Statistical modelling and optimization of cr(vi) biotransformation by Indigenous bacterial strains using response surface methodology

The present study utilizes two indigenous bacterial strains Salmonella sp. S1 and S2 for biotransformation of Cr(VI) into Cr(III). The interactive effect of three crucial operating parameters via pH, temperature and initial Cr(VI) ion concentration were studied. The experiments were designed using Box-Behnken matrix and Response surface methodology. For the construction of quadratic model, total seventeen experiments were conducted for the two bacterial strains. The coefficient of determination (R2) value 0.9452 and 0.9483, model F- value 13.39 and 14.26 and its low P-value (F < 0.0012 and F < 0.0010) in Salmonella sp. S1 and S2 respectively confirmed the fitness of response surface quadratic model. The regression equation coefficients were calculated and the data fitted to second order polynomial equation in both Salmonella sp. S1 and S2.