Modeling of Chromium (VI) Accumulation in Gordonia polyisoprenivoransVH2 Using Response Surface Methodology

An experimental design technique was carried out to investigate the bioaccumulation of chromium VI by the rubber degrading nocardioform actinomycete Gordonia polyisoprenivorans VH2. Response Surface Methodology (RSM) was adopted to acquire the best level of four variables namely, pH, FeSO4, NaNO2 and Cr (VI) which have been optimized to bring about maximum chromium biosorption percentage. In this respect, the 3-level Box-Behnken design was employed. A polynomial model has been created to correlate the relationship between the four variables and chromium biosorption. The optimal combination of those variables for chromium biosorption evaluated from the non-linear optimization algorithm of EXCEL-Solver was as follows (mg L-1): FeSO4, 18; NaNO2, .75; Cr (VI), 41.25 at pH 6.7. Based on the predicted model, an experimental verification of the optimal conditions revealed chromium biosorption percentage of 90%, which is more than 3 folds the basal medium.