A low cost fermentation medium for potential fibrinolytic enzyme production by a newly isolated marine bacterium, Shewanella sp. IND20☆

Agro-residues were used as the substrate for the production of fibrinolytic enzyme in solid state fermentation. In this study, two-level full factorial design (25) and response surface methodology were applied to optimize a fermentation medium for the production of fibrinolytic enzyme from the marine isolate Shewanella sp. IND20. The 25 factorial design demonstrated that the physical factors (pH and moisture) and nutrient factors (trehalose, casein, and sodium dihydrogen phosphate) had significant effect on fibrinolytic enzyme production. Central composite design was employed to search for the optimal concentration of the three factors, namely moisture, pH, and trehalose, and the experimental results were fitted with a second-order polynomial model at 99% level (p < 0.0001). The optimized medium showed 2751 U/mL of fibrinolytic activity, which was 2.5-fold higher than unoptimized medium. The molecular weight of fibrinolytic enzyme was found to be 55.5 kDa. The optimum pH and temperature were 8.0 and 50 °C, respectively.