In our laboratory, a defined microbial consortium was developed and used for the degradation of DDT. The DDT degradation by the consortium was studied for different time intervals. The degradation was maximum in 72 h. DDT-degradation parameters were optimized using Response Surface Methodology (RSM) using this consortium. A Central Composite Rotatable Design (CCRD)with three variables chosen for the study were inoculum concentration (50-1500 μg protein mL-1 i.e., the cells of consortium), temperature (25-35°C) and pH (4-8) each at 5 levels -1.682, -1, 0, 1 and 1.682. Incubation time of 72 h was maintained as constant. Degradation of different concentrations of DDT (5, 10, 20, 30 and 35 ppm) was studied by using this consortium. The optimized conditions were inoculum concentration 1500 μg protein mL-1 and temperature 25°C but pH varied for different concentrations of DDT. Validation of the model was done and experimental values were found to be in agreement with the predicted ones. These conditions can be applied in the degradation of DDT in industrial effluents and other contaminated water bodies.
N. Deepthi , N.K. Rastogi and H.K. Manonmani , 2007. Degradation of DDT by a Defined Microbial Consortium: Optimization of Degradation Conditions by Response Surface Methodology. Research Journal of Microbiology, 2: 315-326.