BIOAUGMENTATION STUDIES ON ENDOSULFAN CONTAMINATED SOILS
Dr.Saisha Vinjamuri, Naila Musharraf Ali, Sadiya Kausar, Megha A Belli,Department of Biotechnology, BMS College of Engineering, Bangalore
This study is mainly concerned with the biodegradation of Endosulfan, a banned pesticide that is still being used in the third world countries and which has physiological as well as neurological side effects to the user and his/her environment. Optimization studies on the moisture content and inoculum level were carried out in soil reactors using two isolates (III-5.2 and I-6.5) which showed maximal degradation of endosulfan to endosulfan diols. Preliminary experiments were performed to study the co-metabolism of organisms in endosulfan contaminated soil. Three bioreactors were designed which imitated the actual environmental conditions soil and the strains I 6 5 and III 5 2 were diluted and inoculated in two different bioreactors along with the control without inoculum. Media optimization studies are carried out by using the Plackett-Burman Design, in order to obtain the variables which most effect degradation of endosulfan.Response Surface Methodology was conducted to know the level of interaction between the reacting variables.RSM analysis indicated that the results obtained are significant and the variables are not interacting with each other. Storage of micro-organisms was done by immobilization, in order to optimize the best possible storage condition for the long term usage of the bacteria. The micro-organisms were stored by using agar in concentrations of 3%, 4%, 5%, and 6%. In case of alginate the beads were formed using concentrations of 3%, 3.5%, 4%, 4.5% and 5% in 0.2M, 0.25M and 0.3M CaCl2.The agar beads showed no significant results, however, in the case of alginate the best concentration was 5% alginate in 0.3M CaCl2 under fridge conditions. Terrestrial ecosystem studies were also carried out by mimicking the natural ecosystem conditions in limited space. This helped to infer the effect of natural environmental factors on the flora and fauna of the soil affected with a known concentration of endosulfan and study the degree of endosulfan degradation under different conditions in the open microcosm model. Soil analysis Tests were performed on the soil samples derived from the microcosm studies to determine the concentration of various elements in the soil and the effect of endosulfan on these elements.